Formulation and evaluation of transdermal patches of duloxetine

Controlled drug delivery systems have generated considerable interest in the pharmaceutical industry due to their potential goals of achieving a continuous drug release profile with zero order kinetics, thus keeping the blood levels of drugs constant through the delivery period. Transdermal drug delivery systems are amongst the successful alternate delivery methods which deliver the drug through the skin, at a controlled rate to the systemic circulation. Duloxetine is a selective serotonin-norepinephrine reuptake inhibitor (SNRI) used in the treatment of depression, stress urinary incontinence and neuropathic pain. Development of transdermal patches of this drug can reduce the frequency of administration, increase its bioavailability, thereby increasing the patient compliance. Transdermal patches of duloxetine have been formulated by solvent evaporation technique. The conditions for the formulation of patches have been optimized in terms of the polymer type, concentration, penetration enhancers, etc. The formulated patches have been evaluated for their characteristic parameters like weight variation, content uniformity, moisture absorption, permeability characteristics, etc.