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Aspek Farmakokimia Obat Anti inflamasi Non Steroid . Kuliah Farmakokimia FSTOA semester 6 Fak. Farmasi USB. Stru ktur enzim COX. Keduanya merupakan dimer yang terikat pada membran mikrosomal 4 domain Domain Dimerization Domain yang terikat Membran
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Aspek Farmakokimia ObatAntiinflamasi NonSteroid Kuliah Farmakokimia FSTOA semester 6 Fak. Farmasi USB
Struktur enzim COX • Keduanya merupakan dimer yang terikat pada membran mikrosomal • 4 domain • Domain Dimerization • Domain yang terikat Membran • Domain katalitik– beda pada struktur • Domain peptida Terminal– beda panjang
A. Physiological stimulus B. Inflammatory stimulus (tissue injury, chronic arthritis) macrophages/other cells clotting, parturition, gastrointestinal and renal protection COX-2 induced by cytokines (e.g., TNF) COX-1 constitutive Proteases Prostaglandins especially PGE2 Other inflammatory mediators (histamine, etc) Prostacyclin endothelium-anticlotting stomach mucosa: H+, HCO3-, mucus PGE2 Kidney: arteriolar dilation; Na+/H2O excretion TXA2 platelet aggregation PGF2 parturition Inflammation, redness, swelling, pain Figure 8. Actions of two known isoforms of cyclooxygenase (COX).
Classification 1. Non-steroidal Anti-inflammatory Agents 1.1 Non-selective COX-1 Inhibitors 1.2 Selective COX-2 Inhibitors 2. Antipyretic Analgesics
1. Anti-inflammatory Agents 1.1 Non-selective Cycloxygenase (COX) -1 Inhibitors 1.1.1 Salicylates 1.1.2 Arylalkanoic Acids 1.1.2.1 Aryl- and Heteroarylacetic Acids 1.1.2.2 Aryl- and Heteroarylpropionic Acids 1.1.3 N-Arylanthranilic Acids (Fenamic Acids) 1.1.4 Oxicams 1.1.5 Phenylpyrazolones 1.2 Selective COX-2 Inhibitors
General Structure of NSAIDs • Acidic functional group –COOH; • Membentuk ionic bond dengan arginine residue (120) dari COX • Aromatic ring / heteroaromatic ring (Acidicfunctional group); • hydrophobic interaction (vander waal force )dengan flat area enzim COX • lipophilic part/ alkyl chain pada aromatic ring • hydrophobic interaction melalui vander waal force
NH3+ Interaksi Indomethacin - COX CARBOXYL OR ACIDIC GROUP CATIONIC SITE (ARG 120) ARYL OR HETERORYL GROUP FLAT AREA ARYL OR ALKYL GROUP LYPOPHILIC GROUP INDOMETHACIN ARACHIDONIC ACID
Physicochemical and Pharmacokinetic Properties of NSAIDs • Strong organic acid; pKa ~ 3-5physiological pH (~7.4) • plasma protein binding (~90-99%)karena ionic bond drug interaction albumin-NSAIDs plasma protein binding • carboxylic group (-COOH) mengalami metabolize glucuronide conjugation (phase II)
Drugs (NSAIDs) Glucuronide Conjugation UDP-Glucuronosyl Transferase (UGT) + UDP Acyl-glucuronide metabolite
Aspirin or Acetylsalicylic Acid Tambahan acyl group pada molekul salicylic acid
Mechanism of action of Aspirin Serine residue acetylation COX-1 (Ser 530), COX-2 (Ser 516) or Circulating protein Irreverseble COX inhibition
Plasma esterase SALICYLURIC ACID Glycine Conjugation Aromatic hydroxylation Glucuronide Conjugation GENTISIC ACID Metabolism of Aspirin and Salicylates
Salsalate • Dimer Salicylic acid • Dihidrolisis menjadi 2 molekul salicylate • Efek samping GI bleeding
Diflunisal • phenyl group (or aromatic ring)pada molekul salicylic acid • Efek samping : GI disturbance, dermatologic reaction , CNS side effect (dizziness and headache)
1.1.2 Arylalkanoic Acids 1.1.2.1 Aryl- and Heteroarylacetic Acids 1.1.2.2 Aryl and Heteroarylpropionic Acids (“-profen”)
SAR 1-C ATOM ACIDITY , ACTIVITY ALKYL GROUP CARBOXYL GROUP ARYL OR HETERO ARYL GROUP ARYL OR ALKYL GROUP
1.1.2.1 Aryl- and Heteroarylacetic Acids • Indomethacin • Sulindac • Tolmetin (Sodium) • Diclofenac(Sodium) • Etodolac • Nabumetone
Indomethacin Indole ring P-Chlorobenzoyl
Metabolism of Indomethacin Serotonin (5HT)
Sulindac INDENE LIPOPHILIC BENZYLIDENE SULFINYL GROUP SOLUBILITY
Metabolism of Sulindac reduction ACTIVE SULFIDE METABOLITE
Tolmetin (Sodium) PYROLE RING
Metabolism of Tolmetin Glucuronide conjugation
Nabumetone NAPHTHALENE naproxen oxidation Nabumetone (pro-drug) 6-MNA (38%) (active metabolite)
1.1.2.2 Aryl- and Heteroarylpropionic Acids • Ibuprofen • Fenoprofen (Calcium) • Ketoprofen • Naproxen • Flurbiprofen • Ketorolac (Tromethamine) • Oxaprozin
Isomerization R-ENANTIOMER S-ENANTIOMER
IBUPROFEN • FLURBIPROFEN ISOBUTYL GROUP • NAPROXEN • CARPROFEN CARBAZOLE NAPHTHALENE
FENOPROFEN • KETOPROFEN KETONE PHENOLIC GROUP • OXAPROZIN
1.1.3 N-Arylanthranilic Acids (Fenamic Acids) Salicylic acid Anthranilic acid Bioisosteric group ของ -OH • Turunan Anthranilic acid merupakan modifikasi salicylic acid dengan bioisosteric replacement
Anthranilic Acid (Fenamic Acid) Anthranilic acid ring N-aryl ring Mefenamic Acid Meclofenamate (Sodium)
SAR OXICAM Enolic group; pKa ~ 4-6 R : aryl atau heteroaryl sybstituent R1–CH3 untuk optimum activity 4-hydroxy-1,2-benxothiazine carboxamides
2-pyridyl group 2-(5-methtyl)thiazolyl group Primary carboxamide Primary carboxamide Meloxicam Piroxicam
Meloxicam selective cox-2 inhibitor (by FDA approving)
Selective COX-2 Inhibitors Celecoxib Rofecoxib
Valdecoxib Parecoxib (IM) (pro-drug of Valdecoxib) Parecoxib Sodium (IV)