Therapeutic Effects of Rebamipide Nanocrystals as Carbopol Gel Formulation Containing Gum Arabic in a Hamster Model of Oral Mucositis.

Abstract

Severe oral mucositis is a major cause of a low quality of life in patients; however, the therapeutic effect of traditional treatments is insufficient. Therefore, we designed a carbopol gel based on rebamipide nanocrystals (REB NCs) and gum arabic (GA-REB@NP), and investigated its efficacy in accelerating wound healing in a hamster model of oral mucositis. REB NCs were prepared by bead milling, and GA- REB@NP were prepared by incorporating REB NCs into a carbopol gel. The REB sizes were measured using a SALD-7100 and NanoSight LM10, and both powder X-ray diffraction and differential thermal analysis were used to analyze the crystalline form. Drug release from the gel formulations and therapeutic effects were evaluated using hamsters. The particles of milled-REB without GA were microsized, whereas the particle size of milled-REB with GA was in the range of 30-180 nm, and the crystalline form was similar to that of REB with or without bead milling. Next, we evaluated the characteristics of GA-REB@NP. The particle size of REB in GA-REB@NP was in the range of 45-200 nm, and drug release from GA-REB@NP was higher than that from the gel incorporating REB microcrystals (GA-REB@MP). In addition, REB nanoparticles were released from GA-REB@NP. Moreover, inhibitors of both clathrin- (dynasore) and caveolae-dependent endocytosis (nystatin) attenuated the enhanced REB levels in the cheek pouches of hamsters treated with GA-REB@NP. GA-REB@NP also enhanced the healing of the wound area compared with GA-REB@MP in hamsters injected with acetic acid. We prepared GA-REB@NP, which provided high REB delivery into the cheek pouch tissue via endocytosis. Additionally, we demonstrated that wound healing in acetic acid-injected hamsters was promoted by the application of GA-REB@NP.