Preparation and Characterization of Gastroreten-tive Sustained Release In-situ Gel of Lafutidine

Background: The in-situ solutions, which float in the gastrointestinal region after gelation, is suited for long-term drug release. In this study, natural and synthetic polymers were used to try to build a Gastro-Retentive controlled release in-situ gel. To modulate the rate of drug distribution and increase bioavailability and stability, gastro-retentive controlled release in-situ gels were prepared.  
Materials and Methods: For this project, 32 factorial designs were chosen. The two independent variables were sodium alginate (X1) and the ratio of HPMC K100M: Gellan Gum (X2) was preserved at the same concentration. As the study mentioned, sodium alginate is a natural polymer that is employed to build the gel matrix, while HPMC K100M and gellan gum serve as release retardants.  
Results and Discussion: The drug and excipients study performed by FTIR and DSC revealed that both the drug and polymers used were compatible with other. Out of all the batches prepared LG7 proved to be the optimized batch because of the acceptable pH with a floating time of more than 24 hours and maximum drug content of 99.92 ± 0.04% and the lag time of 71 ± 0.57seconds. The viscosity of the optimized batch was found to be dependent on the concentration of sodium alginate and the viscosity before gelling and after gelling was found to be 32719 ± 1.65 and 39851 ± 1.77 cps. The mucoadhesion strength of the prepared optimized formulation was found to be 5.621 ± 0.41N/cm2. The optimized LG7 batch showed the most sustained rate of drug release with having a matrix model as the best-fitted model. The histopathology study revealed that the formulation was safe to use without causing any degeneration of the tissues. The stability study showed that the prepared formulation was stable for the time of the study as no significant changes were observed. Lastly, the sustained behavior of the prepared in-situ gel was due to the calcium carbonate in the gelling formulation which released carbon dioxide into the gastrointestinal environment, and the formulation became porous and buoyant, extending the residence period and the floating of the gel was due to the pH-induced ion gelation process that caused the gel to float. 
Conclusion: It was concluded that the prepared controlled release in-situ gel of Lafutidine may prove to be a potential candidate for safe and effective controlled drug delivery for an extended period.