ABSTRACT
A selective reversed-phase (RP) liquid chromatographic (LC) method coupled with UV for the determination of tylosin and its related substances is described. The gradient method uses a Capcell pak C18 ACR column (25 cm×4.6 mm id, 5 µm) maintained at a temperature of 60°C. The mobile phases consist of acetonitrile, phosphate buffer pH 5.5 and water: (A; 27.5:10:62.5 v/v/v) and (B; 50:10:40 v/v/v). The flow rate is 1.0 mL/min and UV detection is performed at 280 nm. It allows the separation of all known and 22 other unknown related substances (≥0.02%) from the main compound and from one another. The method shows good precision, sensitivity, linearity (between 0.2 µg/mL and 1.25 mg/mL) and robustness. The limit of quantification is 0.2 µg/mL, corresponding to 0.020%. Seven bulk tylosin samples containing a large number of impurities were examined using this method.
Subject(s)
Anti-Bacterial Agents/analysis , Chromatography, High Pressure Liquid/methods , Tylosin/analysis , Drug Contamination , Sensitivity and SpecificityABSTRACT
The present study describes the development and validation of a selective liquid chromatographic (LC) method for the analysis of tenofovir disoproxil fumarate (TDF) and its related substances. The gradient method uses a base deactivated C18 column (Hypersil BDS column; 25 cmx4.6 mm I.D.) maintained at a temperature of 30 degrees C. The mobile phases consist of acetonitrile, tetrabutylammonium/phosphate buffer pH 6.0 and water: (A; 2:20:78 v/v/v) and (B; 65:20:15 v/v/v). The flow rate is 1.0 mL/min and UV detection is performed at 260 nm. Good separation of TDF and 21 impurities was achieved. A system suitability test (SST) to check the quality of separation is also specified. The developed method was further validated with respect to robustness, precision, sensitivity and linearity. The method is proved to be robust, precise, sensitive and linear between 0.1 microg/mL and 0.15 mg/mL. The limit of detection and limit of quantification are 0.03 and 0.1 microg/mL, respectively. The method was successfully applied to the quantification of related substances and assay of commercial TDF samples (bulk substances and tablets).
Subject(s)
Adenine/analogs & derivatives , Chromatography, Liquid/methods , Organophosphonates/analysis , Reverse Transcriptase Inhibitors/analysis , Adenine/analysis , Limit of Detection , Reproducibility of Results , Spectrophotometry, Ultraviolet , TenofovirABSTRACT
A selective gradient liquid chromatographic (LC) method for the determination of oxytocin (OT) and its related substances in bulk drugs has been developed. The method uses a reversed-phase C18 column (25 cm x 4.0 mm i.d.), 5 microm kept at 40 degrees C. The mobile phases consist of acetonitrile, dihydrogen phosphate solution pH 4.4 and water. The flow rate is 1.0 ml/min. UV detection is performed at 220 nm. A system suitability test (SST) was developed to govern the quality of the separation. The separation towards OT components was investigated on different C18 columns. The developed method was further validated with respect to robustness, precision, sensitivity and linearity. A central composite design was applied to examine the robustness of the method. The method shows good precision, sensitivity, linearity and robustness. Two commercial OT samples were examined using this method. Furthermore, the method proved to be successful when applied to analyze a marketed OT formulation for injection.
Subject(s)
Chromatography, Liquid/methods , Oxytocics/analysis , Oxytocin/analysis , Drug Contamination , Injections , Reproducibility of ResultsABSTRACT
A robust, precise, sensitive, linear, and simple RP LC method coupled with UV for the determination of emtricitabine or 2',3'-dideoxy-5-fluoro-3'-thiacytidine (FTC) and its related substances is described. The method uses an RP C18 column (25 cm x 4.6 mm i.d.), 5 microm kept at a temperature of 35 degrees C. The mobile phases for gradient elution consist of ACN, phosphate buffer (pH 4.4), and water. The flow rate is 1.0 mL/min and UV detection is performed at 280 nm. A system suitability test (SST) was developed to verify the adequate performance of the chromatographic system. The developed method was further validated with respect to robustness, precision, sensitivity, and linearity. A central composite design was applied to examine the robustness of the method. The method shows good precision, sensitivity, linearity, and robustness. Three commercial FTC samples were examined using this method. This method is suitable to be used for the determination of related substances and assay of FTC.
Subject(s)
Chromatography, Liquid/methods , Deoxycytidine/analogs & derivatives , Chromatography, Liquid/instrumentation , Chromatography, Liquid/standards , Deoxycytidine/analysis , Emtricitabine , Molecular Conformation , Sensitivity and Specificity , Stereoisomerism , Time Factors , Ultraviolet RaysABSTRACT
A gradient LC method for the analysis of capreomycin sulfate and its related substances was developed. The chromatographic conditions include the use of a Hypersil base deactivated C(18) (250 mm x 4.6mm, 5 microm) column maintained at 25 degrees C, a mobile phase containing acetonitrile, phosphate buffer pH 2.3 and 0.025M hexanesulfonate at a flow rate of 1.0 mL/min and UV detection performed at 268 nm. Good separation of the four active components of capreomycin and eleven unknown impurities was achieved. A system suitability test to check the quality of the separation is specified. The method shows good repeatability, linearity and robustness.
Subject(s)
Anti-Bacterial Agents/analysis , Capreomycin/analysis , Chromatography, Liquid/methods , Drug Contamination , Drug Stability , Hydrogen Peroxide/chemistry , Hydrolysis , Least-Squares Analysis , Linear Models , Models, Chemical , Reproducibility of Results , Sensitivity and Specificity , TemperatureABSTRACT
A gradient LC method for the determination of related substances in ritonavir (RTV) has been recently published in the International Pharmacopoeia. The method uses a base-deactivated reversed-phase C18 column kept at a temperature of 35 degrees C. The mobile phases consist of acetonitrile, phosphate buffer pH 4.0 and water. UV detection is performed at 240 nm. A system suitability test (SST) is described to govern the quality of the separation. Since no brand names of columns are mentioned in pharmacopoeial texts, analysts often have problems to select a suitable stationary phase which is only described in general terms. So, the separation towards RTV components was investigated on 18 C18 columns and correlation was made with the column classification system developed in our laboratory. The method was further evaluated using a Hypersil BDS C18 column (25 cm x 4.6mm i.d.), 5 microm, which was also used for the development of the method. A central composite design was applied to examine the robustness of the method. The method shows good precision, linearity, sensitivity and robustness. Four commercial samples were examined using this method.
