UNITED STATES PATENT OFFICE AQUEOUS SOLUTION of RIBOFLAVIN Chester M

Patented June 24, 1952 2,601,569 UNITED STATES PATENT OFFICE AQUEOUS SOLUTION OF RIBOFLAVIN Chester M. Suter, Albany, N. Y., assignor to: Sterling Drug Inc., New York, N.Y., a corpora tion of Delaware No. Drawing. Application April 28, 1951, Serial No. 223,639 4 Claims. (Cl 167-81) 2 This invention relates to vitamin compositions acid, and the other isoners. Non-toxic, Water and, Specifically, to the solubilizing of riboflavin. Soluble Salts of these acids which can be used More particularly, it relates to compositions com as Solubilizers for riboflavin according to my prising essentially riboflavin and, as a solubilizer, invention include besides the Sodium salts also a non-toxic, water-Soluble salt of a hydroxy Such salts as the potassium, lithium, magnesium, naphthoic acid. Such compositions encompass ammonium, organically-substituted ammonium those containing riboflavin as the sole dietary or salts, examples of the last-mentioned type in therapeutic factor as well as those containing, cluding the 2-hydroxyethylammonium salts, the in addition to riboflavin, other vitamins, growth diethylammonium salts, etc., and the like. factors and medicinals. O In addition to being more effective than any Since riboflavin is only very sparingly soluble heretofore known compound in its Solubilizing in water (solubility: 0.013 per cent or 0.013 g. action on riboflavin in Water and aqueous prep per 100ml. of water) and other solvents suitable arations, sodium 3-hydroxy-2-naphthoate and its for pharmaceutical preparations, the use of many related non-toxic, water-soluble salts of 3-hy different agents has been proposed as solubiliz 5 droxy-2-naphthoic acid and other hydroxy ing agents for this vitamin in water and in naphthoic acids also possess the advantage of aqueous preparations. While such proposed providing an aqueous. solution having a pH defi agents may increase the solubility of riboflavin nitely on the acid side. This is of utmost value in water to some extent, the resulting solutions in the formulation of aqueous preparations con of many of them are not satisfactory for phar 20 taining, in addition to riboflavin, other dietary maceutical purposes because of either toxicity factors such as vitamin B1 which is stable in the or undesirable side effects after oral or parenteral form of its salts in acid solutions and unstable administration, usually because of the large in alkaline solutions. amounts of the solubilizer necessary in propor The manufacture of my new aqueous solutions tion to the amount of riboflavin solubilized. In 25 of riboflavin generally involves preparing a water other instances the solutions obtained are un solution of a salt of a hydroxynaphthoic acid, stable and, moreover, the solubilizer itself may preferably sodium 3-hydroxy-2-naphthoate. decompose. - Riboflavin is then very readily dissolved in such I have now found that non-toxic, water-solu solutions. For solutions of sodium 3-hydroxy-2- ble salts of hydroxynaphthoic acids markedly 30 naphthoate up to about 10 per cent, this salt increase the solubility of riboflavin in aqueous was dissolved in water at room temperature. preparations. The resulting aqueous solutions, For higher percentages of this salt, up to 13.5 which contain considerably less solubilizer in per cent, heating was necessary. When heating proportion to the amount of riboflavin than in was used, the resulting solution of Sodium 3 any other aqueous preparation heretofore known, 35 hydroxy-2-naphthoate was preferably cooled to are stable and suitable for oral and parenteral room temperature before addition of the ribo administration. In addition, the preparations of flavin and other dietary factors. The final prod my invention, in having an outstandingly in uct was then diluted with water to the desired creased percentage of riboflavin compared to Volume. known riboflavin-containing aqueous prepara 40 There can be incorporated in my solubilized tions, offer advantages as spraying compositions riboflavin preparations other water-soluble vita for fortifying animal feeds, where a relatively mins such as thiamine hydrochloride, nicotin high concentration of riboflavin is desired. amide, d-pantothenyl alcohol, vitamin B6 hydro Sodium 3-hydroxy-2-naphthoate, because of its chloride, vitamin C, etc., and other Water soluble low cost and ready availability, is the preferred 5 medicinals as, for instance, pantothenic acid, folic Solubilizing agent according to my invention. acid, biotin, choline chloride, inositol, etc. Also, Other solubilizing agents encompassed by my in there can be incorporated in my aqueous prepara vention include other non-toxic, water-soluble tions water-insoluble vitamins, such as vitamin A, salts of 3-hydroxy-2-naphthoic acid as well as vitamin D2, vitamin D3, alpha-tocopherol, etc., non-toxic, water-soluble salts of its isomeric hy 50 and/or other water-insoluble ingredients pro droxynaphthoic acids, including, 1-hydroxy-2- vided, of course, a suitable solubilizing or dis naphthoic acid, 4-hydroxy-2-naphthoic acid, 7 persing agent is added therewith. hydroxy-2-naphthoic acid, 2-hydroxy-1-naph My invention further comprehends dry comi thoic acid, 4-hydroxy-1-naphthoic acid, 6-hy positions comprising riboflavin and a non-toxic, droxy-1-naphthoic acid, 8-hydroxy-1-naphthoic water-soluble salt of a hydroxynaphthoic acid,

2,601,569 3 4. preferably sodium 3-hydroxy - 2 - naphthoate, tion was diluted to 200 ml, with water. Similarly, Such dry compositions, which can be prepared using the other 150 ml. portion, a 200 m. solution by intimately admixing the ingredients or by containing 10.5 g. of riboflavin was prepared. freeze-drying my aforesaid aqueous preparations, The pH of these two solutions was then adjusted for instance, according to the method of U. S. to 6.6 by adding one drop of 1N sodium hydroxide Reissue Patent 20,969, are readily soluble in solution. The riboflavin content of these two water. Such dry preparations can advanta solutions remained constant after standing for geously be marketed and used when desired by three months at room temperature and at 37° C. dissolving in Water. Eacample 4 Specific embodiments of my aqueous prepara 0. An 11 per cent Solution of sodium 1-hydroxy tions are further illustrated in the following ex 2-naphthoate in water was found to dissolve 5 amples. to 6 per cent of riboflavin. Thus, 100 ml. of Eacample 1 such. a. solution contains 11 g. of sodium 1-hy A 10.0 per cent solution of Sodium 3-hydroxy 5 droxy-2-naphthoate and 5 to 6 g. of riboflavin. 2-naphthoate in water was found to dissolve. 7.90, Eacample 5 per cent of riboflavin. In other words, 100 ml. of a water solution containing 10.0 g. of sodium The following formulations are illustrative of 3-hydroxy-2-naphthoate dissolved 7.90 g. of ribo polyvitamin compositions containing, in addition flavin. The pH of this riboflavin-containing So 20 to riboflavin and a salt of a hydroxynaphtholic lution, was 5,90. acid, other water-soluble: dietary factors as well Similarly, 0.5, 1.0, 2.5, and 5.0 per cent. Solu as: one- or more water-insoluble dietary: factors. tions: of sodium. 3-hydroxy-2-naphthoate dis solved, respectively, 0.19, 0:45, 1.43 and 3.60 per Ingredient A. B 25 centriboflavin with the resulting solutions: hav Riboflavin, g------2.625: . 2:625. ing pH values of 6.28, 6:17, 5.92 and 5.88, respec Sodium 3-hydroxy-2-naphthoate, g------10.0. 10.0. tively, Nicotinanide; g------1.75- 75 Choline chloride, g. 2.02; ; 2:02. Eacample:2. dPantothenyl alco 2.8 2.8 Vitamin D3, g------0.045' 0.045 A composition was prepared containing, in each alpha-Tocopherol, g-- -- 0:l li------m, the following ingredients: 30 Tween 80', g------10.0 100 Milligrams Water Q. S. mil------100. 00 Riboflavin ------5 In the preparation of formulation. A the ribo Vitamin B1, hydrochloride------5 flavin was dissolved in 75 ml of a water solu Nicatinamide ------50 35 tion of the solubilizer; sodium 3-hydroxy-2- Vitamin. Bis hydrochloride.------2.5 naphthoate. The nicotinamide, choline chloride Calcium. pantothenate------2.5 and d-pantothenyl alcohol were added to this Sodium: 3-hydroxy-2-naphthoate------15 solution and the mixture' shaken until dissolu The above solution was prepared by dissolving tion was complete. The vitamin D3 and alpha the sodium 3-hydroxy-2-naphthoate in water, thocopherol were then dissolved in "Tween 80' dissolving the riboflavin in the resulting solution (a water-soluble polyoxyethylene Sorbitan monos and then adding the other ingredients and shak oleate), the resulting solution was mixed thors ing the mixture until complete dissolution re oughly with the aforesaid aqueous solution, water sulted. Water was then added to the solution was added to bring the total volume up to 100' to give the desired volume. One hundred ml. 5. ml. and the resulting preparation was agitated of such a solution contains 1.5 g. of sodiun-i 3 until homogeneous. hydroxy-2-naphthoate and 0.5 g; of riboflavin. Formulation B was prepared in the same man Similarly, solutions like the foregoing but con ner as A except no alpha-tocopherol was used. taining larger quantities of riboflavin' can be Formulations A and B were stored at room formulated by using larger amounts of sodium temperature and at 37° C. for three months and, 3-hydroxy-2-naphthoate. In addition, the fore when assayed for riboflavia content, were found going preparation can be carried out using in to contain the original potencies of this vitamin: place of sodium 3-hydroxy-2-naphthoate- other Other aqueous riboflavin-containing composi non-toxic, water-soluble: salts of this acid, in tions can be prepared in accordance with the cluding the potassium, lithium, magnesium, an ' foregoing description by varying the number, monium, 2-hydroxyethylammoniurn, diethylami quantities and form of dietary or therapeutic' monium salts, and the like: ingredients and by adding other desirabler sub Aqueous preparations comparable to the fore stances, e.g., flavoring agents, sweetening agents, going can be obtained by using as the solubiliz etc., provided they are mutually compatible with ing agent non-toxic, water-soluble salts of iso the other ingredients of the composition. meric hydroxynaphthoic acid including sodium Eacample 6. . 4-hydroxy-2-naphthoate, ammonium 7-hydroxy Eight parts of Sodiun-3-hydroxy-2-naphithoate: 2-naphthoate, sodium 2-hydroxy-1-naphtheate, were mixed intimately with four parts of ribo 2-hydroxyethylamnionium 8 - hydroxy-l-lnaph flaving his dry preparation, was readily: solu thoate, and the like. - ble in one-hundred parts'of water. Eacample. 3. Similarly, other dry compositions, can be pre Forty grams of sodium 3-hydroxy-2-naph pared: that have incorporated therein otherme thoate was dissolved in 300 ml of water by heat dicinals as disclosed herein above. ing to boiling. The hot solution was filtered, Alternatively, dry compositions of my inven cooled and divided into two portions- of 150 ml: tion can be obtained by freeze-drying my aqueous each. The pH of these 13.3 per' cent solutions of preparations. For example, when the aqueous. sodium 3-hydroxy-2-naphthoate was:68. To one preparations: describedi above in. Example: 1; or 2. 150 ml, portion was added 525. g. of riboflavin were frozen and then; dehydrated under vacuun which dissolved on-shaking. The resulting Solu 75 while maintained in: the frozen state; there were:

2,601,569 5 6 obtained dry preparations that were readily solu flavin and a non-toxic, water-soluble salt of a ble in Water. hydroxynaphthoic acid in an amount sufficient I claim: to substantially increase the solubility of ribo ... An aqueous composition comprising ribo flavin in Water whereby the resulting aqueous favin in a concentration higher than that Ob 5 Solution has a concentration of riboflavin higher tainable in water alone and a non-toxic, water Soluble salt of a hydroxynaphthoic acid as a than that obtainable in Water alone, the quan solubilizer. tity of the hydroxynaphthoic acid Salt being from 2. An aqueous composition comprising ribo about one to four times that of the riboflavin. flavin in a concentration higher than that ob O CHESTER, MI, SUTER, tainable in Water alone and a non-toxic, water Soluble, alkali metal salt of a hydroxynaphthoic REFERENCES CTE) acid as a Solubilizer. The following references are of record in the 3. An aqueous Solution comprising riboflavin file of this patent: in a concentration higher than that obtainable 15 in Water alone and sodium 3-hydroxy-2-naph UNITED STATES PATENTS thoate as a solubilizer. Number Nanne Date 4. A dry vitamin composition comprising ribo 2,395,378 Miller ------Feb. 19, 1946