Development and Physicochemical, In Vitro and In Vivo Evaluation of Transdermal Patches of Zaleplon

The aim of the present work was to develop and evaluate matrix type transdermal therapeutic system of zaleplon (ZLP) with different ratios of hydrophilic and hydrophobic polymeric combinations. Formulations A1, A2, A3 were composed of Eudragit RL100 (ERL) and hydroxypropyl methyl cellulose (HPMC) in 1:3, 1:1, 3:1 ratios; A4, A5, A6 were composed of Eudragit RS100 (ERS) and hydroxypropyl methyl cellulose in 1:3, 1:1, 3:1 ratios. All the six formulations carried 10mg of ZLP/patch area, 6% v/w of d-limonene, 15% v/w of propyleneglycol in methanol:dichloromethane (1:1). The physicochemical compatibility of the drug and the polymers was studied by infrared spectroscopy and differential scanning calorimetry. All the prepared formulations were subjected to physicochemical studies, in vitro release, ex vivo permeation studies through rat skin, skin irritation, stability and in vivo evaluation. The optimized formulation, A1 was found free of skin irritation and stable at accelerated stability conditions for 3 months. Locomotor activity and rotarod methods were used to study the in vivo performance. The administration of ZLP through patch resulted in sustained and continued action for 24h. Hence, it was concluded that ZLP can be formulated into the transdermal matrix type patch to sustain its release characteristics