Thiolation of arabinoxylan and its application in the fabrication of controlled release mucoadhesive oral films

BACKGROUND: Mucoadhesion is an important property that helps oral drug delivery system to remain attached with buccal mucosa and hence to improve the delivery of the drug. The current study was designed to achieve the thiol modification of Arabinoxylan (ARX) and to develop a mucoadhesive oral film for the improved delivery of tizanidine hydrochloride (TZN HCl). METHOD: Synthesis of thiolated arabinoxylan (TARX) was accomplished by esterification of ARX with thioglycolic acid (TGA). TARX was further used for the development of mucoadhesive oral films which were prepared by using a solvent casting technique. Formulation of the films was designed and optimized by using central composite design (CCRD), selecting TARX (X(1)) and glycerol (X(2)) as variables. Prepared film formulations were evaluated for mechanical strength, ex-vivo mucoadhesion, in-vitro drug release, ex-vivo drug permeation, surface morphology and drug contents. RESULTS: Thiolation of ARX was confirmed by fourier transform infra-red spectroscopy (FTIR) as a peak related to thiol group appeared at 2516 cm(−1). The claim of successful thiolation of ARX was strengthened by the presence of 2809.003 ± 1.03 μmoles of thiol contents per gram of the polymer, which was determined by Ellman’s reagent method. From the results, it was observed that the films were of satisfactory mechanical strength and mucoadhesiveness with folding endurance greater than 300 and mucoadhesive strength 11.53 ± 0.17 N, respectively. Reasonable drug retention was observed during in-vitro dissolution (85.03% cumulative drug release) and ex-vivo permeation (78.90% cumulative amount of permeated drug) studies conducted for 8 h. Effects of varying concentrations of both polymer and plasticizer on prepared mucoadhesive oral films were evaluated by ANOVA and it was observed that glycerol can enhanced the dissolution as well as permeation of the drug while TARX has opposite impact on these parameters. CONCLUSION: In nutshell, TARX in combination with glycerolwas found to be suitable for the development of controlled release mucoadhesive oral films of TZN HCl. GRAPHICAL ABSTRACT: Schematic diagram showing conversion of ARX to TARX, TARX to oral film and evaluation of fabricated oral film