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Biomedical subjects

G S Brenner

Publications and source records attributed to G S Brenner.

6 recordsLinked to original sources
PubMed1999

Investigation of the polymorphism of the angiotensin II antagonist agent MK-996.

The polymorphism of the angiotensin II antagonist agent MK-996 was studied, with particular emphasis on crystal form stability, solubility, and reproducible crystallization of the drug. X-ray powder diffraction patterns indicated differences in the crystal forms of early research and development lots. Solubility data for the different crystal forms in water at 25 degrees C are in agreement with the solution calorimetry data and indicated that crystalline form I is the thermodynamically stable polymorph of MK-996 under ambient conditions. In contrast to the other polymorphs, form I is reproducibly prepared on both the laboratory and production scale. This study examines methodology to determine the most suitable polymorph for development.

Angiotensin Receptor Antagonists↗
PubMed1979

Cefoxitin sodium: solution and solid-state chemical stability studies.

Studies were undertaken to provide the basic physicochemical information necessary for preparing a suitable parenteral formulation of cefoxitin sodium. Emphasis was placed on the physico-chemical properties of the compound in solution and in the solid state. Cefoxitin sodium is very soluble in water and exhibits apparent first-order decomposition in this medium at pH 3-9. Maximum stability in water is at pH 5-7. Under these pH conditions, cefoxitin sodium loses about 10% of its activity in 2 days at 25 degrees. Thermal decomposition rates for amorphous and crystalline cefoxitin sodium samples were determined. Amorphous cefoxitin sodium was considerably less stable than its corresponding crystalline form. Solid-state decomposition plots are biphasic, displaying initial rapid losses followed by a slower decay period. The extent of loss in the crystalline solid at the end of the more rapid initial phase can be correlated with the water content of the solid.

Biological Assay↗