Application of Similarity Factor in Development of Controlled-Release Diltiazem Tablet

Abstract

Controlled-release grade hydroxypropylmethylcellulose (HPMC) or xanthan gum (XG) and microcrystalline cellulose (MCC) were employed to prepare controlled-release diltiazem hydrochloride tablets. The similarity factor f₂ was used for dissolution profile comparison using Herbesser 90 SR as a reference product. Drug release could be sustained in a predictable manner by modifying the content of HPMC or XG. Moreover, the drug release profiles of tablets prepared using these matrix materials were not affected by pH and agitation rate. The f₂ values showed that only one batch of tablets (of diltiazem HCl, HPMC or XG, and MCC in proportions of 3.0:3.0:4.0) was considered similar to that of the reference product, with values above 50. The unbiased similarity factor f*₂ values were not much different from the f₂ values, ascribing to a small dissolution variance of the test and reference products. The amount of HPMC or XG incorporated to produce tablets with the desired dissolution profile could be determined from the curves of f₂ versus polymer content. Hence, the f₂ values can be applied as screening and optimization tools during development of controlled-release preparations.

Key Words:

• Controlled-release diltiazem tablet
• Hydroxypropylmethylcellulose
• Similarity factor
• Xanthan gum