Thiol modified Moringa gum - A potential bioadhesive polymer.

In the present study Moringa gum was modified by thiolation to enhance its mucoadhesive potential. Thiolation was accomplished by esterification with thioglycolic acid. Thiolated Moringa gum was characterized by FT-IR, TGA, DSC, XRD and SEM-EDX studies. Modified gum was found to have 0.956 ± 0.024 mM of thiol groups/g as determined by Ellman's method. The greater force of detachment of polymer compacts of modified gum from the mucin discs as compared to native gum indicates its enhanced mucoadhesive potential. The thiolated Moringa gum was formulated into buccal tablets using metronidazole benzoate as the test drug. A comparative evaluation of buccal tablets revealed 1.5-fold higher ex vivo bioadhesion time of buccal tablets of modified gum than the native gum. The results of in vitro release studies showed that modified gum tablets provided a sustained release of metronidazole over 24 h of the study following First-order kinetics with diffusion mechanism of release.