Microemulsions ocular drug delivery

Yandamme, T.F. 2002. Microemulsions as ocular drug delivery systems Recent developments and future challenges. Prog Retin Eye Res 21 15. 

Microemulsions can be classified into three different types depending on their microstructure oil-in-water (o/w ME), water-in-oil (w/o ME), and bicontinuous ME. They have been investigated by physical chemists since the 1940s but have only gained attention as potential ocular drug delivery carriers within the last two decades. 

Alany, R. G. (2001), Microemulsions as vehicles for ocular drug delivery Formulation, Physical-chemical characterisation and biological evaluation, Ph. D. thesis, University of Otago, Otago. 

Raid G. Alany, The University of Auckland, Auckland, New Zealand, Ocular Drug Delivery Microemulsions as Drug Delivery Systems... 

Chan, J., Maghraby, G., Craig, J.P. and Alany, R.G. (2007) Phase transition water-in-oil microemulsions as ocular drug delivery systems In vitro and in vivo evaluation. Int. J. Pharm., 328, 65-71. 

The production of microemulsions is comparatively simple and cost-effective, and thus, they have attracted a great interest as drug-delivery vehicles. Microemulsions have the capability of transporting lipophilic substances through an aqueous medium, and can also carry hydrophilic substances across lipoidal medium. Based on this attribute, potential of microemulsions has been explored for oral, transdermal, parenteral, topical, and pulmonary administration of lipophilic and hydrophilic drugs. In the last decade, microemulsions have also been explored for their potential as vehicles for topical ocular drug delivery."- ... 

Lv FF, Zheng LQ, and Tung CH. (2005). Phase behavior of the microemulsions and the stability of the chloramphenicol in the microemulsion-based ocular drug delivery system. International Journal of Pharmaceuticals, 301, 237-246. 

The synthesis of polyacrylic acid nanoparticles from inverse microemulsions has also been described in the literature. Polyacrylic acid is a well-known bioadhesive agent. Hence, polyacrylic acid nanoparticles loaded with the drug would have enhanced bioavailability and controlled release characteristics. The synthesis of timolol maleate and bri-monidine nanoparticles for improved ocular and oral delivery has been reported [153, 154]. 

Oil-in-water microemulsion has been widely studied and used for transdermal delivery of the drugs. Apart from its advantages as topical formulation, oil-in-water emulsion also offers numerous advantages such as bioavailability enhancement via transdermal, oral, ocular, and vaginal routes. 

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