Transdermal Drug Delivery System forAtomoxetine Hydrochloride – In vitro and Ex vivo Evaluation

Monolithic matrix type transdermal drug delivery systems (TDDS) of atomoxetine hydrochloride (A-HCl) were prepared by the film casting on a mercury substrate and characterized by physicochemical characteristics like thickness, weight variation, drug content, flatness, folding endurance and in vitro drug release studies, ex vivo skin permeation studies. Eight formulations (carrying Eudragit RL100 and Hydroxypropyl methyl cellulose 15 cps in the ratios of 8:2, 6:4, 4:6, 2:8 in formulations A-1, A-2, A-3, A-4 and Eudragit RS 100 and Hydroxypropyl methyl cellulose 15 cps in the same ratios in formulations B-1, B-2, B-3, B-4 respectively) were prepared. All formulations carried 20 mg of drug, A-HCl, 10% w/w of propylene glycol as penetration enhancer, 10% w/w of dibutyl phthalate as plasticizer in ethanol. The formulations exhibited uniform thickness, weight and good uniformity in drug content. The maximum drug release in 24 hrs for A-series formulations was 95.52% (A3) and for B-series, it was 89.55% (B-4). Again formulations A-3 (Kp = 3.53 X 10⁻² cm h⁻¹) and B-4 (Kp = 3.20 X 10⁻² cm h⁻¹) exhibited the best skin permeation potential in the respective series. On the basis of in vitro drug release and ex vivo skin permeation performance, formulation A-3 was found to be better than the other seven formulations. The results of the study show that A-HCl could be administered transdermally through the matrix type TDDS for effective control of attention-deficit/hyperactivity disorder (ADHD) in children, adolescents, and adults.