Development of a new methodology for dissolving tablets containing diltiazem hydrochloride marketed in Brazil using design of experiment

Diltiazem hydrochloride (DH) is a calcium channel blocker used to modify or restore normal heart rhythm in cardiovascular diseases. The aim of this study was to develop and validate a new innovative method using UV molecular absorption spectrophotometry to evaluate the in vitro dissolution of DH using a factorial design of experiments. Physical and physicochemical tests were performed. The dissolution profiles of DH tablets (30 and 60 mg) available as the reference, generic and similar drugs were compared. The dissolution test was used to obtain and compare dissolution profiles and to determine the similarity of pharmaceutical formulations (USP type 2 apparatus at 75 rpm, with 750 mL of water at 37.0 ± 0.5 oC for 120 minutes). Only samples G30 and G60 showed compliance with the parameters established by the Brazilian Pharmacopoeia in all tests. Drug dissolution percentages are in accordance with the Brazilian and American Pharmacopoeias (>75% dissolution in 180 minutes). Using the proposed new method, it was observed that > 80% of DH was released in approximately 60 minutes. The proposed method was found to be sensitive, rapid and efficient for the quality control of DH tablets.