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Physical characterization of nedocromil sodium hydrates
R Khankari1, L Chen, D J Grant
1Department of Pharmaceutics, College of Pharmacy, University of Minnesota, Weaver-Densford Hall, 308 Harvard Street S.E., Minneapolis, Minnesota 55455-0343, USA.
Journal of Pharmaceutical Sciences
|September 2, 1998
Summary
Nedocromil sodium exhibits multiple hydrate phases, including heptahemihydrate, trihydrate, monohydrate, and amorphous forms. Understanding these phases is crucial for optimizing its use in treating obstructive airway diseases like asthma.
Area of Science:
- Pharmaceutical Sciences
- Solid-State Chemistry
Background:
- Nedocromil sodium is a medication used for reversible obstructive airway diseases, such as asthma.
- The drug's efficacy can be influenced by its solid-state form, particularly its hydration state.
Purpose of the Study:
- To characterize the physical and thermodynamic properties of nedocromil sodium's different hydrate phases.
- To determine the stability ranges and dissolution rates of these hydrate forms.
Main Methods:
- Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were used to assess thermal properties.
- Powder X-ray diffraction (PXRD), hot-stage microscopy (HSM), and microbalance studies investigated phase transitions and stability.
- Intrinsic dissolution rate (IDR) and equilibrium solubility measurements evaluated solution behavior.
Main Results:
- Four distinct hydrate phases (heptahemihydrate, trihydrate, monohydrate, amorphous) and an anhydrate were identified.
- Specific relative humidity (RH) ranges determined the stability of crystalline hydrate phases at 22°C.
- Intrinsic dissolution rate decreased in the order: monohydrate > trihydrate > heptahemihydrate.
Conclusions:
- The study elucidates the complex hydration behavior of nedocromil sodium.
- Knowledge of these hydrate phases and their properties is essential for formulation development and therapeutic application of nedocromil sodium.