Towards clinical adherence monitoring of oral endocrine breast cancer therapies by LC-HRMS-method development, validation, comparison of four sample matrices, and proof of concept.

Oral endocrine therapies (OET) for breast cancer treatment need to be taken over a long period of time and are associated with considerable side effects. Therefore, adherence to OET is an important issue and of high clinical significance for breast cancer patients' caregivers. We hypothesized that a new bioanalytical strategy based on liquid chromatography and high-resolution mass spectrometry might be suitable for unbiased adherence monitoring (AM) of OET. Four different biomatrices (plasma, urine, finger prick blood by volumetric absorptive microsampling (VAMS), oral fluid (OF)) were evaluated regarding their suitability for AM of the OET abemaciclib, anastrozole, exemestane, letrozole, palbociclib, ribociclib, tamoxifen, and endoxifen. An analytical method was developed and validated according to international recommendations. The analytical procedures were successfully validated in all sample matrices for most analytes, even meeting requirements for therapeutic drug monitoring. Chromatographic separation of analytes was achieved in less than 10 min and limits of quantification ranged from 1 to 1000 ng/mL. The analysis of 25 matching patient samples showed that AM of OET is possible using all four matrices with the exception of, e.g., letrozole and exemestane in OF. We were able to show that unbiased bioanalytical AM of OET was possible using different biomatrices with distinct restrictions. Sample collection of VAMS was difficult in most cases due to circulatory restraints and peripheral neuropathy in fingers and OF sampling was hampered by dry mouth syndrome in some cases. Although parent compounds could be detected in most of the urine samples, metabolites should be included when analyzing urine or OF. Plasma is currently the most suitable matrix due to available reference concentrations.

Role of the UGT2B17 deletion in exemestane pharmacogenetics.

Exemestane (EXE) is an aromatase inhibitor used for the prevention and treatment of breast cancer. The major metabolic pathway for EXE is reduction to form the active 17ß-dihydro-EXE (17ß-DHE) and subsequent glucuronidation to 17ß-hydroxy-EXE-17-O-ß-D-glucuronide (17ß-DHE-Gluc) by UGT2B17. The aim of the present study was to determine the effects of UGT2B17 copy number variation on the levels of urinary and plasma 17ß-DHE-Gluc and 17ß-DHE in patients taking EXE. Ninety-six post-menopausal Caucasian breast cancer patients with ER+ breast tumors taking 25 mg EXE daily were recruited into this study. UGT2B17 copy number was determined by a real-time PCR copy number variant assay and the levels of EXE, 17ß-DHE and 17ß-DHE-Gluc were quantified by UPLC/MS in patients' urine and plasma. A 39-fold decrease (P<0.0001) in the levels of creatinine-adjusted urinary 17ß-DHE-Gluc was observed among UGT2B17 (*2/*2) subjects vs subjects with the UGT2B17 (*1/*1) genotype. The plasma levels of 17ß-DHE-Gluc was decreased 29-fold (P<0.0001) in subjects with the UGT2B17 (*2/*2) genotype vs subjects with UGT2B17 (*1/*1) genotype. The levels of plasma EXE-adjusted 17ß-DHE was 28% higher (P=0.04) in subjects with the UGT2B17 (*2/*2) genotype vs subjects with the UGT2B17 (*1/*1) genotype. These data indicate that UGT2B17 is the major enzyme responsible for 17ß-DHE-Gluc formation in vivo and that the UGT2B17 copy number variant may play a role in inter-individual variability in 17ß-DHE levels in vivo.

Identification and Quantification of Novel Major Metabolites of the Steroidal Aromatase Inhibitor, Exemestane.

Exemestane (EXE) is an aromatase inhibitor used for the prevention and treatment of estrogen receptor-positive breast cancer. Although the known major metabolic pathway for EXE is reduction to form the active 17ß-dihydro-EXE (17ß-DHE) and subsequent glucuronidation to 17ß-hydroxy-EXE-17-O-ß-D-glucuronide (17ß-DHE-Gluc), previous studies have suggested that other major metabolites exist for exemestane. In the present study, a liquid chromatography-mass spectrometry (LC-MS) approach was used to acquire accurate mass data in MSE mode, in which precursor ion and fragment ion data were obtained simultaneously to screen novel phase II EXE metabolites in urine specimens from women taking EXE. Two major metabolites predicted to be cysteine conjugates of EXE and 17ß-DHE by elemental composition were identified. The structures of the two metabolites were confirmed to be 6-methylcysteinylandrosta-1,4-diene-3,17-dione (6-EXE-cys) and 6-methylcysteinylandrosta-1,4-diene-17ß-hydroxy-3-one (6-17ß-DHE-cys) after comparison with their chemically synthesized counterparts. Both underwent biosynthesis in vitro in three stepwise enzymatic reactions, with the first involving glutathione conjugation. The cysteine conjugates of EXE and 17ß-DHE were subsequently quantified by liquid chromatography-mass spectrometry in the urine and matched plasma samples of 132 subjects taking EXE. The combined 6-EXE-cys plus 6-17ß-DHE-cys made up 77% of total EXE metabolites in urine (vs. 1.7%, 0.14%, and 21% for EXE, 17ß-DHE, and 17ß-DHE-Gluc, respectively) and 35% in plasma (vs. 17%, 12%, and 36% for EXE, 17ß-DHE, and 17ß-DHE-Gluc, respectively). Therefore, cysteine conjugates of EXE and 17ß-DHE appear to be major metabolites of EXE in both urine and plasma.

Polymorphisms in drug-metabolizing enzymes and steady-state exemestane concentration in postmenopausal patients with breast cancer.

Discovery of clinical and genetic predictors of exemestane pharmacokinetics was attempted in 246 postmenopausal patients with breast cancer enrolled on a prospective clinical study. A sample was collected 2 h after exemestane dosing at a 1- or 3-month study visit to measure drug concentration. The primary hypothesis was that patients carrying the low-activity CYP3A4*22 (rs35599367) single-nucleotide polymorphism (SNP) would have greater exemestane concentration. Additional SNPs in genes relevant to exemestane metabolism (CYP1A1/2, CYP1B1, CYP3A4, CYP4A11, AKR1C3/4, AKR7A2) were screened in secondary analyses and adjusted for clinical covariates. CYP3A4*22 was associated with a 54% greater exemestane concentration (P<0.01). Concentration was greater in patients who reported White race, had elevated aminotransferases, renal insufficiency, lower body mass index and had not received chemotherapy (all P<0.05), and CYP3A4*22 maintained significance after adjustment for covariates (P<0.01). These genetic and clinical predictors of exemestane concentration may be useful for treatment individualization in patients with breast cancer.

The acoustic features of inhalation can be used to quantify aerosol delivery from a Diskus™ dry powder inhaler.

PURPOSE: Some patients are unable to generate the peak inspiratory flow rate (PIFR) necessary to de-agglomerate drug particles from dry powder inhalers (DPIs). In this study we tested the hypothesis that the acoustic parameters of an inhalation are related to the PIFR and hence reflect drug delivery. METHODS: A sensitivity analysis of the relationship of the acoustics of inhalation to simultaneously recorded airflow, in a cohort of volunteers (n = 92) was performed. The Next Generation Impactor (NGI) was used to assess in vitro drug delivery from salmeterol/fluticasone and salbutamol Diskus™ DPIs. Fine particle fraction, FPF, (<5 µm) was measured at 30-90 l/min for 2-6 s and correlated with acoustically determined flow rate (IFRc). In pharmacokinetic studies using a salbutamol (200 µg) Diskus™, volunteers inhaled either at maximal or minimal effort on separate days. RESULTS: PIFRc was correlated with spirometrically determined values (R (2) = 0.88). In in vitro studies, FPF increased as both flow rate and inhalation duration increased for the salmeterol/fluticasone Diskus™ (Adjusted R (2) = 0.95) and was proportional to flow rate only for the salbutamol Diskus™ (Adjusted R (2) = 0.71). In pharmacokinetic studies, blood salbutamol levels measured at 20 min were significantly lower when PIFRc was less than 60 l/min, p < 0.0001. CONCLUSION: Acoustically-determined PIFR is a suitable method for estimating drug delivery and for monitoring inhalation technique over time.

ß-Cyclodextrin sensitized spectrofluorimetry for the determination of abiraterone acetate and abiraterone.

A novel spectrofluorimetric method to determine abiraterone acetate and its active metabolite, abiraterone was developed, based on the fact that fluorescence intensity of abiraterone acetate and abiraterone could be enhanced in ß-cyclodextrin (ß-CD) due to the formation of the inclusion complex. The inclusion interaction of ß-CD and abiraterone acetate and the ß-cyclodextrin sensitized spectrofluorimetry was examined. The various factors influencing fluorescence were discussed in details. The results showed that under the optimized conditions, the linear range of calibration curve for the determination of biraterone acetate and abiraterone was 0.20 ~ 6.0 µg/mL, and the detection limit (LOD) was 6.8 (r = 0.997) or 6.6 ng/mL (r = 0.996), respectively. No interference was observed from common co-existing substances or pharmaceutical excipient. The method was successfully applied to the analysis of abiraterone acetate in pharmaceutical formulation and abiraterone in human serum/urine.

A new methodology for predicting human pharmacokinetics for inhaled drugs from oratracheal pharmacokinetic data in rats.

Prediction of pharmacokinetic (PK) profile for inhaled drugs in humans provides valuable information to aid toxicology safety assessment, evaluate the potential for systemic accumulation on multiple dosing and enable an estimate for the clinical plasma assay requirements. The accuracy in prediction of inhaled human PK profiles for seven inhaled drugs or drug candidates (salmeterol, salbutamol, formoterol, fluticasone propionate, budesonide, CP-325366 and UK-432097) was assessed using rat oratracheal solution and dry powder PK data. The prediction methodology incorporates allometric scaling and mean residence time (MRT) principles with a two compartmental PK approach. Across the range of compounds tested, the prediction of human inhaled maximum concentration (C(max)) and MRT was within 2-fold for 5 of the 7 compounds, providing an accuracy of prediction similar to the current methodologies used to predict human oral C(max) from preclinical data ( De Buck et al. 2007 ). Administering as a dry powder formulation slowed the rat lung absorption rate of the least soluble compound (fluticasone propionate), impacting the prediction of C(max) and MRT. This flags the potential for preclinical studies with dry powder formulations to positively influence predictive accuracy, although further studies with low solubility inhaled drugs are required to confirm this. This study illustrates the value of preclinical assessment of PKs following administration to the lung, and provides a viable means of predicting the human PK profile for inhaled drugs.

Development of a sensitive method for simultaneous determination of fluticasone propionate and salmeterol in plasma samples by liquid chromatography-tandem mass spectrometry.

A new method for the fast simultaneous quantification of fluticasone propionate and salmeterol from plasma samples by liquid chromatography-tandem mass spectrometry, with adequate sensitivity for pharmacokinetic applications, was developed and validated. The chromatographic separation and mass-spectrometric parameters were optimized for the retention and detection of the two compounds, despite quite different structures and properties. Two columns connected in series were used, cation-exchange (Zorbax 300-SCX, 5 cm x 2.1 mm, 5 µm) and octadecyl (Discovery HSC18, 10 cm x 2.1 mm, 5 µm). The mass-spectrometric interface was operated in negative electrospray ionization mode; high sensitivity and lesser matrix effects were obtained, permitting smaller consumption of plasma. The sample preparation was based on supported liquid-liquid extraction in 96-well format plates that provided clean samples with a simplified procedure that was suitable for automation. The method was validated according to regulatory guidelines, by assessing lower limits of quantification, selectivity, linearity, accuracy, precision, extraction recoveries and matrix effects. A comparison with two other methods for the separate determination of fluticasone propionate and salmeterol in plasma samples, previously developed by our group, is presented. The statistical evaluation of the results obtained with the three methods on a set of unknown samples from treated patients demonstrated good correlation (R² 0.987 for fluticasone propionate and 0.967 for salmeterol).

Population Pharmacokinetic Analysis of Fluticasone Furoate/Umeclidinium Bromide/Vilanterol in Patients with Chronic Obstructive Pulmonary Disease.

BACKGROUND: Population pharmacokinetic methods were used to characterize the pharmacokinetics of fluticasone furoate (FF), umeclidinium (UMEC), and vilanterol (VI) in patients with chronic obstructive pulmonary disease (COPD) when administered as a fixed-dose combination via a single closed inhaler. METHODS: Plasma concentration data from three studies were analyzed using non-linear mixed-effects modeling in NONMEM®. RESULTS: The pooled dataset consisted of 2948, 2589, and 3331 FF, UMEC, and VI observations from 714, 622, and 817 patients with COPD, respectively. There were 41%, 13%, and 21% of observations below the quantification limit for FF, UMEC, and VI, respectively. The pharmacokinetics of FF, UMEC, and VI were all adequately described by a two-compartment model with first-order absorption. The following covariates were statistically significant, but none were considered to be clinically relevant. For FF, Japanese heritage and FF/VI treatment on apparent inhaled clearance (CL/F) with FF CL/F 35% lower in patients of Japanese heritage across all treatments and FF CL/F 42% higher in patients with COPD following FF/VI administration. This is in line with the product label. For UMEC, weight, age, and smoking status on CL/F and weight on apparent volume of distribution (V2/F) with every 10% increase in age from 60 years of age leading to approximately a 6% decrease in UMEC CL/F and every 10% increase in weight from 70 kg leading to approximately a 6% increase in UMEC CL/F and approximately an 8% increase in UMEC V2/F. For a subject with COPD who smoked, UMEC CL/F was 28% higher. For VI, weight on CL/F and smoking status on V2/F with an approximately 4% increase in VI CL/F for every 10% increase in weight from 70 kg, and for a subject with COPD who smoked, VI V2/F was 46% higher. The majority of these covariates have been previously identified in historical analyses. None of these effects were clinically relevant in terms of systemic exposures and do not warrant dose adjustment. CONCLUSIONS: All FF, UMEC, and VI plasma concentrations were well interspersed with historical data and were all adequately described by a two-compartment model with first-order absorption. There were no clinically relevant differences in FF, UMEC, or VI systemic exposures when administered as FF/UMEC/VI, FF/VI + UMEC, or the dual combinations FF/VI and/or UMEC/VI.

The bioavailability and airway clearance of the steroid component of budesonide/formoterol and salmeterol/fluticasone after inhaled administration in patients with COPD and healthy subjects: a randomized controlled trial.

BACKGROUND: Airway absorption and bioavailability of inhaled corticosteroids (ICSs) may be influenced by differences in pharmacokinetic properties such as lipophilicity and patient characteristics such as lung function. This study aimed to further investigate and clarify the distribution of budesonide and fluticasone in patients with severe chronic obstructive pulmonary disease (COPD) by measuring the systemic availability and sputum concentration of budesonide and fluticasone, administered via combination inhalers with the respective long-acting beta2-agonists, formoterol and salmeterol. METHODS: This was a randomized, double-blind, double-dummy, two-way crossover, multicenter study. Following a run-in period, 28 patients with severe COPD (mean age 65 years, mean forced expiratory volume in 1 second [FEV1] 37.5% predicted normal) and 27 healthy subjects (mean age 31 years, FEV1 103.3% predicted normal) received two single-dose treatments of budesonide/formoterol (400/12 microg) and salmeterol/fluticasone (50/500 microg), separated by a 4-14-day washout period. ICS concentrations were measured over 10 hours post-inhalation in plasma in all subjects, and over 6 hours in spontaneously expectorated sputum in COPD patients. The primary end point was the area under the curve (AUC) of budesonide and fluticasone plasma concentrations in COPD patients relative to healthy subjects. RESULTS: Mean plasma AUC values were lower in COPD patients versus healthy subjects for budesonide (3.07 microM x hr versus 6.21 microM x hr) and fluticasone (0.84 microM x hr versus 1.50 microM x hr), and the dose-adjusted AUC (geometric mean) ratios in healthy subjects and patients with severe COPD for plasma budesonide and fluticasone were similar (2.02 versus 1.80; primary end point). In COPD patients, the Tmax and the mean residence time in the systemic circulation were shorter for budesonide versus fluticasone (15.5 min versus 50.8 min and 4.41 hrs versus 12.78 hrs, respectively) and Cmax was higher (1.08 microM versus 0.09 microM). The amount of expectorated fluticasone (percentage of estimated lung-deposited dose) in sputum over 6 hours was significantly higher versus budesonide (ratio 5.21; p = 0.006). Both treatments were well tolerated. CONCLUSION: The relative systemic availabilities of budesonide and fluticasone between patients with severe COPD and healthy subjects were similar. In patients with COPD, a larger fraction of fluticasone was expectorated in the sputum as compared with budesonide. TRIAL REGISTRATION: Trial registration number NCT00379028.

HPLC-UV and spectrofluorimetric methods for simultaneous estimation of fluticasone furoate and vilanterol in rabbit plasma: A pharmacokinetic study.

Fluticasone furoate (FF) and vilanterol trifenatate (VT) is a widely prescribed combination in the management of asthma and chronic obstructive pulmonary disease. In the present study, two quantitative methods based on HPLC-UV and spectrofluorimetric analysis had been developed and validated for simultaneous estimation of FF and VT in rabbit plasma using baclomethasone as internal standard (ISTD). Analytes and ISTD were separated from plasma using simple step of protein precipitation with acetonitrile. Chromatographic separation was achieved on Spherisorb S5 ODS2 (250 mm × 4.6 mm, 5.0 µm) column using mobile phase that constitute acetonitrile-0.01% glacial acetic acid in water (70:30, v/v) and then detected on a UV detector at 235 nm wavelength. Spectrofluorimetric detection was performed using absorption/emission wavelength (λabs/em) of 286/352 nm and 362/407 nm for FF and VT, respectively. For both analytes, linearity ranged from 4-200 ng/mL to 10-200 ng/mL using HPLC-UV and spectrofluorimetric method, respectively. Methods were validated as per FDA recommendations. Statistical analysis revealed that these detection methods are statistically insignificant difference and can be used interchangeably without any bias. Further, these methods were applied in pharmacokinetic study for simultaneous estimation of FF and VT in rabbit plasma.

Blood eosinophils and treatment response with triple and dual combination therapy in chronic obstructive pulmonary disease: analysis of the IMPACT trial.

BACKGROUND: Previous studies have highlighted a relationship between reduction in rate of exacerbations with therapies containing inhaled corticosteroids (ICS) and baseline blood eosinophil count in patients with chronic obstructive pulmonary disease (COPD). The IMPACT trial showed that once-daily single-inhaler triple therapy significantly reduced exacerbations versus dual therapies. Blood eosinophil counts and smoking status could be important modifiers of treatment response to ICS. We aimed to model these relationships and their interactions, including outcomes other than exacerbations. METHODS: IMPACT was a phase 3, randomised, double-blind, parallel-group, 52-week global study comparing once-daily single-inhaler triple therapy (fluticasone furoate-umeclidinium-vilanterol) with dual inhaled therapy (fluticasone furoate-vilanterol or umeclidinium-vilanterol). Eligible patients had moderate-to-very-severe COPD and at least one moderate or severe exacerbation in the previous year. We used fractional polynomials to model continuous blood eosinophil counts. We used negative binomial regression for numbers of moderate and severe exacerbations, severe exacerbations, and pneumonia. We modelled differences at week 52 in trough FEV1, St George's Respiratory Questionnaire (SGRQ) total score, and Transition Dyspnoea Index using repeated measurements mixed effect models. IMPACT was registered with ClinicalTrials.gov, number NCT02164513. FINDINGS: The magnitude of benefit of regimens containing ICS (fluticasone furoate-umeclidinium-vilanterol n=4151 and fluticasone furoate-vilanterol n=4134) in reducing rates of moderate and severe exacerbations increased in proportion with blood eosinophil count, compared with a non-ICS dual long-acting bronchodilator (umeclidinium-vilanterol n=2070). The moderate and severe exacerbation rate ratio for triple therapy versus umeclidinium-vilanterol was 0·88 (95% CI 0·74 to 1·04) at blood eosinophil count less than 90 cells per µL and 0·56 (0·47 to 0·66) at counts of 310 cells per µL or more; the corresponding rate ratio for fluticasone furoate-vilanterol versus umeclidinium-vilanterol was 1·09 (0·91 to 1·29) and 0·56 (0·47 to 0·66), respectively. Similar results were observed for FEV1, Transition Dyspnoea Index, and SGRQ total score; however, the relationship with FEV1 was less marked. At blood eosinophil counts less than 90 cells per µL and at counts of 310 cells per µL or more, the triple therapy versus umeclidinium-vilanterol treatment difference was 40 mL (95% CI 10 to 70) and 60 mL (20 to 100) for trough FEV1, -0·01 (-0·68 to 0·66) and 0·30 (-0·37 to 0·97) for Transition Dyspnoea Index score, and -0·01 (-1·81 to 1·78) and -2·78 (-4·64 to -0·92) for SGRQ total score, respectively. Smoking status modified the relationship between observed efficacy and blood eosinophil count for moderate or severe exacerbations, Transition Dyspnoea Index, and FEV1, with former smokers being more corticosteroid responsive at any eosinophil count than current smokers. INTERPRETATION: This analysis of the IMPACT trial shows that assessment of blood eosinophil count and smoking status has the potential to optimise ICS use in clinical practice in patients with COPD and a history of exacerbations. FUNDING: GlaxoSmithKline.

Metabolism and disposition of fluticasone furoate, an enhanced-affinity glucocorticoid, in humans.

The purpose of this study was to investigate the metabolism and disposition of fluticasone furoate, an enhanced-affinity glucocorticoid receptor agonist, in humans. In a two-part, open-label design study, five healthy male subjects received a p.o. dose of 2 mg of [(14)C]fluticasone furoate, followed 4 weeks later by an i.v. dose of 0.25 mg of [(14)C]fluticasone furoate (as a 30-min infusion). Oral absorption was rapid and estimated at approximately 30%, although the oral bioavailability was markedly lower at 1.6%, limited by extensive first-pass metabolism. Plasma clearance was 58.3 l/h, with a volume of distribution of 642 liters and a terminal elimination half-life of 15.3 h. The major circulating component identified in plasma extracts after i.v. and p.o. dosing was unchanged parent compound, with 17beta-carboxylic acid (GW694301X; M10) also being notable after p.o. administration. Mean recovery of radioactivity was approximately 92 and 102% at 216 and 168 h after i.v. and p.o. administration, respectively, with most (at least 90%) recovered in the feces. Fluticasone furoate was extensively metabolized, with only trace amounts of unchanged parent compound observed in feces following either route of administration. The predominant pathway was removal of the S-fluoromethyl carbothioate group to yield GW694301X (M10). Other pathways included oxidative defluorination to yield a hydroxyl at the C6 position. There was no evidence for metabolic loss of the furoate group from fluticasone furoate or any of its metabolites. Evidence presented suggests that enterocytes have a role in the metabolism of unabsorbed fluticasone furoate.

Systemic exposure and urinary cortisol effects of fluticasone propionate formulated with hydrofluoroalkane in 4- to 11-year-olds with asthma.

The systemic exposure of fluticasone propionate with hydrofluoroalkane propellant compared with chlorofluoro-carbon propellant and the effect of fluticasone propionate hydrofluoroalkane on 24-hour urinary cortisol in children aged 4 to 11 years with asthma were evaluated. Study 1 was an open-label, 2-way crossover study in which 16 subjects were randomized to 7.5 days each of fluticasone propionate hydrofluoroalkane 88 mug twice a day or fluticasone propionate chlorofluorocarbon 88 mug twice a day. In study 2, 63 subjects received 13.5 days of placebo followed by 27.5 days of fluticasone propionate hydrofluoroalkane 88 mug twice a day. The main outcome measure for study 1 was the difference between fluticasone propionate hydrofluoroalkane and fluticasone propionate chlorofluorocarbon in fluticasone propionate AUC(last) (area under the plasma fluticasone propionate concentration-time curve from zero up to the last quantifiable plasma concentration), and for study 2, 24-hour overnight urinary cortisol excretion. In study 1, fluticasone propionate systemic exposure was significantly lower (55%) with hydrofluoroalkane metered dose inhaler compared with chlorofluorocarbon metered dose inhaler. Study 2 showed no statistically significant changes in 24-hour overnight urinary cortisol excretion and no relationship to fluticasone propionate systemic exposure at this dose. The results of these 2 studies showed that in children aged 4 to 11 years with asthma, fluticasone propionate hydrofluoroalkane has lower systemic exposure compared with chlorofluorocarbon and no hypothalamic-pituitary-adrenal axis effects as measured by 24-hour urinary cortisol excretion.

Sensitive simultaneous determination of ciclesonide, ciclesonide-M1-metabolite and fluticasone propionate in human serum by HPLC-MS/MS with APPI.

A new and very sensitive analytical method has been developed and validated to jointly determine the anti-inflammatory drug ciclesonide (CIC), its active principle metabolite M1 (CIC-M1) and fluticasone propionate (FP) in human serum, in the low concentration range from 10 to 1000 pg/mL. This was accomplished by high-performance liquid chromatography and tandem mass spectrometry using atmospheric pressure photo ionisation (HPLC-MS/MS with APPI) using 0.5 mL of serum. Serum was mixed with the internal standards (IS) D11-CIC and D11-CIC-M1 and extracted with diisopropylether. A gradient with acetonitrile (containing 10 mM of acetic acid and 10% of acetone) was used. HPLC-MS/MS of the acetic acid adducts of the analytes was performed in negative mode. The novel aspect of this method is that instead of the dopant being introduced directly into the source by means of an external HPLC pump, it was added to the mobile phase. This provided significantly better sensitivity than the usual method of in-source addition of the dopant, and with no loss in HPLC performance. Sensitivity for the analytes was about four times greater than with either APCI or ESI. Validation was performed in three batches. The inter-batch precision (CV) of the quality control samples in human serum ranged from 4.08% to 6.78% for CIC, from 2.57% to 7.74% for CIC-M1, and from 2.38% to 9.61% for FP. The inter-batch accuracy (with reference to the mean value) of the quality control samples in human serum ranged from 99.3% to 110.0% for CIC, from 101.8% to 104.7% for CIC-M1, and from 100.4% to 101.8% for FP. Calibration data and LLOQ data are also presented in this paper. The analytes were stable in human serum over three freeze/thaw cycles, or for 4h at room temperature, or for at least 18 months when stored at below -20 degrees C. This method was used for quantifying the analytes after inhalation of low-mug amounts of the drugs by patients.

Investigation of interaction between salmeterol and fluticasone propionate and its effect on quantitative accuracy of an LC/MS/MS assay in human plasma at low pg/mL concentrations.

This paper reports an LC/MS/MS method for analysis of salemeterol and fluticasone propionate in human plasma based on combined SPE-based extraction and separate LC/MS/MS conditions. Previously reported interaction between analytes was confirmed and eliminated by their separation in the sample preparation step to ensure no negative impact on their quantitation. The method was validated per FDA guidelines in the range of 2.5-500 pg/mL for salmeterol and 5-500 pg/mL for fluticasone propionate. The method is suitable for plasma analysis of combined salmeterol/fluticasone formulation without adverse effects of inter-analyte interactions on quantitation.

Absolute bioavailability of intranasal fluticasone furoate in healthy subjects.

BACKGROUND: Fluticasone furoate (drug code GW685698) is an enhanced-affinity glucocorticoid that has been developed for the treatment of allergic rhinitis. OBJECTIVES: The objectives of this study were to estimate the absolute bioavailability of fluticasone furoate nasal spray and to describe the intranasal (IN) and IV pharmacokinetics of fluticasone furoate in healthy subjects. METHODS: This was a single-center, randomized, open label, 2-period crossover study. Healthy male and female subjects were randomized to receive supra-therapeutic doses of fluticasone furoate 880 microg IN qSh for 10 doses in 1 treatment period, and a single IV dose of 250 pg fluticasone furoate given as an infusion over 20 minutes in the other treatment period. Each treatment period was separated by a 4- to 5-day washout period. Blood sampling was carried out over 8 hours following the final IN dose and 24 hours following the IV dose to determine plasma fluticasone furoate concentrations. Plasma samples were analyzed for fluticasone furoate using online solid-phase extraction with high-performance liquid chromatography with tandem mass-spectrometric detection. The lower limit of quantification was 10 pg/mL. The sample size was based primarily on logistical considerations. Sample-size sensitivity was assessed by estimating the 90% CI for the absolute bioavailability of IN fluticasone furoate, based on different estimated bioavailabilities and within-subject SDs. The following pharmacokinetic parameters were derived: IN administration: AUC from time 0 to the end of the dosing interval (AUC(0-tau)), AUC(0-t), C(max), and T(max); IV administration: AUC(0-infinity), AUC(0-t), t(1/2), C(max), T(max), total systemic clearance, and volume of distribution at steady state. RESULTS: A total of 16 subjects were included in the study. Their mean age was 27.8 years (range, 19-45 years), and their mean body weight was 72.84 kg (range, 55.3-97.2 kg). The geometric mean AUC(0-tau) for 880 microg IN was 74.9 pg x mL/h and geometric mean AUC(0-infinity) for 250 microg IV was 4259 pg x mL/h. The geometric mean of the absolute bioavailability of fluticasone furoate nasal spray in these healthy subjects was 0.50% (90% CI, 0.34%-0.74%). The administration of large doses by the IN route did not elicit clinical concern. Three (19%) of 16 subjects reported adverse events (AEs) during the IN administration period, with 2 subjects experiencing dizziness and 1, toothache. Five (31%) subjects reported AEs during the IV administration period, with 3 subjects experiencing infusion-site or IV catheter-related events; 1 subject, dizziness; and 1 subject, headache. CONCLUSIONS: The geometric mean of the absolute bioavailability of fluticasone furoate 880 microg IN qSh for 10 doses in these healthy subjects was low--0.50%.

Simultaneous analysis of glucocorticosteroid fluticasone propionate and its metabolite fluticasone propionate 17ß-carboxylic acid in human plasma by UPLC-MS/MS at sub pg/mL level.

A highly sensitive and rapid ultra performance liquid chromatography-tandem mass spectrometry method has been developed for the simultaneous determination of fluticasone propionate (FP) and its major metabolite, fluticasone propionate-17beta-carboxylic acid (FP 17ß-CA) in human plasma. The analytes and their deuterated internal standards, FP-d3 and FP 17ß-CA-d3 were extracted from 500µL plasma samples by solid phase extraction on Oasis MAX cartridges. The chromatographic analysis was performed on ACQUITY UPLC BEH C18 (50mm×2.1mm, 1.7µm) column using methanol-acetonitrile (50:50, v/v) and 2.0mM ammonium trifluroacetate (ATFA) (85:15, v/v) as the mobile phase. Following separation of the analytes, protonated precursor→product ion transitions (FP: m/z 501.1→293.2, FP17ß-CA: m/z 453.3→293.2, FP-d3: m/z 504.2→293.2, FP 17ß-CA-d3: m/z 456.3→293.2) were monitored on FP 17ß-CA a triple quadrupole mass spectrometer, operating in multiple reaction monitoring (MRM) and positive ionization mode. The calibration curves were established in the range of 0.5-100pg/mL with a correlation coefficient (r2)≥0.9992 for both the analytes. The intra-batch and inter-batch accuracy and precision varied from 95.5-103.4% and 0.74-5.06% across quality controls for both the analytes. The mean assay recoveries for FP and FP 17ß-CA were 84.2% and 93.5% respectively. The validated method was successfully applied to support a bioequivalence study of 200µg FP, administered using nasal spray formulation in 18 healthy Indian subjects. Reproducibility of the method was assessed by reanalysis of 98 incurred study samples.