Tropical Journal of Pharmaceutical Research
Pharmacotherapy Group, Faculty of Pharmacy, University of Benin, Benin City, Nigeria
Vol. 14, No. 2, 2015, pp. 219-225
Bioline Code: pr15030
Full paper language: English
Document type: Research Article
Document available free of charge
Tropical Journal of Pharmaceutical Research, Vol. 14, No. 2, 2015, pp. 219-225
© Copyright 2015 - Tropical Journal of Pharmaceutical Research
Formulation and In vitro Dissolution Characteristics of Sustained-Release Matrix Tablets of Tizanidine Hydrochloride|
Murtaza, Ghulam; Ullah, Hanif; Khan, Shujaat Ali; Mir, Sadullah; Khan, Abida Kalsoom; Nasir, Bushra; Azhar, Saira & Abid, Mubashir Ali
Purpose: To formulate sustained-release (SR) matrix tablets of tizanidine hydrochloride (THC) and to
investigate the effect of matrix polymer type on drug release profile of drug.
Methods: Matrix tablets of THC were prepared by direct compression method using a combination of
hydroxypropylmethylcellulose (HPMC) and ethylcellulose (EC) in varying ratios. In all the formulations,
the amount of THC was 6.87 mg (equivalent to 6 mg base). USP type-I (basket) apparatus was used for
the dissolution study. The dissolution study was performed in 0.1M HCl for the first 2 h and in phosphate
buffer (pH 6.8) for another 10 h. The dissolution data were subjected to drug release models to
ascertain the kinetics of drug release. Additionally, in vitro swelling and buoyancy studies were carried
out on the optimized formulation. The optimized formulation was compared with a commercial reference
product using similarity factor (ƒ2) test.
Results: F4 formulation, containing 145 g of HPMC only, (with ƒ2 value of 67.38) was selected as
optimized formulation (compared to the reference commercial product), and it released 97.84 % of the
drug in 12 h. The release data showed best fit to first-order kinetics (R2 = 0.9963 - 0.9989), though nonsignificantly
(p > 0.05) different from the Higuchi model (R2 = 0.9813 - 0.9955) except for formulation F6.
Based on Koppcha model data, drug release mechanism involved both diffusion and erosion (n = 0.513
- 0.597) with diffusion being dominant. The optimized formulation exhibited 162 % swelling at the end of
11 h, after which no further weight gain occurred.
Conclusion: Suitable sustained-release tablets of tizanidine hydrochloride have been successfully
prepared using direct compression Drug release is sustained by increasing the content of the matrix
Tizanidine; HPMC; EC; Koppcha; Hixson-Crowell; Stokes-Einstein’s equation
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