REVIEW

Institute of Pharmacy1, Faculty of Medicine, University of , ; Department of Dosage Form Technology2, Faculty of Pharmacy, Riga Stradins University, ; Department of Drug Technology and Social Pharmacy3; Department of Pharmacognosy4, Faculty of Pharmacy, Lithuanian University of Health Sciences, Kaunas, Lithuania; Department of Pharmacognosy5, National University of Pharmacy, Kharkiv, Ukraine; Department of Pharmacognosy and Pharmaceutical Botany6, Faculty of Pharmacy, Nicolae Testemitanu State University of Medicine and Pharmacy, Republic of Moldova; Faculty of Pharmacy7, Hue University of Medicine and Pharmacy, Hue University, Vietnam

Dragendorff’s reagent: Historical perspectives and current status of a versatile reagent introduced over 150 years ago at the University of Dorpat, Tartu, Estonia

A. RAAL1,*, A. MEOS1, T. HINRIKUS1, J. HEINÄMÄKI1, E. ROMĀNE2, V. GUDIENĖ3, V. JAKŠTAS4, O. KOSHOVYI5, A. KOVALEVA5, C. FURSENCO6, T. C HIRU6, H. T. NGUYEN7

Received March 25, 2020, accepted April 23, 2020 *Corresponding author: A. Raal, Nooruse 1, Tartu 50411, Estonia [email protected] Pharmazie 75: 299-306 (2020) doi: 10.1691/ph.2020.0438

The well-known Dragendorff’s reagent (DR) was introduced by an Estonian-German Professor Johann Georg Noel Dragendorff (1836–1898) in the middle of the 19th century (1866). Dragendorff, who was a full-time professor in pharmacy at the university of Dorpat (Tartu) used his reagent originally for the rapid screening of herbal products to find traces of alkaloids. DR is a solution of potassium bismuth iodide composing of basic

bismuth nitrate (Bi(NO3)3), tartaric acid, and potassium iodide (KI), and when contact with alkaloids DR produces an orange or orange red precipitate. In this review article, we make a short historical overview on the biography and scientific research work of Professor Dragendorff at the University of Dorpat. The chemistry, method of preparation, mechanism of action, and practical uses of DR in various disciplines in various European countries including the Baltic countries (Estonia, Latvia, Lithuania), Finland, Ukraine, Moldova, and in Asia (Vietnam), are also discussed. Over several decades, DR and its modifications have found uses in many new applications and disciplines, and a number of commercial DRs are also currently available on the market. Today, DR is used for example in the production of surfactants, where non-ionic surfactant is precipitated in water solution with

modified DR (KBiI4+BaCl2+glacial acetic acid). Total six different potassium iodobismuthate (DR) solutions are also presented in the European Pharmacopoeia. In conclusion, DR (after more than 150 years of its invention in Estonia) has still an important role in pharmaceutical and related sciences all over the world.

1. Introduction Dragendorff`s reagent (DR) was introduced by Johann Georg Noel Dragendorff (1836–1898), who acted as a full-time professor in Pharmacy at the University of Dorpat, Tartu, Estonia (Fig. 1). DR was described for the first time in 1865/1866 (Fig. 2), thus it has more than a 150-year history as a reagent (Dragendorff 1866; Past et al. 2009). Since then, DR has been widely applied e.g., in phar- macy, medicine, forensic chemistry and related sciences all over the world. DR is a color reagent to detect alkaloids in a test sample. Alkaloids, if present in the solution of the sample, react with DR and yield an orange or orange red precipitate. The reagent is a solution of potassium bismuth iodide prepared from basic bismuth nitrate (Bi(NO3)3), tartaric acid, and potassium iodide (KI). In this review article, we make a historical overview on the biog- raphy of Professor J. Georg N. Dragendorff and his scientific research work, when he acted as a full-time professor in pharmacy at the University of Dorpat, Tartu, Estonia. The chemistry, method of preparation, mechanism of action, and practical uses of DR in various disciplines and in various European countries including the Baltic countries (Estonia, Latvia, Lithuania), Finland, Ukraine, Moldova, and in Asia (Vietnam), are also discussed.

1.1. University of Dorpat (Tartu) The University of Dorpat, UD (since 1919, ) (Fig. 3) was founded in 1632 by the Swedish King Gustav II Adolf Fig. 1: Professor Georg Dragendorff Pharmazie 75 (2020) 299 REVIEW

Siller, a Baltic-German chemist, Carl Schmidt, acted as a full-time professor of pharmacy for a short period of time (1850–1852). His research interests included also human physiology. During 1852 and 1864, the professorship of Pharmacy at the UD was hold by Carl Claus. The greatest progress in pharmacy, however, was obtained thanks to Professor J. Georg N. Dragendorff (1864–1894) (Hinrikus et al. 2005; 2007; Raal et al. 2009).

1.2. Professor J. Georg N. Dragendorff Johann Georg Noel Dragendorff (1836–1898) (Fig. 1) was born in Rostock, Germany in the family of medical doctor. He worked Fig. 2: Description of Dragendorff’s reagent (DR) in Pharmaceutische Zeitschrift as a student in Friedrich Witte Pharmacy and passed the pharmacy für Russland 5 (1866), 82-85. exam in 1856. He graduated from the University of Heidelberg in 1858 and worked later at the Universities of Heidelberg, Rostock, and Munich (Germany). He lived a short time in St. Petersburg, (1594–1632). At the UD, pharmacy was adopted as an independent Russia (1862–1864), and edited there the journal Pharmaceutische discipline in 1802. The rapid early-stage development of phar- Zeitschrift für Russland (The Russian Pharmaceutical Journal). In macy as a teaching subject and research discipline was fostered 1864, J. Georg N. Dragendorff came to Tartu starting his scientific by several outstanding scientists acting at the UD. Within the career at the UD for the next thirty years. In 1894, Dragendorff years 1802–2010, in total 6736 students studied pharmacy at the returned to his home town Rostock (Germany), and worked there UD (later University of Tartu), and 4184 of them were graduated in his small in-house laboratory at home. The reason for his deci- (total 583 individuals interrupted their studies). No information, sion to leave Tartu was the beginning of a russification period at the however, is available about the graduation of the remaining 1969 UD. J. Georg N. Dragendorff died in 1898 at the age of 62 after a students in the archives (Kapp et al. 2012). serious heart disease (Tankler et al. 2002; Hinrikus and Raal 2011).

Fig. 4: Dragendorff’s laboratory in Dorpat Fig. 3: University of Dorpat (Tartu). Gravure by August Clara, 1821

In 1799, Russian Tsar Paul I approved the university plan, which In Tartu, Dragendorff focused his teaching and research activities also scheduled the joint professorship in chemistry and pharmacy. solely on pharmacy, pharmacognosy and forensic chemistry for In 1800, the chemist Philipp Arzt came from Tallinn to Tartu as the 30 years. He wrote numerous textbooks and monographs, and first professor of Chemistry and Pharmacy. Unfortunately, Philipp supervised a total of 90 master’s and 87 doctoral theses in the Arzt drowned in August 1802, and thus the position was void fields of pharmaceutical chemistry, pharmacology, pharmacog- for the next one-two years. After this, a German chemist, Alex- nosy, forensic, environmental and food chemistry, physiology and ander Nicolaus Scherer (1772–1824), was nominated as the first bacteriology. The abovementioned number of master and doctoral professor of theoretical and applied chemistry to the UD. After dissertations written under his supervision will probably remain as Scherer, the following scientists hold a professorship in chemistry insurmountable forever (Hinrikus et al. 2005; Tankler et al. 2002). and pharmacy at the UD: David Hieronymus Grindel from Riga, In those times, it was quite usual that research work and doctoral Latvia (1805–1814), Ferdinand Giese from Harkiv, Ukraine (1814– dissertations in pharmacy were interdisciplinary combining espe- 1821), and Gottfried Osann from Weimar, Germany (1823–1828). cially pharmacy with forensic chemistry. The key attribute to the G. Osann was a well-known chemist and researcher of the plat- successful research work of Dragendorff and his students was their inum ore of the Urals, and his scientific work led Carl Claus to success in implementing both qualitative and quantitative analytical discover Ruthenium (Hinrikus et al. 2005, 2007; Raal et al. 2009). methods for alkaloids, glycosides and the other biologically active Professor Friedemann Goebel from Jena, Germany, hold the substances (Tankler et al. 2002; Hinrikus et al. 2005, 2007; Raal et professorship in Chemistry and Pharmacy 1828–1851, and during al. 2009). Unfortunately, the UD had serious financial difficulties his time research work developed a lot at the UD. Furthermore, he by the time of Dragendorff’s stay in Estonia, limiting the research made an initiative for establishing an independent professorship in work of his group. In those times, many Russian universities and pharmacy at the UD, and this professorship was obtained by the act universities abroad had much more resources and funding than in October 19th in 1842. The first Professor of pharmacy, Eduard the UD. On the other hand, Dragendorff noticed that the limited Siller, came to Tartu from Europe via St. Petersburg in summer funding resulted in the higher commitment of the students to make 1843 and remained until 1850. The studies at the UD started a scientific research work. He also showed that all difficulties and in August of the same year, and this can be considered as the challenges related to resources can be overcome with a bright and beginning of a higher pharmaceutical education in Estonia. After strong personality (Raal et al. 2006; Kapp et al. 2012). 300 Pharmazie 75 (2020) REVIEW

In the 30-year period under Dragendorff, the UD became one Then, an ion-exchange reaction takes place between ammonium of the most important higher-education and research centers in salt and potassiumtetraiodo bismuthate leading to the formation of Europe. Hermann Thoms, a former Professor of pharmaceutical an insoluble complex salt. chemistry from Berlin, Germany wrote about J.G.N Dragendorff: [R NH+X- + K[BiI ] → [R NH]+[BiI ]- + KX “From afar and extensively, students came to the famous man to 3 4 3 4 write researches under his supervision. They spread the fame of Depending on the nature of alkaloid (or tertiary amine), this ion Dragendorff to all civilised countries” (Raal at al. 2006). Many pair has a yellow to orange to red to brown color. Secondary amines teachers and lecturers at the UD were former students of Dragen- will create less intensive colors. It is also worth to mention that not dorff (i.e., Melchior Kubli, Emil Masing, Edwin Johanson, Carl all alkaloids are detectable with DR. For example, caffeine and Mandelin). A number of graduated pharmacists worked also as other purine alkaloids do not form a precipitate with DR (Baerhe- university teachers at higher-education schools abroad (i.e., Oskar im-Svendsen and Verpoote 1983; Popl et al. 1990; Pedersen 2006). Zinoffski in Kiev, Ukraine; Wilhelm Adolphi in St. Petersburg, A number of false-positive alkaloid tests based on DR has been Russia; Friedrich Beckmann and Bernhard Grewing in Warsaw, reported in the literature as well. These tests were found to be as a Poland) (Raal et al. 2006). result from the reactions with nitrogenous (e.g. peptides) or non-ni- Many scientific works of Dragendorff were written in a handbook trogenous plant constituents. All non-nitrogenous compounds style, and were published in several editions and in different that were found to give a strong positive reaction with DR, were languages. Perhaps, the most well-known textbook “The foren- oxygen containing compounds (Habib 1980). sic-chemical determination of poisons in food, air mixtures, leftovers, body parts” (Dragendorff 1868) was published in total 3. Use of Dragendorff’s reagent in some selected countries four volumes within 1868-1895. This textbook described the most The uses of DR in higher-education teaching and research work in important analyses in forensic chemistry, and it has been widely some selected European countries and Vietnam is described below. used especially in case of intoxication with alkaloids. Several other The major focus is on pharmaceutical applications of DR and the well-known textbooks written by Dragendorff have been also dedi- historical time-frame of past 100 years. cated to the analysis of different natural substances (Raal et al. 2009). Dragendorff presented and summarized his achievements in the 3.1. Estonia field of alkaloids in a scientific paper published in 1872 (Dragen- Estonia was a part of the Tsarist from the 18th dorff 1872). However, the history of DR began somewhat earlier: century until 1918, and both the Russian (1880, 1891) and German DR was mentioned actually for the first time in a publication in Pharmacopoeias were used in pharmaceutical practice. In the 20th Pharmaceutische Zeitschrift für Russland” (Dragendorff 1866). century, the Russian Pharmacopoeia (the 6th edition, 1910), Russian Military Pharmacopoeia (1913), and German Pharmacopoeia (the 2. Chemistry of Dragendorff’s reagent 6th edition, 1926) were used in Estonia and the other Baltic coun- Interestingly, the European Pharmacopoeia (2019) uses the general tries (Latvia and Lithuania) until the new national pharmacopoeias name “iodobismuthate reagent” instead of DR. The composi- were published in the 1930´s (Kondratas et al. 2015). Interest- tion of DR is not fully elucidated and reported in the literature. ingly, DR was included into the Russian Pharmacopoeia, but the Commonly, the source of bismuth (III) ions is reported to be reagent was not listed in the Estonian Pharmacopoeia (1937). A bismuth subnitrate (bismuth oxinitrate, 4BiNO (OH) ,BiO(OH)) Mayer’s reagent has been used instead of DR for the determination 3 2 of alkaloids in herbal drugs and their preparations (Folium Stra- or (Nitrooxy)oxobismuthine (BiNO4). Both of these chemical names are often considered as synonyms. At least six different monii, Fructus Papaveris, Rhizoma Hydrastides, Rhizoma Veratri, structures for this substance have been fully characterized Tinctura Aconiti, Tinctura et extractum Belladonnae, Tinctura et extractum Cinchonae, Extractum Strychni, Extractum Opii, etc.), with single-crystal studies: Bi6O4(HO)4(NO3)6·H2O (Lazarini 1979a; Sundvall 1979), Bi O (OH) (NO ) ·4H O (Lazarini but not for individual alkaloid substances. The Estonian Pharma- 6 4 4 3 6 2 copoeia presents in total 54 monographs for plant extracts and 104 1979b), [Bi6O4.5(OH)3.5]2(NO3)11 (Christensen and Lebech 2012), Bi O (OH) (NO ) ·3H O (Laxarini 1978), Bi O (OH)NO (Henry monographs for the other dosage forms of plant origin (Kondratas 6 5 3 3 5 2 2 2 3 et al. 2015). et al. 2005), and Bi5O7NO3 (Kodama 1994). DR is prepared by dissolving bismuth subnitrate in diluted acid In the Soviet-Union (USSR) period (1944–1991), the curriculum (acetic or tartaric acid, very rarely hydrochloric or sulfuric acid) of pharmacy at the University of Tartu relied on the Soviet Union and mixing it with a strong solution of potassium iodide. A low pH Pharmacopoeias (1946, 1952, 1961, 1968, 1990). Perhaps surpris- is mandatory for this reagent. ingly, the Soviet Union U.S.S.R. Pharmacopoeia Vol. 8 (1952) The formation of reagent is generally described as follows: The does not mention DR, but in the later volumes 9-10 (1961, 1968) bismuth ions from bismuth subnitrate react with potassium iodide DR is described as a mixture of equal parts of solution 1 (0.85 g and form at first the black precipitate of bismuth iodide of basic bismuth nitrate in 40 ml water and 10 ml acetic acid) and solution 2 (8 g of potassium iodide in 20 ml water). Total 100 ml Bi3+ + 3KI → BiI + 3K+ 3 of water and 20 ml of acetic acid were added to 10 ml of solutions Then, after the complete sedimentation of bismuth(III)iodide, the 1 and 2 (used at a ratio of 1:1). In the latest version of the U.S.S.R excess of iodide ions reacts to latter to form an orange colored, Pharmacopoeia (1990), however, a modified DR is described: 5 ml soluble complex of potassiumtetraiodobismuthate. of 1% water solution of ascorbic acid and 5 ml of 95% ethanol is 3+ Bi + KI → K[BiI4] added into 5 ml of equal parts of solution 1 and 2. So far, very little is known about the mechanism of action of DR. In the Soviet-Union time textbook of pharmaceutical chemistry The key search phrases, such as “Dragendorff reagent reaction (Melentjeva 1976), DR is shown to be applicable for the identi- mechanism” or “iodobismuthate reagent reaction mechanism” fication of alkaloids in their aqueous solutions with sulfuric acid give not any result in the scientific literature data bases. It seems or hydrochloric acid. When DR is used as the mixture of bismuth that the number of scientific research works published in this topic nitrate and potassium iodide, an amorphous, or sometimes also area is very limited (even negligible). The explanation for the color a crystalline orange-red or brick-red precipitate will appear. In reaction induced by DR could be following: another Soviet-Union time textbook of pharmaceutical chemistry Most alkaloids have a tertiary amine group R N. This chemical (Senov 1971), DR is mentioned to indicate the presence of alka- 3 loids in sulfuric acid solutions, if a precipitate of different colors is group can react similarly to ammonia (NH3) and act as a base, which reacts with an acid to form an ammonium salt. formed. DR is also mentioned in a more recent Russian university textbook of pharmacognosy (Jakovlev and Blinova 2004), but not R N + HX → [R NH]+ + X- 3 3 in the Soviet-Union time textbook of pharmacognosy published - - - - (X = anions of acid = Cl , NO3 , HSO4 , CH3COO , ...) earlier in the 1980´s (Muravjova 1981). In conclusion, DR was Pharmazie 75 (2020) 301 REVIEW well known and used in the laboratory works in pharmaceutical Within the post-Soviet-Union period (from 1991 to date), phar- chemistry, forensic chemistry and pharmacognosy at the Univer- macy students at Riga Stradins University have carried out the sity of Tartu within the Soviet-Union period. common alkaloid detection reactions in pharmacognosy classes. Today, the European Pharmacopoeia is being officially used in One of the reagents used in detection reactions is DR. Recently, Estonia. At the University of Tartu, pharmacy students are using an a tropane-group alkaloid paper chromatography was also adopted Estonian textbook of pharmacognosy (Raal 2010; 2016), in which in practical classes, and the presence of such alkaloids in herbal DR and the other corresponding reagents, such as Mandelin’s, medicines was detected using a modified DR. Marquis’s, Sonnenschein’s and Mayer’s reagents, are described in detail. The Pharmacy students have also one specific laboratory 3.3. Lithuania work entitled “Screening of different groups of biologically active compounds in unknown plant material”, where the students first The isolation and properties of two alkaloids (morphine and prepare an aqueous or ethanolic extract from an unknown herbal quinine) were described in the journal “Pamiętnik Farmaceutyczny powder and then determine the presence of alkaloids and other Wileński” (Notes of Vilnius Pharmacy) in 1820 and 1821. Some substances in the extract. In addition to DR, they use also Fröde’s decades later, Dragendorff’s investigations of alkaloids and his and Marquise’s reagents for the precipitation of alkaloids to obtain discoveries (including DR) became well known also in Lithuania, more evidence-based results. and in 1869 he was elected as a member of the Vilnius Medical Society (Gudienė 2017). Furthermore, his personality was well known to the pharmacists of interwar Lithuania. Professor 3.2. Latvia Dragendorff is mentioned frequently as one of the most famous A recent study on higher pharmaceutical education in Latvia pharmacists in the professional journal of Lithuanian pharmacists suggests that the use of DR was very limited in both teaching and ”Farmacijos žinios” (Pharmacy News) (1923–1940) research work within the Soviet-Union (USSR) time period ranging The Lithuanian Pharmacopoeia (1938) presents four reagents in from 1919 to 1953 (Maurina 2008). The only study describing the total: Esbach, Meyer, Milon, Nesler. The Pharmacopoeia describes use of iodine potassium and potassium bismuthiodide (DR) was five alkaloids (morphine, atropine, quinine, caffeine and codeine), conducted by Professor E. Svirlovsky (Department of Pharmacog- but perhaps surprisingly, no reagents for the identification of these nosy, Division of Pharmacy, University of Latvia) on the chemical alkaloids are described. Only a few papers on alkaloid-accumu- composition of Polygonum hydropiper L. (Svirlovskis 1944). He lating plants and alkaloids has been published in the „Farmacijos investigated the presence of alkaloids in an ether extract obtained žinios“ (Pharmacy News) journal. Elena Paškovičaitė Purtokienė, from the plant, and found that the present reagent gave a slight Assistant Professor in the Department of Pharmacy and Pharma- opalescence outcome. In his pharmacognosy textbook he pointed cognosy at the University of Lithuania (known as Vytautas Magnus out that alkaloids can be obtained in the form of complexes with University since 1930) published an article on the methods for the potassium bismuthiodide and other compounds (Svirlovskis 1940). determination of alkaloids (Gudienė 2017). This research work In 1940, the Latvian Pharmacopoeia (1940) was issued, but DR was inspired and partially based on the article published by the was not included in the present national pharmacopoeia. This could German scientists J. Gadamer and E. Neuhoff, who described the be explained by the fact that DR was not involved in the study determination of alkaloids according to the IV German Pharmaco- courses provided by the Division of Pharmacy at the University of poeia and by using a C.C. Keller method. In her article, E. Purtok- Latvia. It should be noted that a leading academic staff (teachers ienė described the use of the German Pharmacopoeia (V and VI) and researchers) in the Division of Pharmacy participated also in and the other related methods for the detection of alkaloids, but DR the development of the pharmacopoeia. According to Professor was not used in these methods (Purtokienė 1929). J. Maizīte, their Pharmacy students verified and compared the In Lithuania, DR has been applied in the laboratory training medicinal preparations and analytical methods described in the courses at the universities since the Soviet-Union (USSR) times. German, Russian, British, USA, Belgian, Swiss, Italian, Roma- The Lithuanian scientists and students read the Soviet-Union nian, Spanish, and Swedish national pharmacopoeias (Kondratas scientific literature in Russian language and learned the methods et al. 2015). for the identification of alkaloids developed by Dragendorff. While being a part of the Soviet Union, the U.S.S.R. Pharma- As already mentioned, the pharmaceutical chemistry textbook copoeia was official pharmacopoeia also in Latvia. As already published by P. L. Senov described the most important alkaloid mentioned, DR was not included in the Soviet Union U.S.S.R. reagents including DR (Senov 1952). In the 1960´s, the Pharmacy Pharmacopoeia Vol. 8 (1952), but in the subsequent volume 9 students were taught to identify alkaloids by DR in Lithuania. In (1961) DR was described among the reagents used for the micro- the 1970´s, however, the new textbooks authored by Professor V. scopic analysis of medicinal herbs. It is evident that the inspira- F. Kramarenko (Kiev) and his prominent student Professor Paulius tion for adopting this new reagent to the Soviet Union U.S.S.R. Vainauskas, Dean of the Faculty of Pharmacy (1996–2006), Lith- Pharmacopoeia was originated from the monographs of interna- uanian University of Medicine, replaced the textbook of Senov. tional scientists, which were translated into Russian language in In 1975, the Lithuanian scientist in pharmacognosy, Eduardas the 1950´s. For example, in the foreword to the monograph on Kanopka, published a book entitled “Alkaloids and their raw mate- organic compound analysis (published in Russian in 1953), it rials“. In this book, he described in detail the methods introduced was stated that this monograph is the most comprehensive publi- by Professor J. Georg N. Dragendorff (University of Tartu) for the cation in the relevant field of organic chemistry (Bauer 1953). qualitative and quantitative analysis of alkaloids. E. Kanopka also In 1954, a monograph on paper chromatography was published mentions the textbook of A. Orechov ”Alkaloid chemistry” (1938) in Russian language (Block et al. 1954). In this monograph, the and emphasizes that until 1938 there was no textbook on alkoloids use of a modified DR in the chromatographic determination of chemistry available in Russian language (Kanopka 1975). Both alkaloids was described. Obviously, the DR-induced reactions authors (Kanopka and Orechov), however, do not describe the use described in this monograph to indicate the presence of alkaloids of the DR in their books. In the Toxicology Laboratory of Lith- and the ease of their application encouraged the universities to uania, DR was a basic reagent until 2000 in the identification of adopt this monograph in the practical work of students as well. alkaloids and in the detection of drug poisoning (in urine or liver) Since the 1960´s, the practical laboratory works in pharmacog- caused by biological materials. nosy were systematically developed by updating materials and Nowadays, pharmacy students of the Lithuanian University of methodologies at the Faculty of Pharmacy of Riga Medical Health Sciences (Kaunas) still are familiar with the identification Institute (Dolgova et al. 1966; Rubene et al. 1975). In these new and testing methods of alkaloid-like substances using reagent laboratory work teaching materials, DR was described as one key developed by Dragendorff. The method based on DR is included reagent for the detection of alkaloids (together with nine other in the study programs of pharmacognosy, toxicology and pharma- corresponding reagents). The modification of DR was used to ceutical chemistry. Qualitative testing of alkaloid containing plant identify alkaloids in the paper chromatograms. material is presented in the lectures of pharmacognosy and in the 302 Pharmazie 75 (2020) REVIEW textbook of phytochemical analysis (Janulis et al. 2008). DR is and the separated bands in the dried paper strips were detected with one of the key reagents in the phytochemistry laboratory training DR. Levonen (1960) applied DR for the identification of seminal course and more specifically in the laboratory work entitled “Isola- stains by paper chromatorgraphy in the field of forensic sciences. tion of alkaloids. Qualitative determination of alkaloids. Assay of The simultaneous detection of choline and spermine was presented. alkaloids.” The set of suitable reagents include Mayer’s reagent, As the samples of interest were sprayed with DR, spermine gave a Wagner’s-Bushard’s reagent, and Marme’s reagent, tannin, sili- pink color and choline a deep purple. The scientists at the Univer- cotungstate, phosphomolybdate, and picric acid. The fingerprints sity of Tampere, Finland applied benzidine-Dragendorff´s reagent of the alkaloids on paper chromatography (Thermopsidis herba, in TLC for rapid testing alkaloids (drugs) and their metabolites semen) and thin-layer chromatography (TLC) (Thermopsidis in human urine samples in emergency situations (Kärkkäinen and herba, semen, Atropae belladonnae folium, Daturae semen) plates Vapaatalo 1978). are visualized by spraying them with a DR solution. The applications of DR and its modifications (i.e., Munier-Mache- 3.5. Ukraine boeuf) in toxicology and forensic chemistry are described in detail. The lectures are given to the 4th and 5th-year pharmacy students The Department of Pharmacognosy of the National University of at the Lithuanian University of Health Sciences. In addition, these Pharmacy originates from the laboratory of the Imperial Kharkiv reagents are also presented in the textbook of toxicology and University, which was founded on the initiative of V. N. Karazin forensic toxicology (Vainauskas and Kazlauskienė 2008). DR is (1805). Its history has something in common with the history of presented not only as an agent for the visualization of TLC spots the University of Tartu. According to the Charter (§22, 1804), of various alkaloids (atropine, codeine, quinine, caffeine, cocaine, the Department of Medicinal Theology, Pharmacy and Medicinal pseudoephedrine, methamphetamines, arecoline, etc.), but also for Literature was established at the University. Such departments the analysis of benzodiazepines, amidopyrin and other substances. in Europe were called “materia medica”. The Department was The application of DR for the identification of some pharmaceu- headed by the famous chemist Johann Emanuel Ferdinand Giese tically active substances (under colour reaction) is also discussed before his moving to the UD (Estonia) in 1814. By the resolution in the lectures of pharmaceutical chemistry. DR is also listed as a of the Medical Faculty in 1839, the teaching course of pharma- reagent to be applicable in the research part of some master-level cognosy was created in the Department of Medicinal Theology, (MSc) theses. The part of MSc students perform their experiments and in 1847-1848 it was separated from pharmacology (Bagaley using DR to identify alkaloids in plant materials and for the TLC 1893-1898). analysis of alkaloid-like markers and reagent-sensitive drugs, such The Kharkiv Pharmaceutical Institute was established on the basis as benzodiazepines. of the laboratory in 1921. In the beginning of the 1950´s, the new directions for studying the alkaloid-based raw material began. The method of isolating alkaloids from the plant raw materials and 3.4. Finland identification with the help of DR were used (Dragendorff 1872). We did not find very much information about the status of DR The methods were described in the theses of I.V. Manko “The in the former Finnish and Nordic Pharmacopoeias and the use of chemical study of blueweed (Echium vulgare) and hound’s-tongue the reagent in the higher education in Pharmacy. In Finland, the (Cynoglossum officinale) of the heliotrope family” (1954) and P.M. bachelor’s, master’s and postgraduate higher-degree education in Lyapunova “The phytochemical study of common periwinkle”, pharmacy are offered by two universities: University of Helsinki 1964). Today, our department is studying alkaloids in the wild and University of Eastern Finland, Kuopio. In addition, the Åbo species of plants of the Ukrainian flora, in particular the Borag- Akademi University, Turku offers bachelor of science in pharmacy, inaceae family. The presence of alkaloids with different chemical BSc (Pharm) programme only in Swedish language. At the Univer- properties and pharmacological action was found in blueweed sity of Helsinki, DR (also called as a “iodobismuthate reagent”) (Echium vulgare). An alkaloid that showed a curare-like activity has been applied in the laboratory training courses in pharmacog- in animal tests was found. A new alkaloid named cynoglossofine nosy for the identification of alkaloids. Pharmacognosy (today was isolated from hound’s-tongue (Cynoglossum officinale). The known also as pharmaceutical biology) has a long-term history as alkaloid composition of individual organs of Vinca minor L. of the a teaching subject at the University of Helsinki, and the subject has Apocynaceae family was studied. For the first time, the alkaloid established its position as one of the major subjects in pharmacy. reserpine was isolated from periwinkle; vincine and vincamine To our best knowledge, the University of Eastern Finland and Åbo were extracted from the domestic raw material. The laboratory Akademi University do not provide any special courses in pharma- regulations for the antihypertensive and antispasmodic drug cognosy, and thus the information on the application of DR in their “vimin” were developed (Koshovyi and Kovalev 2018). teaching courses is negligible. The 1st edition of the State Pharmacopoeia of Ukraine (SphU, 2001, A review of the literature reveals several examples about the use 2004, 2008, 2011) (amendments 1-4), contains ten monographs on of DR in the scientific research works published by Finnish scien- the determination of alkaloids by TLC using DR. The SPhU, 1st tists mainly in 1950´s and 1960´s. Krogerus and Tuderman (1954) edition (2001) recommends to use DR (R1), its modification (R2) studied the mixtures of morphine-HCl, codeine phosphate, scopol- and potassium bismuth iodide diluted solution for the identifica- amine-HBr, strychnine nitrate, ethylmorphine-HCl, diacetylmor- tion of alkaloids. phine-HCl, atropine sulfate, cocaine-HCl, quinidine sulfate, and Potassium bismuth iodide solution R1. 1070601: Dissolve 100 g papaverine-HCl by means of two-dimensional paper chromatog- of tartaric acid R in 400 ml of water R, add 8.5 g of basic bismuth raphy. The authors found that the minimum quantities necessary for nitrate R, shake for 1 hour, add 200 ml of the solution of 400 g/L of the detection of the abovementioned drugs on a two-dimensional potassium iodide R and shake vigorously. Stand for 24 hours and chromatogram with a diluted DR were in the range of 10-60 g. In filter. Store in a place protected from light. another study, papaverine-HCl and narcotine-HCl were separated in Potassium bismuth iodide solution R2. 1070602: Starting solution. an ascending chromatography by using a dioxane-water-formic acid Suspend 1.7 g of basic bismuth nitrate R and 20 g of tartaric acid R (90+9.5+0.5 ml) mixture, and the chromatogram was developed in 40 ml of water R. To the suspension add 40 ml of the solution of with DR (Krogerus 1955). Professor V.E. Krogerus, who was later 400 g/L of potassium iodide R, shake for 1 hour and filter. The shelf in the 1960´s an acknowledged professor in galenical pharmacy life of the solution is several days when stored in orange glass vials. at the University of Helsinki, reported the use of DR in the paper The solution is for spraying. Immediately before use, mix 5 ml chromatographic analysis of opium alkaloids in some galenical of the initial solution with 15 ml of water R. preparations (Krogerus and Tuovinen 1957). Morphine, codeine, Potassium bismuth iodide diluted solution. 1070603: Dissolve 100 g thebaine, narceine, papaverine, and narcotine were well separated of tartaric acid R in 500 ml of water R and add 50 ml of potassium and subsequently identified by comparison with pure alkaloids. bismuth iodide solution R1. Store in a place protected from light. More recently, Liukkonen (1960) analyzed atropine, papaverine According to some articles, the SPhU (2008, 2009, 2011) recom- and morphine in tablets and suppositories by paper electrophoresis, mends treating the chromatograms with DR followed by treating Pharmazie 75 (2020) 303 REVIEW the plate with the solution of sodium nitrite. In this case, the detec- Today, DR has found uses also in other applications. For example, tion sensitivity increases to 0.1 μg, allowing one to differentiate in Romania (a neighboring country of the Republic of Moldova) hyoscyamine from atropine, as well as impurities. DR was applied for the detection of beta-lactam antibiotics. Beta- In the SPhU (1st edition, 2001), DR is recommended to be used lactam antibiotics, however, proved to be less sensitive to this for the identification of biologically active substances by means commonly used chromatographic reagent (penicillin gave a very of chromatography in the following ten monographs: “Atropine pale orange spot) (Hancu et al. 2013). Sulfate” (p. 323); “Econazole Nitrate” (p. 369); “Ethylmorphine Hydrochloride” (p. 370). In the SPhU, 1st edition (2004), there are 3.7. Asia (Vietnam) monographs “Bupivacaine Hydrochloride” (p. 300) and “Codeine” (p. 380); in the SPhU, 1st edition (2008) – “Greater celandine”; in The alkaloids isolated from many Asian herbs are reported to have the SPhU, 1st edition (2010) – “Belladonna Leaf” (p. 156-158); antibacterial, antiviral, antiproliferation and anticancer (cytotoxicity) in the SPhU, 1st edition (2011), – “Standardized Belladonna Leaf effects, and consequently, the use of alkaloids as drugs has gained a Tincture” (p. 293), “Clonwine Hydrochloride” (p. 446), “Stramo- wide interest in Asian countries (Amirkia and Heinrich 2014; Cushnie nium Leaf” (p. 307). et al. 2014; Gyawali and Ibrahim 2014; Qiu et al. 2014). Screening the The SphU (the 2nd edition in three volumes and three amendments, phytochemical properties of plant extracts (from an unknown plant 2011-2018) contains the same monographs with the identification material) is usually the first step to indicate it, if there are any inter- of alkaloids and nitrogen-containing compounds. New mono- esting phytochemicals present in the plant. Mayer reagent, Bouch- graphs on Boldo leaves (Peumus boldus) appear in the SPhU 2.2 ardat reagent and DR are the most common reagents for detecting (p. 142, 2014), Boldo leaf dry extract (p. 140); in the SPhU 2.3 the alkaloids through a precipitation reaction in many Asian countries. monograph on celandine (Chelidonium majus) has the national part DR, however, is especially mentioned in many textbooks as the most concerning the celandine herb (Chelidonii herba) (p. 490, 2014). important reagent for the identification of alkaloids. In the educational process (Bezugly 2008) and in the research of Today, chemistry laboratories in many Asian countries (including phytochemistry (Kolisnyk 2015; Avidzba et al. 2018; Golopyorova Vietnam) are using routinely DR for the detection of alkaloids in et al. 2019; Kovalyova et al. 2019) concerning alkaloids of different TLC. The non-selective methods intended for the detection of a nature, DR and its modifications are currently used in the Department wide range of different organic compounds in TLC, are usually of Pharmacognosy, National University of Pharmacy in Kharkiv. For very fairly sensitive (such as iodine vapor or iodine spray reagents example, the DR by R. Munier; if the sensitivity of chromogenic and concentrated sulfuric acid). DR, however, is selective and developer is 1-3 μg of substances in the sample, DR in the modifi- specific only for alkaloids (Toshiyuki and Fujimura 1975). Indian cation of D. Vagujfalvi is used. The reagent diluted in the ratio of 1:4 scientists used a simple spectrophotometric method to estimate with the subsequent treatment of the chromatogram with sulfuric acid the total amount of alkaloids precipitated by DR in plant materials increases the sensitivity of the detection of alkaloids. In biological (Sreevidya and Mehrotra 2003). materials, DR is used in the Moldaver modification (the minimum In both the Vietnamese Pharmacopeia (2018) and the Chinese detection of 0.30-1 μg, Silufol) and A. S. Tishchenko (1966) modifi- Pharmacopeia (2015), DR is described as a primary reagent for identifying alkaloids. In the Indian Pharmacopoeia (2018), cation (the reagent composition: 1 5 g of NaBiO3, 7 5 g of KI, 100 ml, 2 % H SO ) (Bolotov et al. 2011; Bondar and Bagulya 2013). however, potassium mercuric iodide is presented as a precipitating 2 4 reagent for alkaloids. The first Vietnamese Pharmacopoeia (the 1st edition, Vol. 1) was issued in 1971 with various difficulties due to 3.6. Moldova a war period. Subsequent editions were published in 1978, 1994, Today, the European Pharmacopoeia (Ph.Eur., the 9th edition) is 2002, 2010 and 2017. In the Vietnam Pharmacopoeia (the editions in use in the Republic of Moldova. The provisions of European ranging from the 2nd to 5th one), a DR solution is described as Pharmacopoeia are established as mandatory quality standards follows: Solution 1 (0,85g of bismuth nitrate base in 40 ml of water for both domestic and imported medicinal products for human and 10 ml of acetic acid), and Solution 2 (8 g of potassium iodide use (ORDER Nr. 776, 2017). In addition, the references to the in 20 ml of water). Then, mix the volume of Solution 1 and Solu- provisions of the US Pharmacopoeia (USP), British Pharma- tion 2. Add 100 ml of water and 20 ml of acetic acid to every 10 ml copoeia (BP) and Japan Pharmacopoeia (JP) are in force. These of the obtained mixture. pharmacopoeias are valid in the cases, if there is a need to use According to Vietnamese Pharmacopoeia, the 5th edition (2017), the methods of analysis and control of medicinal substances, and about 20 medicinal herbs out of total 372 medicinal herbs and if the corresponding methods are not included in the current 9th herbal medicines can be determined by DR. In these analyses, edition of the European Pharmacopoeia. The relevant monographs a few drops of a DR solution are added into the extract of the of the Romanian Pharmacopoeia, the Pharmacopoeia of Republic medicinal herbs to yield a precipitate with a specific color ranging of Belarus and the Pharmacopoeia of Russian Federation (current from red brown (orange red) to orange yellow. The examples of editions) are also valid for assessing the quality of medicinal medicinal herbs yielding such a colored precipate by DR include: vegetal products, which are not included in the Ph.Eur., USP, BP Radix Stemonae tuberosae, Tuber Stephaniae, Rhizoma Typhonii or JP (ORDER Nr. 113, 2011). trilobati, Herba Hedyotidis capitellatae, Radix Cantharanthi rosei, In Moldova, the students of the Faculty of Pharmacy at the Nicolae Radix Streptocauli, Rhizoma Cyperi, Herba Leonuri japonici, Testemitanu State University of Medicine and Pharmacy are Herba Passiflorae foetidae, Herba Clerodendri philippini, Cortex using a national textbook of pharmacognosy, which describes the Holarrhenae, Folium Crini asiatici, Radix Aconiti, Radix Aconiti application of DR in a qualitative reaction for the identification of lateralis, Semen Quisqualis, Radix Gentianae, Folium Crini lati- alkaloids (Nistreanu and Calalb, 2016). The present reaction is also folii, Dipsaci, Folium Erythrinae aariegatae, and Rhizoma Ligu- one of the most common sedimentation reactions used with alka- stici wallichii. loids. According to the textbook, DR forms a brown precipitate In some cases, DR has been reported to produce false-positive with most alkaloids in weakly acidic solutions. A number of other results. The positive test may not always indicate the presence of reagents intended for the identification of alkaloids, are also listed alkaloids, since the presence of other plant constituents, such as in this textbook (i.e., Mayer’s, Wagner’s, Bouchardat’s-Marme’s purines, proteins, betaines and ammonium salts, could also yield reagents). The preparation of DR is described in the textbook a positive test results with DR. Moreover, DR does not give precip- follows: For preparing Solution 1, 0.85 g of bismuth sub-nitrate itates with all alkaloids, such as caffeine, strychnine, and brucine. is dissolved in 40 ml of water and 10 ml of acetic acid is added. In our experience, it is necessary to carry out the reaction at least For preparing Solution 2, 20 g of potassium iodide is dissolved with 4-5 reagents to confirm the presence of all alkaloids. in 50 ml of water. Equal volumes of Solutions 1 and 2 are mixed. In addition to the detection of alkaloids, DR is also used in TLC for Finally, 100 ml of water and 20 ml of acetic acid are added in the determination of other active ingredients in herbal medicines 10 ml of the abovementioned mixture of Solution 1 and 2 (Nistreanu (by spraying color reagents on a chromatographed thin plate). In and Calalb, 2016). this procedure, 5-20 μl of standard solutions and the herbal extracts 304 Pharmazie 75 (2020) REVIEW are separately applied onto TLC plates. After deploying a solvent of medicinal plants. In: Proceedings of the International Science-Practical Inter- system, the thin plates are allowed to dry in air. After this, thin net-Conference, November 26-28, Kharkiv, p. 27-29 (in Ukrainian). Baerheim-Svendsen A, Verpoorte R (1983) Chromatography of alkaloids, Part A: plates are sprayed with DR, and inspected under a normal light. On Thin-layer chromatography. Paises Bajos. the chromatogram of a test solution, there should be the traces of Bagaley DI. (1893-1898) Experience of the history of Kharkov University (based on unpublished materials). Vol. 1 (1802-1815). Chapter 5. Teaching and research the same color, and the Rf value with the main active trace on the chromatogram of a reference solution. In Vietnam Pharmacopoeia, activities of professors. Kharkiv, p. 485-778 (in Russian). th Bauer K (1953) The organic compounds analysis. 2nd ed. Moscow, p. 394 (in the 5 edition (2017), the present spraying method (i.e., combining Russian). DR with TLC) is applied for the analysis of numerous active ingre- Bezugly PA (2008) Pharmaceutical chemistry: A textbook for pharm. higher schools dients, such as tetrahydropalmatin in Tuber Corydalis, ajmalicin in and pharm. faculties of med. higher schools of the ІІІ-ІV levels of accreditation. Radix Cantharanthi rosei, palmatin in Caulis et radix Fibraureae, Vinnytsia, p. 192, 308, 396. (in Ukrainian). strychinin and brucin in Cortex Strychni wallichianae, stachydrin Block RJ, LeStrange R, Zweig G (1954) Paper chromatography. Moscow, p. 150 (in Russian). hydrochloride in Herba Leonuri japonicae, strychinin and brucin Bolotov VV, Akhmedov EY, Miroshnichenko YO (2011) Color reactions and thin- in Semen Strychni, conessin in Cortex Holarrhenae, lycorin in layer chromatography of ketotifen. News of Pharmacy 65(1): 43-45 (in Ukrainian). Folium Crini asiatici, aconitin in Radix Aconiti, aconitin in Radix Bondar VS, Bagulya AV (2013) Qualitative reactions and TLC in the chemicotoxi- Aconiti lateralis, and crinamidin in Folium Crini latifolii. cological analysis of diphenine. Pharmacy of Kazakhstan 7: 38–40 (in Russian). Christensen AN, Lebech B (2012). Investigation of the crystal structure of In Vietnam, the Pharmacy students at the universities learn to know a basic bismuth(iii) nitrate with the composition [Bi6O4(OH)4]0.54(1) DR as one of the three specific reagents for the determination of [Bi6O5(OH)3]0.46(1) (NO3)5.54(1). Dalton Transactions 41: 1971-1980. alkaloids. They also get to know the test intended for analyzing Cushnie TP, Cushnie B, Lamb AJ (2014) Alkaloids: an overview of their antibacte- alkaloid extracts, such as the extract of Datura (Vietnamese Phar- rial, antibiotic-enhancing and antivirulence activities. Int J Antimicrob Agents 44: 377–386. macopoeia, 2017). The present test is described in more detail Dolgova AA, Ivanova SD, Ignatjeva NS. et al. (1966) Methodical guidance for phyto- below (two alternative test protocols): chemical analysis of medicinal herbs. Moscow, p. 16–20 (in Russian). (1) Alkaloids are extracted with water or with the mixture of Dragendorff G(1866) Ueber einige neue Reagentien auf Alkaloide. Pharm Zschr ethanol and water. After extraction at least 3 times, take 0.1 ml Russl 5: 82–85. Dragendorff G (1868-1895) Die gerichtlich-chemische Ermittelung von Giften in to 0.2 ml of the next extract, acidify with 2 M hydrochloric acid Nahrungsmitteln, Luftgemischen, Speiseresten, Körpertheilen. St. Petersburg (in solution, add 0.05 ml of potassium tetraiodomercurate solution German). (Mayer’s reagent), or add 0.05 ml of potassium iodobismuthate Dragendorff G. (1872) Beiträge zur gerichtlichen Chemie einzelner organischer Gifte. solution (DR) to the alkaloids of a tomato family. There should be Untersuchungen aus dem pharmaceutischen Institute in Dorpat. 1. Auflage. Sankt no precipitate or cloudy solution. In the case of an extract with an Petersburg (in German). Estonian Pharmacopoeia (1937) Pharmacopoea Estonica. Editio prima. Tallinn, alcohol content greater than 25% or more, after acidification, the p. 665 (in Estonian). solvent should be evaporated before adding a precipitate reagent. European Pharmacopoeia (2019) Vol. 9.8, Strasbourg. (2) Alkaloids are extracted by organic solvent. After extraction at Golopyorova AI, Osmachko AP, Kovalyova AM (2019) Determination of least 3 times, take 1 ml to 2 ml of the next extract, add 1 ml to 2 ml pyrrolizidine alkaloids in medical herbal mix and herbal remedies. Topical issues of new medicines development: In: Proceedings of the XXVI International of 0.1 M hydrochloric acid solution, evaporate run out of the Science-Practical Conference of Young Scientists and Students, Kharkiv, April organic solvent, transfer the remaining liquid into a test tube, and 10–12, 2019. Kharkiv, p. 42–43. add 0.05 ml of potassium tetraiodomercurate solution (Mayer’s Gyawali R, Ibrahim S (2014) Natural products as antimicrobial agents. Food Control reagent), or add 0.05 ml of potassium iodobismuthate solution 46: 412–429. Gudienė V (2017) Social features of Lithuanian pharmacy in the 19th century and the (DR) to the alkaloids belonging to a coffee family, or add 0.05 ml first half of the 20th century. Kaunas, p. 187. of iodine-potassium iodide solution (Bouchardat’s reagent) to Habib A-AM (1980) False-positive alkaloid reactions. J Pharm Sci 69: 37–43. emetin. No obvious turbidity may form in solution. Hancu G, Simon B , Kelemen H, Rusu A, Mircia E, Árpád Gyéresi A (2013) Thin layer chromatography analysis of beta-lactam antibiotics. Adv Pharm Bull 3: 367–371. 4. Commercial Dragendorff’s reagents and modifi cations Henry N, Evain M, Denlard P, Jobic S, Abraham F, Mentre O (2005) [Bi2O2] 2+ layers in Bi2O2 (OH)(NO3): synthesis and structure determination. Zschr To date, DR has been widely used in various pharmaceutical and Naturforsch B 60: 322–327. forensic chemistry applications and the use of this versatile reagent Hinrikus T, Raal A (20011) Georg Dragendorff – the greatest scientist in pharmacy at is steadily increasing. For example, a Google search by the key the University of Tartu. Akadeemia 23: 1227–1259 (in Estonian). phrase “Dragendorff reagent” gives total 47,700 results (hits) Hinrikus T, Raal A, Veski P (2007) Pharmacy at the 375-year-old University of Tartu. Eur J Pharm Sci 32: S1–S2. (17/02/2020). One example of the alternative applications of DR Hinrikus T, Tankler H, Raal A (2005) PhD theses at the university of Tartu/Dorpat is that it is widely used today for the production of surfactants. In supervised by Georg Dragendorff (1864–1894). Pharmazie 60: 388–395 (in this process, a non-ionic surfactant is precipitated in water solution German). Jakovlev GP, Blinova KF (2004) Herbal substances. Pharmacognosy. St. Petersburg, p. 564. with modified DR (KBiI4+BaCl2+glacial acetic acid). DR can be modified in many ways, and some of these chemical modifications Janulis V, Puodžiūnienė G, Malinauskas F (2008) Phytochemical analysis: A text- book. Kaunas, p. 135-136 (in Lithuanian). are currently in use in the quantitative determination of chemical Indian Pharmacopoeia (2018) Volume I, Government of India Ministry of Health & substances (including drugs). Family Welfare, The Indian Pharmacopoeia commission, Ghaziabad. Today, DR (or iodobismuthate reactive) is commercially available Kanopka E (1975) Alkaloids and their raw materials. Kaunas, p. 4 (in Lithuanian). in all over the world. DR has two CAS numbers: 39775-75-2 Kapp K, Talv S, Hinrikus T, Raal A (2012) Pharmacy students at the University of Tartu 1802-2010 – a historical study. Pharmazie 67: 658–664. and 41944-01-8. The complex with potassium iodide is the most Kodama H. (1994) Synthesis of a new compound, Bi5O7NO3, by thermal decompo- common form of the reagent, but sodium iodide is also used for sition. J Solid State Chem 112: 27–30. the complex formation of DR. The most commonly used acid Kolisnyk OV (2015) Development of control procedure for seneciphyline and component is acetic acid, and then DR is applicable as a spray other related impurities in platyphylline hydrotartrate substance and “Platyphyl- line-Zdorovie” injectable preparation by using RP HPTLC method. Pharmacom to visualize the spots on TLC plates. The alternative acid compo- 2: 59–67 (in Ukrainian). nents are tartaric acid alone or combined with acetic acid. Total Kondratas R, Gudienė V, Šimaitiene Z, Maurina B, Paju K, Hinrikus T, Raal A (2015) six (6) different potassium iodobismuthate solutions are presented The national pharmacopoeias of the Baltic States. Pharmazie 70: 684–689. in European Pharmacopoeia (2019): potassium iodobismuthate Koshovyi OM, Kovalev VM (2018) History of the Department of Pharmacognosy of the National University of Pharmacy: Monograph. Kharkiv, p. 16, 101, 181–182 solution R and its variations R1 to R5. (in Ukrainian). Kovalyova AM, Avidzba VY, Ilina TV, Koshovyi OM, A.V. Irzaeva AV (2019) Conflicts of interests: None declared. The study of alkaloids in tea samples from various manufacturers presented at the domestic market. Medicines – to a person. Modern problems of pharmaco- therapy and prescription of medicines. In: Proceedings of the ІІІ International References Science-Practical Conference. 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