Formulation Development and Optimization of Polyherbal Gastro-retentive Floating Tablets Using Central Composite Design

Abstract

Background: The stomach is an organ with a capacity for storage and mixing. The Gastrointestinal tract (GI) is in a state of continuous motility, consisting of two modes: the inter-digestive motility pattern and the digestive motility pattern. The former is dominant in the fasted state with a primary function of cleaning up the residual content of the upper GI tract. Objectives: The present formulation contains a blend of natural ingredients such as Glycyrrhiza glabra (Liquorice), Syzygium aromaticum (Clove), Curcuma longa (Turmeric) and Ocimum sanctum (Tulsi).The existing study is concerned with the formulation development and optimization of polyherbal floating tablets via central composite design.  Materials and Methods: Direct compression method was employed to prepare the tablets. Drug -excipient studies were executed through FT-IR and DSC analysis. The independent variables selected were the concentrations of HPMC K4M  (X1 ) and Ethyl cellulose (X2 ). The dependent variables designated were Floating Lag Time (FLT) and Drug Release (DR) at 8 hrs. The model was found to be nonlinear and the curvature effect was significant. Hence, the system suggested to central composite design. Results: FT-IR studies demonstrated that there is no considerable interaction amid the drug and the excipients. Also, studies revealed that drug and excipient were compatible as there is no significant alteration in melting point of drug when blended with excipients. The pre-compression parameters of the formulations showed good flow properties. The evaluation of post compression parameters indicated that all the prepared formulations were within the specified limits. Floating lag time of formulations (F1-F9) were found to be less than 1 min and total floating time exceeding 8 hrs. Percentage cumulative drug release of all formulations (F1-F9) were in the range of 65% to 95%. The obtained design space/contour plots were used for selecting batches in desirable ranges. Conclusion: The results revealed that experimental design was successfully used to optimize polymer concentrations. It was determined that the central composite design would be used to formulate polyherbal gastro-retentive floating tablets with fewer trials and higher quality features.