Effect of AeroChamber Plus™ on the lung and systemic bioavailability of beclometasone dipropionate/formoterol pMDI

AIM

To assess the effect of AeroChamber Plus™ on lung deposition and systemic exposure to extra-fine beclometasone dipropionate (BDP)/formoterol (100/6 µg) pMDI (Foster®). The lung deposition of the components of the combination given with the pMDI was also evaluated using the charcoal block technique.

METHODS

Twelve healthy male volunteers received four inhalations of extra-fine BDP/formoterol (100/6 µg) using (i) pMDI alone, (ii) pMDI and AeroChamber Plus™ and (iii) pMDI and charcoal ingestion.

RESULTS

Compared with pMDI alone, use of AeroChamber Plus™ increased the peak plasma concentrations (C_max) of BDP (2822.3 ± 1449.9 vs. 5454.9 ± 3197.1 pg ml⁻¹), its active metabolite beclometasone 17-monopropionate (17-BMP) (771.6 ± 288.7 vs. 1138.9 ± 495.6 pg ml⁻¹) and formoterol (38.4 ± 17.8 vs. 54.7 ± 20.0 pg ml⁻¹). For 17-BMP and formoterol, the AUC(0,30 min), indicative of lung deposition, was increased in the AeroChamber Plus™ group by 41% and 45%, respectively. This increase was mainly observed in subjects with inadequate inhalation technique. However, use of AeroChamber Plus™ did not increase the total systemic exposure to 17-BMP and formoterol. Results after ingestion of charcoal confirmed that AUC(0,30 min) can be taken as an index of lung bioavailability and that more than 30% of the inhaled dose of extra-fine BDP/formoterol 100/6 µg was delivered to the lung using the pMDI alone.

CONCLUSIONS

The use of AeroChamber Plus™ optimizes the delivery of BDP and formoterol to the lung in subjects with inadequate inhalation technique. The total systemic exposure was not increased, supporting the safety of extra-fine BDP/formoterol pMDI with AeroChamber Plus™.     

Pharmacokinetics and pharmacodynamics of an extrafine fixed pMDI combination of beclometasone dipropionate/formoterol fumarate in adolescent asthma

Aim

The aim was to investigate the pharmacokinetics and pharmacodynamics of an extrafine pressurized metered-dose inhaler (pMDI) fixed combination of beclometasone dipropionate (BDP)/formoterol fumarate (FF) in adolescent and adult asthma.

Methods

This was a three-way crossover study, on 30 asthmatic adolescents receiving BDP/FF pMDI with or without a valved holding chamber (VHC) or a free licenced combination of BDP pMDI and FF pMDI plus a parallel arm of 30 asthmatic adults receiving BDP/FF pMDI. All patients received a single dose of BDP and FF of 400 µg and 24 µg, for each treatment, respectively. Assessments were performed over 8 hours.

Results

In adolescents, the 90% confidence intervals (CIs) for the systemic exposure (AUC(0,t)) geometric mean ratio of the fixed combination with or without VHC vs. the free combination were within the bioequivalence range 0.80–1.25, both for beclometasone-17-monopropionate (B17MP, the active metabolite of BDP) and formoterol. Pharmacodynamic variables for plasma potassium and glucose, pulse rate and pulmonary function in adolescents were equivalent between treatments, 95% CI within 0.9, 1.09. The upper level of 90% CIs for AUC(0,t) geometric mean ratio adolescents : adults of B17MP and formoterol after treatment with BDP/FF pMDI was lower than 1.25, 90% CI 0.78, 1.04 and 0.86, 1.17, respectively.

Conclusions

In adolescents the pharmacodynamics and the overall systemic exposure to the active ingredients of an extrafine fixed combination of BDP/FF pMDI with or without a VHC was equivalent to that of a free licenced combination of pMDIs of established safety and efficacy profiles. The systemic exposure in adolescents was not higher than in adults. These results support the indication for use of inhaled corticosteroid/long acting β₂-adrenoceptor agonist pMDIs in adolescents at the same dosage as in adults.     

Pharmacokinetic comparison of inhaled fixed combination vs. the free combination of beclomethasone and formoterol pMDIs in asthmatic children

Aim

The fixed combination of beclomethasone (BDP) and formoterol pressurized metered dose inhaler (pMDI) (Foster®, Chiesi Farmaceutici) is being developed in the lower strength (BDP/formoterol: 50/6 μg) to provide an appropriate dosage for children with asthma. The aim of this work was to investigate the systemic bioavailability of beclomethasone-17-monoproprionate (B17MP, the active metabolite of BDP) and formoterol after single inhalation of Foster® pMDI 50/6 μg vs. the free combination of BDP and formoterol pMDIs in asthmatic children.

Methods

Children aged 5–11 years old inhaled BDP 200 μg and formoterol 24 μg as fixed vs. free combination in an open label, randomized, two way crossover single dose study. Blood was collected pre-dose up to 8 h post-dose for pharmacokinetic evaluation (AUC(0,t), AUC(0,∞), AUC(0,0.5 h, C_max, t_max, t_1/2). Pharmacodynamics included heart rate, plasma potassium, urinary glucose and cortisol excretion. Peak expiratory flow and adverse events were monitored.

Results

Twenty subjects were evaluable. The systemic exposure of B17MP and formoterol administered as fixed combination did not exceed the free combination: B17MP AUC(0,t) (pg ml⁻¹ h) ratio test : reference (90% CI), 0.81 (0.697, 0.948) and formoterol AUC(0,t) (pg ml⁻¹ h) ratio test : reference 0.97 (0.85, 1.10). All pharmacokinetic and pharmacodynamic end points showed non-superiority in favour of the test drug. One adverse event (vertigo) occurred but was not considered treatment-related.

Conclusion

BDP and formoterol pharmacokinetic and pharmacodynamic effects are non-superior after administration of the two actives as fixed vs. the free combination in 5–11-year-old asthmatic children.     

Decomposition of beclomethasone propionate esters in human plasma

The kinetics of decomposition of beclomethasone dipropionate (BDP), the 17-monopropionate ester (17-BMP), and beclomethasone (BOH) were characterized in whole human plasma (HP), pH 7.1, and in solutions of 1% human serum albumin (HSA), pH 7.4, and 0.067 M phosphate buffer, pH 7.4 (μ = 0.17). A reversed-phase, high-performance liquid chromatography (HPLC) assay enabled simultaneous separation and quantification of beclomethasone propionate esters and six degradation products including three unidentified products, D1–D3, not previously reported. Following incubation of BDP, products were formed in the following sequence, D1, 17-BMP, beclomethasone-21-monopropionate (21-BMP), D3, BOH, and D2. Following incubation of 17-BMP, the same sequence of degradation products was formed with the exception of D1. Following incubation of BOH, only D2 was formed. The decomposition reactions of BDP, 17-BMP, and BOH in HP exhibit pseudo-first-order kinetics. However the degradation reactions of BDP in solutions of 1% HSA and phosphate buffer were found to follow pseudo-zero-order kinetics. At an initial concentration of 40 μg mL⁻¹, the half-lives for BDP, 17-BMP, and BOH in HP were 10.9±0.4, 3.0±0.2 and 24.8±0.2 h, respectively. © 1998 John Wiley & Sons, Ltd.     

Relative bioavailability of terbutaline to the lung following inhalation, using urinary excretion

AIMS

The aim of the study was to determine the relative lung and systemic bioavailability of terbutaline.

METHODS

On separate days healthy volunteers received 500 µg terbutaline study doses either inhaled from a metered dose inhaler or swallowed as a solution with and without oral charcoal. Urine samples were provided at timed intervals post dosing.

RESULTS

Mean (SD) urinary terbutaline 0.5 h post inhalation, in 12 volunteers, with (IC) and without (I) oral charcoal and oral (O) dosing was 7.4 (2.2), 6.5 (2.1) and 0.2 (0.2) µg. I and IC were similar and both significantly greater than O (P < 0.001). Urinary 24 h terbutaline post I was similar to IC + O. The method was linear and reproducible, similar to that of the urinary salbutamol method.

CONCLUSIONS

The urinary salbutamol pharmacokinetic method post inhalation applies to terbutaline. Terbutaline study doses can replace routine salbutamol during these studies when patients are studied.     

Pharmacokinetics of beclomethasone 17-monopropionate from a beclomethasone dipropionate extrafine aerosol in adults with asthma

OBJECTIVE: The objectives of this study were to test the dose and strength proportionalities of beclomethasone dipropionate (BDP) delivered from two strengths of a pressurized extrafine solution formulation. METHODS: Thirty adults with mild, stable asthma, aged between 18 years and 70 years, completed the study; written informed consent was obtained from all patients. Each patient received, according to a randomized four-period crossover design, 100 microg BDP as two inhalations from 50-microg/actuation strength, 100 microg BDP as one inhalation from 100-microg/actuation strength, 400 microg BDP as eight inhalations from the 50-microg/actuation strength, and 400 microg BDP as four inhalations from the 100-microg/actuation strength. Patients self-administered all inhalations at the same time of day during the study. Blood samples were collected for 12 h during each period to assay for the presence of BDP and metabolites. The log-transformed pharmacokinetic data were compared for proportionality equivalence using a confidence-interval approach. RESULTS: Almost all the BDP-derived material in the plasma was the active metabolite beclomethasone 17-monopropionate (17-BMP). Due to low levels, neither elimination half-life ( t(1/2)) nor the area under the plasma concentration-time curve (AUC) for 17-BMP could be calculated for the 100-microg BDP doses. Dose proportionality of the 100-microg and 400-microg BDP doses, using 17-BMP maximum plasma concentration (C(max)) was demonstrated for each strength. Strength proportionality of the 50-microg and 100-microg/actuation strengths was observed for C(max) at both dose levels and for AUC at the higher dose level. The t(1/2) of 17-BMP was found to be approximately 2.8 h. CONCLUSION: This study demonstrated both the strength and dose proportionalities of the BDP extrafine aerosol. This important information will allow physicians maximum flexibility in prescribing this aerosol product.     

Systemic bioavailability of hydrofluoroalkane (HFA) formulations of fluticasone/salmeterol in healthy volunteers via pMDI alone and spacer

AIM

To compare a test version of HFA fluticasone/salmeterol (FP/SM) combination inhaler (Neolab, UK) with the reference product Seretide (GlaxoSmithKline, UK).

METHODS

An in vitro Anderson cascade impactor was used to compare the fine particle dose (<4.7 µm). Two separate randomized cross-over studies were performed to compare the systemic bioavailability of test vs. reference (T vs. R) formulations of FP/SM 250/25 µg pMDI in healthy volunteers. In study 1 blood pharmacokinetic analysis using oral charcoal block was performed over 24 h following a single dose of four puffs via pMDI alone. In study 2 systemic bioactivity was measured following single doses of four and eight puffs via a spacer device: serum potassium (K⁺) to reflect SM, and overnight urinary cortisol : creatinine (OUCC) for FP. An early pharmacokinetic profile was also assessed over 120 min.

RESULTS

The in vitro fine particle dose was similar for test vs. reference pMDI alone and via spacer. The results of both studies were consistent: No significant differences between formulations were seen in terms of FP kinetics. Analysis of SM kinetics revealed superiority of the test product. No significant dose–response or difference in T : R ratio was noted for OUCC. Fall in K⁺ revealed a significant dose–response with a non-significant T : R ratio.

CONCLUSIONS

The in vitro fine particle dose may not predict pharmacokinetic and systemic pharmacodynamic outcomes. Single dosing studies with fluticasone/salmeterol 250/25 µg via pMDI or with spacer showed pharmacokinetic equivalence with FP, but not SM. No significant difference between formulations was seen with either adrenal suppression or hypokalaemia.     

Short-term effects of inhaled salbutamol on autonomic cardiovascular control in healthy subjects: a placebo-controlled study

AIMS

To investigate short-term effects of inhaled salbutamol on haemodynamic changes and cardiovascular autonomic control.

METHODS

A randomized, single-blinded, placebo-controlled study of 0.2 mg of inhaled salbutamol was conducted on 12 healthy nonsmoking volunteers with a mean age of 24 ± 2 years at two different testing sessions. Non-invasively obtained continuous haemodynamic measurements of cardiac output, beat-to-beat arterial blood pressure, and total peripheral resistance were recorded prior to and for a total of 120 min after inhalation of the respective study drug. Continuous cardiovascular autonomic tone was recorded using power spectral analysis of heart rate and blood pressure variability. Spontaneous baroreceptor activity was assessed by the sequence method.

RESULTS

There were no significant changes in any of the baseline parameters between the different testing sessions. Inhalation of salbutamol caused a significant increase in cardiac output from 6.7 ± 1.3 to 7.7 ± 1.4 l min⁻¹ (P < 0.05), and a decrease in total peripheral resistance from 1076 ± 192 to 905 ± 172 dyne s⁻¹ cm⁻⁵ (P < 0.05) within 15 min after inhalation. Moreover, salbutamol significantly increased sympathetically mediated low-frequency heart rate variability (P < 0.01), whereas parasympathetically mediated high-frequency heart rate variability decreased (P < 0.01). All changes persisted for approximately 30 min and were fully reversible at 120 min. There were no significant changes in systolic blood pressure variability or spontaneous baroreceptor activity.

CONCLUSIONS

Inhalation of therapeutic doses of salbutamol in healthy subjects resulted in significant haemodynamic changes and a shift of sympathovagal balance towards increased sympathetic tone in the absence of baroreceptor activation.     

Investigation of endothelial function by pulse contour analysis: a protocol for drug administration and timing of pulse contour assessment

AIMS

Pulse contour analysis (PCA) obtained by finger photoplethysmography produces a digital volume pulse (DVP) including an inflection point in its down-slope. The reflection index (RI: ratio of the inflection point height over the maximal DVP) is responsive to vasodilatation. We aimed to optimize the drug dose and time interval for assessing endothelial function using PCA in healthy volunteers and patients with severe coronary artery disease.

METHODS

Time and dose to RI response relationships were constructed in 16 volunteers and nine patients to inhaled salbutamol (100–400 µg) or sublingual nitroglycerin (NTG; 25–400 µg).

RESULTS

For the volunteers, the time to maximum RI response to inhaled salbutamol and sublingual NTG was 10.73 ± 0.41 and 3.66 ± 0.21 min, respectively. A plateau in the RI response to salbutamol occurred between 5 and 15 min after inhalation and results were averaged over this period. A dose-dependent response was observed to inhaled salbutamol and sublingual NTG (P= 0.05 and P < 0.001 by repeated-measures anova, respectively) in healthy volunteers. By contrast, in patients with severe coronary artery disease inhaled salbutamol (100–400 µg) did not cause a significant change in RI.

CONCLUSIONS

In healthy volunteers the RI response to inhaled salbutamol (100–200 µg) averaged over 5–15 min after administration may be used to investigate endothelial function by PCA. The response to sublingual NTG (50 µg) should be determined at 4 min. This technique may not be suitable for the assessment of endothelial function in subjects with extensive coronary artery disease owing to the small responses observed and potential confounding effect of vasoactive medication.     

The effect of inhaled corticosteroids on hypothalamic-pituitary-adrenal axis

Objectives:

The aim of this study was to compare systemic effects of high-dose fluticasone propionate (FP) and beclomethasone dipropionate (BDP) via pressurized metered dose inhaler on adrenal and pulmonary function tests.

Materials and Methods:

A total of 66 patients with newly diagnosed moderate persistent asthma without previous use of asthma medications participated in this single blind, randomized, parallel design study. FP or BDP increased to 1 500 μg/d in 62 patients who had not received oral or IV corticosteroids in the previous six months. Possible effects of BDP and FP on adrenal function were evaluated by free cortisol level at baseline and after Synacthen test (250 μg). Fasting plasma glucose and pulmonary function tests were also assessed. Similar tests were repeated 3 weeks after increasing dose of inhaled corticosteroids to 1 500 μg/d.

Results:

No statistically significant suppression was found in geometric means of cortisol level post treatment in both groups. After treatment in FP group, mean forced expiratory volume in one second (FEV1) and mean forced vital capacity (FVC) values improved by 0.17 l (5.66% ± 13.91, P=0.031) and 0.18 l (5.09% ± 10.29, P=0.010), respectively. Although FEV1 and FVC improved in BDP group but was not statistically significant. Oral candidiasis and hoarseness were observed in 6.5% patients receiving BDP, but hoarseness was found in 3.2% patients in FP group (P=0.288).

Conclusions:

The results indicate that safety profiles of high doses of BDP and FP with respect to adrenal function are similar, but FP is more efficacious than that of BDP in improving pulmonary function test.KEY WORDS: Adrenal cortex function tests, adrenal insufficiency, asthma, beclomethasone dipropionate, fluticasone     

The acute effects of dimebolin, a potential Alzheimer's disease treatment, on working memory in rhesus monkeys

BACKGROUND

Dimebolin (latrepirdine), a compound with multiple potential drug targets, is being evaluated in clinical trials for the treatment of Alzheimer''s disease (AD) and preliminary results suggest it can slow the disease process. There is also evidence that dimebolin directly improves aspects of cognition. Here we examined the acute effect of dimebolin on components of working memory in non-human primates, young adult (11–17 years old) and aged (20–31 years old) rhesus macaques.

EXPERIMENTAL APPROACH

The effects of dimebolin (3.9–118 µg kg⁻¹) on working memory, as measured by performance on delayed matching-to-sample (DMTS), were examined in the normal young adult monkeys and aged adult monkeys. All the monkeys studied were proficient in the performance of a computer-assisted DMTS task. In a subsequent experiment in the same subjects, dimebolin was administered 15 min before a cognitively-impairing dose (20 µg kg⁻¹) of scopolamine.

KEY RESULTS

In both the young adult and aged monkeys, dimebolin significantly increased the DMTS task accuracies. In young adults, the task improvement was associated with long (retention/retrieval) delay trials, and a protracted enhancement was observed for sessions run 24 h post administration of a single dose. Dimebolin did not significantly attenuate the scopolamine-induced impairment. In the aged monkeys, dimebolin significantly improved the reduced task accuracies associated with long delay intervals.

CONCLUSIONS AND IMPLICATIONS

Here we demonstrated that dimebolin is able to improve components of working memory in monkeys and to induce a protracted response for at least 24 h after administration of a single dose.     

The pharmacokinetics and pharmacodynamics of cisatracurium in critically ill patients with severe sepsis

AIM

To characterize the pharmacokinetics (PK) and pharmacodynamics (PD) of cisatracurium in critically ill patients with severe sepsis.

METHODS

Blood samples were collected before and over 8 h after a single bolus dose of cisatracurium 0.1 mg kg⁻¹. Neuromuscular block was assessed by accelerometric peripheral nerve stimulation (TOF Watch). Plasma concentration and neuromuscular block data were fitted using population analysis.

RESULTS

Steady-state volume of distribution was determined to be 111 ± 71 ml kg⁻¹ and plasma clearance was 5.2 ± 1.8 ml min⁻¹ kg⁻¹ in these patients with greater inter-patient variability compared with other populations. The time to maximum block (8.3 ± 2.9 min) and delay time of transferring from central to effect compartment (17.2 min) was much longer, while the maximum block (95.0 ± 6.3%) was less compared with those in other patient populations. The effect compartment concentration resulting in 50% of maximum effect (128 ± 58 ng ml⁻¹) was larger than previously described.

CONCLUSIONS

This study suggests that standard dosing of cisatracurium in patients with severe sepsis results in a slower patient response with a reduced effect. Use of a larger dose may overcome this reduced delayed response.     

Pharmacy Students' Ability to Identify Potential Drug-Drug Interactions

Objective

To evaluate the ability of third- and fourth-year pharmacy students to identify clinically significant drug-drug interactions (DDIs)

Methods

A questionnaire designed to measure DDI knowledge was disseminated to fourth-year pharmacy students in a school of pharmacy. A second questionnaire was distributed to third-year pharmacy students in 2 schools of pharmacy (schools A and B) and re-administered to students in 1 of the schools 1 year later.

Results

Class of 2005 fourth-year pharmacy students correctly categorized an average of 52% ± 13% DDI pairs on the first questionnaire. Third-year pharmacy students at schools A and B correctly categorized an average of 61% ± 18% and 66% ± 15% of DDI pairs, respectively. The average percentage of correct responses for fourth-year students from the class of 2007 was 65% (± 17%).

Conclusion

Pharmacy students'' ability to identify important DDIs is far from optimal, even after completing experiential requirements.     

Intradermal capsaicin as a neuropathic pain model in patients with unilateral sciatica

AIM

This study compared the responses between patients with unilateral sciatica and pain-free volunteers following administration of intradermal capsaicin.

METHODS

Fourteen patients with unilateral sciatica and 12 pain-free volunteers received one injection per hour over 4 h of 1 µg and 10 µg capsaicin, into each calf. For each dose, spontaneous pain (10 cm VAS), area of flare (cm²) and the sum of allodynia and hyperalgesia radii across eight axes (cm) were recorded pre-injection and at 5, 15, 30, 45 and 60 min post injection.

RESULTS

Sciatica subjects experienced higher spontaneous pain and hyperalgesia responses in both legs compared with pain-free volunteers. The largest mean difference in spontaneous pain was 2.8 cm (95% CI 1.6, 3.9) at 5 min in the unaffected leg following 10 µg. The largest mean difference in hyperalgesia was 19.7 cm (95% CI 12.4, 27.0) at 60 min in the unaffected leg following 10 µg. Allodynia was greater in patients than in controls with the largest mean difference of 2.9 cm (95% CI 1, 4.8) at 5 min following 10 µg in the affected leg. Allodynia was also higher in the affected leg compared with the unaffected leg in sciatica patients with the highest mean difference of 3.0 cm (95% CI 1.2, 4.7) at 5 min following 10 µg.

CONCLUSIONS

The responses to intradermal capsaicin are quantitatively and qualitatively different in unilateral sciatica patients compared with pain-free controls.     

Involvement of cholinergic system in suppression of formalin-induced inflammatory pain by cobratoxin

Aim:

To investigate the analgesic effect of cobratoxin (CTX), a long-chain α-neurotoxin from Thailand cobra venom, in a rat model of formalin-induced inflammatory pain.

Methods:

Inflammatory pain was induced in SD rats via injecting 5% formalin (50 μL) into the plantar surface of their right hind paw. CTX and other agents were ip administered before formalin injection. The time that the animals spent for licking the injected paw was counted every 5 min for 1 h.

Results:

CTX (25, 34, and 45 μg/kg) exhibited a dose-dependent analgesic effect during the phase 1 (0–15 min) and phase 2 (20–60 min) response induced by formalin. Pretreatment with naloxone (0.5 or 2.5 mg/kg) did not block the analgesic effect of CTX. Pretreatment with atropine at 5 mg/kg, but not at 2.5 mg/kg, antagonized the analgesic effect of CTX. Treatment with the nonselective nAChR antagonist mecamylamine (3 mg/kg) inhibited the analgesic effects of CTX in Phase 1 and Phase 2 responses, while with the selective α7-nAChR antagonist methyllycaconitine (3 mg/kg) antagonized the effect of CTX only in the Phase 1 response. Treatment with the α7-nAChR agonist PNU282987 (3 mg/kg) significantly reduced the formalin-induced phase 2 pain response, but only slightly reduced the Phase 1 pain response.

Conclusion:

The results suggest that CTX exerts an antinociceptive effect in formalin-induced inflammatory pain, which appears to be mediated by mAChR and α7-nAChR.     

Non-invasive measurement of the haemodynamic effects of inhaled salbutamol, intravenous L-arginine and sublingual nitroglycerin

AIMS

To examine the effects of salbutamol and L-arginine, two compounds acting largely on the endothelium, and the endothelium-independent agent nitroglycerin on blood pressure, arterial compliance, cardiac function and vascular resistance.

METHODS

Continuous radial pulse wave analysis, whole-body impedance cardiography, and plethysmographic blood pressure from fingers in the supine position and during head-up tilt were recorded in nine healthy subjects. Data were captured before and after L-arginine (10 mg mg⁻¹ min⁻¹) or saline infusion, salbutamol (400 µg) or placebo inhalation, and sublingual nitroglycerin (0.25 mg) or placebo resoriblet.

RESULTS

The results of all measurements were comparable before drug administration. The effects of inhaled salbutamol were apparent in the supine position: systemic vascular resistance (−9.2 ± 2.6%) and augmentation index (−4.0 ± 1.5%) decreased, and heart rate (8.6 ± 2.5%) and cardiac output (8.8 ± 3.1%) increased. L-arginine had no clear effects on supine haemodynamics, but during head-up tilt blood pressure was moderately decreased and reduction in aortic reflection time prevented, indicating improved large arterial compliance. Nitroglycerin reduced supine vascular resistance (−6.7 ± 1.8%) and augmentation index (−7.4 ± 1.6%), and increased cardiac output (+9.2 ± 2.7%). During head-up tilt, nitroglycerin increased cardiac output (+10.6 ± 5.6%) and heart rate (+40 ± 7.5%), decreased vascular resistance (−7.8 ± 5.8%) and augmentation index (−18.7 ± 3.2%), and prevented the decrease in aortic reflection time.

CONCLUSIONS

Inhaled salbutamol predominantly changed supine haemodynamics, whereas the moderate effects of L-arginine were observed during the head-up tilt. In contrast, small doses of nitroglycerin induced major changes in haemodynamics both supine and during the head-up tilt. Altogether, these results emphasize the importance of haemodynamic measurements in both the supine and upright positions.     

Interleukin-17A is involved in development of spontaneous pulmonary emphysema caused by Toll-like receptor 4 mutation

Aim:

To explore the pathogenic role of Th17 cells and interleukin-17A (IL-17A)-associated signaling pathways in spontaneous pulmonary emphysema induced by a Toll-like receptor 4 mutant (TLR4^mut).

Methods:

Lungs were obtained from wild-type (WT) or TLR4mut mice that were treated with or without recombinant mouse IL-17A (1 μg·kg⁻¹·d⁻¹, ip) from the age of 3 weeks to 3 months. Pulmonary emphysema was determined using histology, immunochemistry, and biochemical analysis. T cell polarization was determined with flow cytometry, the levels of cytokines were measured using ELISA, and the levels of IL-17A-associated signaling molecules were detected using Western blot.

Results:

Compared to WT mice, 3 month-old TLR4^mut mice were characterized by significantly reduced infiltration of Th17 cells into lungs (2.49%±1.13 % νs 5.26%±1.39%), and significantly reduced expression levels of IL-17A (3.66±0.99 pg/μg νs 10.67±1.65 pg/μg), IL-23 (12.43±1.28 pg/μg νs 28.71±2.57 pg/μg) and IL-6 (51.82±5.45 pg/μg νs 92.73±10.91 pg/μg) in bronchoalveolar lavage fluid. In addition, p38 MAPK phosphorylation and AP-1 expression were decreased to 27%±9% and 51%±8%, respectively, of that in WT mice. Treatment of TLR4^mut mice with IL-17A increased the infiltration of Th17 cells into lungs and expression levels of IL-17A, IL-6, and IL-23 in bronchoalveolar lavage fluid, attenuated MDA and apoptosis, and improved emphysema accompanied with increased phosphorylation of p38 MAPK and expression of AP-1.

Conclusion:

Th17 cells, in particular the cytokine IL-17A, play a crucial role in the pathogenesis of TLR4^mut-induced spontaneous pulmonary emphysema. Both of them are potential targets for therapeutic strategies for pulmonary emphysema.     

A monobromobimane-based assay to measure the pharmacokinetic profile of reactive sulphide species in blood

Background and purpose:

Hydrogen sulphide (H₂S) is a labile, endogenous metabolite of cysteine, with multiple biological roles. The development of sulphide-based therapies for human diseases will benefit from a reliable method of quantifying H₂S in blood and tissues.

Experimental approach:

Concentrations of reactive sulphide in saline and freshly drawn whole blood were quantified by reaction with the thio-specific derivatization agent monobromobimane, followed by reversed-phase fluorescence HPLC and/or mass spectrometry. In pharmacokinetic studies, male rats were exposed either to intravenous infusions of sodium sulphide or to H₂S gas inhalation, and levels of available blood sulphide were measured. Levels of dissolved H₂S/HS^- were concomitantly measured using an amperometric sensor.

Key results:

Monobromobimane was found to rapidly and quantitatively derivatize sulphide in saline or whole blood to yield the stable small molecule sulphide dibimane. Extraction and quantification of this bis-bimane derivative were validated via reversed-phase HPLC separation coupled to fluorescence detection, and also by mass spectrometry. Baseline levels of sulphide in blood were in the range of 0.4–0.9 µM. Intravenous administration of sodium sulphide solution (2–20 mg·kg⁻¹·h⁻¹) or inhalation of H₂S gas (50–400 ppm) elevated reactive sulphide in blood in a dose-dependent manner. Each 1 mg·kg⁻¹·h⁻¹ of sodium sulphide infusion into rats was found to be pharmacokinetically equivalent to approximately 30 ppm of H₂S gas inhalation.

Conclusions and implications:

The monobromobimane derivatization method is a sensitive and reliable means to measure reactive sulphide species in whole blood. Using this method, we have established a bioequivalence between infused sodium sulphide and inhaled H₂S gas.     

Comparative evaluation of metered-dose inhaler technique demonstration among community pharmacists in Al Qassim and Al-Ahsa region,Saudi-Arabia

Title

Comparative evaluation of metered-dose inhaler technique demonstration among community pharmacists in Al Qassim and Al Ahsa regions, Saudi Arabia.

Background

Patients rely on the information about use of proper inhaler technique when dispensed by community pharmacists however; several studies have shown that patients are unable to show correct inhalation technique. The aim of this study is to assess the ability of community pharmacists in Al Qassim region to demonstrate proper inhalation technique of metered dose inhaler and compare the baseline outcomes with a similar study at Al-Ahsa region.

Method

We approach 96 pharmacies in Al Qassim region as mock patient (Investigator). The investigator asks the Pharmacist to guide him about proper inhalation technique of metered dose inhaler. Investigator completes a standardized and validated checklist of 8 steps of inhaler device use immediately after leaving the pharmacy. Baseline data were compared between the two study groups et al. Ahsa and Al-Qassim for variables for effectiveness of pharmacist handling of patient queries.

Result

A total number of 96 community pharmacies were approached in five cities of the Al Qassim province in Saudi Arabia This study has found that majority (93.7%) of community pharmacists failed to demonstrate proper inhalation technique of pMDI inhaler.

Conclusion

The pharmacists demonstrated particularly poor skills involving steps for coordination of the actuation process with the mechanics of inhalation with MDI. The errors detected in this simple assessment session, if translated to patient self-medication errors, are potentially significant.     

Safety, tolerability and pharmacokinetics of an intravenous bolus of sildenafil in patients with pulmonary arterial hypertension

AIMS

To assess pharmacokinetics and pharmacodynamics of a 10 mg intravenous sildenafil bolus in pulmonary arterial hypertension (PAH) patients stabilized on 20 mg sildenafil orally three times daily.

METHODS

Pharmacokinetic parameters were calculated using noncompartmental analysis.

RESULTS

After an acute increase, plasma concentrations stabilized within the range reported previously for a 20 mg oral tablet. At 0.5 h, mean ± SD changes from baseline were −8.4 ± 11.7 mmHg (systolic pressure), −2.6 ± 7.3 mmHg (diastolic pressure) and −3.5 ± 10.4 beats min⁻¹ (heart rate). There was no symptomatic hypotension.

CONCLUSIONS

Although further research is warranted, a 10 mg sildenafil intravenous bolus appears to provide similar exposure, tolerability and safety to the 20 mg tablet.