Quantitative determination of fenoterol and fenoterol derivatives in rat plasma using on-line immunoextraction and liquid chromatography/mass spectrometry

Hydrophilic Interaction Liquid Chromatography (HILIC): Latest Applications in the Pharmaceutical Researches

Background:

Significant advances have been occurred in analytical research since the 1970s by Liquid Chromatography (LC) as the separation method. Reverse Phase Liquid Chromatography (RPLC) method, using hydrophobic stationary phases and polar mobile phases, is the most commonly used chromatographic method. However, it is difficult to analyze some polar compounds with this method. Another separation method is the Normal Phase Liquid Chromatography (NPLC), which involves polar stationary phases with organic eluents. NPLC presents low-efficiency separations and asymmetric chromatographic peak shapes when analyzing polar compounds. Hydrophilic Interaction Liquid Chromatography (HILIC) is an interesting and promising alternative method for the analysis of polar compounds. HILIC is defined as a separation method that combines stationary phases used in the NPLC method and mobile phases used in the RPLC method. HILIC can be successfully applied to all types of liquid chromatographic separations such as pharmaceutical compounds, small molecules, metabolites, drugs of abuse, carbohydrates, toxins, oligosaccharides, peptides, amino acids and proteins.

Objective:

This paper provides a general overview of the recent application of HILIC in the pharmaceutical research in the different sample matrices such as pharmaceutical dosage form, plasma, serum, environmental samples, animal origin samples, plant origin samples, etc. Also, this review focuses on the most recent and selected papers in the drug research from 2009 to the submission date in 2020, dealing with the analysis of different components using HILIC.

Results and Conclusion:

The literature survey showed that HILIC applications are increasing every year in pharmaceutical research. It was found that HILIC allows simultaneous analysis of many compounds using different detectors.

Green Approaches to Sample Preparation Based on Extraction Techniques

Preparing a sample for analysis is a crucial step of many analytical procedures. The goal of sample preparation is to provide a representative, homogenous sample that is free of interferences and compatible with the intended analytical method. Green approaches to sample preparation require that the consumption of hazardous organic solvents and energy be minimized or even eliminated in the analytical process. While no sample preparation is clearly the most environmentally friendly approach, complete elimination of this step is not always practical. In such cases, the extraction techniques which use low amounts of solvents or no solvents are considered ideal alternatives. This paper presents an overview of green extraction procedures and sample preparation methodologies, briefly introduces their theoretical principles, and describes the recent developments in food, pharmaceutical, environmental and bioanalytical chemistry applications.

Hydrophilic interaction chromatography in drug analysis

Hydrophilic interaction chromatography (HILIC) is an increasingly popular alternative to conventional HPLC for drug analysis. It offers increased selectivity and sensitivity, and improved efficiency when quantifying drugs and related compounds in complex matrices such as biological and environmental samples, pharmaceutical formulations, food, and animal feed. In this review we summarize HILIC methods recently developed for drug analysis (2006–2011). In addition, a list of important applications is provided, including experimental conditions and a brief summary of results. The references provide a comprehensive overview of current HILIC applications in drug analysis.

Fenoterol enantiomers do not possess beneficial therapeutic properties of their racemic mixture in the rat model of post myocardial infarction dilated cardiomyopathy

PURPOSE

A salutary effect of β(2) adrenergic receptor (AR) agonist, fenoterol has been demonstrated in a rat model of post-myocardial infarction (MI) dilated cardiomyopathy (DCM). Recent reports on single cardiomyocyte experiments suggested that out of two enantiomers, RR and SS, that constitute a racemic mixture of fenoterol, only RR-enantiomer is an active component that might be a promising new drug for treatment of chronic heart failure. The objective of this study was to compare the efficacy of the RR enantiomer of fenoterol with efficacy of racemic fenoterol, and SS, an inactive enantiomer, in whole animal experimental models of DCM.

METHODS

Two weeks after induction of MI by permanent ligation of the anterior descending coronary artery early cardiac remodeling and MI size were assessed via echocardiography and rats were divided into treatment groups. Treatment (placebo, racemic fenoterol, RR- or SS-enantiomers of fenoterol) continued for 6 months while progression of DCM was followed by serial echocardiography.

RESULTS

Compared with untreated rats, rats treated with racemic fenoterol demonstrated previously described attenuation of LV remodeling, functional decline and the arrest of the MI expansion during the first 2 months of treatment. On the contrary, the treatment with either RR-, or with SS-enantiomers of fenoterol was completely ineffective.

CONCLUSION

The conclusion drawn on the basis of previous experiments with single cardiomyocytes that RR-enantiomer of fenoterol represents an active component of racemic fenoterol and can be further investigated as a new drug for treatment of chronic heart failure was not confirmed in the whole animal model of DCM.

LC–MS/MS bioanalytical challenge: ultra-high sensitivity assays

Anne-Françoise Aubry is Director of Bioanalytical Sciences at Bristol-Myers Squibb Co., leading a team in developing bioanalytical methods for early development drug candidates in support of toxicology and clinical studies. Her main research interests are high-speed, high-resolution LC and new approaches for LC–MS/MS drug bioanalysis in regulated laboratories. Anne Aubry is on the executive board of the Eastern Analytical Symposium and on the organizing committee of the Applied Pharmaceutical Analysis and Chemical and Pharmaceutical Structure Analysis (Shanghai 2011) conferences.

The challenges of developing and running low pg/ml LC–MS/MS bioanalytical assays in a regulated laboratory are reviewed. The practical problems encountered in implementing ultrasensitive assays are less in reaching a suitable sensitivity on the instrument than in implementing procedures to control losses and contamination, eliminate matrix interferences and ensure assay robustness so that the assay can be validated to industry standards. Solutions to these problems can be found in each of the three facets of the bioanalytical assay: the sample preparation, the chromatographic separation and the mass spectrometric detection. The key to developing an ultrasensitive assay is to optimize each of these elements. Progress in MS instrumentation has been essential in our ability to reach the low pg/ml limits.

Pharmacokinetics and metabolism of (R,R)-methoxyfenoterol in rat

(R,R)-fenoterol (Fen), a beta(2)-adrenoceptor agonist, is under clinical investigation in the treatment of congestive heart disease. The pharmacokinetics and metabolism of the 4-methoxyphenyl derivative of (R,R)-Fen, (R,R)-MFen, have been determined following intravenous and oral administration to the rat and compared with corresponding results obtained with (R,R)-Fen. Results from the study suggest that (R,R)-MFen can offer pharmacokinetic and metabolic advantages in comparison to an earlier (R,R)-Fen. The oral administration revealed that the net exposure of (R,R)-MFen was about three-fold higher than that of (R,R)-Fen (7.2 versus 2.3 min x nmol ml(-1)), while intravenous administration proved that the clearance was significantly reduced, 48 versus 146 ml min(-1) kg(-1), the T(1/2) was significantly longer, 152.9 versus 108.9 min, and the area under the curve (AUC) was significantly increased, 300 versus 119 min x nmol ml(-1). (R,R)-MFen was primarily cleared by glucuronidation associated with significant presystemic glucuronidation of the compound. After intravenous and oral administration of (R,R)-MFen, (R,R)-Fen and (R,R)-Fen-G were detected in the urine samples indicating that (R,R)-MFen was O-demethylated and subsequently conjugated to (R,R)-Fen-G. The total (R,R)-Fen and (R,R)-Fen-G as a percentage of the dose after intravenous administration was 3.6%, while after oral administration was 0.3%, indicating that only a small fraction of the drug escaped presystemic glucuronidation and was available for O-demethylation. The glucuronidation pattern was confirmed by the results from in vitro studies where incubation of (R,R)-MFen with rat hepatocytes produced (R,R)-MFen-G, (R,R)-Fen and (R,R)-Fen-G, while incubation with rat intestinal microsomes only resulted in the formation of (R,R)-MFen-G.