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Ting-Ting Yang [1] and Yuan-Zheng Cheng [1] and Meng Qin [1] and Yong-Hong Wang [1] and Hong-Li Yu [1] and An-Lin Wang [2] and Wei-Fen Zhang [1]

Academic Editor: Viness Pillay

1, School of Pharmacy, Weifang Medical University, Weifang, Shandong 261031, China, wfmc.edu.cn

2, Life Science and Technology Department, Pharmaceutical University, Nanjing, Jiangsu 211198, China, cpu.edu.cn

Received May 22, 2017; Revised Aug 30, 2017; Accepted Sep 24, 2017

This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

1. Introduction

Vaginal delivery has advantages such as facility of drug application, high contact surface area, high blood supply, and avoidance of first-pass metabolism as a suitable route for systemic and topical drug delivery of antifungals, antibacterials, antivirals, and spermicidal agents [1, 2]. However, vaginal conventional dosage forms, including suppositories, lotions, pellicles, tables, gels, and irrigations, remain for only a short time and have uneven dispersion at the application site due to the physiological removal mechanisms of the vaginal lumen [3].

Thermosensitive hydrogels, intelligent materials endowed with a sol-gel phase transition in response to changes of temperature, have increasingly received considerable attention for local drug delivery based on many advantages including site-specificity, sustained-release behavior, simple drug formulation and administration, and improved safety [4]. The hydrogels are usually made from thermosensitive polymers such as poly(N-isopropylacrylamide) [5], polyethylene glycol [6], and chitosan (CTS) and its derivatives [7, 8].

CTS has a great deal of biomedical and pharmaceutical applications because of its distinctive characteristics such as biocompatibility, biodegradability, nontoxicity, and nonimmunogenicity [9–12]. Meanwhile, the degraded products of CTS are also nontoxic, nonimmunogenic, and noncarcinogenic [13]. CTS can allow better contact with the vaginal surface due to its mucoadhesive property [14]. CTS becomes thermoresponsive upon addition of α,β-glycerophosphate (GP), and the thermosensitive hydrogel (CTS-GP) has been reported by numerous literatures [8]. However, burst release of loaded drugs is becoming a critical challenge when the CTS-based hydrogels are employed as drug delivery systems [15]. To address this challenge, CTS-GP hydrogels containing drug-loaded microspheres (MS, MS-CTS-GP) begin to attract the attention [16]. CTS-GP-MS can localize the MS around the administrating target because the hydrogel can transform itself into semisolid gel...
   
   
   
   
   
   

  

    

 

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