First-in-human study of CPL207280, a novel G-protein-coupled receptor 40/free fatty acid receptor 1 agonist, in healthy volunteers after single and multiple administration.

AIM: To assess the safety, tolerability and pharmacokinetic (PK) profile of single and multiple doses of CPL207280, a new G-protein-coupled receptor 40 agonist developed to treat type 2 diabetes (T2D). METHODS: The phase 1 study in healthy volunteers (White, age 18-55 years, body mass index 18.5-29.9 kg/m2 ) was performed after single (24 subjects, 5-480 mg) and multiple (32 subjects, 60-480 mg) once-daily administration of CPL207280.  The effect of food intake and interaction with metformin were evaluated in additional cohort (12 subjects, 120 mg). The primary objective was the safety and tolerability of CPL207280. Secondary objectives included PK and pharmacodynamic (PD) characteristics (glucose, insulin, C-peptide, proinsulin, glucagon levels) observed during the 14-day treatment period. RESULTS: No deaths or serious adverse events (AEs) were reported. All reported AEs were classified as unrelated to the study product. No clinically significant differences in safety parameters were observed between cohorts and no food or metformin effect on safety parameters was identified. The ascending dose of CPL207280 caused an increase in the PK parameters maximum observed plasma concentration (Cmax ) or area under the plasma concentration-time curve up to 24 h. However, dose-normalized Cmax decreased with ascending dose. There was no relationship between the CPL207280 dose or prandial state and terminal elimination half-life and terminal elimination rate constant. No clear relationship between CPL207280 dose and PD area under the effect curve values was observed. CONCLUSIONS: CPL207280 was found to be safe and well tolerated by healthy volunteers (with a low risk of hepatotoxicity) for up to 14 days of administration. The PK profile of CPL207280 supports single-daily administration and justifies further development of this therapy for patients with T2D.

Cilostazol-imprinted polymer film-coated electrode as an electrochemical chemosensor for selective determination of cilostazol and its active primary metabolite.

An electrochemical chemosensor for cilostazol (CIL) determination was devised, engineered, and tested. For that, a unique conducting film of the functionalized thiophene-appended carbazole-based polymer, molecularly imprinted with cilostazol (MIP-CIL), was potentiodynamically deposited on a Pt disk electrode by oxidative electropolymerization. Thanks to electro-oxidation potentials lower than that of CIL, the carbazole monomers outperformed pyrrole, thiophene, and phenol monomers, in this electropolymerization. The pre-polymerization complexes quantum-mechanical and molecular dynamics analysis allowed selecting the most appropriate monomer from the three thiophene-appended carbazoles examined. The electrode was then used as a selective CIL chemosensor in the linear dynamic concentration range of 50 to 924 nM with a high apparent imprinting factor, IF = 10.6. The MIP-CIL responded similarly to CIL and CIL's pharmacologically active primary metabolite, 3,4-dehydrocilostazol (dhCIL), thus proving suitable for their determination together. Simulated models of the MIP cavities binding of the CIL, dhCIL, and interferences' molecules allowed predicting chemosensor selectivity. The MIP film sorption of CIL and dhCIL was examined using DPV by peak current data fitting with the Langmuir (L), Freundlich (F), and Langmuir-Freundlich (LF) isotherms. The LF isotherm best described this sorption with the sorption equilibrium constant (KLF) for CIL and dhCIL of 12.75 × 10-6 and 0.23 × 10-6 M, respectively. Moreover, the chemosensor cross-reactivity to common interferences study resulted in the selectivity to cholesterol and dehydroaripiprazole of 1.52 and 8.0, respectively. The chemosensor proved helpful in determining CIL and dhCIL in spiked human plasma with appreciable recovery (99.3-134.1%) and limit of detection (15 nM).

LC-MS/MS determination of dutasteride and its major metabolites in human plasma.

Dutasteride is a specific and selective inhibitor of both 5α-reductase isoforms used mainly in benign prostatic hyperplasia and lower urinary tract symptoms. Although the drug is extensively metabolized in humans, data on the concentrations of its main metabolites are lacking. There is also a lack of data on dutasteride stability in frozen plasma samples. Our method was used to determine dutasteride and its active metabolites: 4'-hydroxydutasteride, 6ß-hydroxydutasteride, and 1,2-dihydrodutasteride in plasma after a single administration of 0.5 mg of dutasteride. We also assessed the long-term stability (two years in the freezer) of dutasteride in clinical samples. The developed method covered the range of 0.1-3.5 ng/mL for dutasteride and 0.08-1.2 ng/mL for 1,2-dihydrodutasteride, 4'-hydroxydutasteride, 6ß-hydroxydutasteride. It was proved to be reliable as it met all validation criteria required by the European Medicine Agency for bioanalytical methods. 4'-hydroxydutasteride and 1,2-dihydrodutasteride concentrations in plasma were higher than 6ß-hydroxydutasteride. Dutasteride was stable in the freezer for up to 2 years in clinical samples. Thus within 1014 days of storage (below - 65 °C), samples can be reanalyzed without the risk of unreliable results.

Evaluation of tramadol human pharmacokinetics and safety after co-administration of magnesium ions in randomized, single- and multiple-dose studies.

BACKGROUND: Magnesium ions (Mg2+) increase and prolong opioid analgesia in chronic and acute pain. The nature of this synergistic analgesic interaction has not yet been explained. Our aim was to investigate whether Mg2+ alter tramadol pharmacokinetics. Our secondary goal was to assess the safety of the combination. METHODS: Tramadol was administered to healthy Caucasian subjects with and without Mg2+ as (1) single 100-mg and (2) multiple 50-mg oral doses. Mg2+ was administered orally at doses of 150 mg and 75 mg per tramadol dosing in a single- and multiple-dose study, respectively. Both studies were randomized, open label, laboratory-blinded, two-period, two-treatment, crossover trials. The plasma concentrations of tramadol and its active metabolite, O-desmethyltramadol, were measured. RESULTS: A total of 25 and 26 subjects completed the single- and multiple-dose study, respectively. Both primary and secondary pharmacokinetic parameters were similar. The 90% confidence intervals for Cmax and AUC0-t geometric mean ratios for tramadol were 91.95-102.40% and 93.22-102.76%. The 90% confidence intervals for Cmax,ss and AUC0-τ geometric mean ratios for tramadol were 93.85-103.31% and 99.04-105.27%. The 90% confidence intervals for primary pharmacokinetic parameters were within the acceptance range. ANOVA did not show any statistically significant contribution of the formulation factor (p > 0.05) in either study. Adverse events and clinical safety were similar in the presence and absence of Mg2+. CONCLUSIONS: The absence of Mg2+ interaction with tramadol pharmacokinetics and safety suggests that this combination may be used in the clinical practice for the pharmacotherapy of pain.

Quantitative evaluation of the matrix effect in bioanalytical methods based on LC-MS: A comparison of two approaches.

Liquid chromatography coupled to mass spectrometry (LC-MS) is a powerful tool for studying pharmacokinetics and toxicokinetics. Reliable bioanalysis requires the characterization of the matrix effect, i.e. influence of the endogenous or exogenous compounds on the analyte signal intensity. We have compared two methods for the quantitation of matrix effect. The CVs(%) of internal standard normalized matrix factors recommended by the European Medicines Agency were evaluated against internal standard normalized relative matrix effects derived from Matuszewski et al. (2003). Both methods use post-extraction spiked samples, but matrix factors require also neat solutions. We have tested both approaches using analytes of diverse chemical structures. The study did not reveal relevant differences in the results obtained with both calculation methods. After normalization with the internal standard, the CV(%) of the matrix factor was on average 0.5% higher than the corresponding relative matrix effect. The method adopted by the European Medicines Agency seems to be slightly more conservative in the analyzed datasets. Nine analytes of different structures enabled a general overview of the problem, still, further studies are encouraged to confirm our observations.

Incurred sample reanalysis: adjusted procedure for sample size calculation.

AIM: The incurred sample reanalysis (ISR) helps to assure bioanalysis reliability. The regulatory guidelines recommend the reanalysis of up to 10% of the study samples for this test, but not all reanalyses are necessary to evaluate the test result. MATERIALS & METHODS: We have optimized ISR sample size calculation to eliminate negligible reanalyses. RESULTS: Adjusted procedure eliminates negligible reanalyses - up to 66% of currently analyzed ISRs - without affecting the test outcome. CONCLUSION: The procedure is universal as it may be applied in the studies compliant with EMA and US FDA requirements, for both small and large molecules. It may assist the evolution of bioanalytical method validation as the current ISR sample size recommendations seem to be ill-matched with the acceptance criteria.

Is a deuterated internal standard appropriate for the reliable determination of olmesartan in human plasma?

A right choice of the internal standard is one of the most challenging tasks during bioanalytical method development. Surprisingly, among the HPLC-MS methods for the determination of a cardiovascular drug olmesartan in plasma only structural analogues or similar compounds were used as internal standards. We have tried to answer the question whether the stable isotope labelled (deuterated) internal standard, as recommended by regulatory agencies, can be used for the reliable determination of olmesartan in human plasma. An HPLC-MS method using this standard in a simplified liquid-liquid extraction procedure led to accurate and precise results in the linearity range of 5-2500ng/mL. The method is well suited for pharmacokinetic studies following a single 40mg oral dose of olmesartan medoxomil in humans. The method was fully validated according to international guidelines and successfully applied in a bioequivalence study in humans. The use of deuterated olmesartan as the internal standard afforded a reliable tool for regulatory bioanalysis that can indirectly contribute to therapy efficacy and improve the safety of patients treated with generic medicines.

Bioequivalence study of 2.5 mg film-coated bisoprolol tablets in healthy volunteers.

BACKGROUND: Bisoprolol is one of the most widely used beta-blockers characterised by cardioselectivity, and it has no intrinsic sympathomimetic activity. It is commonly used in the treatment of coronary heart disease and heart failure. AIM: The aim of study was to assess the bioequivalence of the film-coated tablets containing 2.5 mg of bisoprolol (Bisocard® - the medicinal product) to the original medicinal product (Concor Cor 2.5® - the reference). METHODS: A randomised, open-label, two-period, crossover, single-dose, relative bioavailability study was conducted in fasted healthy Caucasian volunteers. A single 10-mg oral dose (four tablets of 2.5 mg) of the test or reference product was followed by a 14-day wash-out period, after which the subjects received the alternative product. Blood was sampled within a period of 60 h post administration in pre-specified time points. Bisoprolol concentrations were determined by a validated LC-MS/MS method. The products were considered bioequivalent if the 90% confidence interval (CI) of the log-transformed geometric mean ratios (test vs. reference) for AUC(0-t), AUC(0-∞), and Cmax were within 80-125% limits. Adverse events were monitored during the study based on the subject claims and clinical parameters. RESULTS: Twenty-six healthy male and female volunteers (mean age ca. 29 years; body mass index 22.7 kg/m²) were in-cluded in the study, and 24 completed the clinical part. The geometric mean ratios (test/reference) for the log-transformed AUC(0-t), AUC(0-∞), and Cmax were 95.16% (90% CI 92.52-97.87%), 95.08% (90% CI 92.40-97.83%), and 100.00% (90% CI 94.83-105.45%), respectively. There were no significant differences in the pharmacokinetic parameters between the test and reference formulations. No serious adverse events were reported. CONCLUSIONS: The results of this single-dose study in healthy Caucasian volunteers indicate that Bisocard®; 2.5 mg film-coated tablets are bioequivalent to the reference product - Concor Cor 2.5®; 2.5 mg film-coated tablets. Both products had similar safety profile and have been well tolerated.

ENVIRONMENTALLY FRIENDLY LC/MS DETERMINATION OF EPLERENONE IN HUMAN PLASMA.

Eplerenone (EPL), a selective aldosterone receptor antagonist, is indicated in the treatment of chronic heart failure and hypertension. It is hard to find a green assay among a few published methods for its determination in human plasma or serum. Following a liquid-liquid extraction with methyl t-butyl ether, eplerenone and isotope labelled eplerenone - used as an internal standard - were separated from the endogenous compounds on an Atlantis dCl8 column (150 x 3 mm, 3.0 [im). An isocratic elution with the mobile phase consisting of methanol and ammonium acetate (3 : 2, v/v) was used. A single quadrupole mass spectrometer was operated in positive electrospray ionization using the selected ion monitoring mode. The method is more environmentally-friendly than the previously reported assays. Acetonitrile in the mobile phase was replaced with methanol which is a removable solvent. Plasma sample volume was reduced to 250 pL which significantly decreased waste volume. Chlorinated solvents used previously for liquid-liquid extraction were eliminated and the safety of the laboratory staff was increased by eliminating diethyl ether. The method is characterized by a short analysis time, simple sample preparation and reduction of waste volume, which are important advantages when analyzing large numbers of samples. The method was validated according to international regulatory guidelines and may be applied to human pharmacokinetic studies following a single 25 or 50 mg oral dose.

Cloud-point extraction is compatible with liquid chromatography coupled to electrospray ionization mass spectrometry for the determination of bisoprolol in human plasma.

Cloud-point extraction (CPE) draws increasing interest in a number of analytical fields including bioanalysis, but combining CPE and LC-MS with electrospray ionization (ESI) in the determination of drugs in biological fluids such as plasma, serum or blood has not been reported so far. Bisoprolol was determined in human plasma by CPE using Trition X-114 as a surfactant and metoprolol as the internal standard. NaOH concentration, temperature and Trition X-114 concentration were optimized. All analyses were performed using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). All validation experiments met international acceptance criteria and no significant matrix effect was observed. The compatibility of CPE and LC-ESI-MS/MS was confirmed using clinical plasma samples and appropriate statistical tests. The determination of bisoprolol concentration in human plasma in the range 1.0-70ngmL(-1) by the CPE method leads to the results which are equivalent to those obtained by the widely used liquid-liquid extraction method. The results revealed that a structural analogue may be an appropriate internal standard when CPE is used as the extraction technique. CPE offers significant practical advantages over the classical extraction methods, including a positive impact on the environment, therefore its wider application in future pharmacokinetic studies is justifiable.

Simplified LC-MS/MS method enabling the determination of azithromycin in human plasma after a low 100mg dose administration.

A sensitive liquid chromatographic-tandem mass spectrometric method was developed and validated to study the pharmacokinetics of a low dose of azithromycin in human plasma. The sample preparation was based on liquid-liquid extraction with the low volume of methyl t-butyl ether. The chromatographic separation was performed on a Symmetry C18 column (50×2.1mm, 3.5µm). Gradient elution with ammonium acetate-acetonitrile and ammonium acetate-methanol was applied. Positive electrospray ionisation tandem mass spectrometry in the multiple reaction monitoring mode was used for the detection of azithromycin. The influence of a major metabolite, including the possibility of its back-conversion, on the quantification of azithromycin was evaluated. Isotope labelled azithromycin was used as the internal standard. The calibration curve was linear in the range of 0.5-250.0ng/mL. The new validated method was successfully applied to a pharmacokinetic study in humans following a single 100mg oral dose.

Bioequivalence and pharmacokinetics of two 10-mg bisoprolol formulations as film-coated tablets in healthy white volunteers: a randomized, crossover, open-label, 2-period, single-dose, fasting study.

OBJECTIVE: The aim of the study was to investigate the bioavailability of a generic formulation of 10-mg bisoprolol film coated tablets (test) as compared to that of a branded formulation (reference) at the same strength to determine bioequivalence and to apply for regulatory approval. The secondary objective of the study was to evaluate tolerability of both formulations. METHODS: A randomized, crossover, open-label, 2-period, single-dose, comparative study was conducted in healthy white volunteers in fasting conditions. A single oral dose administration of the test or reference formulation was followed by a 14-day wash-out period. Blood samples were collected up to 60 hours after dosing. The bisoprolol concentrations in plasma samples were determined using a validated LC-MS/MS method. The formulations were considered bioequivalent if 90% CI of geometric mean ratios (test/reference) for AUC0-t, AUC0-∞ and Cmax were within the range 80.00 - 25.00%. Adverse events were monitored throughout the study based on the clinical parameters and volunteer reports. RESULTS: Healthy male and female subjects participating in the study had a median (range) age of 23 (20 - 43), weight of 68 kg (52 - 84), height of 172 cm (157 - 184), and BMI of 23.1 kg/m2 (19.3 - 24.9). The 26 consented volunteers have been included and 24 of them completed the clinical part of the study. The geometric mean test/referenceratios (90% CI) for AUC0-t, AUC0-∞ and Cmax were 104.12% (100.52 - 107.85%), 104.05% (100.49 - 107.75%) and 107.91% (103.04 - 112.99%), respectively. All 90% CI were embraced by the 80.00 - 25.00% acceptance interval. No serious adverse events were reported. A total number of 6 non-serious, moderate adverse events were registered, including headache and vomiting in one subject. CONCLUSIONS: The results of the single-dose study in healthy white volunteers indicated that the film-coated tablets of Bisocard® 10 mg manufactured by ICN Polfa Rzeszów S.A. (test formulation) are bioequivalent to those of Concor 10® manufactured by Merck KGaA (reference formulation). Both formulations were well tolerated.

Development and validation of a sensitive liquid chromatography/tandem mass spectrometry method for the determination of exemestane in human plasma.

Exemestane, irreversible steroidal aromatase inhibitor, acts as a false substrate for aromatase enzyme and significantly lowers circulating estrogen concentrations in postmenopausal women with hormone-sensitive breast cancer. A sensitive bioanalytical method was developed and validated to study pharmacokinetics of exemestane. The method was based on liquid-liquid extraction of exemestane with methyl t-butyl ether followed by reversed-phase liquid chromatography. Positive electrospray ionization tandem mass spectrometry in multiple reaction monitoring mode was applied for detection of exemestane. Anastrozole was used as internal standard. Calibration curve, fitted to 1/x² weighted linear regression model, was linear in the range of 0.1-40.0 ng/mL. Intra-run precision and accuracy were 1.80-3.17% and 103.4-111.5%, respectively. Inter-run precision and accuracy measured within 3 days were 3.37-4.19% and 101.8-109.6%, respectively. Extraction recoveries of exemestane and internal standard were 79.7-86.2% and 82.9-83.6%, respectively. The method was fully validated and may be applied to pharmacokinetic studies in humans after a single dose administration of 25mg exemestane tablets.