PHARMACOKINETIC EVALUATION OF A CHRONOTHERAPEUTIC SYSTEM LOADED WITH AN ANTIASTHMATIC DRUG AS AN ORAL DRUG DELIVERY SYSTEM

Recent studies proved that the symptoms of bronchial asthma follow the circadian rhythms and become worse in the early morning. In such cases, conventional sustained-release treatment regimens are inappropriate for the delivery of antiasthmatic drugs as they cannot be administrated just prior to the worsening of the symptoms. The current work aimed to explore the pharmacokinetics of a model antiasthmatic drug following oral administration of a chronotherapeutic system in six healthy volunteers. A sensitive and selective chromatoghraphic method was used to determine drug concentration in human plasma. A standard calibration curve of the drug over the concentration range of 0.15 - 80 µg/ml was prepared in human plasma. Anhydrous caffeine was used as an internal standard. The protocol of the studies was approved by the Research Ethics Committee for clinical studies at Faculty of Pharmacy, Cairo University, Egypt. Following oral administration of the treatments, the pharmacokinetic parameters of the drug including C_max (µg/ml), T_max (h),  MRT_{(0– ∞)}, (h), AUC_0–24  (µg h/ml) and AUC_0–∞ (µg h/ml) were derived from the individual plasma concentration time curves. The data were statistically analyzed using two-way ANOVA at P < 0.05. The results confirmed that the drug reached C_max rapidly within two hours following a definite lag time; confirming the potential of the developed chronotherapeutic system in promoting the drug absorption at its site of action at the required time.