Simultaneous determination of ampicillin and metampicillin in biological fluids using high-performance liquid chromatography with column switching

Septic shock due to NSTI caused by Actinomyces Turicensis: the role of clinical pharmacology. Case report and review of the literature

Critical septic patients affected by necrotizing soft tissue infections (NSTI) require an early, aggressive and multidisciplinary treatment. Pharmacokinetic alterations in antibiotic therapy are peculiar in these infections. Clinical pharmacology represents a first step in this setting. We report a case of septic shock due to NSTI in which clinical pharmacology is taken into account.

An UHPLC-MS/MS method for the simultaneous determination of ampicillin and sulbactam in human plasma and urine

BACKGROUND

With few new antibiotics available and an increased prevalence of multidrug-resistant bacteria, optimizing the effectiveness of currently available antibiotics and minimizing the potential for emerging resistance, through PK characterization, is of paramount importance.

RESULTS

Inter- and intra-assay results for ampicillin were within 5% for accuracy and 7% for precision, and for sulbactam within 7% for accuracy and 7% for precision, for both plasma and urine. The plasma Cmax was 38.4 µg/ml for ampicillin and 19.0 µg/ml for sulbactam. The urine concentrations were 668 µg/ml for ampicillin and 438 µg/ml for sulbactam.

CONCLUSION

An UHPLC-MS/MS method to simultaneously measure co-formulated ampicillin and sulbactam in plasma and urine, for use in a patient PK study, has been developed and validated.

Simultaneous determination of methamphetamine and its metabolite, amphetamine, in urine using a high performance liquid chromatography column-switching method

We describe here a simple, precise, and highly sensitive method for the simultaneous determination of methamphetamine (MA) and amphetamine (AM) in urine using a high performance liquid chromatography (HPLC) column-switching method. A PK-2A (Shodex) column was used for extraction and deproteinization, and a CAPCELL PAK SCX semi-micro, polymer-coated cation-exchange column was employed for separation. The urine sample was mixed with an equal volume of borate buffer (0.1M, pH 9.4), and then 100 microl of the mixture was injected into the HPLC column. The column was switched for 6 min, and then 10 min later detection was performed at 210 nm. Recovery yields of the MA and AM spiked in the urine were 93.0-100.4% with a coefficient of variation of less than 1%. The calibration curves of MA and AM were in the range of 0.1-10 microg/ml with good linearity (r(2)=0.999), with the limit of qualification being 0.005 microg/ml. This method of using HPLC with column-switching can be used for both qualification and quantification of MA and its metabolite, AM, in urine, especially in forensic cases.

HPLC for in-process control in the production of sultamicillin

A high-performance liquid chromatographic assay coupled with UV detection (215 nm) was developed for the determination of sultamicillin and its synthesis precursors. The separation of the analytes was performed on a Kromasil C(18) column (15 cm x 4.6 mm i.d., 5 microm) at 20 degrees C. The mobile phase (25 mM phosphate buffer, pH 7.0 and acetonitrile 48%) was pumped at a flow rate of 1.0 ml min(-1). This method is sensitive (limits of detection ranged between 0.4 and 1.2 mg l(-1)) and selective for the determination of sultamicillin and could be used for monitoring different synthetic routes.

Monitoring of ampicillin and its related substances by NMR

A 1H NMR procedure for the monitoring of ampicillin (Amp) and its main related substance in different media, has been developed. The characteristics peak of Amp, 6-aminopenicillanic acid (6-APA), phenylglycine (PhG), and penicilloic acid in the range of 0.5-0.9 and 3.0-4.5 ppm were used for their identification in drugs and serum samples. The quantitative works were performed based on the intensity of protons of the methyl group link to the beta-lactam cyclic of Amp and 6-APA and the aromatic protons of PhG relative to the protons of methylene group of maleic acid, as internal standard, at constant temperature. The resulting data are compared with those obtained with an HPLC method proposed by British Pharmacopoeia. Statistical studies show that, at a confidence limit of %95, there is no significant difference between the two methods. In comparison with the HPLC method, the proposed NMR method does not require any sample pretreatment, standard solution preparation, long analysis time and use of any carcinogenic solvent. The method was applied to the determination of Amp and its related substances in synthetic mixtures, drug powders and serum samples.

Rapid microbore liquid chromatographic analysis of biphenyldimethyl dicarboxylate in human plasma with on-line column switching

A fully automated method including microbore liquid chromatography and column switching was developed for the analysis of biphenyldimethyl dicarboxylate (DDB) from human plasma samples. After direct injection of plasma samples (100 microl) into the system, deproteinization and analyte fractionation occurred on a Capcell Pak MF Ph-1 column (20x4 mm I.D.) and the DDB fraction was transferred from the MF Ph-1 column to an intermediate column (35x2 mm I.D.) using 15% acetonitrile in phosphate buffer (50 mM, pH 7.0). The main separation was performed on a microbore C18 column (150x1.5 mm I.D.) using 45% acetonitrile in water. The method showed excellent sensitivity (detection limit of 5 ng/ml) and good precision (CV.< or =3.0%), and shortened total analysis time (20 min). In the concentration range of 5-200 ng/ml, the mean recovery was 90.7+/-1.8% and the response was linear (r2> or =0.999).

On-line trace enrichment for the simultaneous determination of microcystins in aqueous samples using high-performance liquid chromatography with diode-array detection

The need for a rapid, sensitive and reliable analytical method for cyanobacterial toxins, microcystins, has been emphasized by the awareness of toxic cyanobacteria as a human-health risk through drinking water. A new high-performance liquid chromatographic method with column switching was developed for the determination of microcystin-LR, -RR and -YR from water samples without pre-purification. The filtered water sample was passed through a Zorbax CN precolumn at a flow-rate of 3 ml/min for on-line trace enrichment. After valve switching, concentrated analytes were eluted in back-flush mode and separated on a Luna C18 column with a gradient of acetonitrile -20 mM phosphate buffer (pH 2.5). The method showed excellent precision, accuracy and speed with detection limits of 0.02 microgram/ml from 100 ml of surface water. The total analysis time per sample was about 90 min. This method improves reliability, sensitivity and sample throughput, and shortens the analysis time compared to analysis methods using off-line solid-phase extraction.

Microbore high-performance liquid chromatographic determination of cisapride in rat serum samples using column switching

For the determination of cisapride from serum samples, an automated microbore high-performance liquid chromatographic method with column switching has been developed. After serum samples (100 microl) were directly injected onto a Capcell Pak MF Ph-1 pre-column (10 x 4 mm I.D.), the deproteinization and concentration were carried out by acetonitrile-phosphate buffer (20 mM, pH 7.0) (2:8, v/v) at valve position A. At 2.6 min, the valve was switched to position B and the concentrated analytes were transferred from MF Ph-1 pre-column to a C18 intermediate column (35x2 mm I.D.) using washing solvent. By valve switching to position A at 4.3 min, the analytes were separated on a Capcell Pak C18 UG 120 column (250 x 1.5 mm I.D.) with acetonitrile-phosphate buffer (20 mM, pH 7.0) (5:5, v/v) at a flow-rate of 0.1 ml/min. Total analysis time per sample was 18 min. The linearity of response was good (r=0.999) over the concentration range of 5-200 ng/ml. The within-day and day-to-day precision (CV) and inaccuracy were less than 3.7% and 3.8%, respectively. The mean recovery was 96.5+/-2.4% with the detection limit of 2 ng/ml.

Reversed-phase high-performance liquid chromatographic assay methods for the analysis of a range of penicillins in in vitro permeation studies

Simple, rapid and selective HPLC methods have been developed for the analysis of amoxycillin, ampicillin, epicillin, mecillinam and propicillin. A Hypersil ODS 5 microm (150x4.6 mm I.D.) column was used with mobile phases containing aqueous phosphate buffers, pH 3-4.6 and either methanol or acetonitrile as the organic modifier. Samples were detected by their optimal UV absorption (210-230 nm). The lower limits of quantitation of the compounds (100 microl injection volume) were 0.1 microg/ml. The assays were linear in the range of 0.1-100 microg/ml with r2 values greater than 0.99. The methods have been applied successfully for the measurement of the flux of the compounds across Caco-2 cells monolayers.