Studies on Absolute Bioavailability of Micronized Domperidone Maleate in Dogs

Objective: To evaluate pharmacokinetics and absolute bioavailability of micronized domperidone maleate. Methods: A paired, crossover design was used. 12 dogs were randomly divided into two groups. Group one received the micronized domperidone maleate injection and followed by the membrane tablet and another group was given the membrane tablet and then the injection. Blood samples of two groups were collected at different time spots. Plasma concentration of domperidone maleate was measured by HPLC-FID. The pharmacokinetic parameters were measured by 3p97 program and the absolute bioavailability was calculated. Results: The time-concentration relationship of micronized domperidone maleate in dogs conforms to two compartment model. The major pharmacokinetic parameters of the injection were as follows: t_ 1/2β=14.22 min,CL=16.84 mL/(h·kg),C_ max=25.47 μg/L,t_ max=34.23 min and AUC_ 0→∞= 328?129 μg/(L·min). This analytical method is accurate and sensitive. The absolute bioavailability of micronized domperidone maleate is 40.43%. Conclusions: The absolute bioavailability of micronized domperidone maleate might be better than that of the general domperidone.