摘要:

AbstractAnalytical methods using thin-layer and high pressure liquid chromatographic techniques were developed and utilized for measuring decreases in bitolterol concentrations as a function of time. Pseudo first-order hydrolysis rate constants were determined and shown to be strongly dependent upon pH and solvent polarity for this catecholamine diester. The activation energy was calculated as 18 kilocalories per mole for bitolterol in aqueous buffer solution both with or without 25% alcohol. Large reductions in rate constants as a function of dielectric constant were demonstrated and illustrate that solvent polarity effects may be important for drug stabilization.

ISSN:0363-9045    

DOI:10.3109/03639047909055658

出版商:Taylor&Francis    

年代:1979

数据来源: Taylor

摘要:

AbstractForty percent alcohol in simulated gastric fluid was used as a dissolution medium for two griseofulvin dosage forms. Rank-order correlation of dissolution profiles with plasma levels was obtained.The use of this partially organic dissolution medium for griseofulvin dosage forms is suggested as a convenient alternative to entirely aqueous media employed in large volumes (18 to 72 liters per dosage form).

ISSN:0363-9045    

DOI:10.3109/03639047909055659

出版商:Taylor&Francis    

年代:1979

数据来源: Taylor

摘要:

AbstractThe pharmacokinetic parameters defining the percutaneous absorption of salicylic acid in rabbits have been investigated. A one compartment open model with apparent first order absorption was found to describe adequately the blood level data.

ISSN:0363-9045    

DOI:10.3109/03639047909055660

出版商:Taylor&Francis    

年代:1979

数据来源: Taylor

摘要:

AbstractInterrelationships among moisture, hardness, disintegration and dissolution in compressed tablets were studied by compressing tablets from granulations prepared by the wet granulation process containing low moisture levels. Hardness, disintegration and dissolution of these tablets did not change on exposure to ambient room conditions. After equilibration under high humidities, a decrease in tablet hardness occurred which depended linearly on tablet hardnesses at the time of compression. After overnight exposure to ambient room conditions, the softened tablets increased in hardness and this increase greatly exceeded the initial hardnesses. The magnitude of hardness increase was independent of the hardnesses at the time of compression. Increased tablet hardnesses resulted in an increase in the disintegration time, althoughin vitrodissolution of the drug remained unaffected. The results suggest that moisture gain and subsequent loss on storage under varying humidity conditions could account for major increases in hardness of compressed tablets in storage.

ISSN:0363-9045    

DOI:10.3109/03639047909055661

出版商:Taylor&Francis    

年代:1979

数据来源: Taylor

摘要:

AbstractThe decrease in geometric mean particle size during wet ball milling follows a reciprocal relationship, which predicts an initial rapid rate of comminution, followed by a slow rate of reduction which develops into a situation where the mean particle size virtually remains constant. The initial rate is directly dependent on the weight of the balls, but the final particle size is an inverse function of ball size. Under these conditions the size distributions follow the Gaudin-Schumann equation. The patterns of behaviour breaks down when the process is limited by the viscosity of the charge, preventing the balls from moving within the mill. This occurs when either the solid to liquid ratio of the charge is high or when the balls are small.

ISSN:0363-9045    

DOI:10.3109/03639047909055662

出版商:Taylor&Francis    

年代:1979

数据来源: Taylor

摘要:

AbstractEthanolic solutions of vanillin, used as food flavouring are readily decomposed by the action of sunlight to 6,6′-dihydroxy-5,5′-dimethoxy-1,1′-biphenyl-3,3′-dicarbaldehyde (dehydrodi–vanillin). The decomposition is accompanied by the formation of a yellow colour and a slightly bitter taste. The U.S. Pharm–acopoeia (1975) spectroscopie assay of vanillin would be in–appropriate for samples contaminated with dehydrodivanillin, since the absorption maxima of vanillin are at 279 and 311 nm whereas the maxima for dehydrodivanillin are 279, 310nm with a shoulder at 337 nm.

ISSN:0363-9045    

DOI:10.3109/03639047909055663

出版商:Taylor&Francis    

年代:1979

数据来源: Taylor

摘要:

AbstractN,N-Dialkyloxamides show potent antifungal activity againstPityrosporum ovalewhen used as solutions in polar solvents. The antifungal activity deteriorates rapidly due to decomposition of the oxamides in solution

ISSN:0363-9045    

DOI:10.3109/03639047909055664

出版商:Taylor&Francis    

年代:1979

数据来源: Taylor