Pharmaceutical Research

, Volume 25, Issue 1, pp 207–217 | Cite as

Formulation of Hydrophilic Non-Aqueous Gel: Drug Stability in Different Solvents and Rheological Behavior of Gel Matrices

  • Keat Theng Chow
  • Lai Wah Chan
  • Paul W. S. Heng
Research Paper



This study was aimed at formulating a hydrophilic non-aqueous gel for topical delivery of the model moisture-sensitive drug, minocycline hydrochloride (MH).


Stability study of MH dissolved in water and various hydrophilic non-aqueous solvents was performed over a period of four months in order to select a suitable non-aqueous solvent for MH gel. To improve MH stability, the effect of different cation additives on MH stability in the selected solvent was investigated. Non-aqueous gel matrices were prepared from three different types of hydrophilic polymers in glycerin-propylene glycol mixture with Mg2+ cation additive. Oscillatory shear rheometry was performed on the gel matrices using a cone-and-plate rheometer.


MH stability was affected by the type of solvent employed and the duration of storage. Different cation additives affected the extent of MH stabilization through MH-cation complex formation. Rheological properties of the non-aqueous gel matrices were significantly affected by the type and concentration of polymer, and the vehicle ratios in the formulations.


MH stabilization could be achieved using the selected glycerin-propylene glycol mixture containing MgCl2. Gel matrix formulated using this solvent system and 3%w/w N-vinylacetamide/sodium acrylate copolymer had demonstrated the most favorable rheological properties as a gel for topical application.

Key words

minocycline hydrochloride non-aqueous gel rheology stability viscoelastic 


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Copyright information

© Springer Science+Business Media, LLC 2007

Authors and Affiliations

  • Keat Theng Chow
    • 1
    • 2
  • Lai Wah Chan
    • 1
  • Paul W. S. Heng
    • 1
  1. 1.Department of Pharmacy, Faculty of ScienceNational University of SingaporeSingaporeSingapore
  2. 2.Division of Pharmaceutics, College of PharmacyThe University of Texas at Austin, 1 University StationAustin, TexasUSA

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