In last decades, the study of inorganic and colloidal particles such as nanocapsules, nanospheres, nanostructured lipid carrier, etc. has been focused as dermal/transdermal drug delivery carriers. If compared with the traditional oral administration route, transdermal delivery shows additional advantages: it minimizes the first-pass metabolism, it avoids drug degradation under the extreme acidity of the stomach, it prevents erratic delivery due to food interactions, and it provides more controlled delivery. In the present study topical gel of carbopol containing biodegradable nanocarriers was prepared and evaluate on the basis of drug content, effect of neutralizing agents, pH, viscosity and in-vivo permeation study. The result shows that electrostatic repulsion plays a critical role in forming a gel, its viscosity and gel strength depending on pH. The amount and type of neutralizing agent used affects the viscosity of the formulation significantly.
