Mahajan and Rasal: Microemulsions for Nasal Drug Delivery Systems: An Overview

Most drugs cannot be given orally because of significant degradation in the GIT or first pass metabolism in the liver. Nasal route for the delivery of some drugs offers an alternative in the pharmaceutical industry. The present review deals with the utility of the nasal route for the delivery of drugs to the brain as a microemulsion system in the treatment of a number of ailments like migraine, epilepsy, and hypertension. The nasal route could be important for drugs that are used in crisis treatments, such as for pain, and for centrally acting drugs where the pathway from nose to brain might provide a faster and more specific therapeutic effect. The purpose of the article is to provide an overview of the concept of microemulsion, selection of surfactant, co-surfactant, oils, formulation of microemulsion, phase diagram study, and evaluation of microemulsion. The review also focuses on the excipients available for formulation of microemulsions for nasal delivery and describes the investigations reported for the various classes of therapeutic agents. The interesting features of microemulsion such as spontaneity of formation, ease of manufacturing, high solubilization capacity and selfpreserving properties make them the vehicle of choice for nasal delivery.