SEPARATION OF DIFFERENT IONIC FORMS OF L-Α-Methyldopa AND OTHER AMINO ACIDS BY REVERSED-PHASE ION-PAIR HIGH PERFORMANCE LIQUID CHROMATOGRAPHY

Rembischevski, Peter; Gemal, André Luís

doi:10.1081/jlc-100101736

Cited by 1 publication

(1 citation statement)

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“…The main idea of separation was derived from Rembischevski and Gemal. 15 Mobile phase consisted of Methanol: Buffer at 19:81 v/v ratio. Buffer was prepared as a 20% v/v acetic acid in deionized HPLC water containing 5mM of heptane sulfonic acid as an organic modifier.…”

Section: Methodsmentioning

confidence: 99%

Analytical Investigation of the Possible Chemical Interaction of Methyldopa with Some Reducing Carbohydrates Used as Pharmaceutical Excipients

2018

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Purpose: Assessment of drug substance and excipients compatibility is an important issue during pre-formulation studies as well as the quality control of pharmaceutical dosage forms. In this study, potential incompatibility between methyldopa and reducing excipients was evaluated using physicochemical methods.Methods: Dextrose and lactose (anhydrous & monohydrate) were selected as reducing carbohydrates. The initial incompatibility was studied with DSC and FTIR on binary mixtures with 1:1 mass ratio. Results were confirmed using HPLC studies coupled with mass spectrometry.Results: The DSC curves indicated the elimination of the melting endotherm of methyldopa in the binary mixtures. A new peak at 1719 cm-1 was observed in the FTIR spectra that can be attributed to the loss of type one amine functionality. The m/z of the proposed compound was observed in the mass spectra.Conclusion: The potential incompatibility of Methyldopa with reducing carbohydrates was established using physicochemical methods.

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Section: Methodsmentioning

confidence: 99%