Preparation, structural analysis, and properties of tenoxicam cocrystals.

Cocrystals of tenoxicam, a non-steroidal anti-inflammatory drug, are screened, prepared, and characterized in this study. Nine tenoxicam cocrystals were identified using solvent-drop grinding (SDG) techniques. Structural characterization was performed using powder X-ray diffraction (PXRD), differential scanning calorimetry, and multinuclear solid-state NMR (SSNMR).

Preparation and structural characterization of amorphous spray-dried dispersions of tenoxicam with enhanced dissolution.

Tenoxicam is a poorly soluble nonsteroidal anti-inflammatory drug. In this work, the solubility of tenoxicam is enhanced using amorphous spray-dried dispersions (SDDs) prepared using two molar equivalents of l-arginine and optionally with 10%-50% (w/w) polyvinylpyrrolidone (PVP). When added to the dispersions, PVP is shown to improve physical properties and also assists in maintaining supersaturation in solution.

Characterization, selection, and development of an orally dosed drug polymorph from an enantiotropically related system.

Solid-state characterization methods are used to study a dimorphic pharmaceutical compound and select a form for development. Polymorph screening found that [4-(4-chloro-3-fluorophenyl)-2-[4-(methyloxy)phenyl]-1,3-thiazol-5-yl] acetic acid can crystallize into two non-solvated polymorphs designated Forms 1 and 2. Physical methods including vibrational spectroscopy, X-ray powder diffraction, solid-state NMR (SSNMR), thermal analysis, and gravimetric water vapor sorption are used to fully characterize the two polymorphs.

Enantiotropically-related polymorphs of {4-(4-chloro-3-fluorophenyl)-2-[4-(methyloxy)phenyl]-1,3-thiazol-5-yl} acetic acid: crystal structures and multinuclear solid-state NMR.

Single crystal X-ray diffraction (SCXRD), powder X-ray diffraction (PXRD), and solid-state NMR (SSNMR) techniques are used to analyze the structures of two nonsolvated polymorphs of {4-(4-chloro-3-fluorophenyl)-2-[4-(methyloxy)phenyl]-1,3-thiazol-5-yl} acetic acid. These polymorphs are enantiotropically-related with a thermodynamic transition temperature of 35 +/- 3 degrees C. The crystal structure of Form 1, which is thermodynamically more stable at lower temperatures, was determined by SCXRD.

Charge neutralization in the ESEM for quantitative X-ray microanalysis.

Quantitative chemical analysis by energy-dispersive X-ray spectrometry (EDS) in the environmental scanning electron microscope (ESEM) is difficult. This analysis is complicated by the spread of the electron beam by chamber gas molecules and the necessity for surface charge neutralization. Without charge neutralization, errors in quantitative analysis can range up to 15-20% relative.

Accuracy and precision of quantitative energy-dispersive x-ray spectrometry in the environmental scanning electron microscope.

The accuracy and precision of quantitative energy-dispersive x-ray spectrometry in the environmental scanning electron microscope have been estimated using a series of copper / gold alloys of known composition. The mean values (five to six replicate experiments) had relative errors within +/- 5%, and most were within +/- 3.5%.

Copper Oxide Precipitates in NBS Standard Reference Material 482.

Copper oxide has been detected in the copper containing alloys of NBS Standard Reference Material (SRM) 482. This occurrence is significant because it represents heterogeneity within a standard reference material that was certified to be homogeneous on a micrometer scale. Oxide occurs as elliptically to spherically shaped precipitates whose size differs with alloy composition.