Liquid Chromatographic Analysis of Various Formulations Containing Emtricitabine

A gradient liquid chromatographic (LC) method for control of emtricitabine (FTC) was validated for the analysis of FTC formulations (capsules and oral solution) and fixed-dose-combination tablets containing FTC [FTC combined with tenofovir disoproxil fumarate (TDF) and FTC combined with TDF and efavirenz (EFV)]. The method is based on the purity test recently prescribed in the International Pharmacopoeia and uses a Hypersil BDS C18 column (25 cm × 4.6 mm i.d.), 5 μm kept at a temperature of 35 °C. Other reversed-phase columns were also investigated. The mobile phases for gradient elution consist of acetonitrile, phosphate buffer and water. The flow rate is 1.0 mL min⁻¹ and UV detection is performed at 280 nm. The method is capable of separating the main components from one another, from the inactive ingredients and from the main degradation products. The method was validated with respect to accuracy, precision, sensitivity and linearity for each component and the solution media were optimized. Finally, commercial FTC capsules, FTC oral solution, FTC/TDF tablets and FTC/TDF/EFV tablets were examined.

     

Liquid Chromatographic Analysis of Various Formulations Containing Emtricitabine

A gradient liquid chromatographic (LC) method for control of emtricitabine (FTC) was validated for the analysis of FTC formulations (capsules and oral solution) and fixed-dose-combination tablets containing FTC [FTC combined with tenofovir disoproxil fumarate (TDF) and FTC combined with TDF and efavirenz (EFV)]. The method is based on the purity test recently prescribed in the International Pharmacopoeia and uses a Hypersil BDS C18 column (25 cm × 4.6 mm i.d.), 5 μm kept at a temperature of 35 °C. Other reversed-phase columns were also investigated. The mobile phases for gradient elution consist of acetonitrile, phosphate buffer and water. The flow rate is 1.0 mL min^?1 and UV detection is performed at 280 nm. The method is capable of separating the main components from one another, from the inactive ingredients and from the main degradation products. The method was validated with respect to accuracy, precision, sensitivity and linearity for each component and the solution media were optimized. Finally, commercial FTC capsules, FTC oral solution, FTC/TDF tablets and FTC/TDF/EFV tablets were examined.     

Development of a validated liquid chromatographic method for the determination of related substances and assay of tenofovir disoproxil fumarate

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 cm×4.6 mm I.D.) maintained at a temperature of 30°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 μg/mL and 0.15 mg/mL. The limit of detection and limit of quantification are 0.03 and 0.1 μg/mL, respectively. The method was successfully applied to the quantification of related substances and assay of commercial TDF samples (bulk substances and tablets).     

Development and validation of an LC method for the determination of emtricitabine and related compounds in the drug substance

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×4.6 mm i.d.), 5 μm kept at a temperature of 35°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.     

An improved liquid chromatographic method for the analysis of tylosin and its impurities

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.