d-oxybutynin

d-Oxybutynin (also known as d-OSAB or S-oxybutynin) is the (S)-enantiomer of the racemic muscarinic antagonist oxybutynin. It was developed by Sepracor as a potential treatment for overactive bladder (OAB) with the specific goal of improving the side-effect profile compared to the racemic mixture. Racemic oxybutynin is a potent anticholinergic that effectively reduces urinary urgency and frequency by blocking muscarinic receptors in the detrusor muscle; however, its use is often limited by systemic side effects, most notably severe dry mouth (xerostomia). While the (R)-enantiomer is the primary driver of anticholinergic activity at M1, M2, and M3 receptors, d-oxybutynin was hypothesized to provide therapeutic benefit with a reduced affinity for salivary gland receptors or a more favorable metabolic profile. Despite reaching Phase II/III clinical trials, the development of d-OSAB was terminated in 2001 after it failed to demonstrate a sufficient clinical advantage over existing OAB therapies.

Other names

S-oxybutynin(+)-oxybutynin