Fabrication and in vitro evaluation of subgingival strips of calcium alginate for controlled delivery of ofloxacin and metronidazole

Aim: Subgingival strips of combined ofloxacin (OFX) and metronidazole (MET) were fabricated and evaluated in vitro using biodegradable calcium alginate. Methods: Strips of drug: polymer (10: 90, 25: 75, 50: 50 and 75: 25) were prepared using solvent casting method. A 10% w/v CaCl2 solution was used for gelation of the strips. Results: The thickness of strips were at par of recommended thickness (< 320 mu m). In vitro release of drugs followed a biphasic kinetics which was sufficient to maintain the minimum inhibitory concentrations (MIC) to inhibit the growth of the microorganisms for 5 days. The rate of drug release was inversely proportional to polymer concentration in the formulations. The drug release was by diffusion in second phase of dissolution. Conclusions: The formulations OM1 and OM2 which contain 90 and 75%w/w of polymer could be employed for controlled delivery of combined OFX and MET for 5 days in subgingival infections. Calcium alginate, being a biodegradable is a good choice as drug retarding polymer.