ABSTRACT
The mineral deposits of the human atherosclerotic aorta were prepared by a new method characterized by the use of mild conditions. Both large and small mineral deposits were isolated from the atherosclerotic plaque and were shown to possess essentially the same chemical composition. The deposits consisted mainly of calcium apatite (71%), carbonate (9%) and contained a relatively high percentage of protein (15%). X-ray diffraction pattern analysis revealed the presence of microcrystals with an average size of approximately 0.1 micron. Electron probe analysis showed that the surface and interior of the mineral deposit had the same chemical composition. However, scanning electron microscopy revealed that the deposits were heterogeneous and consisted of five different structures: (1) individual and conglomerates of smooth-surfaced apheres consisting of spherical layers; (2) spheres consisting of spindle-like, radially arranged particles; (3) fibres forming networks and bundles which sometimes included spherical particles; (4) irregularly shaped particles with fuzzy surfaces and (5) flat plates with smooth surfaces.
Subject(s)
Aorta/analysis , Arteriosclerosis/physiopathology , Minerals , Aorta/ultrastructure , Apatites , Chemical Phenomena , Chemistry , Chemistry, Physical , Electron Probe Microanalysis , Humans , Magnesium , Particle Size , X-RaysABSTRACT
Acetaminophen (I), guaifenesin (II), and dextromethorphan hydrobromide (III) were separated and quantitated simultaneously in cough syrup by high-pressure liquid chromatography. A chemically bonded octadecylsilane stationary phase was used with a mobile phase of 48% (v/v) aqueous methanol. The mobile phase pH was stabilized to 4.2 by adding formic acid--ammonium formate buffer (approximately 0.4%). The internal standard was o-dinitrobenzene. Retention volumes were 4 ml for I, 6 ml for II, 11 ml for the internal standard, and 20 ml for III. Inactive syrup components did not interfere, permitting direct diluted sample injection. Results on active ingredients were essentially 100% of the claim, with standard deviations of +/- 1.5, 1.2, and 2.1% for I, II, and III, respectively.
Subject(s)
Acetaminophen/analysis , Dextromethorphan/analysis , Guaifenesin/analysis , Levorphanol/analogs & derivatives , Antitussive Agents/analysis , Chromatography, High Pressure Liquid , Drug Combinations , MethodsABSTRACT
A collaborative study of the USP high-pressure liquid chromatographic assay for folic acid was performed. Two samples were analyzed in duplicate by 14 participating laboratories. Relative standard deviations for a single determination (RSDS) ranged from +/-0.40 to +/-2.39%. Based on an analysis of variance, it was concluded that the method of peak measurement was a major determinant of reproducibility and that graphical measurement was associated with a high standard deviation. Adequate resolution was obtained using a variety of columns and operating conditions. The interlaboratory RSDS was +/-1.8%.
Subject(s)
Folic Acid/analysis , Chromatography, High Pressure Liquid , Leucovorin/analysis , Methods , Quality ControlABSTRACT
A rapid method for extraction of dyes from tablet-coating formulations is described. The dyes were released from their lakes by treatment with concentrated phosphoric acid and dissolved in methanol. After being made alkaline with ammonium hydroxide, the mixture was centrifuged to obtain a clear supernate for application to the TLC plate. With ethyl acetate--methanol--water--concentrated ammonium hydroxide (150:40:35:5) on silica gel, 20 dyes were separated sufficiently to confirm their presence in the coating formulation.
