Development and validation of LC-MS/MS methods to measure tobramycin and lincomycin in plasma, microdialysis fluid and urine: application to a pilot pharmacokinetic research study.

Background The aim of our work was to develop and validate a hydrophilic interaction liquid chromatography-electrospray ionization-tandem mass spectrometry (HILIC-ESI-MS/MS) methods for the quantification of tobramycin (TMC) and lincomycin (LMC)in plasma, microdialysis fluid and urine. Methods Protein precipitation was used to extract TMC and LMC from plasma, while microdialysis fluid and urine sample were diluted prior to instrumental analysis. Mobile phase A consisted of 2 mM ammonium acetate in 10% acetonitrile with 0.2% formic acid (v/v) and mobile phase B consisted of 2 mM ammonium acetate in 90% acetonitrile with 0.2% formic acid (v/v). Gradient separation (80%-10% of mobile phase B) for TMC was done using a SeQuant zic-HILIC analytical guard column. While separation of LMC was performed using gradient elution (100%-40% of mobile phase B) on a SeQuant zic-HILIC analytical column equipped with a SeQuant zic-HILIC guard column. Vancomycin (VCM) was used as an internal standard. A quadratic calibration was obtained over the concentration range for plasma of 0.1-20 mg/L for TMC and 0.05-20 mg/L for LMC, for microdialysis fluid of 0.1-20 mg/L for both TMC and LMC, and 1-100 mg/L for urine for both TMC and LMC. Results For TMS and LMC, validation testing for matrix effects, precision and accuracy, specificity and stability were all within acceptance criteria of ±15%. Conclusions The methods described here meet validation acceptance criteria and were suitable for application in a pilot pharmacokinetic research study performed in a sheep model.

Development of a microsphere-based fluorescence immunochromatographic assay for monitoring lincomycin in milk, honey, beef, and swine urine.

The residue of lincomycin (LIN) in edible animal foodstuffs caused by the widespread use of veterinary drugs is in need of rapid, simple, and sensitive detection methods. The present work introduces a fluorescent microsphere immunoassay (FMIA) for detecting LIN in different samples based on the competitive immunoreaction on the chromatography test strip. The residues of LIN in different samples compete with bovine serum albumin (BSA) labeled LIN conjugates on the T-line to bind to the anti-LIN monoclonal antibody labeled fluorescent microspheres (FM-mAbs). Captured FM-mAbs on the T-line represent the fluorescent intensity, which is detected under UV light and quantified by a fluorescent reader. Under optimized conditions, the dynamic range is from 1.35 to 3.57 ng/mL, and the 50% inhibition concentration (IC50) is 2.20 ng/mL. This method has 4.4% cross-reactivity with clindamycin and negligible cross-reactivity (<0.1%) with other analogues. To reduce the matrix effects, a dilution method is used to pretreat the samples, and the recoveries range from 73.92 to 120.50% with coefficient of variations <21.76%. In comparison with the results of ELISA and colloidal gold immunoassay, FMIA has obvious advantages such as easy operation, time savings, high sensitivity and specificity, and broader prospect.

Determination of lincomycin in urine and some foodstuffs by flow injection analysis coupled with liquid chromatography and electrochemical detection with a preanodized screen-printed carbon electrode.

An electroanalytical method for the determination of lincomycin in feeds, honey, milk and urine was demonstrated in this study. The procedure employed a solid-phase extraction for the isolation of lincomycin from real samples. The antibiotic residues were subsequently analyzed by high-performance liquid chromatography (HPLC) coupled with a disposable electrochemical sensor. The use of a disposable sensor together with the application of solid-phase extraction is attractive in practical application and should be useful in fast screening assay. The electroanalysis of lincomycin was first investigated using a preanodized screen-printed carbon electrode (SPCE*). Note that the SPCE* holds the advantages of low cost and easy to handle. The analytical parameters, such as, preanodization potential, preanodization time, solution pH, detection potential, cartridge, wash solution, elute solution and mobile phase, were further studied in detail. Under optimized conditions, the linear detection range for lincomycin is up to 1mM (correlation coefficient=0.999) with a detection limit of 0.08microM (S/N=3) and a quantification limit of 0.27microM (S/N=10). The applicability of the method was successfully demonstrated in real sample analysis.

Electrochemiluminescence detection with integrated indium tin oxide electrode on electrophoretic microchip for direct bioanalysis of lincomycin in the urine.

In this article, an antibiotic, lincomycin was determined in the urine sample by microchip capillary electrophoresis (CE) with integrated indium tin oxide (ITO) working electrode based on electrochemiluminescence (ECL) detection. This microchip CE-ECL system can be used for the rapid analysis of lincomycin within 40s. Under the optimized conditions, the linear range was obtained from 5 to 100 microM with correlation coefficient of 0.998. The limit of detection (LOD) of 3.1 microM was obtained for lincomycin in the standard solution. We also applied this method to analyzing lincomycin in the urine matrix. The limit of detection of 9.0 microM was obtained. This method can determine lincomycin in the urine sample without pretreatment, which demonstrated that it is a promising method of detection of lincomycin in clinical and pharmaceutical area.

Pharmacokinetics of lincomycin and clindamycin phosphate in a canine model.

Linomycin and clindamycin phosphate were studed in a canine model in which acute biliary obstruction was produced during iv infusion of antibiotic. Hepatic and renal extraction, bilary and renal excretion, and concentrations in liver and kidney were measured. Total and nonesterified clindamycin were assayed. The antibiotics were taken up by the liver at similar rates; however; the rates of excretion and concentration in bile were significantly higher for lincomycin than for clindamycin. Biliary obstruction did not affect the concentration of either antibiotic in canalicular bile. Lincomycin was extracted by the kidneys and excreted into urine at a much higher rate than was clindamycin. Concentrations of nonesterified clindamycin in the hepatic vein were higher than those in the portal vein, an observation suggesting metabolic activation within the liver. This relation was reversed by bilary obstructon. The results in this canine model indicate a greater role for the kedney in the disposition of lincomycin than in that of clindamycin, major differences between the rates of biliary excretion of the two agents, and a probable change in the metabolism of clindamycin procued by acute bilary obstruction.

Microbiological and pharmacological behavior of 7-chlorolincomycin.

Replacement of the 7-(R) hydroxyl group of lincomycin by a 7-chloro-substituent produced a compound with greater in vitro activity than the parent. Laboratory studies of this compound showed it to be highly active against all of the following strains of gram-positive organisms examined, including penicillinase- and nonpenicillinase-producing staphylococci, Diplococcus pneumoniae, Streptococcus viridans and Streptococcus pyogenes. The enterococci, as well as all the gram-negative organisms tested, with the exception of some strains of Haemophilus, were uniformly insensitive to this agent. The activity of 7-chlorolincomycin was not affected by serum or inoculum size. Resistance developed in a slow stepwise pattern. Peak levels of approximately 2 mug/ml were achieved in the serum of volunteers after ingestion of 150 mg either in the fasting state or after a meal. No untoward effects were noted. The antibiotic appears to be of potential value in the treatment of infections due to gram-positive organisms, with the exception of enterococcus.

Study of the use of lincomycin aerosols in dogs.

This paper reports studies on different aspects of the administration of lincomycin by aerosol in dogs.The purpose of the study was to determine the depth of penetration of the drug into the lungs and its transfer into the blood, urine and tissues when administered as an aerosol.Special consideration was given to the possibility of side effects at the level of the bronchial mucosa, since this study was viewed as preliminary to the use of the antibiotic in humans.