Antimicrobial effect of chlorhexidine in a controlled release delivery system.

Chlorhexidine is widely used as a mouth rinse in the prevention and treatment of periodontal diseases and dental caries. The purpose of the present study was to evaluate the in vitro antimicrobial effect of chlorhexidine in a controlled release delivery system. The controlled release dispenser comprised a polymeric inner core matrix containing the medicament with an outer vinyl membrane controlling the drug release. The effect on the following bacteria was studied: Actinobacillus actinomycetemcomitans, Actinomyces viscosus, Streptococcus mutans, Wolinella recta, Bacteroides gingivalis, Bacteroides intermedius, Eikenella corrodens, Pseudomonas aeruginosa, Enterobacter aerogenes, and Enterobacter cloacae. Chlorhexidine-containing vinyl patches with a diameter of 5.5 mm were placed on blood agar plates containing the various bacteria. The plates were incubated aerobically or anaerobically at 37 degrees C for 24 h or longer, when appropriate, and examined for inhibition of bacterial growth. Distinct zones of inhibition were seen surrounding all vinyl patches on all plates with all bacteria. Thus, the vinyl dispenser appeared to be an effective vehicle for releasing chlorhexidine to a localized area such as the surface of a tooth, a periodontal pocket, or a root canal.