Analgesics - antipyretics = „weak“ analgesics = non-opioid analgesics Most of them also • non-steroidal anti-inflamatory drugs (NSAIDs) •antirheumatics Oldřich Farsa 2011 Metabolism of eicosanoids O O arachidonic O H acid = 2 C O R1 R2 OH R2 O OH CH C O P O + 3 H N CH 2 O 3 CH3 glucocorticoids inhibitors of phspholipase A2 prostaglandins sythesis = COOH = "weak" analgesics + lipoxygenase inhibitors + NSAIDs arachidonic acid cyclooxygenases (COX1 + COX2) lipoxygenase OOH O COOH COOH O PG 5-hydroperoxy-6-trans-8,11,14-cis-eikosatetraenoic acid G2 OOH (5-HPETE) cyklooxygenases tromboxan synthase prostacyklin synthase PG H2 PG I2 = prostacyklin TX A2 endothelium cells LT A4 trombocytes isomerases PG D2 PG E2 LT C4 LT B4 PG F2α all the cells LT D4 LT E4 Effects of prostaglandins ↓ Prostaglandin E, F2α : ache, fewer, inflammation, sekretion of HCl , stomach mucosa capilaries dilatation, contraction of + ↑ uterus, kidneys: excretion of Na and H2O Prostacyclin (prostaglandin I ): vasodilatation, platelets aggregation inhibition 2 Tromboxan: vasokonstriction, platelets aggregation activation Leukotriens: alergic reactions (e.g. asthma bronchiale) Cyklooxygenases (= prostaglandin G/H synthases) COX1 Constitutive: in all the tissues Functions: •protection of stomach mucosa (vasodilatation) •diuresis •platelets aggregation (TXA) COX2 Philipp Needlemann Constitutive: kidneys, brain (co-localized with cyclins D and E) inventor of COX 1 isoenzymes Inducible: macrophages, neutrophfils, fibroblasts, endothelium cells (1989) Functions: •vasodilatation (PG I2) •porod (děložní stahy) childbirth (uterus contractions) •inflammation processes COX3 ?? (= COX1b; brain ?) Classification of COX inhibitors (antipyretics, NSAIDs) Non-selective (COX1 + COX2) •Anilides •Salicylates •Phenamates •Aryl- and heteroaryl alkanoic acids •Aryl- and heteroaryl acetic acids •Aryl- and heteroaryl propionic acids •Oxicames •1,2-Dihydropyrazolidine-3-ones •2,5-Pyrazolidinediones Selective (COX1<COX2): nimesulide Specific (COX2) •Coxibes Anilides HN O HN O HN O OH O acetanilide paracetamol phenacetin (acetaminophen) N-(4-ethoxyphenyl)acetamide N-phenylacetamide 4-(acetylamino)phenol nephrotoxicity 1886: Antifebrin® para-(acetylamino)phenol Dinyl® - analg. p-(acetylamino)phenol mixture with caffeine, Paralen, Panadol…. aminophenazone and barbiturates Paracetamol • inhibits COX only in CNS (COX3 ?) not in periphery ⇒ •effects: analgesic, antipyretic (not antiinflamatory, antirheumatic) Použití ve směsích s(e) Usage in mixtures with HN O •codeine, caffeine ⇒ effect enhancement (Korylan tbl.®, Panadol tbl.®, Efferalgan codein tbl. eff.®) •expectorants (guajfenesin, terpin) •antitussives (dextromethorphan) OH •H1-antihistaminines (pheniramine, chlorphenamine, dimenhydrinate, promethazin, doxylamin) together with α-sympatomimetics (phenylefrine, pseudoephedrine) •spasmolytics (pitophenon) •myorelaxants (chlorzoxan, carisoprodol) •NSAID (acetylsalicylic acid, propyphenazon – Valetol®) Metabolism of paracetamol O O urine 2% urine O S HO O OH O O 42 % 52 % HO O urine conjugation conjugation HO OH N O N O N O CH CH3 3 CH3 paracetamol glucuronide paracetamol sulfate 4 % cytochrome P-450 O R-SH OH R (glutahione, S N-acetylcysteine) R-SH = glutathion ⇒ ⇒ merkapturic acid N O N O CH3 CH3 N-acetyl-p-benzoquinoneimine urine N-(4-oxocyclohexa-2,5-diene-1-ylidene)acetamide NAPQI HEPATOTOXIC Thiols detoxicating N-acetyl-p-benzoquinoneimine γ − Glu-Cys-Gly HS O O O HO N O N H N H H H OH glutathione SH O OH H C N 3 H O N-acetyl-L-cysteine mucolytic ACC®, Mucobene® Synthesis of paracetamol OH OH Sn CH3COOH Morse, Chem. Ber. 11, 232 (1878) HN O NO2 CH3 OH O NO2 2-nitrophenol H3C O OH OH OH OH H3C HNO3 Fe, HCl O HN O NO2 NH2 CH3 phenol 4-nitrophenol 4-aminophenol 4-(acetylamino)phenol Propacetamol – paracetamol prodrug • for intravenous application O Cl + H N O HN O CH3 4-(acetylamino)phenyl-N,N-diethylglycinate hydrochloride 2-[4-(acetylamino)phenoxy]-N,N-diethyl-2-oxoethaneaminium chloride propacetamol hydrochloreid Pro-Dafalgan® (UPSA Laboratoires) O N O H O esterase O H O + N 2 HO HN O HN O CH3 CH 3 Salicylates O HO H3C HO O OH O OH O O hydrolýza H C HO O OH 3 O CH3 oxidace O O HO OH salicin salicylic acid acetylosalicylic acid (2-hydroxymethylphenyl)-β -D-glucopyranoside 2-hydroxybenzoová kys. 2-acetoxybenzoic acid 1827 Leroux: isolation from willow 1838 Piria: the first synthesis since 1878 used as antipyretic 1897 Felix Hoffmann - industrial and antirheumatic synthesis 1899 – Aspirin® (Bayer) Felix Hoffmann Sir John R. Vane Effects of acetylosalicylic acid O OH „Wanted“: •antipyretic O CH3 •analgesic O •anti-inflamatory •antirheumatic •antithrombotic (↓ platelets aggregation) – Anopyrin® „Unwanted“: •ulcerogenic •Rey syndrom in childern after viral infection (hepatopathy, encefalopathy) ⇒ contra-indication in childern •bleeding (e.g. from nose - ↓ platelets aggregation) Intoxication = „salicylism“ – infliction of CNS (psychical malfunctios, buzz in ears, dizzines, deafness), methabolic acidosis Mechanis of action of acetylosalicylic acid (ASA) • irreversible inhibition od cyclooxygenases by acetylation of serine rest Ser HO O O O CH3 H C O COX OH + 3 + COX O O NH2 O NH2 HO O + OH O OH O O CH3 HO Metabolism of ASA O OH O O • HO O ASA proceeds in liver •all metabolits are excreted HO OH t1/2= 15 min. by urine O1-salicyoylglucuronic acid 5 % O OH OH glucuronation + CH3COOH O OH O HO O salicylic acid. 10 % conjugation with Gly O OH HO O O NH HO OH hydroxylation OH O1-(2-carboxyphenyl)glucuronic acid 10 % salicyluric acid (N-salicyoylglycine) O OH 75 % OH HO gentisic acid < 1 % Syntheses of ASA O OH O O OH Gerhardt, Justus Liebigs Ann. Chem. 87, 164 (1853) Gilm, Justus Liebigs Ann. Chem. 112, 181 (1859) OH H3C Cl O O Kraut, Justus Liebigs Ann. Chem. 150, 10 (1869) CH3 O H3C O OH O O OH H3C OH O O O Felix Hoffmann CH3 Other salicylates CH 3 CH3 CH3 O O O O O O F O O O O O O O Al Al Al OH O O O O O O F OH O O O O CH3 CH3 pentakis(acetylosalicyoyloxy)trialuminium dioxide 2',4'-difluoro-4-hydroxy-1,1'-biphenyl-3-carboxylic acid aloxiprin diflunisal Superpyrin® Unisal® tbl. Anthranilic acid derivatives – phenamates = substition derivatives of 2-phenylaminobenzooic acid •derived from salicylates by substitution of hydroxy group with (phenyl)amino moiety O OH 3 H R N R1 R2 •aromatic amino acids •substituted on the aniline ring only •inhibit both COX1 and COX2 (selectivity?; COX3?) •analgesics, antipyretics, antimigrenics, anti-inflammatory Phenamates O OH 3 H R N R1 R2 R1 R2 R3 Chemica name INN / preparation 2-(2,3-dimethylphenylamino)- -CH3 -CH3 -H mephenamic acid benzoic acid 2-(2,6-dichloro-3- -Cl -CH3 -Cl meclophenamic acid methylphenylamino)benzoic acid 2-(3-chloro-2- -CH3 -Cl -H tolphenamic acid methylphenylamino)benzoic acid Migea rapid® 2-(3-trifluoromethylphenylamino)benzoic -H -CF3 -H fluphenamic acid acid Tolphenamic acid Synthesis + N OH K O O O NH2 H CH 3 Br N + O 1.(CH COO) Cu, DMF Cl 3 2 2. H+ H3C Cl Kaltenbronn J.S. et al., Arzneim. Forsch 33, 621-627 (1983) Selectivity against COXs IC (COX1) 50 = 10 IC50 (COX 2) Grossmann C. J. et al., Inflammation Res. 44, 253-257 (1995) Niflumic acid and its esters F F F F F F H H C N N N O O OH OH 2-{[3-(trifluoromethyl)phenyl]amino}nicotinic acid fluphenamic acid niflumic acid •isosteric substitution benzene ⇒ pyridine, or –CH= ⇒ -N= •inhibit both COX1 and COX2 •anti-inflamatory, antirheumatics; usually topically administered Niflumic acid and its esters •esters are prodrugs which can better penetrate through the skin R 2-{[(3-trifluormethyl)phenyl]amino}nicotinic acid H niflumic acid Niflugel®, Nifluril® F F F H -||- 2-(morpholine-4-yl)ethylester N N N O morniflumate O O R -||- 1-oxo-2-(3H)-benzofurane-3-ylester talniflumate O O Aryl- and heteroarylalkanoic acids Structure-activity relationships (SAR) •the aliphatic part of the molecule is more specific for the effect than the aromatic one ARY O O ARY O ARY O O = = > > ARY OH ARY OH OH H3C OH OH ARY = aryl, heteroaryl Aryl- and heteroarylacetic acids and their functional derivatives O H2C Y R R = aryl or heteroaryl Y = OH, NHOH, NHR, OCH2COOH, or other • antirheumatics, anti-inflamatory, analgesics, antipyretics •inhibition of both COX1 and COX2 •adverse effects (AE) like in salicylates Aryl- and heteroarylacetic acids and their functional derivatives O (fenacs) H C O R Cl 3 Cl N NH CH3 O O O R O Cl R = H R = H [1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indol-3-yl]acetic acid {2-[(2,6-dichlorophenyl)amino]phenyl}acetic acid indomethacin diclofenac •used since 1963 •used since 1975 •now mainly topically Voltaren®, Veral®, Myogit®, Dicloreum® Indobene® cps, Bonidon® gel, Elmetacin® spr R= OCH COOH R = OCH COOH 2 2 {2-[(2,6-dichlorophenyl)amino]phenyl}acetic acid [1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indol-3-yl]acetic acid carboxymethylester caboxymethylester acemetacin aceclofenac Heteroarylacetic acids and their derivatives O O HN O N O O N O N O CH3 H3C N O H3C CH3 proglumetacin Cl Cl Cl N N N S OH OH O O [3-(4-chlorophenyl)-1-phenyl-1H-pyrazole-4-yl]acetic acid [4-(4-chlorophenyl)-2-phenyl-1,3-thiazole-5-yl]acetic acid lonazolac fentiazac •isosteres Aryl- a heteroarylacetic acids CH CH3 O O 3 O N N OH H2C OH OH O O O H C Cl Cl 3 H3C alclofenac tolmetin zomepirac Aryl- a heteroarylacetic acids •examples of isosterism of rings and functional groups O O OH OH O F N O Cl O S [1-(4-chlorobenzoyl)-5-methoxy-2-methyl- [6-fluoro-3-(4-methanesulfinylbenzylidene)-2-methyl- 1H-indol-3-ylacetic acid 3H-indene-1-yl]acetic acid indomethacin sulindac Nitrogeneous functional derivatives of aryl- and heteroarylacetic acids H3C O OH N O H 2-(4-butoxyphenyl)-N-hydroxyacetamide 2-(4-butoxyphenyl)acetohydroxamic acid bufexamac O Cl N H O N N CH O3 1,1´-biphenyl-4-yl-N-pyridine-2-yl-acetamide H C OH 3 O N difenpiramide H 2-[1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indole-3-yl]- N-hydroxyacetamide 2-[1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indole-3-yl]- acetohydroxamic acid oxametacin Nabumeton •a prodrug O OH O metabolism liver O O 4-(6-methoxynaphtalene-2-yl)butan-2-one 2-(6-methoxynaphtalene-2-yl)acetic acid (6MNA) nabumetone active metabolit Relifex® tbl.