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ROLE OF ADHESIVES IN TRANSDERMAL DRUG DELIVERY: A REVIEW

Transdermal drug delivery systems (TDDS) also commonly known as “patches” are dosage forms designed to deliver a therapeutically effective amount of drug across a patient’s skin. The therapeutic performance of a transdermal delivery system (TDS) can be affected by the quality of contact between the patch and the skin. The adhesion of the TDS to the skin is obtained by using pressure-sensitive adhesives (PSAs), which are defined as adhesives capable of bonding to surfaces with the application of light pressure. This article provides an overview of types of transdermal, the anatomical considerations and role of adhesion, the possible adhesion failure modes and how adhesion can be measured. Several in vitro techniques have been used to monitor adhesive performance such as peel adhesion, tack and shear strength. This article provides a frame work for further discussion and scientific work to improve transdermal adhesive performance. INTRODUCTION: Transdermal patches are innovative drug delivery systems intended for skin application to achieve a systemic effect. Among the different types of systems, the drug-in-adhesive products-in which the drug is included in the adhesive layer contacting the skinare commonly used. They also have the advantage of being thin and comfortable to wear. A transdermal patch is a medicated adhesive patch that is placed on the skin to deliver the medication through the skin to treat systemic conditions. The adhesive of the TDDS is critical to the safety, efficacy and quality of the product. To begin with, the therapeutic effect of the drug is linked to the adhesive performance of the TDDS. Reduction in the surface area of contact as a result of patch lift, or even the patch falling off, diminishes the delivery of drug from the patch. In other words, poor adhesion results in improper dosing of patients. Secondly, patches that fail to adhere for their prescribed time period must be replaced more often, thereby increasing the cost to the patient. Thirdly, lack of adhesion is a safety issue 1, . Transdermal Drug Delivery offers several important advantages like: 1. Transdermal medication delivers a steady infusion of a drug over an extended period of time. 2. Adverse effects or therapeutic failures frequently associated with intermittent dosing can be avoided.