THE PHARMACOKINETICS AND RELATIVE BIOAVAILABILITY OF A SUSTAINED-RELEASE PREPARATION OF ALBUTEROL SULFATE

AIM　To study the pharmacokinetics and relative bioavailability of a sustained-release capsule (SRC) of albuterol in 20 healthy male volunteers in a randomized 2-way cross-over study by taking a controlled-release tablet (CRT) of albuterol as reference preparation. METHODS　A simple and sensitive HPLC method with UV-detection was developed to determine the plasma albuterol concentration and the pharmacokinetic parameters of the two formulations. Two one-sided tests and analysis of variance were performed to evaluate the bioequivalence of the two formulations. RESULTS　After a single oral dose in healthy volunteers, the C_max, T_max and AUC were of no significant difference between SRC and CRT (P>0.05). The relative bioavailability of SRC was found to be 98.98％. Following multiple dosing, the mean steady state C^ss_max values were (12.94±3.35) ng.mL^-1 and (12.60±3.36) ng.mL^-1, mean C^ss_min values were (5.84±1.34) ng.mL^-1 and (6.16±1.33) ng.mL^-1, degrees of fluctuation (DF) were 0.82 and 0.76 for SRC and CRT, respectively. No significant difference was found between them. CONCLUSION　The two preparations were bioequivalent and the new sustained-release capsule exhibited good sustained-release property as the reference.