Tropical Journal of Pharmaceutical Research

Original Research Article | OPEN ACCESS

Development and Evaluation of Controlled-Release Bilayer Tablets Containing Microencapsulated Tramadol and Acetaminophen

M A Naeem , A Mahmood, S A Khan, Z Shahiq

Faculty of Pharmacy & Alternative Medicine, The Islamia University of Bahawalpur, Punjab, Pakistan;

For correspondence:- M Naeem Email: mna19bwp@yahoo.com Tel:00923214527428

Received: 10 November 2009 Accepted: 10 May 2010 Published: 25 August 2010

Citation: Naeem MA, Mahmood A, Khan SA, Shahiq Z. Development and Evaluation of Controlled-Release Bilayer Tablets Containing Microencapsulated Tramadol and Acetaminophen. Trop J Pharm Res 2010; 9(4):347-354 doi: 10.4314/tjpr.v9i4.4

© 2010 The authors.
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Abstract

Purpose: To develop and characterize bilayer tablet formulations of tramadol HCl (TmH) and acetaminophen (AAP) microparticles.

Methods: Coacervation via temperature change was the encapsulated method used for the preparation of the microparticles, with ethyl cellulose (EC) of medium viscosity as the polymer for extending drug release. The microparticles of the two drugs were prepared separately and then compressed into bilayer tablets. The physicochemical compatibility and stability of the tablets were determined by Fourier transform infrared spectroscopy (FTIR), x-ray diffractometry (XRD), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) while their mechanism and pattern of drug release were assessed by applying Higuchi, Zero order, First order and Korsmeyer-Peppas kinetic models. Bilayer tablets were subjected to accelerated stability studies for three months.

Results: FTIR, XRD, DSC and TGA data for the formulations indicate good compatibility and stability. Furthermore, accelerated stability studies confirmed the stability of the formulations. Controlled drug release from the microparticles and bilayer tablets was observed for 8 h and 12 h, respectively. The Higuchi model produced the best fit, with regard to release profile, for both drugs, with correlation coefficient (R²) of 0.966 and 0.960 for AAP and TmH, respectively.

Conclusion: Microencapsulated TmH and AAP can be developed into suitable bilayer tablets that are stable and capable of releasing the drugs over 12 h.

Keywords: Acetaminophen; Tramadol; Ethyl cellulose; Microparticles; Bilayer tablets; Kinetic models