Nanoemulsion

Nanoemulsions appeared as a novel drug delivery system which allows controlled or sustained release of drug and biological active ingredients. Nanoemulsion is a dispersion consisting of oil, surfactant and an aqueous phase, which is an isotropically clear and thermo-dynamically or kinetically stable liquid solution, usually with droplet diameter within the range of 1-100 nm. This review gives the idea about the nanoemulsions system and provides brief information about the method of preparation and evaluation of nanoemulsion as well as various pharmaceutical applications of nanoemulsions in drug delivery including parenteral and pulmonary drug delivery, cosmetics, cancer therapy, vaccine delivery, formulations for improved oral delivery of poorly soluble drug and in cell culture technology.

Psoriasis is a prolonged, immune-mediated inflammatory skin disease. It is characterized by sharply demarcated, red, scaly, coin-sized skin lesions most often on the elbows, hands, knees, scalp and feet. Around 10% of individuals with psoriasis develop arthritis, which may affect the hands, feet, wrists, ankles, neck and lower back. In some cases joints become deformed, causing significant disability. The worldwide prevalence of psoriasis is around 2%, but studies in developed countries have reported higher incidence rates of on average about 4.6%.  In India the prevalence of psoriasis fluctuates from 0.44 to 2.8%, it is two times more common in males compared to females, and most of the patients are in their third or fourth decade at the time of presentation. Nearly two thirds of people with psoriasis have a mild form of the disease, Therefore in most of the cases first line treatment approach is topical. Betamethsone dipropionate (BD) loaded in omega-3- fatty acid fish oil nanoemulsion for the healthier absorption of BD in deeper layer of the skin to stop further progression of inflammatory cycle. For the preparation of nanoemulsion different types of preformulation studies require to perform because every drug has its specific intrinsic chemical and physical property which has been consider before development of pharmaceutical formulation. This property provides the framework for drug's combination with pharmaceutical ingredients in the fabrication of dosage form.

The present study attempted to evaluate acyclovir loaded PLGA nanoemulsions for ocular delivery. The acyclovir loaded PLGA nanoemulsions were prepared by spontaneous emulsification method. Five batches were prepared and labeled as NE-1, NE-2, NE-3, NE-4 and NE-5 by changing the concentration of PLGA polymer. The prepared nanoemulsions were subjected for its physico-chemical characterization, in-vitro diffusion, release kinetics and stability studies. FT-IR and DSC shown the drug and polymer were compatible with each other and no change in their chemical nature. The morphology of nanoemulsion shows spherical in shape with smooth surfaces. The particle size and zeta potential and Poly dispersity index were determined by malvern instrument and the results shown that the prepared nanoemulsion has significant ranges of particle size (164.67 - 244.43nm), zeta potential (-33.20 to -37.60) and poly dispersity index (0.256-0.499). Drug entrapment efficiency and % practical yield ranges between (54.97-79.67) and (46.83-58.01) respectively. The in-vitro % drug release of acyclovir indicates formulation NE-4 has significant sustained release compared with other formulations. The release kinetic data of all formulations are fitted with Higuchi’s model and non-fickian diffusion mechanism. The stability study indicates 5°C±3°C and 25°C±2°C/60%±5% RH is ideal storage condition for nanoemulsion for longer period. Thus it can be conclusively stated that the acyclovir loaded PLGA nanoemulsions may be considered as an improved ophthalmic drug delivery system for the treatment of ocular viral infections.