Journal of Bioequivalence & Bioavailability

Abstract

Enhanced Bioavailability of Fenoterol Transdermal Systems in Rabbits

Ahmed Elshafeey, Y.E. Hamza, S.Y. Amin, F. Akhlaghi and H. Zia

The pharmacokinetic and bioavailability of fenoterol, a B 2 adrenergic agonist were studied to determine the feasibility of enhanced transdermal delivery. Fenoterol has been widely used to treat asthmatic patients. Two fenoterol formulations were studied; the first was a liquid formulation of fenoterol in Transcutol: Oleic acid in a ratio 1:1(F1), while the second was a matrix system of fenoterol in Duro-tak ® 87-2074 adhesive with 10% 1-dodecyl-2- pyrrolidinone as an enhancer (F2). For comparison, control matrix with fenoterol without any enhancer (F3) was also tested. The tested formulations were applied to the shaved back skin of rabbits using HILL TOP CHAMBER ® in case of liquid formula. Blood samples were collected via auricle central vein for 24 hours and the plasma concentrations of fenoterol were determined by LC-MS/MS method. Pharmacokinetic parameters were calculated using the WinNonlin computer program. The results showed a maximum concentration of fenoterol in plasma of 514.8 ng/ml after application of the liquid formula while its AUC 0-∞ amounted to be 485972(ng*min/ml) with a dose of 3mg/kg. The transdermal matrix prepared with 10% 1-dodecyl-2-pyrollidinone had a C max of 219 ng/ml and AUC 0-∞ was 124636 (ng*min/ml) which is significantly higher than that obtained after application of the control patch without any enhancer. Therefore, the transdermal systems will offer an efficient drug delivery system for the treatment of bronchial asthma.