Abstract
Optimum therapeutic outcomes requires not only proper drug selection but also effective delivery of drug. Over the past three decades, controlled drug delivery has become increasingly important in the pharmaceutical industry. The pharmacological response, i.e desired therapeutic and undesired therapeutic effect of a drug depends on concentration of drug reached to its site of action and in turn depends on dosage form. With conventional drug delivery systems, poor patient compliance is a major problem observed in clinical practice. Human skin is a readily accessible surface of drug delivery. The potential of using skin as a target has been recognized but its outermost layer acts as a barrier to the ingress of materials allowing only small molecules to penetrate over a period of time. Recently various strategies has been used to evade the stratum corneum and to increase flux through the skin membrane using different permeation enhancement techniques. For a drug to be delivered passively via skin needs to have enough lipophilicity and also a molecular weight less than 500 Da. These requirements have restricted the number of commercially available commodities based on transdermal or dermal delivery. Therefore the key function of a topical delivery system is to enhance the dermal permeability enabling it to cross the epidermis and retain in the dermis. The aim of this paper is to review non-invasive topical drug delivery employing sophisticated carrier systems leading to advancements in dosage forms.
