Pseudoboehmite as a drug delivery system for acyclovir.

Herpes simplex virus is among the most prevalent sexually transmitted infections. Acyclovir is a potent, selective inhibitor of herpes viruses and it is indicated for the treatment and management of recurrent cold sores on the lips and face, genital herpes, among other diseases. The problem of the oral bioavailability of acyclovir is limited because of the low permeability across the gastrointestinal membrane. The use of nanoparticles of pseudoboehmite as a drug delivery system in vitro assays is a promising approach to further the permeability of acyclovir release. Here we report the synthesis of high purity pseudoboehmite from aluminium nitrate and ammonium hydroxide containing nanoparticles, using the sol-gel method, as a drug delivery system to improve the systemic bioavailability of acyclovir. The presence of pseudoboehmite nanoparticles were verified by infrared spectroscopy, transmission electron microscopy, and X-ray diffraction techniques. In vivo tests were performed with Wistar rats to compare the release of acyclovir, with and without the addition of pseudoboehmite. The administration of acyclovir with the addition of pseudoboehmite increased the drug content by 4.6 times in the plasma of Wistar rats after 4 h administration. We determined that the toxicity of pseudoboehmite is low up to 10 mg/mL, in gel and the dried pseudoboehmite nanoparticles.

Preparation and characterization of a polymeric blend of PVP/PVAL for use in drug delivery system.

The aim of the present study was the characterization of a polymeric blend composed of PVP/PVAL that can be used to obtain a biocompatible hydrogel, appropriate as a controlled drug release system. Polymeric blends could be the solution for the creation of new hydrogel, due to the improvement of individual polymer properties. The PVP and PVAL are used as a biocompatible hydrogel because they present high water absorption the main required characteristics for the formation of a hydrogel. This absorption is favored by the presence of the nitrogen of PVP and the hydroxyl of PVAL, and also by the formation of cross-links. Although the PVAL is a synthetic polymer, it is used as a basic material for different applications in biomedicine, once it is non toxic and also not carcinogenic. For this reason, PVP and PVAL were chosen combining the high flexibility of PVP with the mechanical resistance of PVAL, since it will able to form more resistant films. The characterization of the films obtained by mixing mechanically PVP and PVAL at different concentration was carried through several tests as spectroscopy in the infrared region (FTIR), differential scanning calorimetry (DSC) and tensile strength. Increasing the PVAL concentration increases the interaction between the polymers. This can be justified by the results obtained with the tensile test and with the spectrum obtained with the film which contain 0.9 g of PVAL and 0.1 g of PVP that shows the bonds between the polymers.