Disposition and metabolism of formoterol fumarate, a new bronchodilator, in rats and dogs

Influence of β2-adrenergic selective agonist formoterol on the motor unit of a mouse model of a congenital myasthenic syndrome with complete VAChT deletion

Congenital Myasthenic Syndromes (CMS) are a set of genetic diseases that affect the neuromuscular transmission causing muscular weakness. The standard pharmacological treatment aims at ameliorating the myasthenic symptom by acetylcholinesterase inhibitors. Most patients respond well in the short and medium term, however, over time the beneficial effects rapidly fade, and the efficacy of the treatment diminishes. Increasing evidence shows that β2-adrenergic agonists can be a suitable choice for the treatment of neuromuscular disorders, including CMS, as they promote beneficial effects in the neuromuscular system. The exact mechanism on which they rely is not completely understood, although patients and animal models respond well to the treatment, especially over extended periods. Here, we report the use of the long-lasting specific β2-adrenergic agonist formoterol in a myasthenic mouse model (mnVAChT-KD), featuring deletion of VAChT (Vesicular Acetylcholine Transporter) specifically in the α-motoneurons. Our findings demonstrate that formoterol treatment (300 μg/kg/day; sc) for 30 days increased the neuromuscular junction area, induced skeletal muscle hypertrophy and altered fibre type composition in myasthenic mice. Interestingly, β2-adrenergic agonists have shown efficacy even in the absence of ACh (acetylcholine). Our data provide important evidence supporting the potential of β2-adrenergic agonists in treating neuromuscular disorders of pre-synaptic origin and characterized by disruptions in nerve-muscle communication, through a direct and beneficial action within the motor unit.

Formoterol PLGA-PEG Nanoparticles Induce Mitochondrial Biogenesis in Renal Proximal Tubules

Formoterol is a long-acting β₂ agonist (LABA). Agonism of the β₂-adrenergic receptor by formoterol is known to stimulate mitochondrial biogenesis (MB) in renal proximal tubules and recover kidney function. However, formoterol has a number of cardiovascular side effects that limits its usage. The goal of this study was to design and develop an intravenous biodegradable and biocompatible polymeric nanoparticle delivery system that targets formoterol to the kidney. Poly(ethylene glycol) methyl ether-block-poly(lactide-co-glycolide) nanoparticles containing encapsulated formoterol were synthesized by a modified single-emulsion solvent evaporation technique resulting in nanoparticles with a median hydrodynamic diameter of 442 + 17 nm. Using primary cell cultures of rabbit renal proximal tubular cells (RPTCs), free formoterol, encapsulated formoterol polymeric nanoparticles, and drug-free polymeric nanoparticles were biocompatible and not cytotoxic over a wide concentration range. In healthy male mice, polymeric nanoparticles were shown to localize in tubules of the renal cortex and improved the renal localization of encapsulated formoterol compared to the free formoterol. At a lower total formoterol dose, the nanoparticle localization resulted in increased expression of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), the master regulator of MB, and increased electron transport chain proteins, markers of MB. This was confirmed by direct visual quantification of mitochondria and occurred with both free formoterol and the encapsulated formoterol polymeric nanoparticles. At the same time, localization of nanoparticles to the kidneys resulted in reduced induction of MB markers in the heart. These new nanoparticles effectively target formoterol to the kidney and successfully produce MB in the kidney.

Pharmacokinetics, pharmacodynamics and safety of a novel extrafine BDP/FF/GB combination delivered via metered-dose inhaler in healthy Chinese subjects

BACKGROUND

BDP/FF/GB pMDI is a novel triple fixed-dose combination of extra-fine inhalation aerosol beclomethasone dipropionate (BDP)/formoterol fumarate (FF)/glycopyrronium bromide (GB). Limited data on the pharmacokinetic (PK) and pharmacodynamic (PD) properties of BDP/FF/GB fixed-dose combination in healthy subjects was available.

PURPOSES

This study aimed to evaluate the pharmacokinetics, pharmacodynamics and safety of BDP/FF/GB pMDI in healthy Chinese subjects.

METHODS

This is an open-label, parallel-group, randomized, single and multiple dose study. In the single dose group, subjects received single supra-therapeutic inhaled dose of BDP/FF/GB pMDI (BDP/FF/GB 400/24/50 µg). In the multiple dose group, subjects received therapeutic inhaled dose of BDP/FF/GB pMDI (BDP/FF/GB 200/12/25 µg), twice daily, for 7 consecutive days. Plasma BDP, B17MP, formoterol and GB were determined by a validated ultra performance liquid chromatography method with tandem mass spectrometric detection (UPLC/MS-MS). Heart rate (HR), QTcF, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were evaluated as the surrogate indicators of pharmacodynamic effects.

RESULTS

A total of 24 subjects were randomized and 22 (11 in each group) completed the study. The dose adjusted pharmacokinetic profiles of BDP, beclomethasone-17-monopropionate (B17MP, the most active metabolite of BDP), formoterol and GB were overall similar in therapeutic and supra- therapeutic dose group, showing dose proportional increase of the systemic exposure to BDP, B17MP, formoterol and GB. The pharmacodynamic variables were within the normal range and showed no significant difference between the two groups. All the treatment-emergent adverse events (TEAEs) were mild and no severe TEAE was reported.

CONCLUSIONS

Dose adjusted PK profiles were similar between therapeutic and supra-therapeutic dose for all compounds, nearly dose proportional systemic exposure to B17MP, formoterol and GB after BDP/FF/GB pMDI administration in healthy Chinese subjects. BDP/FF/GB pMDI was safe and well tolerated in healthy Chinese subjects. The PK profiles were comparable to previously published data from Western European healthy Caucasian subjects.

On the pharmacokinetics of two inhaled budesonide/formoterol combinations in asthma patients using modeling approaches

Dry powder inhalers containing the budesonide/formoterol combination have currently a well-established position among other inhaled products. Even though their efficacy mainly depends on the local concentrations of the drug they deliver within the lungs, their safety profile is directly related to their total systemic exposure. The aim of the present investigation was to explore the absorption and disposition kinetics of the budesonide/formoterol combination delivered via two different dry powder inhalers in asthma patients. Plasma concentration-time data were obtained from a single-dose, crossover bioequivalence study in asthma patients. Non-compartmental and population compartmental approaches were applied to the available datasets. The non-compartmental analysis allowed for an initial characterization of the primary pharmacokinetic (PK) parameters of the two inhaled drugs and subsequently the bioequivalence assessment of the two different dry powder inhalers. The population pharmacokinetic analysis further explored the complex absorption and disposition characteristics of the two drugs. In case of inhaled FOR, a five-compartment PK model including an enterohepatic re-circulation process was developed. For inhaled BUD, the incorporation of two parallel first-order absorption rate constants (fast and slow) for lung absorption in a two-compartment PK model emphasized the importance of pulmonary anatomical features and underlying physiological processes during model development. The role of potential covariates on the variability of the PK parameters was also investigated.

Formoterol, a long-acting β2 adrenergic agonist, improves cognitive function and promotes dendritic complexity in a mouse model of Down syndrome

BACKGROUND

Down syndrome is associated with significant failure in cognitive function. Our previous investigation revealed age-dependent degeneration of locus coeruleus, a major player in contextual learning, in the Ts65Dn mouse model of Down syndrome. We studied whether drugs already available for use in humans can be used to improve cognitive function in these mice.

METHODS

We studied the status of β adrenergic signaling in the dentate gyrus of the Ts65Dn mouse model of Down syndrome. Furthermore, we used fear conditioning to study learning and memory in these mice. Postmortem analyses included the analysis of synaptic density, dendritic arborization, and neurogenesis.

RESULTS

We found significant atrophy of dentate gyrus and failure of β adrenergic signaling in the hippocampus of Ts65Dn mice. Our behavioral analyses revealed that formoterol, a long-acting β2 adrenergic receptor agonist, caused significant improvement in the cognitive function in Ts65Dn mice. Postmortem analyses revealed that the use of formoterol was associated with a significant improvement in the synaptic density and increased complexity of newly born dentate granule neurons in the hippocampus of Ts65Dn mice.

CONCLUSIONS

Our data suggest that targeting β2 adrenergic receptors is an effective strategy for restoring synaptic plasticity and cognitive function in these mice. Considering its widespread use in humans and positive effects on cognition in Ts65Dn mice, formoterol or similar β2 adrenergic receptor agonists with ability to cross the blood brain barrier might be attractive candidates for clinical trials to improve cognitive function in individuals with Down syndrome.

Characterisation of beta2-adrenoceptors, using the agonist [11C]formoterol and positron emission tomography

The agonist radioligand N-[2-hydroxy-5-[1-hydroxy-2-[[2-(4-[11C]-methoxyphenyl)-1-methylethyl]am ino]ethyl]phenyl]formamide ([11C]formoterol) was synthesised in order to test its ability to visualise pulmonary beta2-adrenoceptors in vivo, with positron emission tomography (PET). Formoterol was labelled via reaction of a dibenzyl-protected precursor with [11C]CH3I. Subsequent deprotection with Pd/C and H2 yielded [11C]formoterol in 5-15% (corrected for decay) and the specific activity ranged from 5.5-22.2 TBq mmol (150-600 Ci mmol(-1)), 60-70 min after end of bombardment. Biodistribution studies with [11C]formoterol were performed in male Wistar rats which were either untreated or predosed with (D,L)-propranolol hydrochloride (2.5 mg kg(-1), beta-adrenoceptor antagonist), erythro-DL-1-(7-methylindan-4-yloxy)-3-isopropylaminobuta n-2-ol hydrochloride (ICI 118551, 0.15 mg kg(-1), beta2-adrenoceptor antagonist), isoprenaline (15 mg kg(-1), non-subtype selective beta-adrenoceptor agonist) or (+/-)-(2-hydroxy-5-[2-((2-hydroxy-3-(4-((1-methyl-4-trifluoromethyl)1H-i midazol-2-yl-)phenoxy)propyl)amino)ethoxy]benzamide)monomethane sulfonate (CGP 20712A, 0.15 mg kg(-1), beta1-adrenoceptor antagonist). Lungs, heart, liver and plasma were analysed for radioactive metabolites. The kinetics of [11C]formoterol in the lungs of male Wistar rats were investigated by means of a dynamic PET study. The biodistribution studies showed significant specific binding in tissues known to contain beta2-adrenoceptors (lungs, spleen, and heart). Binding in these organs was blocked by ICI 118551 and isoprenaline, but not by CGP 20712A. [11C]Formoterol was rapidly metabolised in rats but lungs and heart did not substantially take up the labelled metabolites. The binding of [11C]formoterol in various tissues of rats is consistent with the beta2-selectivity of formoterol. Whether [11C]formoterol selectively binds to the high affinity state of beta2-adrenoceptors remains to be elucidated. [11C]Formoterol is potentially useful for studying beta2-adrenoceptors with PET and this radioligand may provide new insights in the mechanisms underlying prolonged sympathomimetic action.

Formoterol. A review of its pharmacological properties and therapeutic potential in reversible obstructive airways disease

Formoterol, a long-acting beta 2-selective adrenoceptor agonist, produces dose-proportional bronchodilation in patients with obstructive airways disease with a reversible component. A significant effect occurs within minutes of inhalation of a therapeutic formoterol dose and persists for approximately 12 hours. Oral formoterol has a slower onset of action than the inhaled formulations, but also produces prolonged bronchodilatory effects. Inhaled formoterol has shown a therapeutic efficacy equivalent to or better than comparable dosages of the conventional beta 2-agonists salbutamol, fenoterol and terbutaline in short and long term trials, in both adults and children with asthma. Its prolonged duration of action permits a twice-daily dosage regimen and results in improved control of nocturnal symptoms by reducing the 'morning dip'. Formoterol also compares well with oral slow release theophylline. In addition, significantly more patients with chronic obstructive airways disease (COAD) had an improvement in symptoms when treated with formoterol compared with salbutamol or fenoterol. Noncomparative studies indicate formoterol also provides effective prophylaxis of exercise-induced asthma. Development of tachyphylaxis has not been observed. Formoterol is generally well tolerated. Adverse effects observed represent predictable extensions of its pharmacology. Tremor and palpitations are most frequently reported. The incidence of adverse events is dose-proportional and therefore related to the route of administration, being more frequent following oral than inhalation therapy. The long-acting beta 2-agonists, including formoterol, represent a significant advance over current maintenance or prophylactic bronchodilator therapy with intermediate-acting beta 2-agonists such as salbutamol, fenoterol and terbutaline, predominantly because of the twice daily administration regimen. However, comparisons with other long-acting beta 2-agonists, such as salmeterol, evaluation of its role in improving symptom control in patients failing to respond to prophylactic therapy, and clarification of the optimal role of beta 2-agonists in asthma maintenance therapy are required to fully determine the value of formoterol in the management of obstructive airways disease.

The development of a radioimmunoassay for formoterol

The development of a radioimmunoassay (RIA) for the beta 2-stimulant formoterol is described. The sensitivity of the method is 0.1 ng/ml in plasma and urine, when a 1-ml sample is used. The cross-reactivity of the antiserum with formoterol glucuronide was 30%. Since formoterol is metabolized extensively to formoterol glucuronide in rats, dogs and humans, extraction with ethyl ether prior to the radioimmunoassay was carried out. Satisfactory agreement was obtained for levels of formoterol in plasma and urine when they were determined by RIA and gas chromatography-mass spectrometry. The concentration of formoterol was determined in dog plasma and human urine after oral administration of formoterol fumarate to dogs (61 mcg/kg) and humans (40 mcg).