• Home
  • Search Results
  • Impurity profiling of carbocisteine by HPLC-CAD, qNMR and UV/vis spectroscopy.

Impurity profiling of carbocisteine by HPLC-CAD, qNMR and UV/vis spectroscopy.

Journal of pharmaceutical and biomedical analysis (2014-03-19)
Oliver Wahl, Ulrike Holzgrabe
ABSTRACT

For the impurity profiling of the mucolytic and anti-inflammatory drug carbocisteine a high performance liquid chromatographic (HPLC) method using corona charged aerosol detection (CAD) was developed and fully validated following the ICH guideline Q2(R1). The response was linear (R²>0.995) over a small concentration range (0.05-0.25 or 0.10-0.60% respectively) and a detection limit of at least 0.03% was registered. The separation was achieved on a mixed mode column combining hydrophobic C18 and strong cation exchange retention mechanisms using a mass spectrometer compatible volatile mobile phase consisting of trifluoroacetic acid 10 mM and acetonitrile 12% (V/V). Impurities, not assessable by HPLC-CAD such as the volatile chloroacetic acid and the unstable cysteine, were determined by quantitative NMR (qNMR) with maleic acid as internal standard and UV/vis spectroscopy after reaction with Ellman's reagent, respectively. Six batches of three different manufacturers were tested by means of those methods. The purity varied from below 99.0 to higher than 99.8 per cent. The major impurities of all batches were the starting material cystine and N,S-dicarboxymethylcysteine being a synthesis by-product.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Acetonitrile, suitable for HPLC, gradient grade, ≥99.9%
Sigma-Aldrich
Acetonitrile, anhydrous, 99.8%
Sigma-Aldrich
Deuterium oxide, 99.9 atom % D
Sigma-Aldrich
Trifluoroacetic acid, suitable for HPLC, ≥99.0%
Sigma-Aldrich
Trifluoroacetic acid, ReagentPlus®, 99%
Sigma-Aldrich
Ammonium hydroxide solution, ACS reagent, 28.0-30.0% NH3 basis
Sigma-Aldrich
Sodium hydroxide, reagent grade, ≥98%, pellets (anhydrous)
Sigma-Aldrich
Sodium hydroxide, ACS reagent, ≥97.0%, pellets
Sigma-Aldrich
Sodium hydroxide solution, 50% in H2O
Sigma-Aldrich
Potassium phosphate monobasic, ACS reagent, ≥99.0%
Sigma-Aldrich
Sodium hydroxide, BioXtra, ≥98% (acidimetric), pellets (anhydrous)
Sigma-Aldrich
Potassium phosphate monobasic, powder, suitable for cell culture, suitable for insect cell culture, suitable for plant cell culture, ≥99.0%
Sigma-Aldrich
Sodium hydroxide solution, BioUltra, for molecular biology, 10 M in H2O
Sigma-Aldrich
5,5′-Dithiobis(2-nitrobenzoic acid), ≥98%, BioReagent, suitable for determination of sulfhydryl groups
Sigma-Aldrich
Sodium hydroxide solution, 1.0 N, BioReagent, suitable for cell culture
Sigma-Aldrich
Maleic acid, ReagentPlus®, ≥99% (HPLC)
Sigma-Aldrich
Ammonium hydroxide solution, 28% NH3 in H2O, ≥99.99% trace metals basis
Sigma-Aldrich
Acetonitrile, for HPLC, for UV, ≥99.9% (GC)
Sigma-Aldrich
Acetonitrile, suitable for HPLC, gradient grade, ≥99.9%
Sigma-Aldrich
Potassium phosphate monobasic, ReagentPlus®
Sigma-Aldrich
Glycolic acid, ReagentPlus®, 99%
Sigma-Aldrich
Acetonitrile solution, contains 0.1 % (v/v) trifluoroacetic acid, suitable for HPLC
Sigma-Aldrich
Trifluoroacetic acid, puriss. p.a., suitable for HPLC, ≥99.0% (GC)
Supelco
Sodium hydroxide concentrate, 0.1 M NaOH in water (0.1N), Eluent concentrate for IC
Sigma-Aldrich
Acetonitrile, ACS reagent, ≥99.5%
Sigma-Aldrich
Sodium hydroxide, puriss., meets analytical specification of Ph. Eur., BP, NF, E524, 98-100.5%, pellets
Sigma-Aldrich
Chloroacetic acid, ACS reagent, ≥99.0%
Sigma-Aldrich
Potassium phosphate monobasic, for molecular biology, ≥98.0%
Supelco
Sodium hydroxide solution, 49-51% in water, eluent for IC
Sigma-Aldrich
Deuterium oxide, 99.9 atom % D, contains 0.05 wt. % 3-(trimethylsilyl)propionic-2,2,3,3-d4 acid, sodium salt