Phase Equilibria of Nafcillin Sodium-Water
| Autor: | Joseph B. Bogardus |
|---|---|
| Rok vydání: | 1982 |
| Předmět: |
Calorimetry
Differential Scanning Chemistry Analytical chemistry Water Pharmaceutical Science Nafcillin Sodium Nafcillin Crystallography Freeze Drying Differential scanning calorimetry Phase (matter) medicine Thermodynamics Lamellar structure Microscopy Polarization Crystallization Supercooling Eutectic system Phase diagram medicine.drug |
| Zdroj: | Journal of Pharmaceutical Sciences. 71:105-109 |
| ISSN: | 0022-3549 |
| DOI: | 10.1002/jps.2600710125 |
| Popis: | The phase diagram for the binary system nafcillin sodium-water, was determined using differential scanning calorimetry (DSC) and polarized light microscopy. In the temperature range of -20-30 degrees, three crystalline forms and an amphiphilic liquid crystalline phase were detected. The stable crystalline form of nafcillin sodium (form alpha) and water exhibit a eutectic mixture containing 28% drug (w/w) at -1 degrees. In more dilute solutions a lower temperature eutectic (-5 degrees) occurs. The composition and form of nafcillin sodium in this eutectic are not known. The form -5 degrees eutectic was found to be metastable above 28% concentration and converted to form alpha. Two other crystalline forms were observed at 9 degrees (form beta) and 22 degrees (form gamma) at concentrations above 40%. The crystalline forms could not be further characterized due to their transient nature and existence in highly concentrated mixtures. A lamellar mesophase is present near ambient temperature in mixtures containing more than 55% nafcillin sodium. The phase equilibria were highly susceptible to supercooling. Temperature cycling methods were devised which gave reproducible DSC data and allowed construction of the phase diagram. |
| Databáze: | OpenAIRE |
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