Formulation and Evaluation of Sol-Gel Drug Delivery System for Intracanal pH Sensitive Controlled Delivery of Chlorhexidine

Abstract

Persistence of viable micro-organisms even after thorough chemomechanical debridement has been cited as a major cause for endodontic failure. Chlorhexidine is a drug, which has shown marked efficacy against Enterococcus faecalis and Candida spp., which are mostly accounted for endodontic failure and it has demonstrated high degree of substantivity to dentin by adsorption. Another issue with chlorhexidine and other intracanal medicaments is the excessive or premature peaking of the drug leading to possible side effects. The objective of this experimental work undertaken was to formulate a pH sensitive sol-gel sustained drug delivery system containing chlorhexidine. The formulations were prepared using different concentrations of GELRITE® (0.1% and 0.2%) and Chlorhexidine (0.1% and 0.2%). The prepared solutions were evaluated for pharmacological properties like sterility test, viscosity, drug content, drug release characteristics, drug excipient compatible study. The drug excipient compatibility studies showed no interaction between the excipient and the active constituent. The microbial analysis showed good efficacy against the test micro-organisms and Minimum Inhibitory Concentration (MIC) values against Candida albicans (ATCC® 14053™) was observed as 4 μl/ml for both formulation containing 0.1% and 0.2% of GELRITE® Gellan (polymer). Whereas, MIC values against Enterococcus faecalis was observed to be 3.2 μl/ml and 6 μl/ml for formulation containing 0.1% and 0.2% of GELRITE® Gellan (polymer) respectively. From the present study, it could be successfully demonstrated that sol-gel formulations can be simple, easy to administer mode of intracanal drug delivery system. Localized pH changes present within the canal can trigger sol-gel conversion thereby releasing the drug in sustained manner with less toxicity and side effects.