Design and in vitro characterization of buccoadhesive tablets of timolol maleate.

OBJECTIVE

The purpose of this work was to develop and evaluate buccoadhesive tablets of timolol maleate (TM) due to its potential to circumvent the first-pass metabolism and to improve its bioavailability.

METHODS

The tablets were prepared by direct compression using two release modifying polymers, Carbopol 974P (Cp-974p) and sodium alginate (SA). A 3(2) full factorial design was employed to study the effect of independent variables, Cp-974p and SA, in various proportions in percent w/w, which influences the in vitro drug release and bioadhesive strengths. Physicochemical properties of the drug were evaluated by ultraviolet, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and powder X-ray diffraction (P-XRD). Tablets were evaluated for hardness, thickness, weight variation, drug content, surface pH, swelling index, bioadhesive force and in vitro drug release.

RESULTS

The FTIR and DSC studies showed no evidence of interactions between drug, polymers and excipients. The P-XRD study revealed that crystallinity of TM remain unchanged in optimized formulation tablet. Formulation F9 achieves an in vitro drug release of 98.967% ± 0.28 at 8 h and a bioadhesive force of 0.088 N ± 0.01211.

CONCLUSION

We successfully developed buccal tablet formulations of TM and describe a non-Fickian-type anomalous transport as the release mechanism.