Water Determination in Erythromycin A and Erythromycin by Karl Fischer Titration

Erythromycin is a common antibiotic used for the treatment of bacterial infections. Standard erythromycin contains four related compounds, erythromycin A, B, C and D. Each of them has different antibacterial activity, where erythromycin A is the most active.

During the Karl Fischer titration of different erythromycin samples we found out that they can behave differently. Erythromycin A undergoes a pH-dependant side reaction causing unstable endpoints, so the working medium needs additional buffering. In a sample declared as Erythromycin only, the end points have been much more stable and standard reagents can be used. Both one-component and two-component volumetric titration is recommended.

Hydranal-Water Standard 10.0, Hydranal-Water Standard 1.0, and Hydranal-Standard Sodium Tartrate Dihydrate are suitable for determination of the titer or control of the volumetric determination.

Download the full Laboratory Report for Erythromycin A and Erythromycin (L 242) here

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Volumetric reagents: Coulometric reagents: Auxiliaries:
34805 HYDRANAL-Composite 534741 HYDRANAL-Methanol dry37817 HYDRANAL-Methanol Rapid34804 HYDRANAL-Buffer Acid34801 HYDRANAL-Titrant 534800 HYDRANAL-Solvent 34849 HYDRANAL-Water Standard 10.034425 HYDRANAL-CRM Water Standard 10.034828 HYDRANAL-Water Standard 1.0
34426 HYDRANAL-CRM Water Standard 1.034696 HYDRANAL-Standard Sodium Tartrate
34424 HYDRANAL-CRM Sodium Tartrate Dihydrate
34241 HYDRANAL-Molecular Sieve 0.3 nm34788 HYDRANAL-Humidity Absorber
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