ABSTRACT
The compatibility of kanamycin with sodium citrate for the formulation of kanamycin sulfate injection was determined, including optimization of the amount of sodium citrate in the injection and the sterilization process. An HPLC coupled with an evaporative light scattering detector (ELSD) was used to measure the amount of sodium citrate and the impurity profiles. A validated post-column derivatization HPLC coupled with a fluorescence detector (FLD) was used to determine the correlation between specific impurities in a domestic factory and sodium citrate, and then the formulation was evaluated by HPLC coupled with mass detector (MS) characterization of degradation products. The results show that the amount of sodium citrate in kanamycin sulfate injection from a domestic factory is about 40 times higher than that of the Meiji formulation. Several specific impurities can be detected in solutions heated under simulated sterilization conditions (121 ℃), which were correlated with the amount of sodium citrate. Impurities were characterized by HPLC-MS/MS, and data showed that the identified impurities were interaction products of kanamycin and sodium citrate. These results indicate that greater attention should be directed at formula optimization in domestic factories, as it is crucial to the safety and efficacy of the preparations. Drug-excipient chemical compatibility should also be evaluated in the development of pharmaceutical dosages forms especially when the active pharmaceutical ingredients have a primary amine group.
ABSTRACT
OBJECTIVE: To establish a method for analysis of related substances in biapenem with micellar electrokinetic capillary chromatography(MEKC). METHODS: In order to improve the separation selectivity, a zwitterionic surfactant, 3-(N, N-dimethylhexadecylammonium)-propanesulfonate(PAPS) was used. The optimal separation conditions were as follows: the total length of the capillary was 48.5 cm (the effective length was 48 cm), the buffer was 90 mmol•L-1 tris(hydroxymethyl)aminomethane (tris)-phosphate buffer containing 17 mmol•L-1 PAPS and 3 mg•mL-1 polyoxyethylene 23 lauryl ether (Brij 35), the applied voltage was 22 kV, and the capillary temperature was controlled at 30℃. Further more, the specificity, linearity, precision, repeatability, stability and durability were studied. The contents of related substances in biapenem commercial samples were analyzed. RESULTS: The MEKC method, which was a comparable analysis method to HPLC, successfully separated the adjacent impurities of biapenem by using the zwitterionic surfactant PAPS. The specific test showed that this method was especially suitable for the detection of biapenem dimers A, B and open-ring compound. CONCLUSION: In this method, MEKC with zwitterionic surfactant is for the first time applied to the analysis of related substances in biapenem (amphoteric drugs). It provides a feasible analysis method with high sensitivity, good specificity and reproducibility for the quality control of biapenem.
ABSTRACT
OBJECTIVE: To establish an HPLC-MS/MS method to identify the unknown impurities in polymyxin B sulfate. METHODS: The analysis was performed on Agilent 1260-6550 Q/TOF-MS with a Diamonsil Plus C18 column(4.6 mm×250 mm, 5 μm). Mobile phase A was 0.01 mol•L-1 trifluoroacetic acid-acetonitrile(95:5), and mobile phase B was acetonitrile containing 0.1% formic acid. Mobile phase A and B were set at the volume ratio of 79:21 at a flow rate of 1 mL•min-1 under isocratic elution. The detection wavelength was set at 254 nm. ESI source was used. Positive ion scanning was conducted in the range of m/z 50-1 700 for MS and MS/MS. The unknown components were identified by comparing the MS and MS/MS with the known reference standards like polymyxin B1 and B2. The photochemical Paterno-Büchi reaction was performed using a low-pressure mercury lamp as the light source at emission wavelength of 254 nm with acetone/water(50/50, V/V) as the reaction solvent. RESULTS: The structures of seven unknown related substances in polymyxin B sulfate were identified. The most abundant impurity was identified to be vinyl polymyxin B1, for which the double bond was at the end of the fatty acyl residue. CONCLUSION: Vinyl polymyxin B1 is reported for the first time. The method provides a good idea for the identification of related substances in drugs.
ABSTRACT
OBJECTIVE: To develop a suitable HPLC method combined with component preparation to analyze the related substances and effective contents in bacitracin.METHODS: The separation was performed on Agilent HPLC system with a Diamonsil Plus C18 column (4.6 mm×250 mm, 5 μm) using 50 mmol•L-1 ammonium formate (pH adjusted to 4.0 with formic acid) as mobile phase A and acetonitrile as mobile phase B at a flow rate of 1 mL•min-1 under gradient elution. The detection wavelength was set at 254 nm. The HPLC method was carried out by adjusting the pH of ammonium formate solution, the ratio of mobile phase and the solvent. Furthermore, the specificity, linearity, precision, repeatability, stability and durability were studied. The known components like bacitracin A, B1/B2/B3, C1/C2/C3 and F were collected by preparative HPLC according to the HPLC method for bacitracin in USP 40. They were positioned in ammonium formate-acetonitrile HPLC system.RESULTS: The established HPLC method was verified to be suitable for analyzing the related substances and effective contents in bacitracin. Baseline separation between the known components and adjacent impurities was achieved, especially the B1/B2. The elution positions of the known component were clearly defined. The contents of the known components in different batches of bacitracin were compared. More detailed sample information was provided in this research.CONCLUSION: The HPLC method can simultaneously analyze the related substances and effective contents in bacitracin, and is suitable for the quality control of the product.