Bioequivalence assessment of two enteric-coated aspirin brands, Nu-Seals and Loprin, after a single oral dose of 150 mg in healthy male adults

AIM: The bioequivalence of aspirin from two enteric-coated brands, Nu-seals and Loprin, identified as the reference (R) and test (T) products, respectively, was assessed.

METHODS: A two-period randomised crossover design with a washout interval of 15 days was used in this study. The study results were determined in 16 healthy volunteers, all males with ages ranging from 19-28 (23.33 +/- 3.74) years and bodyweights of 52-92 (65.89 +/- 11.39) kg. After oral ingestion of 150mg of the either brand with 200 mL of water, serial blood samples were obtained over a period of 24 hours. Plasma, harvested from blood was analysed for the concentration of salicylic acid, a deacetylated metabolite of aspirin, by a validated high performance liquid chromatography (HPLC) method. Pharmacokinetic parameters were determined for both formulations by an interactive computer-assisted PK II procedure. A general linear model for repeated measures and 90% confidence intervals (CI) was employed to assess the sequence of treatment effects and to exclude differences between the parameters due to the product and period of administration, respectively.

RESULTS: The observed 90% CI ratios (Loprin/Nu-seals) for peak concentration, time to reach the peak and area under the plasma-concentration time curve from zero to infinity of 1.03,1.08; 1.04,1.05 and 1.01,1.15, respectively, were within the bioequivalence range (0.80,1.25) stipulated by the US Food and Drug Administration.

CONCLUSION: On the basis of the findings, the test (Loprin) and reference drug (Nu-seals) were deemed bioequivalent.