Thymoquinone (THQ) is known for its neuroprotective and anti-convulsant properties in preclinical studies. We herewith describe a simple, rapid, selective, sensitive and stability-indicating UPLC method for the estimation of THQ and its application to biopharmaceutical studies such as in vitro release from nanoparticulate system and in vivo pharmacokinetic study. The method employed gradient elution using a Waters Acquity HSS-T3 C(18) (100 × 2.1 mm, 1.8 µm) UPLC column. The mobile phase consisted of water and acetonitrile, pumped at a flow rate of 0.5 mL/min. The injection volume was 5 µL and THQ was monitored at 294 nm wavelength with a total run time of 6 min. In solution as well as in plasma, the method was found to be linear (r ≥ 0.998), precise (CV ≤ 2.45%) and accurate (recovery ≥ 84.8%) in the selected concentration range of 0.1-0.8 µg/mL. Forced degradation studies revealed that THQ undergoes degradation under acidic, basic, oxidation and UV light stress conditions. However, the developed UPLC method could effectively resolve degradation product peaks from THQ. Further, no interference was found at the retention time of THQ from any plasma components, indicating selectivity of the developed method. For solutions, the limits of detection and quantitation of the method were found to be 0.001 and 0.0033 µg/mL, respectively; while in plasma they were 0.006 and 0.02 µg/mL, respectively. The validated method was successfully applied to quantify THQ in dissolution medium as well as oral in vivo pharmacokinetic study of THQ suspension and THQ- solid lipid nanoparticle (THQ-SLN) formulation. A 2-fold increase in the relative bioavailability was observed with the THQ-SLN compared with THQ. The results indicate that the SLN significantly increased plasma concentrations and retention within the systemic circulation.

A rapid, specific, and sensitive ultra-performance liquid chromatographic (UPLC) method for quantitative analysis of sparfloxacin in bulk drug and pharmaceutical formulations has been developed and validated. In this work, a new gradient reversed-phase chromatographic method was developed. The newly developed method is applicable for assay determination of the active pharmaceutical ingredient. The chromatographic separation of sparfloxacin was achieved on a Waters Acquity HSS T-3 column (100 x 2.1 mm, 1.8 microm) within a short runtime of 5 min. The method was validated according to the ICH guidelines with respect to system suitability, linearity, limit of quantitation and detection, precision, accuracy, robustness, and specificity. Forced degradation studies were also performed for sparfloxacin bulk drug samples to demonstrate the stability indicating power of the UPLC method. Comparison of system performance with conventional HPLC was made with respect to analysis time, efficiency, and sensitivity. The developed method was applied for the assay of marketed sparfloxacin formulations like tablets and eye drops.

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An attempt was made to develop a single, rapid, specific, and sensitive gradient reversed-phase ultra-performance liquid chromatographic method for quantitative analysis of levofloxacin. The single method thus developed is applied for the quantification of levofloxacin both in aqueous humour as well as pharmaceutical dosage forms (i.e., tablets and eye drops). The newly developed method is applicable for pharmacokinetic studies of eye formulations. The chromatographic separation of levofloxacin was achieved on a Waters Acquity HSS T-3 column (100 x 2.1 mm, 1.8 microm) within a short run-time of 5 min. The method was validated according to the ICH guidelines with respect to system suitability, linearity, limit of quantitation and detection, precision, accuracy, robustness, and specificity. Forced degradation studies were also performed in levofloxacin bulk drug samples to demonstrate the stability-indicating power of the developed ultra-performance liquid chromatography method. The developed method was then successfully applied for the ocular pharmacokinetic study of levofloxacin eye formulations and assay of levofloxacin pharmaceutical dosage form.

Recently, ultra performance liquid chromatography (UPLC) has proven to be one of the most promising developments in the area of fast chromatographic separations, as it's been true to the objective of reducing analysis time and maintaining good efficiency. The present report describes development and validation of a new, rapid, and sensitive UPLC method with UV detection to quantify acyclovir in bulk sample using a Waters Acquity HSS T-3 (100 × 2.1 mm, 1.8 µm) column maintained at a temperature of 50 °C with a gradient elution consisting of 1.0% triethyl amine in water and acetonitrile at a flow rate of 0.4 mL/min and detected at 254 nm. Method was found to be selective, linear, accurate, and precise as per ICH guidelines. Detection and quantitation limits of drug were 3 and 8 ng/mL, respectively.