Quantitative analysis of tiropramide in human blood by gas chromatography with nitrogen-phosphorus detector

Population Pharmacokinetic Analysis of Tiropramide in Healthy Korean Subjects

The purpose of this study was to perform population pharmacokinetic (PPK) analysis of tiropramide in healthy Korean subjects, as well as to investigate the possible effects of various covariates on pharmacokinetic (PK) parameters of tiropramide. Although tiropramide is commonly used in digestive system-related diseases as an antispasmodic, PPK reporting and factors affecting PKs are not clearly reported. Thus, this study for healthy subjects is very significant because it could find new covariates in patients that had not been reported before or predict PPK for patients in the clinic by establishing PPK in healthy adults. By using Phoenix NLME, PK, demographic, and genetic data (collected to explain PK diversity of tiropramide in population) analyses were performed. As a basic model, a one-compartment with first-order absorption and lag-time was established and extended to include covariates that influenced the inter-subject variability. The total protein significantly influenced the distribution volume and systemic clearance of tiropramide, but genetic factors such as ABCB1 (1236C>T, 2677G>T/A, and 3435C>T), CYP2D6 (*1 and *10), OCT2 (808G>T), and PEPT1 (1287G>C) genes did not show any significant association with PK parameters of tiropramide. The final PPK model of tiropramide was validated, and suggested that some of the PK diversity in the population could be explained. Herein, we first describe the establishment of the PPK model of tiropramide for healthy Korean subjects, which may be useful as a dosing algorithm for the diseased population.

A simple sample preparation with HPLC-UV method for estimation of tiropramide from plasma: application to bioequivalence study

A simple, rapid and selective method was developed for estimation of tiropramide from human plasma. The method involves extracting the tiropramide with n-hexane using diphenhydramine hydrochloride as internal standard. Chromatographic separation was carried out on a reversed phase C(18) column using mixture of water and acetonitrile as mobile phase with UV detection set at 230 nm. The retention time of internal standard and tiropramide were 5.6+/-0.2 and 8.3+/-0.3 min, respectively. The method was validated and found to be linear in the range of 10-200 ng/ml. The co-efficient of variation for intra-day and inter-day accuracy and precision was less than 12.8%. The mean recovery was found to be 89%. An open, randomized, two-treatment, two period, single dose crossover, bioequivalence study in 12 fasting, healthy, male, volunteers was conducted. After dosing, serial blood samples were collected for the period of 12 h. Various pharmacokinetic parameters including AUC(0-t), AUC(0-infinity), C(max), T(max), T(1/2), and elimination rate constant (K(el)) were determined from plasma concentration of both formulations. Log transformed values were compared by analysis of variance (ANOVA) followed by classical 90% confidence interval for C(max), AUC(0-t) and AUC(0-infinity) and was found to be within the range. These results indicated that the analytical method was linear, precise and accurate. Test and reference formulation were found to be bioequivalent.

Quantitative analysis of tiropramide in human plasma by gas chromatography coupled to mass spectrometry for application to a bioequivalence test

BACKGROUND

Tiropramide is used as an antispasmodic agent. A sensitive, selective and simple gas chromatography coupled to mass spectrometry (GC/MS) was developed for quantification of tiropramide in human plasma using internal standard (ISD, (+/-) alpha-benzoylamino-4-[2-(dimethylamino) ethoxy]-N,N-dipropylbenzenepropanamide).

METHODS

Tiropramide and ISD were extracted from plasma by solid-liquid extraction and analyzed on a HP-5MS column with mass selective detector.

RESULTS

The retention times of tiropramide and ISD were approximately 9.8 and 10.2 min, respectively. The calibration curve showed good linearity in the concentration range 5-500 ng/ml (r2=0.998) for tiropramide in human plasma and showed good precision with CVs between 0.24% and 7.69%, respectively. The method was showed good accuracy with all intra-day (n=5) and inter-day (n=5) mean concentrations within 87.9-114.1% from nominal. The recovery of tiropramide and ISD were about 75.1% and 71.0% on the average, respectively. This method was successfully applied for the bioequivalence test of 2 formulations of tiropramide in 18 healthy male volunteers who received a single 100 mg dose of each formulation.

Enantioseparation of tiropramide by HPLC

Tiropramide is an antispasmodic drug that has a chiral center. Resolution of tiropramide enantiomers on various kinds of chiral stationary phases was performed by HPLC. A good resolution on a leucine-derived chiral stationary phase was found. An improved chromatographic condition to resolve racemic tiropramide on the CSP was examined by changing the flow rate, composition, and kind of mobile phases.