In vitro- In vivo Correlation Studies of Modified Release Tolterodine Tablet Dosage form in Rabbits.

Tolterodine is an antimuscarnic drug that is used for sympathetic treatment of urinary incontinence. Tolterodine modified release tablet, was investigated in rabbit for pharmacokinetic and in vitro–in vivo correlation studies. Tablets were prepared and in vitro release was studied in simulated gastric fluid at 150RPMs. New Zealand albino male rabbits have been used as animal model for in vivo study. A sensitive and simple HPLC method was developed for the determination of Tolterodine content in rabbit plasma. In vitro release studies showed that release patterns followed zero order for around 24h. The in vivo–in vitro correlation coefficients obtained from point-to-point analysis were greater than 99% between concentrations at certain time points obtained from release study in simulated gastric fluid and HPLC analysis of rabbit’s plasma. From the in vitro–in vivo correlation prediction it was evident that the Tolterodine matrix assisted tablet is a good for controlled delivery of Tolterodine.

Quantification of desloratadine in human plasma by LC-ESI-MS/MS and application to a pharmacokinetic study / 药物分析学报

A simple,sensitive,and specific liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed for the quantification of desloratadine (DL) in human plasma using desloratadine-d5 (DLD5) as an internal standard (IS).Chromatographic separation was performed using an Xbridge C18 column (50 mm × 4.6 mm,5 μm) with an isocratic mobile phase composed of 10 mM ammonium formate:methanol (20∶80,v/v),at a flow rate of 0.7 mL/min.DL and DLD5 were detected with proton adducts at m/z 311.2→259.2 and 316.2→264.3 in multiple reaction monitoring (MRM)positive modes,respectively.Liquid-liquid extraction (LLE) method was used to extract the drug and the IS.The method was validated over a linear concentration range of 5.0-5000.0 pg/mL with a correlation coefficient of (r2)(≥)0.9994.This method demonstrated intra- and inter-day precision within 0.7-2.0％ and 0.7-2.7％,and an accuracy within 101.4-102.4％,and 99.5-104.8％.DL was found to be stable throughout the freeze-thaw cycles,bench-top,and postoperative stability studies.This method was successfully applied in the analysis of plasma samples following oral administration of DL (5 mg) in 35healthy Indian male human volunteers under fasting conditions.