Development and validation of an improved HPLC-MS/MS method for comparative pharmacokinetics of penehyclidine hydrochloride following a single intravenous or intramuscular injection

Penehyclidine hydrochloride (PHC) is an anticholinergic drug with both antimuscarinic and antinicotinic activity. In order to compare the pharmacokinetics of two administration routes (intravenous injection (i.v.) and intramuscular injection (i.m.)) of PHC, an improved High Performance Liquid Chromatography Tandem Mass Spectrometry (HPLC-MS/MS) bioanalytical method was developed for the quantification of PHC in plasma and urine using verapamil as the internal standard (I.S.). Chromatography was performed using a Thermo Hypersil GOLD column (30 mm x 2.1 mm, 3 mu.m), with a gradient elution of 1 parts per thousand. formic acid-10 mmol/L ammonium acetate and acetonitrile at 0.3 mL/min. Detection and quantitation were performed by electrospray ionization (ESI) and multiple reaction monitoring (MRM) in the positive ion mode. The most intense [M + H](+) MRM transition of PHC at m/z 316.2 -> 128.3 was used for PHC quantitation, and the transition at m/z 454.6 -> 303.2 was used to monitor I.S. The lower limit of quantification (LLOQ) was 0.05 ng/mL. The intraday precision was <6.71% and the interday precision was <11.69%. The pharmacokinetic parameters of i.v. and i.m. administration routes were as follows (i.v. vs i.m.): t(1/2) 15.73 vs 17.24h, T-max 0.06 vs 0.26 h, AUC(0-t) 69.35 vs 67.90 h ng/mL, AUC(0-inf) 78.24 vs 79.67 h ng/mL, C-max 37.5 vs 9.1 ng/mL, Ae(0-24h) 22.7 vs 25.21 mu g. There were no significant differences between parameters t(1/2) and AUC (P > 0.05), but significant differences were observed in C-max, T-max and Ae(0-24h) between the two administration routes (P < 0.05). The mean absolute bioavailability of the i.m. administration route was 98.4% (95% confidence interval, 93.4-103.6%). Safety results showed that PHC appeared to be well tolerated in both i.v. and i.m. administration routes and pharmacokinetic results showed that PHC was nearly completely absorbed via i.m. administration route. (C) 2015 Elsevier B.V. All rights reserved.