Green Automated Solid Phase Extraction to Measure Levofloxacin in Human Serum via Liquid Chromatography with Fluorescence Detection for Pharmacokinetic Study

A simple, selective, rapid, sensitive and less costly green automated solid phase extraction bio-analytical high-performance liquid chromatographic-based technique with fluorescence detection (Aut-SPE-BA-HPLC-FL) for the quantification of levofloxacin in human serum samples has been developed and validated. The serum samples were loaded into the chromatographic system without prior treatment and then injected into short (20 mm × 4.6 mm, 20 µm) protein-coated (PC) µBondapak CN (µBCN) silica pre-column (PC-µBCN-pre-column). Levofloxacin was retained and pre-concentrated on the head of the PC-µBCN-pre-column, while proteins and other polar components were eliminated using phosphate buffer saline (PBS), pH 7.4, as the first mobile phase in the extraction step. Levofloxacin is then transferred to the analytical column; ZORBAX Eclipse XDB-C18 (150 mm × 46 mm, 5 µm), through the aid of a column-switching valve technique, on-throughs the elution mode using the second mobile phase containing a methanol and phosphate buffer (0.05 M, pH 5) in a ratio of 70:30 (v/v). Levofloxacin signals were detected using a fluorescence detector operated at excitation/emission wavelengths of 295/500 nm. The proposed Aut-SPE-BA-HPLC-FL methodology showed linearity over a levofloxacin concentration range of 10–10,000 ng/mL (r2 = 0.9992), with good recoveries ranging from 87.12 to 97.55%. Because of the validation qualities in terms of linearity, recovery, precision, accuracy, selectivity and robustness, the Aut-SPE-BA-HPLC-FL method has been used in some clinical trials for therapeutic drug monitoring and the pharmacokinetic study of levofloxacin in human serum.

Methods for the analysis of fluoroquinolones in biological fluids

Methods for the analysis of ten selected fluoroquinolone antibiotics in biological fluids are reviewed. Approaches for sample preparation, detection methods, limits of detection and quantitation, and recovery information are provided for both single analyte and multi-analyte fluoroquinolone methods.

Simple extractive colorimetric determination of levofloxacin by acid-dye complexation methods in pharmaceutical preparations

Two simple and sensitive extractive spectrophotometric methods have been described for the assay of levofloxacin (LVFX) either in pure form or in pharmaceutical formulations. The developed methods involve formation of colored chloroform extractable ion-pair complexes (1:1 and 1:2 drug/dye) of levofloxacin with bromophenol blue (BPB) and bromocresol green (BCG) in aqueous acidic medium. The extracted complexes showed absorbance maxima at 424 and 428 nm for LVFX-BPB and LVFX-BCG, respectively. Beer's law is obeyed in the concentration ranges 1.85-31.5 and 1.85-25 microg ml(-1) with BPB and BCG, respectively. The methods have been applied to the determination of drug in commercial tablets. Results of analysis were validated statistically. The excipients present in the formulations do not interfere with the assay procedure.

Interindividual variability in the absorption of ciprofloxacin and hydrocortisone from continent ileal reservoir for urine

OBJECTIVE

The neobladder created with a detubularized segment of ileum as standard treatment for the transitional cell carcinoma of the bladder may permit absorption of drugs. As a consequence, on the one hand the elimination of drugs excreted in the urine may be delayed and a change of dosage may be required, and on the other hand the intravesical administration of a drug may produce blood levels capable of inducing unwanted systemic effects. The purpose of the present study was to explore the possibility of drug absorption from a continent ileal reservoir for urine.

METHODS

The possibility of drug re-absorption from a continent ileal reservoir for urine was studied in 12 patients with well functioning reservoirs after a time interval of 3 months from surgery and also, in 7 of them, 6 months later. Saline solutions of ciprofloxacin or hydrocortisone were instilled and maintained in the reservoir for 2 h, and drug concentrations in plasma were measured 1 and 2 h after instillation.

RESULTS

Both ciprofloxacin and to a lower extent hydrocortisone were adsorbed from the reservoir, but with large interindividual variability. A comparison of the plasma concentrations produced by the two drugs 3 and 9 months after creation of the new bladder revealed that after 9 months the absorption was decreased in 3 patients, substantially unchanged in 2, and increased in 2.

CONCLUSIONS

The results of this study show that both ciprofloxacin, chosen for its use as possible radiosensitizing agent in bladder cancer patients, and hydrocortisone, chosen as an example of lypofilic endogenous compound, can be absorbed through the intestinal mucosa of a continent ileal reservoir, but to a different extent and with high interindividual variability.