Titration of Pharmaceuticals in Nonaqueous Solvents *

Pifer, C. W.; Wollish, E. G.; Schmall, Morton.

doi:10.1002/jps.3030420902

Cited by 47 publications

(14 citation statements)

References 44 publications

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“…The chemical purity of the D-alanine crystals was determined by a non-aqueous titration method (Pifer et al 1953). The optical purity of the crystals was expressed as an enantiometric excess (e.e.…”

Section: Methodsmentioning

confidence: 99%

d-Alanine production from dl-alanine by Candida maltosa with asymmetric degrading activity

Umemura

Yanagiya

Komatsubara

et al. 1992

Appl Microbiol Biotechnol

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To develop a practical process for D-alanine production from oL-alanine, we screened 107 yeasts for their asymmetric degrading activity against DL-alanine. Candida maltosa JCM1504 degraded the L-isomer ten times more rapidly than the D-isomer. The cells of this strain were used as a biocatalyst for eliminating the Lisomer. However, when the degradation reaction was conducted in the presence of a high concentration of DL-alanine, the pH of the reaction mixture was rapidly increased by the liberation of ammonia from L-alanine, and consequently the reaction stopped. This hindrance was overcome by controlling the pH value at 6.0 with H2SO4 during the reaction. Additionally, we found that the maximum rate of L-isomer degradation was obtained at 30°C and pH 6.0 under conditions of high aeration (1.0 vvm) and agitation (1200 rpm). Under the optimal conditions, the L-isomer of 200 g oL-alanine/l was completely degraded within 40 h and 90 g D-alanine/l remained in the reaction mixture, o-Alanine was easily isolated from the reaction mixture. The chemical and optical purity of the D-isomer product so obtained was 99.0% and 99.9% enantiomeric excess, respectively.

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Section: Methodsmentioning

confidence: 99%

d-Alanine production from dl-alanine by Candida maltosa with asymmetric degrading activity

Umemura

Yanagiya

Komatsubara

et al. 1992

Appl Microbiol Biotechnol

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show abstract

“…Often, they are applicable where other methods fail. Excellent reviews on this subject are available (3)(4)(5).…”

Section: He Monograph For Aminoacetic Acid Elixirmentioning

confidence: 99%

The Assay of Aminoacetic Acid Elixir by Nonaqueous Titration*

Meland¹,

Blake²

1956

Journal of the American Pharmaceutical Association (Scientific

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“…In a recent survey, Riddick (1) discusses the theoretical concepts of the reactions involved and j$ves a comprehensive review of the history and development of this procedure, including an excellent bibliography. Pifer, Wollish, and Schmall (2) have collected a great amount of data on the application of this method to the analysis of pharmaceutical preparations. They summarize the advantages of titration in nonaqueous solvents and recommend it for its "specificity, solubility, simplicity, sensitivity] selectivity, accuracy, and precision. '…”

Section: Max Hubacher and Ihor Lysyjmentioning

confidence: 99%