RESUMEN
Objective: To establish a simple,rapid and novel Rayleigh light scattering(RLS)method for rapid determination of mexiletine hydrochloride in drugs. Methods: In the presence of acid Tris-HCl medium and cetylpyri- dinium bromide,eosin Y reacted with mexiletine hydrochloride to form a ternary ion association complex with two charac- teristic scattering peaks by electrostatic attraction. The detection wavelengths were 368 and 586 nm. There was a linear relationship between the mexiletine hydrochloride concentration in a certain range and the Rayleigh light scattering en- hancement intensity(ΔIRLS)of the association complex. Single-wavelength Rayleigh scattering(SWO-RLS)method or dualwavelength Rayleigh light scattering(DWO-RLS)method was used to determine the content of mexiletine hydrochloride, and the mexiletine hydrochloride content was calculated according to the regression equation of standard curve. Results: The linear ranges of mexiletine hydrochloride were 0.005-0.65 mg/L(SWO-RLS method,368 nm),0.004-0.65 mg/L (SWO-RLS method,586 nm)and 0.004-0.65 mg/L(DWO-RLS method,368 nm+586 nm),respectisely. Detection lim- its were 0.0033(SWO-RLS method,368 nm),0.0040(SWO-RLS method,586 nm)and 0.0018 mg/L(DWO-RLS method, 368 nm+586 nm),respectisely. The recovery and relative standard deviation(RSD,n=5)for a SWO-RLS method were 98.6-103% and 1.4-1.8%,respectively(SWO-RLS method,368 nm). Conclusion: The method is simple,rapid, highly sensitive and high selectie.
RESUMEN
OBJECTIVE: To compare several common staining and detection methods using NFS-60 cells for biological activity test of recombinant human granulocyte colony stimulating factor (rhG-CSF). METHODS: The biological activity of rhG-CSF was detected using some common methods, named NFS-60 cells/MTT staining, NFS-60 cells/MTS staining, NFS-60 cells/CCK-8 staining, and NFS-60 cells/fluorescence staining. The biological activity was detected using the NFS-60 cells/MTT method using dual wavelength (570 nm detection, 630 nm reference) and single wavelength (570nm detection and 630nm detection). The biological activity was detected using NFS-60 cells/MTS dynamic detection method and NFS-60 cell/CCK-8 dynamic method. Then, the results were analyzed and compared. RESULTS: The different methods were not significantly different (P>0.05); the difference between the dual wavelength detection and single wavelength detection of NFS-60 cells/MTT was not significant (P>0.05). The results from NFS-60 cells/MTS dynamic detection method, NFS-60 cells/CCK-8 dynamic method and NFS-60 cells/MTT method had not significant difference (P>0.05). CONCLUSION: The biological activity determination results of the tested methods using NFS-60 cells are consistent. This study provides basis for utilization of results from different laboratories using different methods, support for expansion of the biological activity detection method of rhG-CSF in Chinese Pharmacopoeia, and reference for expansion of the biological activity detection method of other cytokines.
RESUMEN
Phasing of lysozyme crystals using co-crystallized barium ions was performed using single-wavelength anomalous diffraction (SAD) method using Cu Kα radiation with in-house source of data collection. As the ion binding sites vary with respect to the pH of the buffer during crystallization, the highly isomorphic forms of lysozyme crystals grown at acidic and alkaline pH were used for the study. Intrinsic sulphur anomalous signal was also utilized with anomalous signal from lower occupancy ions for phasing. The study showed that to solve the structure by SAD technique, 2.8-fold data redundancy was sufficient when barium was used as an anomalous marker in the in-house copper X-ray radiation source for data collection. Therefore, co-crystallization of proteins with barium containing salt can be a powerful tool for structure determination using lab source.