A pharmacokinetic and bioequivalence study of Contiflo ICON 400 µg tablets in healthy Indian subjects.

INTRODUCTION

Tamsulosin, an alpha1 adrenoceptor blocking agent, exhibits selectivity for alpha1 receptors in human prostate. Blockade of these adrenoceptors can cause smooth muscles in the bladder neck and prostate to relax, resulting in an improvement in urine flow rate and a reduction in symptoms of benign prostatic hypertrophy. A new formulation Contiflo ICON 400 µg has been developed by Ranbaxy Laboratories Limited, India similar to Flomaxtra XL 400 µg of Astellas Pharma Limited, United Kingdom. This product is specifically designed to achieve a more consistent plasma concentration over a period of 24-h, a lower maximum plasma concentration (Cmax) and an independence of pharmacokinetics (PKs) on food intake.

METHODS

The objective of the present study was to evaluate the pharmacokinetics and bioequivalence of the new formulation Contiflo ICON 400 µg of Ranbaxy Laboratories Limited, India and Flomaxtra XL 400 µg prolonged release tablets (containing tamsulosin hydrochloride prolonged release 400 µg) of Astellas Pharma Limited, United Kingdom. Study was conducted as an open label, balanced, randomized, two-treatment, two-period, two-sequence, cross over, single-dose bioequivalence study in 32 adult male human subjects under fed conditions. The mean (range) age, weight and height of the study subjects were 27.03 years (19 - 40 years), 57.19 kg (48 - 72 kg) and 166.81 cm (154 - 181 cm) respectively. Blood samples were collected at pre-dose and at 0.5, 1, 2, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 8, 9, 10, 12, 16, 20, 24, 36, 48, 72, and 96 h post dose in each period. Plasma samples were analyzed for tamsulosin by using validated liquid chromatographic mass spectrometry (LC-MS/MS) method.

RESULTS

The Mean ± SD of pharmacokinetic parameters tmax, Cmax, AUC24, AUClast and AUCinf for Tamsulosin were 11.741 ± 4.7201 and 12.155 ± 6.3077 h, 10.7614 ± 4.76709 and 10.4954 ± 5.08979 ng/ml, 171.4674 ± 77.39695 and 160.6738 ± 77.98628 ng.h/ml, 262.7771 ± 150.21432 and 250.6854 ± 156.75581 ng.h/ml, 280.0702 ± 152.14253 and 273.5078 ± 156.85910 ng.h/ml for test and reference formulations respectively. The ratios of least square means and the 90% confidence interval of log transformed pharmacokinetic parameter Cmax, AUC24, AUClast and AUCinf were within 80 - 125% acceptance range.

CONCLUSION

In conclusion, Contiflo ICON 400 µg tablets developed by Ranbaxy Laboratories Limited is bioequivalent to the reference formulation in healthy adult male volunteers under fed condition.