Microemulsions transdermal/dermal delivery

The number of studies reported on the utility of the micro emulsions is the highest for dermal delivery. Numerous studies are reported in the literature which establish the utility of the microemulsions to improve the transdermal delivery of APIs. However, only some important examples will be discussed in this chapter. 

The cosmetics and transdermal drug delivery fields are also expected to further benefit from the formulation of microemulsions from mild sugarbased surfactants. Lehmann et al. have studied the effect of such a microemulsion on dermal and corneal irritation, and hydrocortisone incorporation [105]. A microemulsion containing commercially available sucrose esters, isopropyl myristate, and propylene glycol and water was prepared as a water continuous system, and 16.5% hydrocortisone was loaded into the anhydrous base mixture. The formulation spread well on the skin due to the low surface tension of the system at 26 mN/m. While the microemulsion provided greater drug penetration, it also resulted in irritation and barrier compromise. The authors make the point that the formulation may be better suited to drugs that do not induce an irritation themselves. 

In addition to traditional dermal and transdermal delivery formulations, such as creams, ointments, gels, and patches, several other systems have been evaluated. In the pharmaceutical semisolid and liquid formulation area,these include sprays, foams, multiple emulsions, microemulsions, liposomal formulations, transfersomes, niosomes, ethosomes, cyclodextrins, glycospheres, dermal membrane structures, and microsponges. Many of these novel systems use vesicles to modulate drug delivery. Novel transdermal... 

Microemulsions as smart dermal/transdermal delivery vehicles... 

Microemulsions have gained a considerable interest in deep dermal and transdermal delivery of an array of therapeutic agents. The local anesthetic, Lidocaine, has reached commercialization for delivery (94). 

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