RESUMEN
The purity of 4,4′-dimethoxy-5,6,5′,6′-bis (methylenedioxy)-2′-morpholine methylenebiphenyl-2-methyl formate methanesulfonate (IMH), a new drug for fatty liver treatment, was determined through differential scanning calorimetry (DSC). Analysis of two-factor non repeatability method was performed in the investigation the effects of two factors (heating rate and sample weight) on purity determination. The DSC experimental parameters were optimized as follows: heating rate was 10 ℃·min-1, temperature range was 150-300 ℃, sample weight was 2.0-4.1 mg, and N2 flow rate was 80 mL·min-1. The linear correlation coefficient (r) of this DSC method was 0.999 8. The RSD value (n = 6) of precision was 0.03%. The standard value and uncertainty of the purity results of the multiple batches of IMH drugs were (99.74 ± 0.29)%, (99.91 ± 0.28)%, (99.90 ± 0.28)%, and (99.81 ± 0.28)% with inclusion factor (K) of 2 and confidence probability (P) of 0.95. The results were basically consistent with the results of the mass balance method. The DSC mehod is a simple, rapid and accurate method, and provides a new reference method for determining the purity of IMH drugs, improves the accuracy and reliability of purity determination.
RESUMEN
Objective To determine the purity of sodium nitrite(NaNO2) using in stray light standard substance which was applied to check semiautomatic clinical chemistry analyzer.Methods Titration was used to determine the purity of NaNO2,the uncertainty of the purity was assessed,and a parallel test was used to validate the uncertainty.Results The purity of NaNO2 was 99.81%,and its uncertainty was 0.86%.Conclusion The uncertainty of the purity passes the validation,it shows that the purity test is credible,and its uncertainty assessment is logical.