Development of Cutaneous Bioadhesive Ureasil-Polyether Hybrid Films

João Augusto Oshiro Junior,Leila Aparecida Chiavacci,Marlus Chorilli,Christiane Pienna Soares,Flávia Chiva Carvalho

doi:10.1155/2015/727324

João Augusto Oshiro Junior, Leila Aparecida Chiavacci + Show 3 more

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https://doi.org/10.1155/2015/727324

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Abstract

The hydrolysis and condensation reactions involved in synthesis of ureasil-polyether films influence the film formation time and the number of chemical groups able to form hydrogen bonds, responsible for the bioadhesion, with the biological substrate. The objective of this work was to study the influence of the use of an acid catalyst (hydrochloric acid) and a basic catalyst (ammonium fluoride) in the hydrolysis and condensation reactions on the time formation and bioadhesion of ureasil-polyether films. The toxicity of the films was evaluated. The MTT assay has shown cell viability of human skin keratinocytes higher than 70% of all analyzed materials suggesting low cytotoxicity. The bioadhesion of the films is strongly dependent on the viscosity and hydrophilic/hydrophobic balance of the polyether chains used to synthetize the hybrid molecules. The use of acid catalyst promotes the formation of less viscous films with higher bioadhesion. The hybrids formed by more hydrophilic PEO chains are more bioadherent, since they can interact more efficiently with the water present in the stratum corneum increasing the bioadhesion. Due to their low toxicity and high bioadhesion, the ureasil-PEO films obtained by using HCl as catalyst agent are good candidates for application to the skin as bioadhesive films.

Highlights

Several types of polymeric materials have been studied over the last decade, in order to form bioadhesive films for controlled release of drugs through the skin [1, 2]
Bioadhesive film formers can be used to control drug release and for this purpose the materials must have the following characteristics: (a) sufficient chemical groups capable of forming hydrogen bonds (OH and COOH, e.g.) to the biological substrate; (b) high molecular mass, which is related to the size of the polymer chain; (c) high flexibility of the polymer chain, because low flexibility leads to wrinkling of the film on the skin, decreasing its bioadhesiveness; and (d) suitable surface tension to induce the diffusion of the drug through the layer of epithelial tissue [6, 7]
The objective of this work was to control the hydrolysis and condensation reactions during the formation of biocompatible films composed of ureasil-PPO and ureasilPEO hybrid materials, with the aim of producing strongly bioadhesive systems to act as skin and wound protectors and potential drug delivery systems for dermal application

Summary

Introduction

Several types of polymeric materials have been studied over the last decade, in order to form bioadhesive films for controlled release of drugs through the skin [1, 2]. These devices can improve the bioavailability of drugs that suffer presystemic hepatic metabolism when administered orally and optimize the pharmacotherapy, since they can maintain the correct concentration in the plasma, not requiring multiple daily administrations [3]. A study involving materials based on polyethylene oxide demonstrated that functional groups such as COOH are strongly correlated with the bioadhesive process on the oral mucosa, since high moisture at the site favours the formation of hydrogen bonds between water and COOH groups, which increase

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