Development of Tizanidine HCl-Meloxicam loaded mucoadhesive buccal films: In-vitro and in-vivo evaluation

Abstract

The purpose of the study was to develop Tizanidine HCl (TZN) and Meloxicam (MLX) loaded bilayer mucoadhesive films intended for buccal administration, aiming to enhance the bioavailability. Bilayer films were prepared by solvent evaporation technique selecting arabinoxylan (ARX) as a sustained release (SR) layer forming polymer and hydroxypropyl methylcellulose (HPMC) E-15 as an immediate release (IR) layer-forming polymer. Prepared films were subjected to in-vitro drug release, surface morphology, mechanical strength, compatibility of the ingredients, drug contents, ex-vivo mucoadhesion strength and drug permeation. Crossover study design was applied to study the in-vivo pharmacokinetics by using albino rabbits. Various pharmacokinetic parameters including AUC, Cmax, tmax and t1/2 of both drugs loaded in films were compared with standard solution/dispersion administered to the rabbits at the dose of 1mg/kg. The results unveiled instant release and permeation of MLX from IR layer, while good controlled release and permeation characteristics of TZN from SR films over 8 h. films were of uniform thickness with smooth surface and satisfactory mechanical strength. Mucoadhesion strength was sufficient to provide suitable contact time with mucosal membrane. The pharmacokinetic study exhibited prompt absorption of MLX with better AUC 0-t (6655.64 ng/ml*h vs 6538.99 ng/ml*h) and Cmax (436.98 ng/ml vs 411.33 ng/ml) from oral dispersion. Similarly buccal films has shown enhanced half-life (9.91hr vs 2.51 hr), AUC 0-t (1043.4 ng/ml*h vs 149.1 ng/ml*h) and Cmax (91.92 ng/ml vs 42.29 ng/ml) from oral solution. A statistical investigation disclosed a significantly improved pharmacokinetics of TZN and MLX after their absorption across buccal route following administration of buccal film (p<0.05). ARX proved expedient and bilayer buccal films as a drug delivery system ascertained the dual effect of providing instant release of one active agent and persistent release of another one with improved pharmacokinetics.

Fig 1

Image taken by the digital camera (Nikon Coolpix p500) showing shiny and smooth surface of the SR layer of TZN (A) and IR layer of MLX (B), Optical microscopic image of bilayer buccal film taken by an optical microscope at 40X (C) and SEM image of bilayer buccal film taken at 2000X (D) showing uniform mixing of ingredients (blue arrow with white outline is indicating polymeric meshwork while white arrow with blue outline is pointing out the imbedded drug).

Fig 2. Graphical illustration of in-vitro dissolution and ex-vivo permeation of MLX and TZN.

A and B are showing drug release and permeation of MLX while C and D are describing release and permeation of TZN from bilayer mucoadhesive buccal film.

Fig 3. Figure showing FTIR spectrum of different ingredients and prepared films.

Fig 4. Pharmacokinetics of TZN and MLX after administration of SR films and standard oral solution containing 1mg/kg of the drug.

Absorption of TZN from buccal films (A) and from oral solution (B), and MLX from buccal film (C) and oral dispersion (D).