Pharmaceutical equivalent studies of some commercially available brands of Loratadine hydrochloride tablets.

BACKGROUND: This study was undertaken with the objective of evaluating the pharmaceutical and chemical equivalence of some commercially available loratadine tablets, and offers a possible explanation for the therapeutic failure of the drug products.

METHOD: The equivalence of eight brands of loratadine hydrochloride tablets labelled A to H was assessed and compared with the Innovator brand labelled I. Visual observation and uniformity of weight tests were carried out on the tablets, mechanical properties were assessed using friability and crushing strength tests as parameters. Release properties of the tablets were assessed by disintegration and dissolution tests. Assay was based on non-aqueous titration procedure using crystal violet solution indicator.

RESULT: All the brands studied were white in colour with different shapes and lustre, and complied with the official specification for uniformity of tablet weight. Friability tests showed that only brand G lost more than 1% of its initial weight, while brands A and E failed the crushing strength test. Brand C did not undergo complete disintegration within 15 minutes, while brands A, B, F and G had less than 70% of the active drug content still in solution after 45 minutes. Two of the brands had active drug content between officially specified range of 98.5% and 101.5% for loratadine tablets.

CONCLUSION: There was a large variation in the pharmaceutical properties of the commercially available loratadine hydrochloride tablets that were selected for this study. Six of the brands evaluated exhibited poor pharmaceutical properties. Generally, only two of the brands were pharmaceutically equivalent with the innovator brand.