Arbaclofen placarbil, a novel R-baclofen prodrug: improved absorption, distribution, metabolism, and elimination properties compared with R-baclofen.
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Lal R, Sukbuntherng J, Tai EH, Upadhyay S, Yao F, Warren MS, Luo W, Bu L, Nguyen S, Zamora J, Peng G, Dias T, Bao Y, Ludwikow M, Phan T, Scheuerman RA, Yan H, Gao M, Wu QQ, Annamalai T, Raillard SP, Koller K, Gallop MA, Cundy KC
Arbaclofen placarbil, a novel R-baclofen prodrug: improved absorption, distribution, metabolism, and elimination properties compared with R-baclofen.
J Pharmacol Exp Ther. 2009 Sep;330(3):911-21. doi: 10.1124/jpet.108.149773. Epub 2009 Jun 5.
- PubMed ID
- 19502531 [ View in PubMed]
- Abstract
Baclofen is a racemic GABA(B) receptor agonist that has a number of significant pharmacokinetic limitations, including a narrow window of absorption in the upper small intestine and rapid clearance from the blood. Arbaclofen placarbil is a novel transported prodrug of the pharmacologically active R-isomer of baclofen designed to be absorbed throughout the intestine by both passive and active mechanisms via the monocarboxylate type 1 transporter. Arbaclofen placarbil is rapidly converted to R-baclofen in human and animal tissues in vitro. This conversion seems to be primarily catalyzed in human tissues by human carboxylesterase-2, a major carboxylesterase expressed at high levels in various tissues including human intestinal cells. Arbaclofen placarbil was efficiently absorbed and rapidly converted to R-baclofen after oral dosing in rats, dogs, and monkeys. Exposure to R-baclofen was proportional to arbaclofen placarbil dose, whereas exposure to intact prodrug was low. Arbaclofen placarbil demonstrated enhanced colonic absorption, i.e., 5-fold higher R-baclofen exposure in rats and 12-fold higher in monkeys compared with intracolonic administration of R-baclofen. Sustained release formulations of arbaclofen placarbil demonstrated sustained R-baclofen exposure in dogs with bioavailability up to 68%. In clinical use, arbaclofen placarbil may improve the treatment of patients with gastroesophageal reflux disease, spasticity, and numerous other conditions by prolonging exposure and decreasing the fluctuations in plasma levels of R-baclofen.
DrugBank Data that Cites this Article
- Drugs
- Drug Transporters
Drug Transporter Kind Organism Pharmacological Action Actions Arbaclofen Placarbil Monocarboxylate transporter 1 Protein Humans UnknownSubstrateDetails