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In the present work, a solution blow spun nanofibrous mat comprised of chitosan (CS) and poly(ethylene oxide) (PEO) was obtained as vaginal platform for tenofovir disoproxil fumarate (TDF) to prevent sexually transmitted infections. Apart from physicochemical and mechanical analysis, the specific steps involved studies on nanofibrous mat mucoadhesive and swelling characteristics upon pH fluctuations over the physiological range. Physicochemical analysis showed uniform drug distribution within the CS/PEO mat volume and pointed toward physical interactions between the drug and polymers. TDF-loaded CS/PEO nanofibrous mat was shown potentially safe when evaluated by the MTT metabolic activity and JC-1 assays in human vaginal epithelial cells VK2-E6/E7. In vitro antiviral studies indicated inhibition efficacy of TDF-CS/PEO nanofibrous mat toward HSV-2 virus and proved the SBS process does not change the microbicidal activity of drug molecule. Fluctuations in the physiological vaginal pH range of 3.8 to 5.0 substantially affected mucoadhesive and swelling behavior of chitosan which in turn impacted drug dissolution rate from polymer carrier. The rate of permeation and accumulation of TDF in vaginal tissue differed in response to vaginal pH. Faster drug permeation assessed at pH 5.0 suggests that an increase in vaginal pH could improve TDF bioavailability at earlier time points. [ABSTRACT FROM AUTHOR]

• Formation of PECs aims to enhance chitosan stability. • Applicability of PECs with chitosan in skin and mucosal drug delivery was discussed. • Technological factors deeply affect chitosan – polyanion interactions. • Selection of optimal processing parameters is crucial for PECs formation. Chitosan, a biocompatible positively charged polysaccharide from natural origin, is regarded as a promising compound in medical and pharmaceutical technology. However, despitehigh application potential of chitosan, its susceptibility to the presence of ions, pH – dependent solubility, insufficient rheological properties or poor mechanical characteristics, can be a serious limitation in the technology of modified release drug carriers. To date, different strategies have been applied to overcome too rapid disintegration of chitosan carriers and to improve theirphysical properties. Among modifications of chitosan backbone, particular attention has been paid toward polyelectrolyte complexes spontaneously formed by mixing chitosan with oppositely charged polymers from both natural or synthetic origin under mild conditions. The aim of this review is to highlight the most recent advances and current applications of chitosan – based polyelectrolyte complexes as potential drug delivery systems and medical devices for local (skin and mucosal) application. Regarding the fact that pharmaceutical processing appears particularly important in proper polyelectrolyte complexes formation, this review covers the influence of selected technological factors on final polyelectrolyte complexes characteristics. The influence of a type of an applied polyanion on the polyelectrolyte complexes properties including swelling capacity, bio – and mucoadhesiveness or biological activity was also briefly described. [ABSTRACT FROM AUTHOR]