Prostaglandins - Synthesis and Drug Profile

SYNTHESIS AND DRUG PROFILE

i. Prostaglandin E₁ (PGE₁)

Synthesis

Dose: A dose of misoprostol, 2oo μg three times a day for acute duodenal ulcer and comparable with cimetidine.

ii. Prostaglandin D₂ [PGD₂]

Synthesis

PGF₂α

Synthesis

Metabolism: PGs are rapidly metabolized and inactivated by various oxidative and reductive pathways. The initial step involves rapid oxidation of the 15 α-OH group to the corresponding ketone by the PG-specific enzyme called PG 15 α-OH dehydrogenase. This is followed by a reduction of the C-13 and C-14 double bond by PG Δ¹³-reductase to the corresponding dihydroketone, which represent the major metabolite in plasma. Subsequently, enzymes normally involved in 13 and ω oxidation of fatty acids more slowly cleave the α-chain and oxidize the C-20 terminal methyl group to the carboxylic acid derivative, respectively.