Formulation and evaluation of a sustained-release tablets of metformin hydrochloride using hydrophilic synthetic and hydrophobic natural polymers

Abstract

Metformin hydrochloride has relatively short plasma half-life, low absolute bioavailability. The need for the administration two to three times a day when larger doses are required can decrease patient compliance. Sustained release formulation that would maintain plasma level for 8-12 h might be sufficient for daily dosing of metformin. Sustained release products are needed for metformin to prolong its duration of action and to improve patient compliances. The overall objective of this study was to develop an oral sustained release metformin hydrochloride tablet by using hydrophilic Eudragit RSPO alone or its combination with hydrophobic natural polymers Gum copal and gum damar as rate controlling factor. The tablets were prepared by wet granulation method. The in vitro dissolution study was carried out using USP 22 apparatus I, paddle method and the data was analysed using zero order, first order, Higuchi, Korsmeyer and Hixson-Crowell equations. The drug release study revealed that Eudragit RSPO alone was unable to sustain the drug release. Combining Eudragit with gum Copal and gum Damar sustained the drug release for more than 12 h. Kinetic modeling of in vitro dissolution profiles revealed the drug release mechanism ranges from diffusion controlled or Fickian transport to anomalous type or non-Fickian transport. Fitting the in vitro drug release data to Korsmeyer equation indicated that diffusion along with erosion could be the mechanism of drug release.

Metformin loaded non-ionic surfactant vesicles: optimization of formulation, effect of process variables and characterization

“…tablet has been modified by various approaches to get the desired results. Matrix tablets with sustained release have been prepared using hydroxypropyl methyl cellulose as a hydrophilic polymer, hydrophilic synthetic polymers and hydrophobic natural polymers and by incorporation of lipophillic waxes by melt granulation [14,16]. With the view to enhance patient compliance taste masked tablets and oro-dispersible tablets have also been formulated, also the FDA (Food and Drug Administration) has approved metformin-glipizide tablets for oral suspension, metformin-glyburide oral solution and linagliptin-metformin hydrochloride tablets [17-19].…”

Formulation and in vitro evaluation of Eudragit S-100 coated naproxen matrix tablets for colon-targeted drug delivery system

“…The other reason may be the presence of Eudragit RSPO which is less swellable due to the presence of least amount of quaternary ammonium groups in the structure and less impermeable to the dissolution media due to which the drug release decreased. [2829]…”

Formulation of Atovaquone Tablet Using Biosurfactant in a Ternary Solid Dispersion System: In Vitro and in Vivo Evaluation

“…Aliquot samples of dissolution media (5 ml) were withdrawn through a filter (0.45µ) syringe at different intervals of time up 60 min. All the samples were suitably diluted and assayed at λmax 220 nm and sink condition was maintained [11,12].…”