Column-switching high-performance liquid chromatographic method for the determination of zaltoprofen in rat plasma

Economical spectrophotometric method for estimation of zaltoprofen in pharmaceutical formulations

Aim:

A simple, rapid, precise, and economical spectrophotometric method has been developed for quantitative analysis of zaltoprofen (ZLT) in pharmaceutical formulations.

Materials and Methods:

A mixture of methanol and water was used as a solvent. Initial stock solution of ZLT was prepared in methanol and subsequent dilution was done in water. The standard solution of ZLT in water showed two absorption maxima, one at 243.5 nm and another at 338.0 nm.

Results:

The drug obeyed Beer–Lambert's law in the concentration range of 1–40 μg/mL with regression 0.9999 at 243.5 nm and 5–100 μg/mL with regression 0.9999 at 338.0 nm. The overall % recovery was found to be 99.53% and 99.77% at 243.5 nm and 338.0 nm, respectively, which reflect that the method is free from interference of the impurities and other additives used in tablet formulation. Relative standard deviations of absorbance from six measurements were always less than 2%.

Conclusions:

The results of analysis have been validated as per ICH guidelines. Both the wavelengths can be adopted in routine analysis of ZLT in tablet dosage form.

Chiral pharmacokinetics of zaltoprofen in rats by HPLC with solid-phase extraction

We investigated the pharmacokinetic profile of (R)- and (S)-zaltoprofen (ZPF) in rats using rapid and selective liquid chromatography with solid-phase extraction (SPE). The ZPF enantiomers were extracted from a small volume of plasma (0.2 mL) by means of SPE using cartridges and were analyzed on a Chiralcel OJ-H (4.6 mm × 150 mm, 5 μm) column with ultraviolet detection at 244 nm. The lower limit of quantification of the ZPF enantiomers in plasma was 0.1μg/mL. The validated method was successfully applied to chiral pharmacokinetic studies of oral administration of racemic ZPF to rats. (S)-ZPF showed significantly higher AUC, T(max), and C(max) and a longer half-life than (R)-ZPF, indicating higher bioavailability of the (S)-isomer. A total of 8 samples (about 12% of the total number of samples) were selected for incurred sample reanalysis (ISR). The % difference between the re-assay concentrations and the original concentrations were all less than 15% of their mean values and met the acceptance criteria for ISR.

Biosynthesis and stereoselective analysis of (-)- and (+)-zaltoprofen glucuronide in rat hepatic microsomes and its application to the kinetic analysis

Zaltoprofen, available commercially as a racemic mixture, is a propionic acid derivative of non-steroidal anti-inflammatory drugs (NSAIDs). Firstly, (+)- and (-)-zaltoprofen glucuronide was biosynthesized and purified. Then a simple and rapid RP-HPLC analysis method for direct determination of (+)- and (-)-zaltoprofen glucuronide in rat hepatic microsomes was developed and validated. The calibration curves of (+)- and (-)-zaltoprofen glucuronide both showed good linearity in the concentration range from 0.15 to 31.13 μM. The lower limit of quantification was 0.15 μM. Finally, this method was used to investigate the enantioselectivity of zaltoprofen glucuronidation in rat hepatic microsomes. The kinetics of zaltoprofen glucuronidation in rat hepatic microsomes for 40 min incubation fit the Michaelis-Menten model. Kinetic analysis indicated that (-)-zaltoprofen had a higher glucuronidation rate in rat liver microsome than that of (+)-zaltoprofen. The catalyzing efficiency (V(max)/K(m)) ratio of (+)-zaltoprofen to (-)-enantiomer is 0.8 times in rat liver microsomes.

Application of column-switching HPLC method in evaluating pharmacokinetic parameters of zaltoprofen and its salt

The objective of this study was to compare the pharmacokinetic parameters of zaltoprofen and those of its sodium salt in rats. Zaltoprofen, a potent non-steroidal anti-inflammatory agent, was virtually insoluble in water, but its sodium salt had excellent water solubility. To investigate the effect of aqueous solubility differences upon their pharmacokinetic parameters, minicapsules containing the drug powders were administrated orally to rats, and blood samples were taken via the common carotid artery. A column-switching high-performance liquid chromatographic analytical procedure was developed and validated for the quantitation of zaltoprofen in rat plasma samples. Our study demonstrated that the time required to reach maximum plasma concentration (T(max)) of zaltoprofen sodium was significantly reduced and its maximum plasma concentration (C(max)) was increased 1.5-fold, relative to the values for zaltoprofen. It is anticipated that the sodium salt of zaltoprofen will allow the rapid onset of the drug's action in the treatment of inflammatory diseases.

Determination of the active metabolites of sibutramine in rat serum using column-switching HPLC

A simple and direct analysis using column-switching HPLC method was developed and validated for the quantification of active metabolites of sibutramine, N-mono-desmethyl metabolite (metabolite 1, M1) and N-di-desmethyl metabolite (metabolite 2, M2) in the serum of rats administered sibutramine HCl (5.0 mg/kg, p.o.). Rat serum was directly injected onto the precolumn without sample prepreparation step following dilution with mobile phase A, i. e., methanol-ACN-20 mM ammonium phosphate buffer (pH 6.0 with phosphoric acid) (8.3:4.5:87.2 by volume). After the endogenous serum components were eluted to waste, the system was switched and the analytes were eluted to the trap column. Active metabolites M1 and M2 were then back-flushed to the analytical column for separation with mobile phase B, i. e., methanol-ACN-20 mM ammonium phosphate buffer (pH 6.0 with phosphoric acid) (35.8:19.2:45 by volume) and detected at 223 nm. The calibration curves of active metabolites M1 and M2 were linear in the range of 0.1-1.0 microg/mL and 0.15-1.8 microg/mL. This method was fully validated and shown to be specific, accurate (10.4-10.7% error), and precise (1.97-8.79% CV). This simple and rapid analytical method using column-switching appears to be useful for the pharmacokinetic study of active metabolites (M1 and M2) of sibutramine.

The Effect of Zaltoprofen on Physiotherapy for Limited Shoulder Movement in Breast Cancer Patients: A Single-Blinded Before-After Trial

OBJECTIVE

To determine the efficacy of oral administration of zaltoprofen on shoulder range of motion (ROM) exercises for breast cancer patients after surgery.

DESIGN

Single-blind, before-after trial.

SETTING

Rehabilitation facility in a Japanese university hospital.

PARTICIPANTS

Forty breast cancer patients (age range, 37-72y) with limited shoulder movement after surgery.

INTERVENTION

Single session of physiotherapy (PT) with or without oral administration of zaltoprofen.

MAIN OUTCOME MEASURES

Active shoulder ROM in flexion, abduction, and external rotation, as well as subjective pain score during shoulder movements.

RESULTS

Active shoulder movements after ingesting a zaltoprofen tablet significantly improved in flexion, abduction (P<.001), and external rotation (P<.005). PT treatment improved flexion and abduction ROM in both the zaltoprofen and control groups and led to significantly larger flexion and abduction movements in the zaltoprofen group than in the control group (P<.01). There were no differences in pain scores between groups, but 2 patients who did not receive zaltoprofen complained of increased pain just after ROM exercises.

CONCLUSION

Zaltoprofen taken orally before ROM exercises for painful shoulder after breast cancer surgery may enhance the effects of PT.

Identification of metabolites of 4,4'-methylenedianiline in vascular smooth muscle cells by liquid chromatography-electrospray tandem mass spectrometry

A capillary liquid chromatography-electrospray tandem mass spectrometry (LC-ES-MS/MS) method was developed for the identification of metabolites of 4,4'-methylenedianiline (diaminodiphenyl methane, (DAPM)) derived from exposure of vascular smooth muscle cells (VSMC) to this compound. The use of precolumn concentration and column switching techniques prior to reversed-phase liquid chromatography coupled online to ES-MS enabled the separation and detection of low-level DAPM and its metabolites in the exposed cell samples. The employed LC-ES-MS method, and further LC-ES-MS/MS analysis enabled the structural assignments for two DAPM metabolites from vascular smooth muscle cells: N-acetyl methylenedianiline (N-acetyl-DAPM) and N,N'-diacetyl methylenedianiline (N,N'-diacetyl-DAPM).

Determination of zaltoprofen in human plasma by liquid chromatography with electrospray tandem mass spectrometry: Application to a pharmacokinetic study

In the present study, we developed a method coupling liquid-liquid extraction (LLE) to high-performance liquid chromatography (HPLC) with positive ion electrospray ionization tandem mass spectrometry (ESI-MS/MS) to determine zaltoprofen levels in human plasma, using enalapril as internal standard (IS). The high sensitivity and specificity of MS/MS detection enabled the use of small plasma volumes (250 microL) and a simple LLE procedure. Furthermore, the short run-times (2 min) involved are compatible with the requirements of large-scale clinical studies. Ion acquisition was performed in multiple reaction monitoring (MRM) mode by monitoring the transitions m/z 299.3 > 225.0 for zaltoprofen and m/z 377.4 > 234.2 for the IS enalapril. The limit of detection (LOD) was 0.01 microg/mL and the lower limit of quantitation (LLOQ) was 0.05 microg/mL. The devised method was linear over the studied range (0.05-20 microg/mL), with r2 > 0.99 and a run-time of 2 min. Intra-day precisions fell in the range 2.0-13.8%, inter-day precisions in the range 2.1-3.9%, and intra- and inter-day accuracies in the range 102.8-114.1%. The described method provides a fast and sensitive analytical tool for zaltoprofen and was successfully applied to a 24-subject pharmacokinetic study.