1. Oxybutynin hydrochloride is an antimuscarinic agent prescribed to patients with an overactive bladder (OAB) and symptoms of urinary urge incontinence. Oxybutynin undergoes pre-systemic metabolism, and the N-desethyloxybutynin (Oxy-DE), is reported to have similar anticholinergic effects.

2. We revisited the oxidative metabolic fate of oxybutynin by liquid chromatography–tandem mass spectrometry analysis of incubations with rat and human liver fractions, and by measuring plasma and urine samples collected after oral administration of oxybutynin in rats. This investigation highlighted that not only N-deethylation but also N-oxidation participates in the clearance of oxybutynin after oral administration.

3. A new metabolic scheme for oxybutynin was delineated, identifying three distinct oxidative metabolic pathways: N-deethylation (Oxy-DE) followed by the oxidation of the secondary amine function to form the hydroxylamine (Oxy-HA), N-oxidation (Oxy-NO) followed by rearrangement of the tertiary propargylamine N-oxide moiety (Oxy-EK), and hydroxylation on the cyclohexyl ring.

4. The functional activity of Oxy-EK was investigated on the muscarinic receptors (M_1-3) demonstrating its lack of antimuscarinic activity.

5. Despite the presence of the α,β-unsaturated function, Oxy-EK does not react with glutathione indicating that in the clearance of oxybutynin no reactive and potentially toxic metabolites were formed.

1.盐酸奥昔布宁是一种抗毒蕈碱药，适用于膀胱过度活动症（OAB）和尿急失禁症状的患者。奥昔布宁进行全身代谢，据报道，N-去乙基奥昔布宁（Oxy-DE）具有类似的抗胆碱作用。

2.我们通过液相色谱-串联质谱分析大鼠和人类肝脏的温育，并通过测量大鼠口服奥昔布宁后收集的血浆和尿液样品，重新研究了奥昔布宁的氧化代谢命运。该研究强调口服给药后，不仅N-脱乙基，而且N-氧化也参与了奥昔布宁的清除。

3.描绘了奥昔布宁的新代谢方案，确定了三种不同的氧化代谢途径：N-脱乙基化（Oxy-DE），然后氧化仲胺功能以形成羟胺（Oxy-HA），N-氧化（Oxy -NO），然后重排炔丙基胺N-氧化物部分（Oxy-EK），并在环己基环上羟基化。

4.研究了Oxy-EK对毒蕈碱受体（M _1-3）的功能活性，表明其缺乏抗毒蕈碱活性。

5.尽管存在α，β-不饱和功能，但是Oxy-EK不与谷胱甘肽反应，这表明在奥昔布宁的清除中没有形成反应性和潜在毒性的代谢产物。