ABSTRACT:
In the present study, an attempt was made to develop a low-dose controlled-release delivery system for the treatment of periodontal infections. Nylon fibres were taken as core material. The coating solution contained polyvinyl acetate and metronidazole. The fibres were coated five times to maximize drug loading. The coating composition was optimized and fibres were subjected to in vitro release studies. For the study, a continuous-flow-through apparatus for in situ drug release, simulating the in vivo conditions of periodontal pocket, was designed in a manner that the drug released was well above the minimum inhibitory concentration of metronidazole. In situ samples were further subjected to microbiological evaluation against the microorganisms which are implicated in periodontal infections. Optimized fibre was further subjected to permeation rate study using modified Franz diffusion cell. The drug-coated fibres provided sustained effect up to a period of 11 days (264 h) and followed first order release. The drug release followed Fickian diffusion mechanism. In situ samples revealed that the drug level at different time intervals remained above its minimum inhibitory concentration (1.5 µg/ml) for a period of 11 days. In situ release samples when subjected to microbiological evaluation against microorganisms inhibited the growth of S. aureus, S. mutans and B. cereus. Permeation rate studies through bovine cheek pouch membrane revealed that only a low level of drug permeated through the membrane and it followed zero-order permeation rate. The retentive fibres were shown to provide controlled delivery of metronidazole.