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Eutectics and Salt of Dapsone With Hydroxybenzoic Acids: Binary Phase Diagrams, Characterization and Evaluation
Wanya Li1, Peng Shi1, Lina Jia1
1School of Chemical Engineering and Technology, State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin 300072, PR China; The Co-Innovation Center of Chemistry and Chemical Engineering of Tianjin, Tianjin 300072, PR China.
Journal of Pharmaceutical Sciences
|April 16, 2020
Summary
Developing new multicomponent solids of dapsone (DAP) with hydroxybenzoic acids significantly improves its dissolution rate and bioavailability. This strategy, utilizing salt and eutectic formation, offers a promising approach for enhancing poorly soluble drugs.
Area of Science:
- Pharmaceutical Science
- Materials Science
- Drug Delivery
Background:
- Poor solubility and low dissolution rates of drugs like dapsone (DAP), a BCS class IV compound, limit their bioavailability and therapeutic efficacy.
- Multicomponent solid forms represent a promising strategy to overcome these limitations in drug formulation.
Purpose of the Study:
- To synthesize and characterize novel multicomponent solid forms of dapsone (DAP) using hydroxybenzoic acid coformers.
- To investigate the impact of salt and eutectic formation on the dissolution properties of DAP.
- To understand the role of coformer acidity in enhancing drug dissolution.
Main Methods:
- Synthesis of dapsone-based multicomponent solids (salts and eutectics) with hydroxybenzoic acids.
- Characterization using powder X-ray diffraction (PXRD), Differential Scanning Calorimetry (DSC), FT-IR, and Raman spectroscopy.
- Determination of salt stoichiometry and eutectic composition via phase diagrams.
- Computational analysis using molecular electrostatic potential (MEP).
- In vitro dissolution studies and microenvironment pH measurements.
Main Results:
- A new 1:1 salt of DAP with 2,6-dihydroxybenzoic acid (26DHBA) and four eutectics were successfully synthesized and characterized.
- Evidence of ionic interactions confirmed salt formation.
- Molecular electrostatic potential calculations indicated 26DHBA possesses the greatest acidity, correlating with salt formation.
- Both DAP salt and eutectics demonstrated significantly improved dissolution rates and equilibrium concentrations compared to pure DAP.
- Coformer acidity was identified as a key factor influencing dissolution enhancement.
Conclusions:
- The formation of dapsone salts and eutectics with hydroxybenzoic acids effectively enhances drug dissolution and solubility.
- Coformer acidity plays a dominant role in improving the dissolution behavior of these multicomponent systems.
- This study provides a valuable framework for screening coformers to develop improved solid forms of poorly soluble drugs.
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