Abstract:
The objective of the study was to develop a drug delivery system for localised controlled release of Doxycycline following insertion into and/or around the periodontal pocket which would ensure increased local drug concentration over an extended period of time with a subsequent decrease in the side effects associated with systemic administration. Hydroxypropyl Guar, a biodegradable polymer, was used in the preparation of microspheres by employing water in oil emulsification solvent evaporation technique. The formulations were evaluated for particle size, particle shape and surface morphology by Scanning Electron Microscopy, percentage yield, drug entrapment efficiency, in vitro mucoadhesion test, degree of swelling and in vitro drug diffusion through sheep buccal mucosa. The microspheres obtained were free flowing, spherical and had a mean particle size of 110.2 ± 1.13 µm. Increasing polymer concentration resulted in increased drug entrapment efficiency and increased particle size. Doxycycline Hydrochloride was entrapped into the microspheres with an efficiency of 74.7 ± 2.11 % to 83.9 ± 1.54 %. The prepared microspheres showed good mucoadhesion properties, swellability and sustained the release of the drug over a period of 8 h. The data obtained were analysed by fitment into various kinetic models; it was observed that the drug release was matrix diffusion controlled and the release mechanism was found to be non-Fickian. Stability studies were carried out on select formulations at 5°C ± 3°C, 25°C ± 2°C / 60% RH ± 5% RH and 40°C ± 2°C / 75% RH ± 5% RH for 90 days. The drug content was observed to be within permissible limits and there were no significant deviations in the in vitro mucoadhesion and in vitro drug diffusion characteristics.

Keywords: Periodontitis, Doxycycline Hydrochloride, Mucoadhesive Microspheres, Hydroxypropyl Guar, Water in Oil Emulsification Solvent Evaporation Technique, In vitro Mucoadhesion Studies,