ABSTRACT
Objective To improve the related substances analysis method of cobamamide.And to further research light degradation characteristics of cobamamide.Methods Determined the related substances of solid and aqueous solution of cobamamide after light degradation by high performance liquid chromatography(HPLC) conditions,which is Merck Hibar C18 column (4.6 mm ×250 mm, 5μm), 0.05 mol/L KH2PO4 solution:acetonitrile (90:10) -80% acetonitrile as mobile by gradient elution and detection wavelength 260 nm.And compared their light stability.The main three kinds of light degradation impurities were determinate from LC-MS.Results Gradient elution made the light degradation impurities separate better.The results of precision and reproducibility tests increased to RSD =0.2% (n=6) and RSD =8% (n=5) from RSD =3.8% (n =6) and RSD=38%(n=5). Cobamamide solution was very sensitive to light, the preparation should be strict dark operation.Two of the light degradation impurities were adenosine and hydroxycobalamin, with the relative response factor 2.5 and 0.7.Conclusion New method is specific, durable and reproducible, which can be used for quality control of cobamamide.
ABSTRACT
Objective To establish the dissolution curves test method of Ribavirin capsules, and investigate dissolution behavior of domestic Ribavirin capsules.To provide experimental basis for generic drugs quality consistency evaluation.Methods According to the first dissolution method (basket method)stated in appendix Ⅹof Chinese Pharmacopeia(2010 edition),the rotation speed was 50 r/min with dissolution medium volume of 900 mL.The dissolution profiles of Ribavirin capsules in four different mediums( pH 1.2 hydrochloric acid solution,pH 4.5 acetic buffer,pH 6.8 phosphate buffer and water) were determined by HPLC.The determination was performed on C18 column with mobile phase consisted of 4 g/L sodium dihydrogen phosphate solution(pH adjusted to 5.0 ±0.05 using 5% sodium hydroxide solution)-acetonitrile(98:2)at the flow rate of 1.0 mL/min.The detection wavelength was 225 nm,and sample size was 10μL.Results The linear range of ribavirin was 2.5-200μg/mL(r=1).RSD of precision and stability tests were lower than 0.5%.The average recoveries were 101.3%, 100.7%, 100.2%, 100.4% in four mediums.Dissolution behavior of capsules can be more consistent and rapid dissolution in pH4.5 and pH6.8 mediums.But they were quite different in pH1.2 and water mediums, and some of their average dissolution at 15 min could not reach 85%.Conclusion This method is accurate and reliable.There is a difference between domestic Ribavirin capsules dissolution behavior, and the formulation processes have room for improvement.
ABSTRACT
Objective To analyze peroxide value and anisidine value of ethyl polyenoate soft capsules and imported drugs and evaluate the oxidative stability.Methods The analysis was carried out on a TSK gel ODS-100 V(250 mm ×4.6 mm,5μm)with methanol-water(98:2,V/V)as the mobile phase to determine the structure of the vitamin E as antioxidant.The influence on the antioxidation effect of tocopherol acetate andα-tocopherol as excipient in omega-3 polyunsaturated fatty acid ethyl ester drugs was evaluated.Results The structure of vitamin E as antioxidant in domestic drugs was acetate, while vitamin E as excipient in foreign drugs had the structure of α-tocopherol monomer.As antioxidant, the antioxidation effect of tocopherol acetate was better thanα-tocopherol.The structure of vitamin E had a direct impact on the antioxidation effect of omega-3 polyunsaturated fatty acid ethyl ester drugs.Conclusion The studies provide the basis for evaluate rationality of antioxidant in ethyl polyenoate soft capsules scientifically, which has positive significance for controlling the quality of the drug effectively.