Periodontitis is an inflammatory disease of the supporting structures of the tooth caused by bacterial infection which can result in tooth loss. The local intra-pocket drug delivery system was interesting and highly effective for periodontitis treatment. In situ forming gel system is the polymeric solution which could transform into gel for localizing and sustaining the drug release at desired site. This system has been recommended as one of suitable delivery system for this purpose. Benzoyl peroxide (BPO) in situ forming gels were developed using Eudragit RS as polymer dispersed in N-methyl-pyrrolidone (NMP). Peppermint oil and polyethylene glycol 1500 were also incorporated as the excipients. The prepared systems were evaluated for rheology, syringeability (using texture analyzers), in situ gel formation (after injection into PBS pH 6.8), antimicrobial activity (against Streptococcus mutans with agar diffusion) and drug release (with dialysis method in PBS pH 6.8 at 50 rpm, 37 °C). The viscosity and syringeability of the prepared systems was increased as the amount of BPO, peppermint oil or PEG 1500 was increased. All prepared gels showed the Newtonian flow which the viscosity was decreased as the temperature was increased. All prepared gels comprising peppermint oil and PEG 1500 could form in situ gel in used medium which the pH was close to the environment pH of periodontal pocket. The inhibition zone against Streptococcus mutans of the prepared system was significantly decreased when the peppermint oil and PEG 1500 was incorporated owing to the higher viscous environment and thereafter retardation of drug diffusion was evident. This effect could prolong the drug release. From drug release test, all prepared gels could sustain the BPO release for at least 96 hrs. Release kinetic obtained from curve fitting with various release equations using least square fit technique indicated that the release patterns were as Higuchi’s model therefore the release of BPO was performed with diffusion control. This developed BPO in situ forming gel presented its ability as the controlled drug delivery system for localized antimicrobial activity at periodontal pocket.
Role of clove oil in solvent exchange-induced doxycycline hyclate-loaded Eudragit RS in situ forming gel
