In situ gel

The conventional dosage forms have the disadvantages like frequent administration, poor bioavailability, unpredictable doses etc. To overcome the problems of the conventional dosage forms, newer research in drug delivery systems directed towards a amalgamation of several technologies, leads to the development of in-situ oral gels, which extend the contact time and slows down the removal of the drug. To improve the bioavailability and to prevent rapid loss of drug, the drug can be formulated as oral in-situ gel using stimuli sensitive polymers. Gel dosage forms are successfully used as drug delivery systems to control drug release and protect the medicaments from a hostile environment. This review work gives information about oral diseases, in situ gel, approaches and polymers used for in situ gelation.

  Periodontitis is an inflammatory disease of the supporting tissues of the teeth caused by groups of specific microorganisms. The concept that localized problem sites may be treated by local drug delivery appears attractive as the antimicrobial agent is delivered within periodontal pockets and the therapy is targeted on specific pathogenic microorganisms. Local delivery of antimicrobial agents using controlled release systems should be considered as adjunctive to mechanical debridement for the treatment of localized forms of periodontal destruction. Local delivery of in situ gelling system to periodontal pockets has the benefit of putting more drugs at target site while minimizing exposure of the total body to the drug. In situ gelling system helps in maintaining effective levels of drug in gingival cervicular fluid to produce desirable clinical effects. In situ gel for controlled drug delivery system of periodontal pocket has received greater interest and appears to hold some promise in periodontal therapy. They are designed to release drug slowly with more prolonged drug availability and sustained drug action. Controlled release systems offer an advantage of decrease in frequency of administration, improving patient compliance. The dose of the drug can also be decreased and hence, the toxicity when compared to conventional therapy. In controlled drug delivery, the drug is released over an extended period of time by zero order kinetics and hence constant plasma drug concentration can be achieved. Key words: Periodontitis, Periodontal pocket, In situ gel, Controlled drug delivery

The aim of this study was to develop a new intra-gastric floating in situ gelling system for controlled delivery of levetiracetam for the treatment of partial onset seizures. High dose of levetiracetam (750 to 1000 mg) is difficult to incorporate in floating tablets but can easily be given in liquid dosage form released. Sodium alginate-based in-situ gelling systems were prepared by dissolving various concentrations of sodium alginate in deionized water, to which drug and calcium carbonate were added. Fourier transform infrared spectroscopies (FTIR) were used to check the presence of any interaction between the drug and the excipients. A 32 full factorial design was used for optimization. The concentrations of sodium alginate (X1) and calcium carbonate (X2) were selected as the independent variables. The amount of the drug released after 1 h (Q1) and 6 h (Q6) and 12 h (Q12) and the viscosity of the solution were selected as the dependent variables. The gels were studied for their viscosity, in-vitro buoyancy and drug release. Other ingredient like HPMC K100M used for strength forming polymer, sodium citrate is used for liquefying solution. The drug release from the in-situ gel follows the Higuchi model and Korsemeyer-peppas model, which indicates a diffusion-controlled release. Key word: In situ gel, Levetiracetam, Floating.