AAPS PharmSciTech

, Volume 19, Issue 5, pp 2144–2154 | Cite as

Design and Evaluation of Hydrophilic Matrix System for pH-Independent Sustained Release of Weakly Acidic Poorly Soluble Drug

  • Huang Jinheng 
  • Lin Huaqing Email author
  • Peng Bingxin 
  • Huang Qianfeng 
  • Shuai Fangzhou 
  • Xie Yanxian 
Research Article


The aim of this research was to design and evaluate a hydrophilic matrix system for sustained release of glipizide, a weakly acidic poor soluble drug. A combination of inclusion complexation and microenvironmental pH modification techniques was utilized to improve the dissolution and pH-independent release of glipizide. Hydroxypropyl-β-cyclodextrin (HP-β-CD) was used as the complexation agent while sodium citrate and magnesium oxide (MgO) were used as model pH modifiers. The hydrophilic matrix tablets were prepared by powder direct compression and evaluated by in vitro dissolution study respectively in pH 6.8 and pH 1.2 dissolution media. The formulations containing MgO exhibited increased cumulative drug release from less than 40% in the reference formulation to 90% within 24 h in acidic media (pH 1.2). The release profile in acidic media was similar to the alkaline media (pH 6.8) with a similarity factor (f2) of 55.0, suggesting the weakening of the effect of pH on the dissolution efficiency of glipizide. The release profile fitted well into the Higuchi model and the dominant mechanism of drug release was Fickian diffusion while case II transport/polymer relaxation occurred. In conclusion, combining inclusion complexation agents and pH modifiers had improved the dissolution of glipizide as well as achieved the pH-independent release profile.


inclusion complex microenvironmental pH pH-independent release sustained release hydrophilic matrix system 


Funding Information

This research was supported by Funds of Shenzhen Science and Technology Innovation Commission (Program No. JCYJ20160428091243299).

Compliance with Ethical Standards

Conflict of Interest

The authors declare that they have no conflicts of interest.


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Copyright information

© American Association of Pharmaceutical Scientists 2018

Authors and Affiliations

  • Huang Jinheng 
    • 1
  • Lin Huaqing 
    • 1
    Email author
  • Peng Bingxin 
    • 1
  • Huang Qianfeng 
    • 1
  • Shuai Fangzhou 
    • 1
  • Xie Yanxian 
    • 2
  1. 1.Guangdong Key Laboratory of Pharmaceutical New Dosage Form, School of PharmacyGuangdong Pharmaceutical UniversityGuangzhouChina
  2. 2.Shenzhen Shiyan People’s HospitalShenzhenChina

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