Development of metformin HCl granules using brown flaxseed mucilage as a retardant polymer: effects of polymer and drug ratio

Abstract Flaxseed (Linum usitatissimum L.) is the seed of a multipurpose plant of pharmaceutical interest, as its mucilage can be used as a natural matrix to develop extended-release dosage forms and potentially replace synthetic polymers. In this study, a 3² factorial design with two replicates of the central point was applied to optimize the development of extended-release granules of metformin HCl. The total fiber content of the mucilage as well as the friability and dissolution of the formulations were evaluated. The lyophilized mucilage presented a high total fiber content (42.63%), which suggests a high efficiency extraction process. Higher concentrations of the mucilage and metformin HCl yielded less friable granules. In addition, lower concentrations of metformin HCl and higher concentrations of the mucilage resulted in slower drug release during the dissolution assays. The release kinetics for most formulations were better represented by the Hixson-Crowell model, while formulations containing a higher concentration of the mucilage were represented by the Korsmeyer-Peppas model. Nonetheless, five formulations showed a longer release than the reference HPMC formulation. More desirable results were obtained with a higher concentration of the mucilage (13-18%) and a lower concentration of metformin (40%).

The gelling properties of Dillenia indica mucilage in benzyl benzoate emulgel formulations

Abstract The objective of the study was to evaluate the gelling properties of Dillenia indica mucilage in benzyl benzoate emulgel formulation. Mucilage was extracted from the fruits of Dillenia indica using established methods and characterized by rheology and swelling. Emulsion (F1) was prepared using the continental emulsification method. Gelling agents (2 %w /v) were prepared by dispersing in distilled water with constant stirring at a moderate speed using a magnetic stirrer. F1 was added to the gel (0-75 %w /w) to obtain emulgel formulations and evaluated using viscosity, globule size, pH, release profiles and kinetic modeling. Data were expressed as mean ± SD, and similarity factor (f2) was used to compare all formulations. Formulation viscosity was significantly higher with carbopol than with Dillenia; globule sizes increased with concentration of gelling agents, and pH reduced as the concentration of Dillenia increased. All formulations showed controlled release properties with t80 ranging between 114 and 660 min. The release was governed by Korsmeyer-Peppas model. Formulation F5 prepared with 50 % Dillenia showed highest similarity to F4 prepared with 75 %w /w carbopol. Dillenia indica demonstrated acceptable gelling properties comparable with that of carbopol and could be improved for use in emulgel formulations.