Human skin penetration and distribution of nimesulide from hydrophilic gels containing nanocarriers.

The objective of this work was to study the in vitro skin penetration of a drug model (nimesulide) from semi-solid topical formulations containing nanospheres, nanocapsules or nanoemulsion. Nanoprecipitation, interfacial deposition and spontaneous emulsification methods were used to prepare the nanostructured suspension. The hydrodynamic diameters were 252nm for the nanoemulsion, 277nm for the nanocapsules and 202nm for the nanospheres containing nimesulide. The different nanocarrier systems were incorporated in the hydrophilic gels and their ability of delivering the drug into the human skin were investigated using stripping technique and Franz-type diffusion cells. The amount of nimesulide released into the stratum corneum (SC) from the gel containing nanocapsules (GNM-NC) and the gel containing nanospheres (GNM-NS) was similar. On the other hand, for the gel containing nanoemulsion (GNM-NE), the nimesulide was not quantified in SC, but it has been directly permeated for the dermis. The penetration of the nimesulide using the gel containing nanocapsules (GNM-NC) was larger in the deeper skin than using the gel containing nanospheres (GNM-NS) or the one containing nanoemulsion (GNM-NE). The gels containing nanocarriers (GNM-NC, GNM-NS and GNM-NE) were able to release the drug in the viable layer of the skin, comparing to a non-particulated nimesulide-loaded formulation at the same concentration.