A sensitive LC-MS/MS method for the quantification of fluticasone propionate in human plasma

Quantification of fluticasone propionate in human plasma by LC-MS/MS and its application in the pharmacokinetic study of nasal spray at clinical doses

We developed a method for quantifying fluticasone propionate (FP) using general-purpose liquid chromatography-tandem mass spectrometry equipment to measure the plasma concentration of FP for the pharmacokinetic study of FP following the administration of a prescribed nasal spray dose (100 μg). Using ammonium acetate (0.01 M)-formic acid (pH 2.9; 499:1, v/v) and methanol as the mobile phase, 3 pg/mL of FP was quantified. The relative error and standard deviation of the lower limit of quantification were <3.1%. The intra- and interday assay reproducibility was <3.5%. After 15 min of administering 200 μg FP nasal spray as the first dose, the FP concentration detected in the plasma of the two participants was 3.99 and 3.69 pg/mL. Subsequent doses of 100 μg FP were administered twice daily. The area under the plasma concentration-time curve values after 8-10 days of repeated administration of 100 μg of FP were approximately 1.6-fold higher than those achieved following a single administration of 200 μg of FP, which confirmed drug accumulation. The bioavailability of nasal FP was estimated to be 2% and 4%. This knowledge might help in reducing anxiety among patients who avoid using FP nasal spray, fearing its adverse effects.

Can Pharmacokinetic Studies Assess the Pulmonary Fate of Dry Powder Inhaler Formulations of Fluticasone Propionate?

In the context of streamlining generic approval, this study assessed whether pharmacokinetics (PK) could elucidate the pulmonary fate of orally inhaled drug products (OIDPs). Three fluticasone propionate (FP) dry powder inhaler (DPI) formulations (A-4.5, B-3.8, and C-3.7), differing only in type and composition of lactose fines, exhibited median mass aerodynamic diameter (MMAD) of 4.5 μm (A-4.5), 3.8 μm (B-3.8), and 3.7 μm (C-3.7) and varied in dissolution rates (A-4.5 slower than B-3.8 and C-3.7). In vitro total lung dose (TLDin vitro) was determined as the average dose passing through three anatomical mouth-throat (MT) models and yielded dose normalization factors (DNF) for each DPI formulation X (DNFx = TLDin vitro,x/TLDin vitro,A-4.5). The DNF was 1.00 for A-4.5, 1.32 for B-3.8, and 1.21 for C-3.7. Systemic PK after inhalation of 500 μg FP was assessed in a randomized, double-blind, four-way crossover study in 24 healthy volunteers. Peak concentrations (Cmax) of A-4.5 relative to those of B-3.8 or C-3.7 lacked bioequivalence without or with dose normalization. The area under the curve (AUC0-Inf) was bio-IN-equivalent before dose normalization and bioequivalent after dose normalization. Thus, PK could detect differences in pulmonary available dose (AUC0-Inf) and residence time (dose-normalized Cmax). The differences in dose-normalized Cmax could not be explained by differences in in vitro dissolution. This might suggest that Cmax differences may indicate differences in regional lung deposition. Overall this study supports the use of PK studies to provide relevant information on the pulmonary performance characteristics (i.e., available dose, residence time, and regional lung deposition).

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 (λ_abs/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.

Use of PBPK Modeling To Evaluate the Performance of Dissolv It, a Biorelevant Dissolution Assay for Orally Inhaled Drug Products

The dissolution of inhaled drug particles in the lungs is a challenge to model using biorelevant methods in terms of (i) collecting a respirable emitted aerosol fraction and dose, (ii) presenting this to a small volume of medium that is representative of lung lining fluid, and (iii) measuring the low concentrations of drug released. We report developments in methodology for each of these steps and utilize mechanistic in silico modeling to evaluate the in vitro dissolution profiles in the context of plasma concentration–time profiles. The PreciseInhale aerosol delivery system was used to deliver Flixotide aerosol particles to DissolvIt apparatus for measurement of dissolution. Different media were used in the DissolvIt chamber to investigate their effect on dissolution profiles, these were (i) 1.5% poly(ethylene oxide) with 0.4% l-alphaphosphatidyl choline, (ii) Survanta, and (iii) a synthetic simulated lung lining fluid (SLF) based on human lung fluid composition. For fluticasone proprionate (FP) quantification, solid phase extraction was used for sample preparation with LC–MS/MS analysis to provide an assay that was fit for purpose with a limit of quantification for FP of 312 pg/mL. FP concentration–time profiles in the flow-past perfusate were similar irrespective of the medium used in the DissolvIt chamber (∼0.04–0.07%/min), but these were significantly lower than transfer of drug from air-to-perfusate in isolated perfused lungs (0.12%/min). This difference was attributed to the DissolvIt system representing slower dissolution in the central region of the lungs (which feature nonsink conditions) compared to the peripheral regions that are represented in the isolated lung preparation. Pharmacokinetic parameters (C_max, T_max, and AUC_0-∞) were estimated from the profiles for dissolution in the different lung fluid simulants and were predicted by the simulation within 2-fold of the values reported for inhaled FP (1000 μg dose) administered via Flixotide Evohaler 250 μg strength inhaler in man. In conclusion, we report methods for performing biorelevant dissolution studies for orally inhaled products and illustrate how they can provide inputs parameters for physiologically based pharmacokinetic (PBPK) modeling of inhaled medicines.

Maternal inhaled fluticasone propionate intake during pregnancy is detected in neonatal cord blood

BACKGROUND

Despite recommendations to use inhaled corticosteroids as treatment to control asthma during pregnancy, it is unknown whether inhaled fluticasone propionate (FP) reaches the fetus. Results & methodology: We collected maternal blood on the morning following delivery. FP was detected by ultra-performance LC-MS/MS (UPLC-MS/MS) in 9/17 asthmatic women using FP. Delay between last FP inhalation and maternal blood sampling ranged between 3 and 33 h and FP was detected in a range of 1.572-46.440 pg/ml. Among the nine offspring of these FP users, FP was detected in five cord blood samples. Delay between last predelivery FP inhalation and cord blood sampling ranged from 4 to 20 h and FP was detected in a range of 0.423-4.510 pg/ml.

CONCLUSION

Our findings demonstrate placental passage of inhaled FP.

Intranasal Loteprednol Etabonate in Healthy Male Subjects: Pharmacokinetics and Effects on Endogenous Cortisol

Loteprednol etabonate (LE) is a glucocorticoid soft drug that is currently in development for intranasal use. The main objectives of this study were to examine the pharmacokinetics and potential effects on systemic cortisol of two intranasal suspension formulations of LE and to compare these findings with placebo and fluticasone propionate (FP, Flonase) control treatments. In this randomized, double-blind (except for FP), parallel-group study (n = 8/group), all subjects received for 14 days once daily in the morning two puffs of the following nasal spray formulations into each nostril: LE 0.1% (400 microg/day), LE 0.2% (800 microg/day), FP 0.05% (200 microg/day), and placebo. Drug trough levels were determined on days 1, 5, 12, 13, and 14, and a full pharmacokinetic profile was established on day 14, and 24-hour serum cortisol profiles were assessed prior to treatment (i.e., at baseline) and after the last dose. All subjects completed the protocol without treatment-emergent adverse findings. All formulations were rapidly absorbed (t(max) less than 1 h). The rather short mean terminal half-lives of 2.2 +/- 1.5 hours and 1.8 +/- 1.0 hours for LE 400 microg and LE 800 microg, respectively, and 4.2 +/- 1.8 hours for the 200-microg FP treatment explained the lack of any accumulation. Mean peak concentrations (C(max)) were 139 +/- 57 pg/mL with LE 400 microg and 164 +/- 54 pg/mL with LE 800 microg and thus fairly independent from dose. The 200-microg FP treatment resulted in a C(max) of only 15.5 +/- 5.9 pg/mL. Mean measured AUC(0-t) values (193 +/- 87 pg/h/mL(-1), 300 +/- 183 pg/h/mL(-1), and 40 +/- 34 pg/h/mL(-1) for LE 400 microg, LE 800 microg, and FP 200 microg, respectively) showed high variability and suggested nonlinear pharmacokinetics for the LE formulations, indicative of a less complete systemic uptake of LE from the 0.2% concentration. None of the treatments (LE 400 microg, LE 800 microg, and FP 200 microg) showed evidence for serum cortisol suppression when compared with placebo, respectively. The uptake and systemic exposure appears less complete from the 0.2% LE concentration, which principally favors this formulation for further clinical development.

Ultrasensitive and automated 1 pg/ml fluticasone propionate assay in human plasma using LC–MS/MS

Background: To develop and validate an ultrasensitive bioanalytical assay for quantitation of fluticasone propionate in human plasma, aliquots of 0.6 ml of K3EDTA human plasma were treated with zinc sulfate solution and loaded onto a preconditioned SPE plate. The sample solutions were washed, eluted, dried and reconstituted. The extracted sample was injected onto a LC–MS/MS system and separated by a reverse-phase HPLC column with a 5 min gradient program, and detected by MS/MS for fluticasone propionate quantitation. Results: Linearity was from 1 to 200 pg/ml. The intra- and inter-day accuracy and precision of the assay met validation acceptance criteria. Various stabilities were established and interference drug assessment was evaluated. The assay has been used for clinical studies. Conclusion: This ultrasensitive method has been successfully validated using LC–MS/MS for determination of fluticasone propionate in human plasma at low pg/ml level.

Simultaneous determination of montelukast as sparing therapy with some inhaled corticosteroids in plasma of asthmatic patients

Montelukast (MKST) is a leukotriene receptor antagonist that has been concomitantly used with inhaled corticosteroids (ICS) for its steroid-sparing effect in the long-term management of asthma. However, the simultaneous determination of MKST, when used as ICS tapering therapy, with ICS in human plasma has not yet been reported. A fast and efficient reversed phase monolith HPLC method was developed for simultaneous determination of MKST with some ICS in plasma of asthmatic patients. The separation was achieved on monolith reversed phase column by isocratic mode at a flow rate of 1.0 ml min(-1) using a mobile phase consisted of a mixture of acetonitrile and 10mM phosphate buffer adjusted to pH 3.5 (40:60, v/v) and detected at 240 nm. Betamethasone dipropionate (BDP) was used as the internal standard. All the studied ICS and MKST were efficiently separated within less than 6 min. The obtained linearity range for the developed HPLC method was 0.03-10 μg ml(-1) with correlation coefficients>0.9995 and the detection limits were 0.009-0.016 μg ml(-1) in plasma for all the studied drugs. The method was validated in agreement with the requirements of US-FDA guideline and was recommended for the target applications. The method is valuable for investigations concerned with the effective tapering of ICS therapy with MKST in patients with chronic asthma in clinical practice without loss of asthma control.

Inhaled fluticasone and the hormonal and inflammatory response to brief exercise

PURPOSE

Inhaled corticosteroids (ICS) improve symptoms in lung diseases, such as asthma. Initial data suggest that the effects of ICS remain localized in the lung; however, recent studies demonstrate alteration to the peripheral immune system in patients with asthma. We sought to evaluate the effect of ICS on peripheral immune mediators and hypothalamic-pituitary-adrenal axis and their response to exercise in healthy men.

METHODS

Eleven healthy males (18-30 yr old) were placed on 2 wk of fluticasone proprionate (440 μg) twice daily. A 30-min bout of exercise was performed on a cycle ergometer at approximately 70% of peak work rate before and after the start of ICS. Blood was sampled before and after exercise. Cytokines and hypothalamic-pituitary-adrenal axis mediators were measured by ELISA, and fluticasone was measured by liquid chromatography/tandem mass spectrometry.

RESULTS

After ICS treatment, cortisol and adrenocorticotropin were decreased, and a blunted exercise response was observed for cortisol, adrenocorticotropin, and growth hormone. Peripheral leukocytes and neutrophils were significantly increased in response to exercise in both the untreated and the ICS-treated conditions and at baseline after ICS treatment. Interleukin-6 was elevated with ICS treatment, but the exercise response was blunted. Circulating median fluticasone levels were 0.15 ng·mL(-1) and were increased to 0.20 ng·mL(-1) in response to exercise.

CONCLUSIONS

Exercise revealed deficits in growth hormone production after ICS treatment not identified by static markers. Neutrophils were shown to be surrogate markers of the systemic effect of ICS. Exercise significantly increased circulating levels of fluticasone. Exercise challenge tests can be used to assess the physiological effect of exogenous corticosteroids.

HPTLC-densitometric method for simultaneous determination of salmeterol xinafoate and fluticasone propionate in dry powder inhalers

A high performance thin layer chromatography (HPTLC) method was developed and validated for determination of two anti-asthmatic drugs, salmeterol xinafoate and fluticasone propionate in co-formulations. Study was performed on pre-coated silica gel HPTLC plates using n-hexane:ethyl acetate:acetic acid (5:10:0.2) as a mobile phase. A TLC scanner set at 250 nm was used for direct evaluation of the chromatograms in reflectance/absorbance mode. Method was validated according to ICH guidelines. Determination coefficients of calibration curves were found 0.9977 and 0.9936 in the ranges 100-1000 and 200-2000 ng band(-1) for salmeterol and fluticasone, respectively. Method had an accuracy of 99.5% for salmeterol and 102.01% for fluticasone. Method had the potential to determine these drugs simultaneously from dosage forms without any interference.

A high-throughput liquid chromatography tandem mass spectrometry method for the comparative determination of fluticasone propionate by reversed-phase liquid chromatography and capillary electrophoresis methods in pharmaceutical nasal sprays

A simple, specific, rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the analysis of fluticasone propionate (FP) in pharmaceutical formulations was developed and validated using deflazacort as internal standard (IS). The LC-MS/MS method was carried out on a C8 column (50 mm) with a mobile phase consisted of methanol : water (95 : 5, v/v) 100 mM formic acid-50 mM ammonium acetate (90 : 5 : 5, v/v/v). The mass spectrometry method was performed employing positive atmospheric pressure chemical ionization technique, operating in multiple reaction monitoring mode. The chromatographic separation was obtained within 1.5 min and it was linear in the concentration range of 10-1000 ng mL(-1). Moreover, method validation demonstrates acceptable results for the specificity, accuracy, precision and robustness. The proposed method was successfully applied for the quantitative analysis of FP nasal sprays and the results were compared to validated liquid chromatography and capillary electrophoresis methods with photodiode array detectors showing non-significant difference (P > 0.05).

Plasma concentrations of fluticasone propionate and budesonide following inhalation: effect of induced bronchoconstriction

AIMS

To determine whether and to what extent bronchoconstriction affects plasma concentrations of fluticasone and budesonide following inhalation.

METHODS

Twenty people with mild asthma inhaled 1000 microg fluticasone (Accuhaler) plus 800 microg budesonide (Turbohaler) on two visits. On one occasion, prior to drug inhalation, FEV(1) was decreased by at least 25% using inhaled methacholine. Plasma drug concentrations were measured for each drug over 5 h and area under the plasma concentration-time curve (AUC(0,5 h)) compared between visits.

RESULTS

The mean difference in FEV(1) prior to drug inhalation on the 2 days was 33%. AUC(0,5 h) values for fluticasone and budesonide were lower by a median of 60% (IQR 36-75) and 29% (IQR 2-44), respectively, when administered following bronchoconstriction; the reduction was greater for fluticasone than for budesonide, P = 0.007.

CONCLUSIONS

The lower plasma concentrations of fluticasone and, to a lesser extent, budesonide seen when the drugs were inhaled following induced bronchoconstriction, is likely to reflect variations that will occur with fluctuations in airway caliber in asthma.

Minimizing matrix effects in the development of a method for the determination of salmeterol in human plasma by LC/MS/MS at low pg/mL concentration levels

Salmeterol is an inhaled bronchodilator drug used for treatment of asthma. Its concentrations in plasma are very low or undetectable by previously developed methods. The present paper describes a method for analysis of salmeterol in human plasma with 2.5 pg/mL lower limit of quantitation. Despite the basic character of the drug the method uses mixed mode anion-exchange solid phase extraction for sample preparation combined with a column switching approach to minimize matrix effects. Samples are separated and detected by LC/MS/MS. The method is easy to use, only requires 0.5 mL of plasma and was validated for use in bioanalytical applications. The method does not suffer from interference from co-administered fluticasone propionate.

Lung bioavailability of hydrofluoroalkane fluticasone in young children when delivered by an antistatic chamber/mask

OBJECTIVE

To determine whether an antistatic valved holding chamber/mask improves lung bioavailability of hydrofluoroalkane (HFA) fluticasone in young children.

STUDY DESIGN

Twelve patients, age 1 to 6 years, with well-controlled asthma were treated with an HFA fluticasone metered-dose inhaler (Flovent HFA) twice daily (440 microg/day). The drug was delivered by tidal breathing through conventional (AeroChamber Plus) and antistatic (AeroChamber MAX) valved holding chambers (VHCs) with masks in a randomized, crossover manner, each for 3 to 7 days. When adherence was 100% at home, blood was collected for measurement of steady-state fluticasone plasma concentration (FPC) 1 hour after the last dose was administered in the clinic. FPC indicates systemic exposure directly and airway delivery indirectly. It was measured by liquid chromatography-mass spectrometry. Data were analyzed by regression analysis.

RESULTS

The mean +/- SD FPC was 107 +/- 30 pg/mL after conventional VHC and 186 +/- 134 pg/mL after the antistatic VHC (P = .03). In 5 patients (40%), the antistatic VHC increased FPC by >/= 100%, to potentially excessive levels in 4 of them; it had little effect in 7 patients.

CONCLUSIONS

HFA fluticasone was delivered to the airways by both devices even though the patients could not inhale deeply and breath hold. The antistatic VHC variably increased lung bioavailability. To reduce systemic exposure, the dose should be weaned to the minimum required to maintain asthma control.

Plasma concentrations of inhaled corticosteroids in relation to airflow obstruction in asthma

AIMS

To compare the pharmacokinetic profiles of beclometasone, budesonide, fluticasone and mometasone following inhalation in patients with asthma, and explore the relationship between lung function and plasma drug concentrations.

METHODS

Thirty subjects with asthma and a forced expiratory volume in 1 s (FEV(1)) ranging from 36 to 138% predicted, inhaled 800 microg beclometasone, budesonide and mometasone and 1000 microg fluticasone in random order. Plasma drug concentrations were measured over 8 h and the relationship between the area under the plasma concentration-time curve (AUC(0-8)) and lung function was modelled using linear regression. Estimated AUC(0-8) values at 50 and 100% predicted FEV(1) were compared for each drug.

RESULTS

Pharmacokinetic profiles differed markedly between the drugs. Correlation coefficients for the relation between FEV(1)% predicted and AUC(0-8) values for beclometasone, budesonide, fluticasone and mometasone were 0.37 (P = 0.05), 0.33 (P = 0.08), 0.25 (P = 0.2) and 0.52 (P = 0.004), respectively, and estimated AUC(0-8) values were 1.3 [95% confidence interval (CI) 1.0, 1.8], 1.3 (95% CI 1.0, 1.8), 1.4 (95% CI 0.9, 2.2) and 2.2 (95% CI 1.3, 3.5) times higher for the four drugs, respectively, at 100 compared with 50% predicted FEV(1.)

CONCLUSION

The higher plasma concentrations of inhaled corticosteroids in patients with a higher FEV(1)% predicted suggests that, for any given dose, these patients will be at greater risk of developing adverse systemic effects with long-term use.

A sensitive liquid chromatography-tandem mass spectrometry method for the quantification of mometasone furoate in human plasma

A robust, rapid, selective and sensitive liquid chromatography-negative atmospheric pressure chemical ionization (LC-(APCI(-))-MS-MS) method has been developed for the quantification of mometasone furoate (MF) in human plasma utilizing a solid-phase extraction clean-up step and 13C-fluticasone propionate as internal standard. The intra- and inter-day coefficients of variation were < or = 15% and the lower limit of quantification (LLOQ) was 15 pg/ml. This method is ideally suited for pharmacokinetic investigations of low MF levels following inhalation of MF.

Differences in inhaled fluticasone bioavailability between holding chambers in children with asthma

STUDY OBJECTIVE

To determine if differences between holding chambers in previous in vitro aerosol studies would agree with the bioavailability of inhaled fluticasone propionate between the same holding chambers in children with asthma.

DESIGN

Double-blind, randomized, crossover study

SETTING

University of Florida Clinical Research Center.

PATIENTS

Eight children (aged 5-9 yrs) with stable asthma.

INTERVENTION

Under observation, the children inhaled two 110-microg puffs of fluticasone twice/day through the InspirEase or E-Z Spacer holding chamber.

MEASUREMENTS AND MAIN RESULTS

Blood samples were collected at baseline and then at 0.5, 1, 1.5, 2, 4, and 6 hours after the last dose of fluticasone. Primary outcome measures were peak fluticasone steady-state plasma concentration (Cmax) and area under the fluticasone plasma concentration-time curve from 0-6 hours (AUC0-6). The fluticasone plasma concentrations were determined by high-performance liquid chromatography-mass spectrometric assay. Mean +/- SD Cmax from InspirEase (245 +/- 77 pg/ml) was 18% higher than that after E-Z Spacer (199 +/- 58 pg/ml, p < 0.05). Mean +/- SD AUC0-6 from InspirEase (1103 +/- 305 pg x hr(-1) x ml(-1) was 22% higher than that delivered from E-Z Spacer (863 +/- 258 pg x hr(-1) x ml(-1), p = 0.06).

CONCLUSION

Differences in inhaled fluticasone bioavailability between these holding chambers in children with asthma corroborate differences reported in earlier in vitro aerosol studies.

Single-dose and steady-state pharmacokinetic and pharmacodynamic evaluation of therapeutically clinically equivalent doses of inhaled fluticasone propionate and budesonide, given as Diskus or Turbohaler dry-powder inhalers to healthy subjects

Direct comparisons of the pharmacokinetic (PK) and systemic pharmacodynamic (PD) properties of inhaled corticosteroids after single and multiple dosing in the same subjects are scarce. The objective of this study was to compare thePK/PDproperties of clinically equivalent, single, and multiple doses of dry-powder formulations of inhaled fluticasone propionate (FP 200 and 500 microg via Diskus) and budesonide (BUD, 400 and 1,000 microg via Turbohaler). Fourteen healthy subjects completed a double-blind, double-dummy, randomized, placebo-controlled, five-way crossover study consisting of a single dose administered at 8 a.m. on day 1 followed by 4 days of twice-daily dosing at 8 a.m. and 8 p.m. on days 2 to 5. Serum concentrations of FP and BUD were measured using validated liquid chromatography/ mass spectrometry assays. The 24-hour cumulative cortisol suppression (CCS) in serum was monitored as the pharmacodynamic surrogate marker. Peak serum concentrations following single and multiple dosing were observed 10 to 30 minutes after inhalation for BUD and 30 to 90 minutes afterinhalation of FP with no influence of dose ordosingregimen. After a single dose of 1000 microg BUD and 500 microg FP the median estimates of terminal half-life and mean residence time were 3.5 and 3.9 hours for BUD and 10.1 and 12.0 hours for FP, respectively. Using previously reported intravenous data, the mean absorption times (MAT) were calculated to be around 2 hours and 7 hours for BUD and FP respectively. On average, the area under the curve (A UC) at steady state (day 5) was up to 30% higher for BUD compared to that over a 12-hour period following the first dose on day 1, whereas A UC estimates were 50% to 80% higherforFP at steady state, indicating accumulation. However, the steady-state Cmax values were seven to eight times and AUC values three to four times higher for BUD than for FP. Comparison of active treatment data with placebo showed that CCS after a single dose was not pronounced for any of the doses/drugs studied. On day 5, both doses of BUD caused statistically significant suppression (CCS of 19% for the 400 microg dose and 36% for the 1,000 microg dose). For FP only the high dose had a statistically significant effect on serum cortisol (CCS of 14% for the 200 microg dose and 27% for the 500 microg dose). Compared to BUD, FP has slower pulmonary absorption and slower elimination kinetics. However, following inhalation of therapeutically equipotent, multiple twice-daily doses in healthy subjects, the systemic effects of FP delivered via Diskus on AUC24 serum cortisol were relatively low and similar to those of BUD delivered via Turbohaler.

Quantification of epimeric budesonide and fluticasone propionate in human plasma by liquid chromatography-atmospheric pressure chemical ionization tandem mass spectrometry

A highly sensitive and selective liquid chromatography-atmospheric pressure chemical ionization tandem mass spectrometry assay was developed and validated for simultaneous determination of epimeric budesonide (BUD) and fluticasone propionate (FP) in plasma. The drugs were isolated from human plasma using C18 solid-phase extraction cartridges, and epimeric BUD was acetylated with a mixture of 12.5% acetic anhydride and 12.5% triethylamine in acetonitrile to form the 21-acetyl derivatives following the solid-phase extraction. Deuterium-labelled BUD acetate with an isotopic purity >99% was synthesized and used as the internal standard. The assay was linear over the ranges 0.05-10.0 ng/ml for epimeric BUD, and 0.02-4.0 ng/ml for FP. The inter- and intra-day relative standard deviations were <14.3% in the assay concentration range.