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. 2003 Aug 7;4(3):110–115. doi: 10.1208/pt040343

Effect of microenvironment pH of swellable and erodable buffered matrices on the release characteristics of diclofenac sodium

Bashar M Al-Taani 1, Bassam M Tashtoush 1,✉
PMCID: PMC2750636  PMID: 14621975

Abstract

The aim of this work is to design pH-dependent swellable and erodable-buffered matrices and to study the effect of the microenvironment pH on the release pattern of diclofenac sodium. Buffered matrix tablets containing diclofenac sodium, physically mixed with hydrophilic polymer (hydroxypropyl methylcellulose [HPMC]) and pH-dependent solubility polymer (Eudragit L100-55) were prepared with different microenvironment pHs. The release of diclofenac sodium from the buffer matrices was studied in phosphate buffer solutions of pH 5.9 and 7.4. The swelling and erosion matrices containing only HPMC and Eudragit L100-55 were studied in phosphate buffer solution of pH similar to the microenvironment pHs of the matrices. Drug release from matrices was found to be linear as a function of time. Amount of drug released was found to be higher in the medium of pH 7.4 than that of pH 5.9. The rate of drug release increased with the increase of the microenvironment pH of the matrices as determined from the slope. The pattern of drug release did not change with the change of microenvironment pH. The swelling and erosion occurred simultaneously from matrices made up of HPMC and Eudragit L100-55. Both extent of swelling and erosion increased with increase of the medium pH. It was concluded from this study that changing the pH within the matrix influenced the rate of release of the drug without affecting the release pattern.

Keywords: controlled release, buffered matrix, swelling, erosion, sustained release

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References

  • 1.Chien YW. Novel Drug Delivery Systems. 2nd ed. New York, NY: Marcel Dekkar; 1992. Fundamentals of rate-controlled drug delivery; pp. 43–137. [Google Scholar]
  • 2.Gao P, Meury RH. Swelling hydroxypropyl methylcelloluse matrix tablets. 1. Characterization of swelling using a novel optical imaging method. J Pharm Sci. 1996;85(7):725–731. doi: 10.1021/js950458c. [DOI] [PubMed] [Google Scholar]
  • 3.Ammar HO, Khalil RM. Preparation and evaluation of sustained-release solid dispersions of drugs with Eudragit polymers. Drug Dev Ind Pharm. 1997;23(11):1043–1054. doi: 10.3109/03639049709150492. [DOI] [Google Scholar]
  • 4.Kislalioglu MS, Khan MA, Blount C, Goettch RW, Bolton S. Physical characterization and dissolution properties of ibuprofen: eudragit coprecipitates. J Pharm Sci. 1991;80:799–804. doi: 10.1002/jps.2600800820. [DOI] [PubMed] [Google Scholar]
  • 5.Wade A, Weller PJ, editors. Handbook of Pharmaceutical Excipients. London, UK: Pharmaceutical Press; 1994. pp. 362–366. [Google Scholar]
  • 6.Bainchini R, Resciniti M, Vecchio C. Technological evaluation of aqueous enteric coated systems with and without insoluble additives. Drug Dev Ind Pharm. 1991;17:1779–1794. doi: 10.3109/03639049109074392. [DOI] [Google Scholar]
  • 7.Durig T, Venkatesh GM, Fassihi R. An investigation into the erosion behavior of high drug-load (85%) particulate system designed for an extended-release matrix tablet: analysis of erosion kinetics in conjunction with variation in lubrication, porosity, and compaction rate. J Pharm Pharmacol. 1999;51:1085–1092. doi: 10.1211/0022357991776769. [DOI] [PubMed] [Google Scholar]
  • 8.Mehta KA, Kislalioglu MS, Phuapradit W, Malick AW, Shah NH. Release performance of a poorly soluble drug from a novel, Eudragit-based multi-unit erosion matrix. Int J Pharm. 2001;213:7–12. doi: 10.1016/S0378-5173(00)00594-9. [DOI] [PubMed] [Google Scholar]
  • 9.Khan MZI, Stedul HP, Kurjakovic N. A pH-dependent colon targeted oral drug delivery system using methacrylic acid copolymers. II. Manipulation of drug release using Eudragit L100 and Eudragit S100 combinations. Drug Dev Ind Pharm. 2000;26(5):549–554. doi: 10.1081/DDC-100101266. [DOI] [PubMed] [Google Scholar]
  • 10.Terao T, Matsuda K, Shougi H. Improvement in site specific intestinal absorption of furocemide by Eudragit L100-55. J Pharm Pharmacol. 2001;53:433–440. doi: 10.1211/0022357011775721. [DOI] [PubMed] [Google Scholar]
  • 11.Lee PI. Diffusional release of a solute from a polymeric matrix—approximate analytical solutions. J Memb Sci. 1980;7:255–275. doi: 10.1016/S0376-7388(00)80474-3. [DOI] [Google Scholar]
  • 12.Blase CM, Peck GE. Development of a unique buffered matrix aspirin tablet. Drug Dev Ind Pharm. 1992;18(8):869–893. doi: 10.3109/03639049209069304. [DOI] [Google Scholar]
  • 13.Finne U, Vaisanen V, Urtti A. Modification of ocular and systemic absorption of timolol from ocular inserts by a buffering agent and a vasoconstrictor. Int J Pharm. 1990;65:19–27. doi: 10.1016/0378-5173(90)90004-N. [DOI] [Google Scholar]
  • 14.Martin A, Bustamante P, Chun A, editors. Buffered and isotonic solutions. 4th ed. Philadelphia, PA: Lea & Febiger; 1993. pp. 169–189. [Google Scholar]
  • 15.Abrahamsson B, Alpesten M, Bake B, Larsson A, Sjogren J. In vitro and in vivo erosion of two different hydrophilic gel matrix tablets. Eur J Pharm Biopharm. 1998;46:69–75. doi: 10.1016/S0939-6411(98)00002-2. [DOI] [PubMed] [Google Scholar]
  • 16.Sheu M, Chou H, Kao C, Liu C, Sokoloski T. Dissolution of diclofenac sodium from matrix tablet. Int J Pharm. 1992;85:57–63. doi: 10.1016/0378-5173(92)90134-N. [DOI] [Google Scholar]
  • 17.Carelli V, Colo G, Nannipieri E, Poli B, Serafini MF. Poly(oxyethylene)-Poly(methacrylic acid-co-methyl methacrylate) compounds for site specific per oral delivery. Int J Pharm. 2000;202:103–112. doi: 10.1016/S0378-5173(00)00429-4. [DOI] [PubMed] [Google Scholar]
  • 18.Bettini R, Colombo P, Peppas NA. Solubility effects on drug transport through pH sensitive swelling-controlled release system: transport of theophylline and metaclopramide monohydrochloride. J Control Release. 1995;37:150–111. doi: 10.1016/0168-3659(95)00069-K. [DOI] [Google Scholar]
  • 19.Kim CJ, Lee PI. Hydrophobic anionic gel beads for swelling-controlled drug delivery. Pharm Res. 1992;9:195–199. doi: 10.1023/A:1018929205254. [DOI] [PubMed] [Google Scholar]
  • 20.Kim C. Application of shrinking-core model for ionization of hydrophobic ionic beads. Drug Dev Ind Pharm. 1996;22:307–311. doi: 10.3109/03639049609041994. [DOI] [Google Scholar]
  • 21.Cameron CG, McGinity JW. Controlled release theophylline tablet formulations containing acrylic resins. Part 2. Combination resin formulations. Drug Dev Ind Pharm. 1987;13(8):1409–1427. doi: 10.3109/03639048709068383. [DOI] [Google Scholar]
  • 22.Avdeef A, Berger CM, Brownell C. pH-metric solubility. 2. Correlation between the acid-base titration and the saturation shake-flask solubility pH methods. Pharm Res. 2000;17:85–89. doi: 10.1023/A:1007526826979. [DOI] [PubMed] [Google Scholar]
  • 23.Sarjeev C, Saha RN. Formulation and comparative evaluation of controlled release diclofenac tablets prepared by matrixembedding technique, membrane barrier technique, and combination of the two. Drug Dev Res. 2001;53:1–8. doi: 10.1002/ddr.1162. [DOI] [Google Scholar]
  • 24.Padmalatha DK, Ranga Rao KV, Baveja S, Fathi M, Roth M. Zero-order release formulation of oxprenolol hydrochloride with swelling and erosion control. Pharm Res. 1989;6:313–317. doi: 10.1023/A:1015998424548. [DOI] [PubMed] [Google Scholar]
  • 25.Efentakis M, Koutlis A. Release of furosemide from multiple unit and single unit preparations containing different viscosity grades of sodium alginate. Pharm Dev Tech. 2001;6(1):91–98. doi: 10.1081/PDT-100000048. [DOI] [PubMed] [Google Scholar]

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