Target Retentive Biodegradable Periodontal Disks for Simultaneous Extended Release of Metronidazole and Doxycycline:Formulation Consideration

Buccoadhesive erodible disks of metronidazole and doxycycline were prepared using different bioadhesive polymers along with excipients like magnesium stearate. The purpose of designing the erodible disk was to obviate the need for removal of exhausted device. The optimized disk containing 3% w/w of magnesium stearate along with hydroxypropylmethylcellulose K4M and sodium carboxy methyl cellulose in the ratio of 1:3 was found to release the drug for a period of over 6.0 h without getting dislodged. Maximum in vitro drug release was found to be 94.78% in 6.0-h study. In situ release characteristics were evaluated using a 'flow-through assembly', which simulated the conditions of the human buccal cavity. The drug concentrations in the in situ samples were found to be above minimum inhibitory concentration (MIC) of the drug. The bioadhesive performance and the surface pH of the disks were satisfactory. Metronidazole and Doxycycline disks were tested against microorganisms commonly found in oro-dental infections namely Staphylococcus aureus, Escherichia coli and Streptococcus mutans. The disk as well as the in situ samples showed inhibition of growth of microorganisms. Thus a stable, extended release periodontal disks containing both metronidazole and doxycycline with satisfactory bioadhesion was developed.