Evaluation of Methylcellulose Gel as a Vehicle for Metronidazole Compared to Commercially Available Topical Metronidazole Gel - An In Vitro Study

Background: The pathogenesis of the periodontal disease is primarily due to the gram-negative bacteria found in the plaque. Adjunctive to the routine mechanical debridement, use of systemic and local antimicrobials for reduction and eradication of specific periodontal pathogens have also been used for quite some time. Various locally delivered therapeutic drugs have been used. The success of the locally delivered therapeutic drugs are determined by the usage of vehicles.

Aim: The purpose of this study was to evaluate the efficacy of carboxy methyl cellulose gel as a vehicle for metronidazole when compared to commercially available Metrogyl® DG gel in an in vitro condition.

Methods: 20 patients with chronic periodontitis were selected and subgingival plaque samples were collected using curettes and then subjected to anaerobic culture. The samples were inoculated on Brucella Blood Agar (BBA) plates by streaking the plate with the swab sticks within 12 hours from sample collection. A well with a diameter of 8 mm is punched and 100 μm of the 1.5% metronidazole with the 2 different vehicles ((methyl cellulose gel, Metrogyl® DG gel) were introduced into the wells. These plates were kept in an an anaerobic jar along with an aero gas pack and incubated at 37°C for 48 hours to 72 hours. The antimicrobial activity was quantitatively assessed by the presence or absence of inhibition zone and zone diameter.

Result: It was found that anaerobic bacteria found in subgingival plaque, showed sensitivity to the drug released from both the vehicles. The inhibition zone diameter present around methylcellolose gel + metronidazole was 23.85 ± 1.73 mm and that around Metrogyl® was 14.4 ± 1.76 mm.

Conclusion: Methylcellulose gel is a more effective vehicle than commercially available vehicles in releasing metronidazole for use in subgingival delivery in the management of chronic periodontitis.