title: Formulation and design of sustained release matrix tablets of metformin hydrochloride: Influence of hypromellose and polyacrylate polymers.
abstract: OBJECTIVE
  The current paper was an attempt to design a sustained release dosage form using various grades of hydrophilic polymers, Hypromellose (hydroxyl-propyl methylcellulose [HPMC] K15M, HPMC K100M and HPMC K200M) and Polyacrylate polymers, Eudragit RL100 and Eudragit RS100 with or without incorporating ethyl cellulose on a matrix-controlled drug delivery system of Metformin hydrochloride.
  
  
  METHODS
  Laboratory scale batches of nine tablet formulations were prepared by wet granulation technique (Low shear). Micromeritic properties of the granules were evaluated prior to compression. Tablets were characterized as crushing strength, friability, weight variation, thickness, drug content or assay and evaluated for in-vitro release pattern for 12 h using Phosphate buffer of pH 6.8 at 37 ± 0.5°C. The in-vitro release mechanism was evaluated by kinetic modeling.
  
  
  CONCLUSIONS
  The results obtained revealed that HPMC K200M at a concentration of 26% in formulation (F6) was able to sustain the drug release for 12 h and followed the Higuchi pattern quasi-Fickian diffusion. With that, combined effect of HPMC K15M as an extragranular section and Eudragit RS100 displayed a significant role in drug release. Dissolution data were compared with innovator for similarity factor (f2), and exhibited an acceptable value of ≥50 Three production validation scale batches were designed based on lab scale best batch and charged for stability testing, parameters were within the limit of acceptance. There was no chemical interaction found between the drug and excipients during Fourier Transform Infrared Spectroscopy (FTIR) and Differential scanning calorimetry study.
  
  
  CONCLUSIONS
  Hence, combinely HPMC K200M and Eudragit RS100 at a suitable concentration can effectively be used to sustain drug release.
authors.affiliation: Department of Pharmatechnology, Vikas College of Pharmaceutical Sciences, Suryapet, Nalgonda, Andhra Pradesh, India.
authors.forename: Harekrishna
authors.initials: H
authors.lastname: Roy
authors.forename: Chandan K
authors.initials: CK
authors.lastname: Brahma
authors.forename: Sisir
authors.initials: S
authors.lastname: Nandi
authors.forename: Kirti R
authors.initials: KR
authors.lastname: Parida
keywords: Hydrophilic polymer; Metformin hydrochloride; innovator; micromeritic properties; sustained release tablet matrix