Bioavailability of Beclometasone From Two HFA-BDP Formulations With a Spacer.

BACKGROUND: The drug delivery characteristics of each inhaler/spacer combination are unique. The spacer size as well as the presence of electrostatic charge greatly influence the inhaler dose emission and in vivo delivery. Using a previously developed urinary pharmacokinetic method, we have measured the relative lung and systemic bioavailability of beclometasone dipropionate (BDP) after inhalation from 2 hydrofluroalkane-beclometasone dipropionate (HFA-BDP) formulations when used with a spacer. METHODS: 12 healthy volunteers received 8 randomized doses, separated by 7 d, of inhaled of BDP with either the Clenil pressurized metered-dose inhaler (pMDI; 250 µg) or the breath-actuated Qvar Easi-Breathe inhaler (100 µg), used alone or with a spacer. The urinary amounts of BDP excreted and retained in the spacer were assayed using a liquid chromatographic mass spectrometer. The spacer was assessed after washing with a detergent solution that was either rinsed or not rinsed with water. In addition, the aerodynamic characterization of each inhaler/spacer combination was assessed using the Andersen Cascade Impactor operated at 28 L/min using a 4-L inhalation volume. The amount of BDP deposited in the induction port, spacer, and various Anderson Cascade Impactor stages were determined. RESULTS: The in vivo 30-min urinary excretion and the in vitro fine particle dose results were only slightly affected by adding the spacer to the Clenil pMDI or the Qvar Easi-Breathe inhaler. However, the spacer significantly reduced drug particle impaction in the oropharynx and minimized deposition in the gastrointestinal tract. Therefore, using spacers with BDP inhalers is associated with a more favorable therapeutic ratio because it has little effect on lung dose, but it significantly reduced throat deposition. An improved lung deposition was achieved with non-rinsed spacers compared to spacers rinsed with water. CONCLUSION: The difference in the BDP particle size between formulations as well as spacer size greatly affected drug deposition in different regions of the respiratory tract.

Urinary fluticasone propionate-17beta-carboxylic acid to assess asthma therapy adherence.

Although the National Asthma Education and Prevention Program Expert Panel Report 3 recommends referral to specialists to address adherence, guidelines do not provide a tool to determine nonadherence. This study was designed to prospectively evaluate the characteristics of urinary analysis of fluticasone propionate-17beta-carboxylic acid (FP17betaCA) as a test to verify if a specific patient has not taken fluticasone propionate (FP) within 16-24 hours. Urine of asthmatic subjects was prospectively analyzed 16-24 hours after witnessed administration of orally inhaled FP using liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis; limit of quantitation was 10.3 pg/mL. Results were compared with those from asthmatic subjects not receiving inhaled FP. Thirty asthmatic subjects receiving inhaled FP (2 oral inhalations of FP at 110 micrograms each or 1 oral inhalation twice daily of fluticasone and salmeterol in fixed combination at 250/50 micrograms for 1 week) were compared with 30 asthmatic subjects not receiving FP. FP17betaCA was detected in the urine of 30 of 30 asthmatic subjects receiving FP (median, interquartile range [IQR; 413.5, 212.8-1230.0] range 12.4-3290.0 pg/mL [corrected for urine creatinine: median, IQR {576.2, 188.1-1306.6} range 6.3-5425.9 ng/g Cr]) and was undetectable in 30 of 30 subjects not receiving inhaled FP. The sensitivity and specificity of LC-MS/MS to detect FP17betaCA in urine were 100% (95% exact binomial confidence interval, 88-100) and 100% (95% exact binomial confidence interval, 88-100), respectively. Analysis of FP17betaCA in urine provides a sensitive method that may be used to verify that a specific patient may not have administered FP within a 16- to 24-hour window before testing.

Lung deposition after inhalation with various nebulisers in preterm infants.

AIM: To compare pulmonary deposition after inhalation with three different nebulisers in preterm infants under conditions relevant to practice. METHODS: The relative lung deposition (bioavailability) was estimated by inhalation of the marker substance, sodium cromoglycate (SCG), and measurement of urinary excretion of SCG. Seventeen spontaneously breathing preterm infants received 20 mg of SCG as nebuliser solution by means of (a) an LC Star jet nebuliser; (b) an LS 290 ultrasonic nebuliser; and (c) a Projet ultrasonic nebuliser in a randomised three-period, crossover design. Serial urine samples were collected until about 12 hours after inhalations, and the excreted SCG was determined by high-performance liquid chromatography. RESULTS: The mean (SD) total amounts of SCG excreted in urine measured after inhalation with the LC Star nebuliser (0.089 (0.036) mg) were significantly higher than those obtained with the LS 290 (0.055 (0.019) mg) or the Projet nebuliser (0.046 (0.025) mg). The average pulmonary deposition after inhalation using the LC Star, LS 290 and Projet devices was estimated as 0.89%, 0.55% and 0.46% of the nominal dose, respectively. CONCLUSION: Inhalation with the LC Star jet nebuliser producing the greatest proportion of droplets <2 mum yielded a higher lung deposition in preterm infants than the LS 290 and Projet ultrasonic nebulisers.

Ciclesonide disposition and metabolism: pharmacokinetics, metabolism, and excretion in the mouse, rat, rabbit, and dog.

The pharmacokinetics, metabolism, and excretion of ciclesonide, a novel and effective inhaled glucocorticoid for the treatment of asthma, were investigated after intravenous and oral administration of 14C-ciclesonide in the mouse, rat, rabbit, and dog. The pharmacokinetics of ciclesonide in all animal species were characterized by a low oral bioavailability (approximately 6% or less), a high clearance, and a large volume of distribution. The apparent terminal half-life of ciclesonide was short; the apparent terminal half-life of the active desisobutyryl-ciclesonide metabolite (des-CIC or M1) was longer and ranged from 2.4 to 6.9 hours in the 4 species. Metabolites derived from ciclesonide in serum (or plasma) and excreta samples from the 4 animal species were profiled and identified by LC/RAM/MS (liquid chromatography/radioactivity monitor/mass spectrometry). Ciclesonide was extensively metabolized to yield des-CIC, which was further metabolized to primarily yield hippuric acid and hydroxylated metabolites, namely, isomers of cyclohexane-monohydroxylated des-CIC and B-ring-monohydroxylated des-CIC. Greater than 90% of intravenous and oral 14C-ciclesonide doses were recovered in all species; the main elimination route was fecal/biliary. A comparison of in vitro and in vivo metabolite profiles between mice, rats, rabbits, and dogs with those from humans indicated that metabolic pathways for ciclesonide were qualitatively similar in humans and in the 4 animal species.

HPLC-radiometric determination of quinlukast in biological fluids.

An analytical method for the analysis of a novel antiasthmatic drug quinlukast and its metabolites in the plasma, bile and urine was developed. For the analysis, the solid phase extraction method and the C(8) RP-HPLC with radiometric detection of the drug were used. This method enables a quantitative determination of the agent and all of its metabolites (even of those with an unknown structure) in a biological system. The procedure is, therefore, suitable both for the pharmacokinetic analysis of quinlukast and the determination of its elimination pathways.

A simple pharmacokinetic method to evaluate the pulmonary dose in clinical practice--analyses of inhaled sodium cromoglycate.

When the expected effect of an inhaled drug is not achieved, the cause could be poor inhalation technique and consequently a low pulmonary dose. A simple in vivo test to evaluate the pulmonary dose would be a benefit. This study evaluates the relative and systemic bioavailability following inhalation of nebulized sodium cromoglycate (SCG) in healthy subjects. Blood samples were collected during 240 min and urine was collected in two portions, up to 6 h post-inhalation. Two exposures were performed and comparisons based on the quantification of drug in plasma and urine by a high-performance liquid chromatography (HPLC) procedure were done. In one of the exposures, a pulmonary function test was performed to study if an expected effect of increased absorption could be detected. There was a good correlation between the two exposures shown in the plasma concentrations, but not in the urine analyses. The forced exhaled volume manoeuvres were associated with a higher Cmax and plasma concentrations up to 60 min post-inhalation (P<0.01). This effect was not detected in the urine analyses. We conclude that this pharmacokinetic method with inhaled SCG and plasma analyses could be used to evaluate individual inhalation technique. The HPLC method used was rapid and had adequate sensitivity.

Relative lung and systemic bioavailability of sodium cromoglycate inhaled products using urinary drug excretion post inhalation.

The relative lung and systemic bioavailability of sodium cromoglycate following inhalation by different methods have been determined using a urinary excretion pharmacokinetic method. On three separate randomised study days, 7 days apart, subjects inhaled (i) 4x5 mg from an Intal metered dose inhaler (MDI), (ii) 4x5 mg from an MDI attached to a large volume spacer (MDI+SP) and (iii) 20 mg from an Intal Spinhaler (DPI). Urine samples were provided at 0, 0.5, 1, 2, 5 and 24 h post dose. The mean (S.D.) amount of sodium cromoglycate excreted in the urine during the first 30 min post inhalation was 38.1 (27.5), 222.3 (120.3) and 133.1 (92.2) microg following MDI, MDI+SP and DPI, respectively. The mean ratio (90% confidence interval) of these amounts excreted in the urine over the first 30 min for MDI+SP vs. MDI, DPI vs. MDI and MDI+SP vs. DPI was 801.0 (358.0, 1244; p<0.002)%, 457.0 (244.0, 670.0; p<0.02)% and 262.4 (110.2, 414.5)%, respectively. Similarly for the 24 h cumulative amount of sodium cromoglycate excreted over the 24 h post inhalation the ratios were 375.4 (232.9, 517.9; p<0.005)%, 287.5 (183.4, 391.6; p<0.02)% and 211.4 (88.3, 334.5)%, respectively. The results highlight better lung deposition of sodium cromoglycate from a metered dose inhaler attached to a large volume spacer.

LC/MS/MS plasma assay for the peptidomimetic VLA4 antagonist I and its major active metabolite II: for treatment of asthma by inhalation.

In vitro and in animals, I is a potent and specific peptidomimetic for the potential treatment of airway inflammation in the pathogenesis of asthma. Preclinical studies indicated extensive conversion of I to an active metabolite II, and thus, a very sensitive assay for I and II was needed to support an inhalation ascending-dose study in man. The LC/MS/MS plasma/urine assay method (1.0 ml of sample) involves the following: liquid-liquid extraction of acidified plasma into pentane-ethyl acetate (90:10 v/v); evaporation of the organic extract, reconstitution into methanol; addition of water to the methanolic extract and freezing. After thawing, the extract is centrifuged and the clear supernatant injected for chromatography. Extract is chromatographed on a YMC ODS-AM column (50 x 2.0 mm). For detection, a Sciex 365 LC/MS/MS with an electrospray inlet and used in the positive ion, multiple reaction monitoring mode was used to monitor precursor-->fragment ions of m/z 709-->594 for I and m/z 513-->380 for II. The plasma assay was linear over the concentration range of 0.1-100 ng/ml in plasma for I and II. Accuracy and precision for I ranged from 97.9 to 102.1% of nominal with a 0.84-10.65% CV; similarly for II, 98.0-101.7% and 1.39-9.28% CV, respectively. Extraction recovery averaged 63.7% for I and 64.9% for II. This general assay methodology may be applied to assay small acidic peptides and peptidomimetics from biological fluids by LC/MS/MS.

Relative lung bioavailability of generic sodium cromoglycate inhalers used with and without a spacer device.

The relative lung bioavailability of sodium cromoglycate following inhalation has been evaluated using urinary drug excretion in nine healthly volunteers. Each inhaled four 5 mg sodium cromoglycate doses from a generic metered dose inhaler (MDI) and when it was attached to large volume spacer (MDI + VOL). A breath-actuated MDI was also evaluated either used on its own (EB) or attached to a small volume spacer tube (EBO). The mean (SD) urinary excretion of sodium cromoglycate in the first 30 min post-inhalation was 34.1 (20.2), 211.7 (123.5), 29.3 (19.5) and 52.8 (36.0) microg following MDI, MDI+VOL, EB and EBO, respectively. The cumulative mean (SD) urinary excretion of sodium cromoglycate over the 24 h post-inhalation was 364.7 (266.2), 1227.1 (459.0), 280.2 (155.4) and 429.5 (176.7) microg. A metered dose inhaler attached to a large volume spacer delivers more sodium cromoglycate to the lungs than any other inhalation method.

Bioequivalence of inhaled formoterol fumarate assessed from pharmacodynamic, safety and urinary pharmacokinetic data.

This paper deals with a crossover trial on healthy volunteers performed to obtain combined pharmacodynamic, safety and pharmacokinetic data in order to assess the bioequivalence of formoterol fumarate (CAS 43229-80-7) delivered by mono-dose dry powder inhalers, as test and reference. The trial was carried out on 24 Caucasian healthy male and female volunteers treated with 12 micrograms formoterol fumarate bihydrate capsules for inhalation route. Pharmacodynamics was evaluated through a challenge test with methacholine on the forced expiratory volume in 1 s (FEV1). Safety was achieved from glucose and potassium serum levels assayed on timed samples over a 12-h period cost-dosing and from blood pressure, heart rate and ECG recording. Pharmacokinetics was obtained from urinary excretion of formoterol, assessed by a highly sensitive analytical method (LC-MS-MS). Pharmacodynamic, safety and pharmacokinetic results evidenced the bioequivalence of the two formulations investigated. This investigation is an interesting approach how to assess bioequivalence when the classical approach based on the similarity of plasma concentrations can not be applied.

Validation of a high-performance liquid chromatography assay for urinary nedocromil sodium following oral and inhaled administration.

The validation of a solid-phase extraction and an ion pair high-performance liquid chromatographic assay for the determination of nedocromil sodium (NCS) in urine samples following oral and inhaled administration to healthy volunteers is described. NCS and its internal standard sodium cromoglycate (SCG) were extracted from urine samples using solid-phase extraction and then quantified using high-performance liquid chromatography (HPLC). A 25-cm C8 Spherisorb 5 microm stationary phase with a mobile phase containing a long alkyl chain ion-pair reagent (methanol-0.045 M phosphate buffer-0.05 M dodecyl triethyl ammonium phosphate; 550:447.6:2.4, v/v) was used. The mean (S.D.) intra-day accuracy and precision of the HPLC assay was 99.9 (1.6) and 7.05 (4.9)%, respectively. These values for the inter-day data were 102.4 (4.07) and 10.5 (2.7)%, respectively, over the concentration range investigated. The method described permits the detection of NCS in human urine at concentrations as low as 0.04 microg ml(-1) where the signal-to-noise ratio is greater than 3:1. In 10 healthy volunteers a significantly greater amount of NCS was excreted in the urine following inhalation than after oral dosing (p<0.001). The mean (S.D.) amount of NCS renally excreted at 0.5, 1.0 and 24 h following inhalation of four 2-mg doses of NCS from a metered dose inhaler (MDI) was 0.513 (0.24), 1.163 (0.49) and 4.00 (1.73)% of the nominal dose. Similar values after oral administration of 8 mg of NCS were 0.026 (0.03), 0.079 (0.06) and 0.930 (0.74)%, respectively.

Determination of the relative bioavailability of nedocromil sodium to the lung following inhalation using urinary excretion.

OBJECTIVE: To determine the relative lung deposition of nedocromil sodium following inhalation by comparing the amounts of nedocromil sodium excreted in the urine after oral and inhaled dosing. METHODS: Ten healthy volunteers swallowed 8 mg of nedocromil and inhaled 4 x 2-mg doses on separate days. Urine was collected at 0.0, 0.5. 1.0, 2.0, 5.0, 24 h and 36 h after dosing. Urinary excretion of nedocromil was determined by high-performance liquid chromatography. RESULTS: A significantly greater amount of nedocromil was excreted following inhalation than after oral dosing. The mean with (SD) amount excreted at 0.5, 1.0 h and 24 h following inhalation of 4 x 2-mg doses was 41.0 (19.5), 93.0 (39.1) and 319.9 (138.1) microg. Corresponding values after oral administration of 8 mg of nedocromil were 2.1 (2.2), 6.3 (4.7) microg and 74.4 (58.8) microg, respectively. CONCLUSION: Nedocromil excreted in the urine at 0.5 h and 1.0 h after dosing is representative of the amount of drug delivered to the lungs. This method could be used to compare the relative bioavailability to the lungs following inhalation, and hence the performance of different inhaled products and inhalation techniques. The amount of nedocromil excreted in 24 h post-dose is representative of the emitted dose which was delivered to the body.

Determination of disodium cromoglycate in human urine by high-performance liquid chromatography with post-column photoirradiation-fluorescence detection.

For the determination of disodium cromoglycate in urine, a fluorimetric method using HPLC post-column photoirradiation has been developed. The mobile phase consisted of a 35 mmol l-1 phosphate buffer (pH 8)-methanol (7 + 3, %v/v) containing 75 mmol l-1 hydrogen peroxide and 20 mmol l-1 18-crown-6. The 18-crown-6 was used for separation adjustment of the disodium cromoglycate in the urine sample. Photoirradiation was carried out in tubing wound around a germicidal light in a reactor equipped with an air-cooling fan. The fluorescence was monitored with excitation at 325 nm and emission at 448 nm. The calibration graph for disodium cromoglycate was linear over the range 38-2340 ng ml-1 using an injection volume of 100 microliters. The pretreatment of the urine samples consisted of diluting and filtering steps. The mean recovery of disodium cromoglycate from urine was 99.1 +/- 2.4% (n = 6).

Development and validation of an ion-pair liquid chromatographic method for the quantitation of sodium cromoglycate in urine following inhalation.

An ion-pair liquid high-performance chromatography method with solid-phase extraction for measuring urinary concentrations of sodium cromoglycate following inhalation has been developed and validated. Sodium cromoglycate was extracted from urine on a 100-mg phenyl cartridge (Isolute, Jones Chromatography) and then quantified on a 25-cm C8 Spherisorb 5 microns stationary phase with a mobile phase of methanol-0.045 M phosphate buffer-0.05 M dodecyl triethyl ammonium phosphate (550:447.6:2.4, v/v) pH 2.3, at 0.85 ml min-1 using nedocromil sodium as an internal standard and UV detection at 238 nm. The inter- and intra-day reproducibilities were 8.33 and 13.63%, respectively, at 0.25 mg l-1. The limit of determination for sodium cromoglycate was 0.25 mg l-1 (with a signal-to-noise ratio of greater than 10:1). Following oral and inhaled administration of 20 mg of sodium cromoglycate to eight healthy volunteers, the mean and S.D. of sodium cromoglycate excreted in the urine at 0.5, 1 and 24 h post-dose were 0.02, 0.05 and 0.33%, and 0.16, 0.30 and 1.55% of the dose, respectively. The urinary recovery of sodium cromoglycate at 0.5 and 1 h following inhalation can therefore be used to compare the amount of drug reaching the respiratory tract using different sodium cromoglycate inhaled products or inhalation methods.