Simultaneous determination of atorvastatin and niacin in human plasma by LC-MS/MS and its application to a human pharmacokinetic study

A review on liquid chromatographic methods for the bioanalysis of atorvastatin

Background

The unsatisfied clinical need has encouraged the development and validation of bioanalytical procedures for the quantification of drugs in biological samples because the monitoring of drug concentrations helps in personalizing the patient’s pharmacotherapy, assessing the adherence to therapy, and is also extensively useful for pharmacokinetics and drug-drug interactions studies.

Main Body

The present review aimed to provide insightful information about the various liquid chromatographic methods developed till 2019 for the analysis and quantification of atorvastatin, its metabolites, and co-administered drugs in the various biological matrices like the serum, plasma, and urine with special emphasis on sample preparation techniques applied before chromatographic analysis along with different chromatographic conditions and their validation data. A total of 88 published papers that have used liquid chromatography techniques to quantify atorvastatin in biological fluids are included in the study. Out of the total reported liquid chromatographic methods, 34% used UV spectrophotometer as a detector, and 55% used MS/MS as a detector. Whereas 38% of them used protein precipitation procedure, 33% applied liquid-liquid extraction approach, and 12% employed solid-phase extraction technique for sample preparation.

Conclusion

In the last decade, numerous bioanalytical procedures have been developed for the quantification of atorvastatin in different biological samples using liquid chromatographic techniques. Moreover, advancement in technology developed several new and advanced sample preparation approaches like dispersive liquid-liquid extraction, microextraction by packed sorbent, which have high recovery rates than conventional procedures. Thus, the summarized review may be consulted as an informative tool to support the optimization of new bioanalytical methods for the quantification of atorvastatin.

Microdosing Cocktail Assay Development for Drug-Drug Interaction Studies

Methodology for analysis of a microdosing drug cocktail designed to evaluate the contribution of drug transporters and drug metabolizing enzymes to disposition was developed using liquid chromatography-mass spectrometry-based detection. Fast and sensitive methods were developed and qualified for the quantification of statins (pitavastatin, pitavastain lactone, rosuvastatin, atorvastatin, 2-hydroxy, and 4-hydroxy atorvastatin), midazolam, and dabigatran in human plasma. Chromatographic separation was accomplished using reversed-phase liquid chromatography or hydrophilic interaction liquid chromatography with gradient elution and detection by tandem mass spectrometry in the positive ionization mode using electrospray ionization. The lower limit of quantitation (LLOQ) for the statins assay was 1 pg/mL for the 6 analytes with a linear range from 1 to 1000 pg/mL processing 250 μL plasma sample. The midazolam assay LLOQ was 0.5 pg/mL with a linear range of 0.5 to 1000 pg/mL. For the dabigatran assay, the LLOQ was 10 pg/mL with a linear range of 10 to 5000 pg/mL processing 100 μL plasma sample. The intraday and interday precision and accuracy of the assays were within acceptable ranges, and the assays were successfully applied to support a study where a microdose cocktail was dosed to healthy human subjects for simultaneous assessment of clinical drug-drug interactions mediated by major drug transporters and CYP3A.

Quantification of Niacin and Its Metabolite Nicotinuric Acid in Human Plasma by LC-MS/MS: Application to a Clinical Trial of a Fixed Dose Combination Tablet of Niacin Extended-Release/Simvastatin (500 mg/10 mg) in Healthy Chinese Volunteers

Our paper aimed to develop rapid, sensitive, and specific LC-MS/MS method for the quantification of niacin (NA) and its metabolite nicotinuric acid (NUA) in human plasma. Following protein precipitation with acetonitrile, the NA, NUA, and internal standard (5-fluorouracil) were separated on a Zorbax 300SB-C8 column (250 mm × 4.6 mm, 5 μm) with a mobile phase consisting of methanol-2 mM ammonium acetate (3 : 97, v/v) at a flow rate of 1 mL/min (split 1 : 1). A tandem mass spectrometer equipped with electrospray ionization source was used as the detector and operated in negative ion mode. The linear concentration ranges of the calibration curves were 5-800 ng/mL for NA and NUA. The intra-assay RSD for quality control (QC) samples were from 5.0% to 8.7% for NA, and 5.5% to 7.6% for NUA. The interassay RSD for QC samples were from 2.8% to 9.4% for NA, and 3.7% to 5.8% for NUA. The relative errors for QC samples were from -2.2% to 2.3% for NA, and -0.6% to 3.2% for NUA. The method was successfully applied to the investigation of the pharmacokinetic profiles of NA, NUA in human after single dose administration of Niacin extended-release/Simvastatin tablet (500 mg/10 mg).

A critical review of microextraction by packed sorbent as a sample preparation approach in drug bioanalysis

Sample preparation is widely accepted as the most labor-intensive and error-prone part of the bioanalytical process. The recent advances in this field have been focused on the miniaturization and integration of sample preparation online with analytical instrumentation, in order to reduce laboratory workload and increase analytical performance. From this perspective, microextraction by packed sorbent (MEPS) has emerged in the last few years as a powerful sample preparation approach suitable to be easily automated with liquid and gas chromatographic systems applied in a variety of bioanalytical areas (pharmaceutical, clinical, toxicological, environmental and food research). This paper aims to provide an overview and a critical discussion of recent bioanalytical methods reported in literature based on MEPS, with special emphasis on those developed for the quantification of therapeutic drugs and/or metabolites in biological samples. The advantages and some limitations of MEPS, as well as its comparison with other extraction techniques, are also addressed herein.

Development and validation of a liquid chromatography-tandem mass spectrometry method for simultaneous determination of amlodipine, atorvastatin and its metabolites ortho-hydroxy atorvastatin and para-hydroxy atorvastatin in human plasma and its application in a bioequivalence study

A sensitive, simple and rapid high-performance liquid chromatography coupled with positive ion electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS) method was developed for the simultaneous determination of amlodipine, atorvastatin and its metabolites ortho-hydroxy atorvastatin and para-hydroxy atorvastatin in human plasma. The analytes were extracted from human plasma through liquid-liquid extraction method. A mixture of methyl tert-butyl ether and ethyl acetate (50:50, v/v) was used as the extractant. The chromatographic separation was achieved on a CAPCELLPAK CR 1:4 (5 μm, 150 mm × 2.0 mm i.d.) column within 6.0 min with the mobile phase consisted of acetonitrile and ammonium acetate buffer (20mM) containing 0.3% formic acid (50:50, v/v). Data acquisition was carried out in multiple reaction monitoring (MRM) mode. The method was validated and was successfully applied to the bioequivalence study of combination tablets containing AM and AT with coadministered individual drugs in 50 healthy Chinese male volunteers.

Stress Degradation Behavior of Atorvastatin Calcium and Development of a Suitable Stability-Indicating LC Method for the Determination of Atorvastatin, its Related Impurities, and its Degradation Products

A rapid, reversed-phase liquid chromatographic method was developed for the quantitative determination of Atorvastatin calcium, its related substances (12 impurities), and degradation impurities in bulk drugs. The chromatographic separation was achieved on a Zorbax Bonus-RP column by employing a gradient elution with water–acetonitrile–trifluoroacetic acid as the mobile phase in a shorter run time of 25 min. The flow rate was 1.0 mL/min and the detection wavelength was 245 nm. The drug substance was subjected to stress studies such as hydrolysis, oxidation, photolysis, and thermal degradation, and considerable degradation was observed in acidic hydrolysis, oxidative, thermal, and photolytic stress conditions. The formed degradation products were reported and were well-resolved from the Atorvastatin and its related substances. The stressed samples were quantified against a qualified reference standard and the mass balance was found to be close to 99.5% (w/w) when the response of the degradant was considered to be equal to the analyte (i.e. Atorvastatin), which demonstrates the stability-indicating capability of the method. The method was validated in agreement with ICH requirements. The method developed here was single and shorter (25 min method for the determination of all 12 related impurities of Atorvastatin and its degradation products), with clearly better resolution and higher sensitivity than the European (85 min method for the determination of six impurities) and United States pharmacopeia (115 min and 55 min, two different methods for the determination of six related substances).

Simultaneous determination of atorvastatin, metformin and glimepiride in human plasma by LC-MS/MS and its application to a human pharmacokinetic study

A simple, rapid and sensitive liquid chromatography-tandem mass spectrometric (LC–MS/MS) assay method has been developed and fully validated for the simultaneous quantification of atorvastatin, metformin and glimepiride in human plasma. Carbamazepine was used as internal standard (IS). The analytes were extracted from 200 μL aliquots of human plasma via protein precipitation using acetonitrile. The reconstituted samples were chromatographed on a Alltima HP C18 column by using a 60:40 (v/v) mixture of acetonitrile and 10 mM ammonium acetate (pH 3.0) as the mobile phase at a flow rate of 1.1 mL/min. The calibration curves obtained were linear (r²≥0.99) over the concentration range of 0.50–150.03 ng/mL for atorvastatin, 12.14–1207.50 ng/mL for metformin and 4.98–494.29 ng/mL for glimepiride. The API-4000 LC–MS/MS in multiple reaction monitoring (MRM) mode was used for detection. The results of the intra- and inter-day precision and accuracy studies were well within the acceptable limits. All the analytes were found to be stable in a battery of stability studies. The method is precise and sensitive enough for its intended purpose. A run time of 2.5 min for each sample made it possible to analyze more than 300 plasma samples per day. The developed assay method was successfully applied to a pharmacokinetic study in human male volunteers.

Simultaneous Determination of Atorvastatin and Aspirin in Human Plasma by LC-MS/MS: Its Pharmacokinetic Application

A simple, rapid, and sensitive liquid chromatography tandem mass spectro-metric (LC-MS/MS) assay method has been developed and fully validated for the simultaneous quantification of atorvastatin and aspirin in human plasma using a polarity switch. Proguanil and furosemide were used as the internal standards for the quantification of atorvastatin and aspirin, respectively. The analytes were extracted from human plasma by the liquid-liquid extraction technique using methyl tert-butyl ether. The reconstituted samples were chromatographed on a Zorbax XDB Phenyl column by using a mixture of 0.2% acetic acid buffer, methanol, and acetonitrile (20:16:64, v/v) as the mobile phase at a flow rate of 0.8 mL/min. Prior to detection, atorvastatin and aspirin were ionized using an ESI source in the multiple reaction monitoring (MRM) mode. The ions were monitored at the positive m/z 559.2→440.0 transition for atorvastatin and the negative m/z 179.0→136.6 transition for aspirin. The calibration curve obtained was linear (r(2) ≥ 0.99) over the concentration range of 0.20-151 ng/mL for atorvastatin and 15.0-3000 ng/mL for aspirin. The method validation was performed as per FDA guidelines and the results met the acceptance criteria. A run time of 3.0 min for each sample made it possible to analyze more than 300 human plasma samples per day. The proposed method was found to be applicable to clinical studies.