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ACS Omega

ACS Omega

IF: 3.7
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Effect of 18-Crown-6 on Oxytocin Stability in Aqueous Buffer Solutions

Published:15 February 2021 DOI: 10.1021/acsomega.0c06248 PMID: 33681619
Mostafa Ghasemisarabbadieh, Sveinbjorn Gizurarson, Benjamín Ragnar Sveinbjornsson*

Abstract

In this study, the effect of 18-crown-6 on the stability of oxytocin in aqueous solution was explored. The study found that while 12-crown-4 and 15-crown-5 do not stabilize oxytocin, 18-crown-6 does have a stabilizing effect in citrate/phosphate buffer at pH 4.5. However, in acetate buffer at the same pH, the presence of 18-crown-6 had a destabilizing effect, possibly leading to a different degradation pathway. Both the stabilizing and destabilizing effects, depending on the buffer used, are concentration dependent where a higher concentration of 18-crown-6 is linked to a stronger effect. It is hypothesized that this effect may be linked to 18-crown-6 binding to the protonated ammonium group of oxytocin. Upon changing the mobile phase used in high-performance liquid chromatography experiments, we observed evidence supporting this binding hypothesis. When an acidic mobile phase was used (0.01% trifluoroacetic acid (TFA)), a partial shift in oxytocin retention time was observed for samples in acetate buffers in the presence of 18-crown-6 when using a 150 mm column (C18). The amount of the peak that shifted depended on the 18-crown-6 concentration used. A similar shift in oxytocin peak retention time was observed for samples in both acetate and citrate/phosphate buffers when using a 250 mm column (C18), but the peak completely shifted in those samples. When using an even more acidic mobile phase (0.1% TFA), the oxytocin peaks all had the same retention time again. Ultraviolet and nuclear magnetic resonance spectroscopy experiments also showed that the presence of 18-crown-6 has an observable effect on the resulting oxytocin spectra.

Substances (8)

Related products
Procduct Name CAS Molecular Formula Supplier Price
Trifluoroacetic acid 76-05-1 C2HF3O2 769 suppliers $9.00-$8444.80
18-Crown-6 17455-13-9 C12H24O6 727 suppliers $5.00-$1652.00
15-Crown-5 33100-27-5 C10H20O5 493 suppliers $8.00-$2571.95
12-Crown-4 294-93-9 C8H16O4 225 suppliers $22.40-$940.53
Dimethylphenylsilane 766-77-8 C8H12Si 197 suppliers $12.00-$1130.40
Oxytocin free acid 24346-32-5 C43H65N11O13S2 99 suppliers Inquiry
METHYL STEARATE 27234-05-5 C19H38O2 51 suppliers Inquiry
Mcilvaine Buffer 1 suppliers Inquiry

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