Hydrogel microspheres based on Bletilla striata polysaccharide as a promising cervical positioning drug delivery system

• Published in: Journal of drug delivery science and technology Vol. 95; p. 105525
• Main Authors: Li, Wei-Ze, Han, Wen-Xia, Guan, Li, Chen, Cheng, Zhao, Ning, Liang, Fei, Guo, Wei, Fu, Li-Na, Yang, Li-Bin
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.05.2024
• Subjects: Bletilla striata polysaccharide; Cervical positioning; Drug delivery system; Hydrogel microspheres; Local treatment; Mucoadhesion; Spreadability; Mucoadhesion; Cervical positioning; Bletilla striata polysaccharide; Drug delivery system; Hydrogel microspheres; Spreadability; Local treatment
• ISSN: 1773-2247
• DOI: 10.1016/j.jddst.2024.105525

Due to female cervical mucosa is smooth and covered with a mucous layer, so the spreadability and mucoadhesion are crucial for the development of cervical positioning drug delivery system (CPDDS). In this work, the natural polymer Bletilla striata polysaccharide (BSP) as a hydrogel matrix-forming material was used for the preparing of hydrogel microspheres (HMs) by an improved emulsion crosslinking method. The prepared HMs have a spherical or quasi-spherical shape with a size of 115 ± 27 μm, resulting a good fluidity for spreading well at the administration site. By the physical entanglements of hydrophilic polymer chains of BSP, the matrix of HMs presents a microporous structure. With microporous matrix, the HMs could absorb water from mucous layer and achieve an optimum hydration required for mucoadhesion when they contact the cervical mucosa, also could keep their mucoadhesion behavior and morphology for a long time even after absorbing more water. As a result, the cervical positioning drug release behavior and long retention time at the cervical mucosa obtained. The loaded drug release profile of HMs include a low initial burst release and subsequent a longer sustained release, this is beneficial for the local treatment of cervical diseases. Owing to the BSP is a natural biodegradable polymer, the HMs have better biocompatibility with mucosal tissues and without causing irritation. In conclusion, this work suggest that the HMs based on BSP polymer is a promising CPDDS for clinical applications. The cervical cancer has become one of the important causes of death for women, and the cervicitis and cervical erosion are the risk factors of cervical cancer. The local treatment is an effective remedy for the cervical diseases, however, the cervix is located deeply in the vagina, and the cervical mucosal surface is smooth and covered with a mucus layer which as the potential diffusion barrier for the drug delivering and absorption. Thus, it is very difficult for conventional carriers to deliver medications to cervical mucosa effectively. In order to develop a novel cervical positioning drug delivery system (CPDDS), the natural polymer Bletilla striata polysaccharide (BSP) as a hydrogel matrix-forming material was used for preparing the hydrogel microspheres (HMs), which combining the advantages of hydrogel and microspheres. Owing to the physical entanglements of hydrophilic long chains of BSP polymer, the HMs matrix presents a microporous structure and with a spherical morphology. This morphological structure makes the HMs have better flowability and water absorption capacity, and thus allowing them could spread well on the cervical mucosa and absorb a large amount of water from cervical mucus. As a result, the mucus barrier for the medication intimate contact with cervical mucosa was conquered and reach the optimum hydration required for mucoadhesion. Due to the better water-absorbing capacity caused by the hydrophilic microporous structure, the HMs could keep their morphological structure and bioadhesion behavior for a longer time at the cervical mucosa. Subsequently, the HMs have the ideal drug release profile namely a low initial burst release with a longer sustained release later on for the cervical local treatment. In addition, the natural biodegradable nature of the BSP polymer, result in the HMs could not cause irritation and allergies to cervical mucosa. This work established the foundation and potential for the HMs based on BSP polymer as a promising CPDDS for clinical applications. [Display omitted]