Aims The present study was undertaken to see whether the difference in plasma cortisol suppression between single and repeated dosing of fluticasone propionate (FP) can be explained by systemic accumulation. Methods Twelve healthy subjects (six women) were given, in a crossover fashion, a single dose inhalation (1000 mg ) of FP via DiskhalerA and repeated inhalations (1000 mg twice daily) every 12 h during 7 days. There was a washout period of 2 weeks between the treatments. An intravenous dose of 20 mg FP was given as a reference. Plasma concentrations of FP for each treatment were determined by liquid chromatography plus tandem mass spectrometry. Plasma cortisol after the inhaled doses was determined using an immunoassay and was compared with baseline values. Results The average plasma concentration of FP was about 1.7 times higher after multiple inhalations than after a single dose. Systemic availability, mainly attributable to pulmonary deposition, was 15.6 [13.6-18.0]% of the nominal dose. Daytime plasma cortisol suppression vs baseline was 47 [20-65]% and 95 [93-97]% for the single and repeated doses, respectively. Conclusions To conclude, a slow elimination of FP leads to accumulation during repeated dosing. This accumulation may explain the marked decrease in plasma cortisol seen during treatment with fluticasone propionate within the clinical dose range.
Inhaled AZD4818 was well tolerated at 300mug twice daily for 4 weeks in patients with COPD; however, there was no indication of a beneficial treatment effect despite exposure as expected. These findings in COPD are in line with other studies reporting a lack of clinical efficacy with CCR1 antagonists in other therapy areas.
The pharmacokinetics and systemic availability of budesonide after rectal administration of two single enema doses (2 mg in 100 ml fluid of almost identical composition) were compared in 15 healthy volunteers. In 11 of these subjects, 2 mg oral budesonide in a gelatine capsule was given on a separate occasion. An intravenous administration (0.5 mg) was given as reference. With this design, individual hepatic bypass of the rectally administered budesonide dose could be estimated. The pharmacokinetics of the two enema formulations were similar, although not bioequivalent. Mean systemic availability was 16% (range 4.2-43%) and 15% (3.2-50%) after rectal administration and 6.3% (2.4-10%) after oral administration. The rectal data revealed a small intra- but a substantial inter-subject variability in systemic availability. Cmax was 3.3 nmol center dot l-1 (0.95-8.2), 3.0 nmol center dot l-1 (0.64%-8.9) and 1.3 nmol center dot l-1 (0.61-3.0), respectively, for the three formulations. Absorption was rapid and essentially terminated within 3 h after rectal dosing [tmax = 1.3 h for both formulations (range 0.5-2.0)], but was slower after oral dosing [tmax = 2.1 h (1.0-6.0)]. If a complete absorption after oral and rectal dosing is assumed, the fraction of the rectal dose entering the liver at first pass can be calculated to be 88% (55-99%). The higher systemic availability and intersubject variability after rectal dosing does not seem to be caused by differences in first-pass liver metabolism but rather by hepatic bypass of a varying portion of administered drug. This portion seems to be typical for an individual and might be explained by anatomical differences between subjects.
BackgroundThe CC-chemokine receptor-3 (CCR3) has emerged as a target molecule for pharmacological intervention in allergic inflammation.ObjectiveTo examine whether a dual CCR3 and H1-receptor antagonist (AZD3778) affects allergic inflammation and symptoms in allergic rhinitis.MethodsPatients with seasonal allergic rhinitis were subjected to three seven days' allergen challenge series. Treatment with AZD3778 was given in a placebo and antihistamine-controlled design. Symptoms and nasal peak inspiratory flow (PIF) were monitored in the morning, ten minutes post challenge, and in the evening. Nasal lavages were carried out at the end of each challenge series and α2-macroglobulin, ECP, and tryptase were monitored as indices of allergic inflammation.ResultsPlasma levels of AZD3778 were stable throughout the treatment series. AZD3778 and the antihistamine (loratadine) reduced rhinitis symptoms recorded ten minutes post challenge during this period. AZD3778, but not the anti-histamine, also improved nasal PIF ten minutes post challenge. Furthermore, scores for morning and evening nasal symptoms from the last five days of the allergen challenge series showed statistically significant reductions for AZD3778, but not for loratadine. ECP was reduced by AZD3778, but not by loratadine.ConclusionsAZD3778 exerts anti-eosinophil and symptom-reducing effects in allergic rhinitis and part of this effect can likely be attributed to CCR3-antagonism. The present data are of interest with regard to the potential use of AZD3778 in allergic rhinitis and to the relative importance of eosinophil actions to the symptomatology of allergic rhinitis.Trial registrationEudraCT No: 2005-002805-21.
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