Pharmacokinetics and bioequivalence of mesalamine suppository in healthy volunteers

Objective To study the pharmacokinetics and bioequivalence of mesalamine (5-ASA) and its active metabolite acetyl mesalamine (Ac-5-ASA) of imported mesalamine suppository in healthy volunteers. Methods A single rectal dose 2 g of tested mesalazine suppository and referenced mesalmine suppository were given to 18 healthy volunteers in a randomized cross-over. The plasma concentrations of unaltered 5-ASA and its active metabolite Ac-5-ASA were determined by pre-column derivation HPLC method. The pharmacokinetic parameters and relative bioavailability were measured. Results The main pharmacokinetic parameters of 5-ASA were as follow: AUC0-1 were 3.20 ±2.35 and 3.34±2.83 μg·h·mL-1AUC0-8 were 3.22±37 and 3.38±2.83 μg·h·mL-1; Cmax were 0.48±0.16 and 0.42±0.17 μg-mL-1; tmax were 4.61±2.8 and 5.72±3.30 h; t1/2were3.66±1.44 and 3.97±2.24 h for test and reference masalamine, respectively. The main pharmacokinetic parameters of Ac-5-ASA were as follow: AUC0-1were 9.68± 6.26 and 10.26 ±7.53 μg·h·mL-1; AUC0-8 were 10.01±6.79 and 10.74±8.57 μg·h·mL-1;Cmaxwere 1.23±0.41 and 1.10 ±0.37 μg·mL-1;tmaxwere 5.00± 2.20 and 6.11 ±3.48 h; t1/2 were 5.99±3.33 and 6.64 ± 4.22 h for test and reference, respectively. The relative bioavailability of test mesalamine suppository was (103.7 ±19.4)%. Conlusions The results of statistics analysis demonstrated that two suppository were bioequivalent.