Stability study of Prulifloxacin and Ulifloxacin in human plasma by HPLC-DAD.

A new and specific HPLC-DAD method for the direct determination of Prulifloxacin and its active metabolite, Ulifloxacin, in human plasma has been developed. Plasma samples were analysed after a simple solid phase extraction (SPE) clean-up using a new HILIC stationary phase based high-performance liquid chromatography (HPLC) column and an ammonium acetate buffer (5 mM, pH 5.8)/acetonitrile (both with 1% Et(3)N, v/v) mobile phase in isocratic elution mode, with Danofloxacin as the internal standard. Detection was performed using DAD from 200 to 500 nm and quantitative analyses were carried out at 278 nm. The LOQ of the method was 1 µg/mL of the cited analytes and the calibration curve showed a good linearity up to 25 µg/mL. For both analytes the precision (RSD%) and the trueness (bias%) of the method fulfil with International Guidelines. The method was applied for stability studies, at three QC concentration levels, in human plasma samples stored at different temperature of + 25, + 4 and -20 °C in order to evaluate plasma stability profiles.

Microextraction by packed sorbent and HPLC-PDA quantification of multiple anti-inflammatory drugs and fluoroquinolones in human plasma and urine.

We developed and validated an analytical method based on microextraction packed sorbent (MEPS) and high-performance liquid chromatography (HPLC) coupled to photodiode array (PDA) detector to simultaneously quantify multiple nonsteroidal anti-inflammatory drugs (NSAIDs) and fluoroquinolones (FLQs), which may provide as combination several adverse reactions in nephrology and neurology. The linearity range from LOQs (0.1 µg/mL) to 10 µg/mL, and LODs values were 0.03 µg/mL for both NSAIDs and FLQs. The validation was performed according to international guidelines and the accuracy was tested measuring the precision, intermediate precision and trueness. The drugs stability was tested under different storage conditions (+4 °C and -20 °C) and after three different cycles of freezing and thawing. The method can be a suitable tool to simultaneously detect a possible association of drugs in human biological samples and provide several potentialities for clinical applications, bioequivalence studies, pharmacodynamics and toxicodynamics of different pharmaceutical dosage forms showing NSAIDs and FLQs.

Analytical methods for the endocrine disruptor compounds determination in environmental water samples.

The potential risk of exposure to different xenobiotics, which can modulate the endocrine system and represent a treat for the wellness of an increasing number of people, has recently drawn the attention of international environmental and health agencies. Several agents, characterized by structural diversity, may interfer with the normal endocrine functions that regulate cell growth, homeostasis and development. Substances such as pesticides, herbicides, plasticizers, metals, etc. having endocrine activity (EDCs) are used in agriculture and industry and are also used as drugs for humans and animals. A difficulty in the analytical determination of these substances is the complexity of the matrix in which they are present. In fact, the samples most frequently analyzed consist of groundwater and surface water, including influent and effluent of wastewater treatment plants and drinking water. In this review, several sample pretreatment protocols, assays and different instrumental techniques recently used in the EDCs determination have been considered. This review concludes with a paragraph in which the most recent hyphenated-instrument techniques are treated, highlighting their sensitivity and selectivity for the analyses of environmental water samples.

Simultaneous determination of eperisone hydrochloride and paracetamol in mouse plasma by high performance liquid chromatography-photodiode array detector.

This paper reports the validation of a quantitative high performance liquid chromatography-photodiode array (HPLC-PDA) method for the simultaneous analysis, in mouse plasma, of eperisone hydrochloride and paracetamol by protein precipitation using zinc sulphate-methanol-acetonitrile. The analytes were resolved on a Gemini C18 column (4.6 mm × 250 mm; 5 µm particle size) using a gradient elution mode with a run time of 15 min, comprising re-equilibration, at 60°C (± 1°C). The method was validated over the concentration range from 0.5 to 25 µg/mL for eperisone hydrochloride and paracetamol, in mouse plasma. Ciprofloxacin was used as Internal Standard. Results from assay validations show that the method is selective, sensitive and robust. The limit of quantification of the method was 0.5 µg/mL for eperisone hydrochloride and paracetamol, and matrix-matched standard curves showed a good linearity, up to 25 µg/mL with correlation coefficients (r(2))≥ 0.9891. In the entire analytical range the intra and inter-day precision (RSD%) values were ≤ 1.15% and ≤ 1.46% for eperisone hydrochloride, and ≤ 0.35% and ≤ 1.65% for paracetamol. For both analytes the intra and inter-day trueness (bias%) values ranged, respectively, from -5.33% to 4.00% and from -11.4% to -4.00%. The method was successfully tested in pharmacokinetic studies after oral administration in mouse. Furthermore, the application of this method results in a significant reduction in terms of animal number, dosage, and improvement in speed, rate of analysis, and quality of pharmacokinetic parameters related to serial blood sampling.

Microextraction by packed sorbent and high performance liquid chromatography determination of seven non-steroidal anti-inflammatory drugs in human plasma and urine.

This paper reports a new MEPS-HPLC-PDA method for the simultaneous analysis of seven non-steroidal anti-inflammatory drugs (Furprofen, Indoprofen, Ketoprofen, Fenbufen, Flurbiprofen, Indomethacin, and Ibuprofen) in human plasma and urine. NSAIDs were resolved on a Gemini C18 column (4.6 mm × 250 mm; 5 µm particle size) using a gradient elution mode with a run time of 25 min, comprising re-equilibration, without further purification. The method was validated over the concentration range from 0.1 to 10 µg/mL for all the analytes both in human plasma and urine, using Benzyl 4-hydroxybenzoate as the internal standards. This method was successfully tested to NSAIDs analyses in real matrices, in order to check the method potentiality and the correct response. The results from assay validations show that the method is selective, sensitive and robust. The limit of quantification of the method was 0.1 µg/mL for all analytes, and weighted-matrix-matched standard curves showed a good linearity up to 10 µg/mL. In order to check the correct response for over-range samples, parallelism tests were also assessed. In the entire analytical range the intra and inter-day precision (RSD%) values were ≤ 7.31% and ≤ 13.5%, respectively. For all the analytes the intra and inter-day trueness (Bias%) values ranged from -11.3% to 10.2%. To our knowledge, this is the first MEPS-HPLC-PDA based method that uses MEPS procedure for simultaneous determination of these seven NSAIDs in plasma and urine samples.