Tropical Journal of Pharmaceutical Research

Original Research Article | OPEN ACCESS

Formulation and pharmacokinetic evaluation of controlled-release oxybutynin tablets in dogs

Joonho Bae¹, Jin Woo Park²

¹Amorepacific Corporation R&D Center, 314-1, Bora-dong, Giheung-gu, Yongin-si, Gyeonggi-do, 446-729; ²College of Pharmacy and Natural Medicine Research Institute, Mokpo National University, 1666 Youngsan-ro, Muan-gun, Jeonnam 534-729, Republic of Korea.

For correspondence:- Jin Park Email: jwpark@mokpo.ac.kr Tel:+82-61-450-2704

Received: 27 September 2014 Accepted: 27 December 2014 Published: 31 March 2015

Citation: Bae J, Park JW. Formulation and pharmacokinetic evaluation of controlled-release oxybutynin tablets in dogs. Trop J Pharm Res 2015; 14(3):363-369 doi: 10.4314/tjpr.v14i3.2

© 2015 The authors.
This is an Open Access article that uses a funding model which does not charge readers or their institutions for access and distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0) and the Budapest Open Access Initiative (http://www.budapestopenaccessinitiative.org/read), which permit unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited..

Abstract

Purpose:To develop and optimize controlled-release (CR) oxybutynin chloride matrix tablets.

Methods:Oxybutynin CR tablets were prepared by embedding drug-containing granules into a hydrogel matrix of hydroxypropyl methylcellulose (HPMC). A coating layer was then applied with a mixture of HPMC, ethylcellulose, shellac, and HPMC phthalate. The effect of several formulation variables on in vitro drug release was studied; furthermore, the drug release kinetics of the optimized formulation was evaluated. The in vivo pharmacokinetics of the optimized formulation was compared with those of commercial immediate-release and CR tablets in dogs.

Results:The core tablets exhibited extended release consisting of drug release from the embedded granules through the erodible hydrogel matrix. Release rate was controlled by the amounts of swelling-control agent and hydrogel used. The optimized formulation followed zero-order release up to 24 h after an initial lag time. Maximum plasma drug concentration for the optimized and commercial CR tablets was 5.90 ± 1.42 and 6.47 ± 3.73 ng/mL, respectively, while the area under the plasma concentration–time curve was 101.40 ± 51.41 and 112.68 ± 65.89 ngW29;h/mL, respectively.

Conclusion:The formulated oxybutynin CR tablets exhibit prolonged drug release, thus rendering it a potentially suitable once-daily oral formulation for improved patient compliance.

Keywords: Oxybutynin, Matrix tablet, Hydrogel, Oral controlled-release, Zero-order release, Pharmacokinetics