Abstract:
Crude extract from dried fruit rinds of Garcinia mangostana Linn. was prepared and purified as yellow crystalline powder of mangostin. The extract showed antibacterial activity against Staphylococcus aureus ATCC 25923, Streptococcus mutans ATCC KPSK₂ and Streptococcus sanguis (a clinical isolate). Bilayered buccal mucoadhesive films which comprised of a mucoadhesive layer prepared from hydrophilic polymer with the extract and the backing layer prepared from ethylcellulose were investigated. Various types of mucoadhesive polymers included chitosan of low, medium and high molecular weight (LMW, MMW, HMW), carboxymethylcellulose sodium (SCMC), hydroxypropyl methyl cellulose (HPMC), Carbopol 934 (CP934) and combined polymers. Effects of molecular weight of chitosan, types and concentration of acid used in the preparation of chitosan film, concentration of CP934 in SCMC or HPMC films on the physical properties of the film were studied. They included appearance, swelling, mechanical resistance, water repellent, mucoadhesive force and time and release of mangostin from films. As the MW of chitosan increased, the tensile strength, swelling property and the mucoadhesive force increased, however, the percentage elongation decreased. Chitosan films prepared from acetic acid showed higher degree of swelling than those prepared from lactic acid. Combination of CP934 10 and 20% w/w with SCMC exhibited better mechanical properties, whereas, the different results obtained from those prepared from CP934 and HPMC. However, CP934 improved the mucoadhesive force and time of HPMC films. Bilayered films containing mangostin were prepared from three selected formulations included HPMC combined with 20% CP934, chitosan MMW prepared with 1% acetic acid and 1% lactic acid for release study. The release mechanism was demonstrated to follow diffusion-controlled mode. All formulations were stable under the storage at 40℃ and 75% relative humidity for 3 months with respect to the mangostin content analysed by HPLC method.