Improvement of Class II Drug Properties by Crystal Agglomeration Design

Document Type : Original research articles

Authors

Department of Pharmaceutics and Pharmaceutical Technology, Faculty of Pharmacy (Girls), Al-Azhar University, Cairo, Egypt.

Abstract

Repaglinide (RPG) is an antihyperglycemic drug; according to the Biopharmaceutical Classification System (BCS), it is considered a class II drug. It exhibits low oral bioavailability (about 56%) due to its poor water solubility and dissolution rate; also, it has very poor flowability. This study was introduced to design an RPG drug in the form of spherical crystal agglomerates using the spherical agglomeration technique to improve and solve these problems with the drug. Three solvents are used in this technique: a good solvent (acetone), a bad solvent (water), and a bridging liquid (chloroform). Different polymers were added in this process, like HPMC E5, Poloxamer 407, or PEG 6000, in various concentrations as a stabilizer. All developed agglomerates under an optical microscope have a nearly spherical shape with a particle size range of 342.52 to 529.2 μm. The percentage yield was 85.06% to 89.16%, and the drug content was 95.57% to 99.18%. Their flowability considerably improved where angle of repose (23.05 to 29.16), CI (12.73% to 18.92%), and HR (1.15 to 1.23) compared to pure RPG (49.36, 36.84%, and 1.58, respectively). The solubility improved by 1.8 to 3 folds compared to the drug, and the dissolution rate was significantly enhanced in all prepared agglomerates, where the complete release (99.89%) was observed in SA8 after 60 minutes. Scanning Electron Microscopy (SEM) confirmed that the crystals became more regular and spherical in shape. These results concluded that spherical crystallization could be an effective alternative method to improve RPG properties and enhance its bioavailability.

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