Comparative bioavailability studies of citric acid and malonic acid based aspirin effervescent tablets

PURPOSE: The present investigation is aimed at comparing the pharmacokinetic profile (Bioavailability) of aspirin in tablet formulations, which were prepared by using different effervescent excipients such as citric acid and malonic acid. MATERIALS AND METHODS: The relative bioavailability and pharmacokinetics of citric acid based aspirin effervescent tablet (Product A) and malonic acid based aspirin effervescent tablet (Product B) formulations were evaluated for an in-vitro dissolution study and in-vivo bioavailability study, in 10 normal healthy rabbits. The study utilized a randomized, crossover design with a one-week washout period between doses. Blood samples were collected at 0, 1, 2, 4, 6, 8, 12 and 24 hours following a 100 mg/kg dose. Plasma samples were assayed by High Performance Liquid Chromatography. T(max), C(max), AUC(0-24), AUC(0- ∞,) MRT, K(a,) and relative bioavailability were estimated using the traditional pharmacokinetic methods and were compared by using the paired t-test. RESULT: In the present study, Products A and B showed their T(max), C(max), AUC(0-24), AUC(0- ∞,) MRT, and K(a) values as 2.5 h, 2589 ± 54.79 ng/ml, 9623 ± 112.87 ng.h/ml, 9586 ± 126.22 ng.h/ml, 3.6 ± 0.10 h, and 0.3698 ± 0.003 h (-1) for Product A and 3.0 h, 2054 ± 55.79 ng/ml, 9637 ± 132.87 ng.h/ml, 9870 ± 129.22 ng.h/ml, 4.76 ± 0.10 h, and 0.3812 ± 0.002 h (-1) for Product B, respectively. CONCLUSION: The results of the paired t-test of pharmacokinetics data showed that there was no significant difference between Products A and B. From both the in vitro dissolution studies and in vivo bioavailability studies it was concluded that products A and B had similar bioavailability.