Determination of Amino Acid Ratios in Plecanatide by DTDPA-OPA Combined with Pre-column Derivatization HPLC
An pre-column derivatization HPLC method with dithiodipropionic acid(DTDPA)and o-phthalaldehyde(OPA)was established to determine the amino acid ratios in plecanatide.The results showed that the quantitative limits were 0.006 9-0.012 7 μmol/mL,the detection limits were 0.003 5-0.006 3 μmol/mL.The linearity and solution stability of all amino acids were good with minimum r of 0.999 6 and the maximum RSD(n=9)of 4.058%.The precision was good with the maximum RSD(n=12)of 2.41%.The mean recoveries(n=9)were 97.32%-101.96%,the maximum RSD was 1.22%.In case of detection parameters slight change,the durability was good with the maximum RSD(n=16)of 1.61%.The established method is specific,accurate and efficient,which can be used for determination of the amino acid ratios of plecanatide.