The duration of bronchodilation of salmeterol and salbutamol as measured by specific airway conductance in healthy subjects

Ultrasensitive Magnetic Assisted Lateral Flow Immunoassay Based on Chiral Monoclonal Antibody against R-(-)-Salbutamol of Broad-Specificity for 38 β-Agonists Detection in Swine Urine and Pork

Screening for ″zero tolerance″ β-agonists requires broad-specificity and sensitivity methods. Herein, R-(-)-salbutamol (SAL) is chirally separated and designed as a hapten, and a monoclonal antibody (mAb) was first prepared with an IC₅₀ of 0.27 ng/mL, which can recognize 38 β-agonists simultaneously. The broad-specificity of chiral mAb was explored by molecular simulation technology. Magnetic nanoparticles (MNPs) were then synthesized and applied as a signal tracer to develop a lateral flow immunoassay (LFIA). The limits of detection of MNPs-LFIA for SAL in swine urine and pork were 0.05 and 0.09 μg/kg, which was (2-125)-fold lower than that of the reported LFIAs. The recoveries were between 95.8 and 116.7%, with the coefficient of variation from 2.7 to 15.4%. Parallel analysis of 44 samples by commercial ELISA kits confirmed the reliability. Therefore, our work not only provides a broad-specificity and ultrasensitive method for β-agonists but also suggests that chirality is the new general theory that guided the rational hapten design.

Detection and pharmacokinetics of salmeterol in thoroughbred horses following inhaled administration

Salmeterol is a man-made beta-2-adrenergic receptor agonist used to relieve bronchospasm associated with inflammatory airway disease in horses. Whilst judicious use is appropriate in horses in training, they cannot race with clinically effective concentrations of medications under the British Horseracing Authority's Rules of Racing. Salmeterol must therefore be withdrawn prior to race day and pharmacokinetic (PK) studies used to establish formal detection time advice. Salmeterol xinafoate (Serevent Evohaler^® ) was administered (0.1 mg twice daily for 4.5 days) via inhalation to six horses. Urine and blood samples were taken up to 103 h postadministration. Hydrolysed samples were extracted using solid phase extraction. A sensitive Ultra high performance tandem mass spectrometry (UPLC-MS/MS) method was developed, with a Lower limit of quantification (LLOQ) for salmeterol of 10 pg/mL in both matrices. The majority of salmeterol plasma concentrations, postlast administration, were below the method LLOQ and so unusable for PK analysis. Urine PK analysis suggested a half-life consistent with duration of pharmacological effect. Average estimated urine concentration at steady-state was obtained via PK modelling and used to estimate a urine concentration of 59 ± 34 pg/mL as a marker of effective lung concentration. From this, potential detection times were calculated using a range of safety factors.

Use of propranolol blockade to explore the pharmacology of GSK961081, a bi-functional bronchodilator, in healthy volunteers: results from two randomized trials

PURPOSE

The objective of this study was to explore the pharmacology of GSK961081, a bi-functional bronchodilator, in healthy volunteers.

METHODS

Two randomized, double-blind, placebo-controlled studies were conducted. Following optimization of the propranolol dosing regimen (study 1), we conducted a five-period crossover study (study 2) in which subjects received the following treatments: dry powder inhaler (DPI) GSK961081 400 µg + oral placebo, DPI GSK961081 1,200 µg + oral placebo, DPI GSK961081 400 µg + oral propranolol 80 mg, DPI GSK961081 1,200 µg + oral propranolol 80 mg and DPI and oral placebo. GSK961081 (or inhaled placebo) was dosed at 0 h. Propranolol (or oral placebo) was dosed at -8, -2, 4, 10, and 16 h. The primary endpoint for both studies was bronchodilation, measured by specific airway conductance (sGaw), which was assessed at 0, 1, 4, 7, 12, 22, and 24 h in study 2. Tolerability and pharmacokinetics were secondary endpoints.

RESULTS

Studies 1 and 2 enrolled 18 and 23 subjects, respectively. In study 2, bronchodilation was seen for 24 h following GSK961081 400 and 1,200 μg. In the presence of β2 blockade, GSK961081 1,200 μg demonstrated bronchodilation in the first 4 h after dosing (treatment difference from placebo at 1 h: 1.206; 90% confidence interval [CI] 1.126-1.292; and at 4 h: 1.124; 90% CI 1.078-1.173) but not at 7 h onwards. In the presence of β2 blockade, GSK961081 400 μg demonstrated bronchodilation in the first 1 h after dosing (treatment difference from placebo: 1.193; 90% CI 1.117-1.274), but not at 4 h onwards. Adverse events were reported for 21 (study 1) and 15 subjects (study 2); none were serious, and there were no deaths.

CONCLUSION

The duration of bronchodilation as a result of receiving the muscarinic antagonist component alone was shorter than that from the muscarinic antagonist β2 agonist combination. Removing the β2 agonist component may underestimate the contribution of the muscarinic antagonist component to the bronchodilation of the combination.

First-in-human study of the safety, tolerability, pharmacokinetics and pharmacodynamics of abediterol (LAS100977), a novel long-acting Β2 -agonist

Here we report the results of a first-in-human study to evaluate the safety, tolerability pharmacokinetics, and pharmacodynamics of abediterol, a new β2 -adrenergic agonist. Forty-eight healthy males aged 18-45 years received abediterol doses of 5, 10, 25, or 50 µg, or placebo. Safety and tolerability assessments included adverse event reporting, pulse and blood pressure monitoring, 12-lead electrocardiograms, laboratory tests, and physical examination. Pharmacodynamic assessments included whole body plethysmography to determine the bronchodilatory effect by means of airway conductance and resistance. Blood and urine samples were obtained for pharmacokinetic analyses. Abediterol showed an overall good safety and tolerability profile in the dose range tested, consistent with the expected characteristics of a β2 -adrenergic agonist. A dose-dependent increase of systemic treatment-emergent adverse events was observed, the most frequent being palpitations, tremor, nausea, and asthenia; most were mild in intensity and resolved without the need for intervention. Improvements in airway conductance (increase) and resistance (decrease) were greater for all doses of abediterol tested compared with placebo at all time-points up to 36 hours. This first-in-human study suggests a potent, rapid, and sustained bronchodilatory effect of abediterol in healthy male subjects. Lower doses are currently under investigation in patients with asthma and in patients with COPD.

Pharmacology and therapeutics of bronchodilators

Bronchodilators are central in the treatment of of airways disorders. They are the mainstay of the current management of chronic obstructive pulmonary disease (COPD) and are critical in the symptomatic management of asthma, although controversies around the use of these drugs remain. Bronchodilators work through their direct relaxation effect on airway smooth muscle cells. at present, three major classes of bronchodilators, β(2)-adrenoceptor (AR) agonists, muscarinic receptor antagonists, and xanthines are available and can be used individually or in combination. The use of the inhaled route is currently preferred to minimize systemic effects. Fast- and short-acting agents are best used for rescue of symptoms, whereas long-acting agents are best used for maintenance therapy. It has proven difficult to discover novel classes of bronchodilator drugs, although potential new targets are emerging. Consequently, the logical approach has been to improve the existing bronchodilators, although several novel broncholytic classes are under development. An important step in simplifying asthma and COPD management and improving adherence with prescribed therapy is to reduce the dose frequency to the minimum necessary to maintain disease control. Therefore, the incorporation of once-daily dose administration is an important strategy to improve adherence. Several once-daily β(2)-AR agonists or ultra-long-acting β(2)-AR-agonists (LABAs), such as indacaterol, olodaterol, and vilanterol, are already in the market or under development for the treatment of COPD and asthma, but current recommendations suggest the use of LABAs only in combination with an inhaled corticosteroid. In addition, some new potentially long-acting antimuscarinic agents, such as glycopyrronium bromide (NVA-237), aclidinium bromide, and umeclidinium bromide (GSK573719), are under development, as well as combinations of several classes of long-acting bronchodilator drugs, in an attempt to simplify treatment regimens as much as possible. This review will describe the pharmacology and therapeutics of old, new, and emerging classes of bronchodilator.