Levalbuterol hydrochloride

Protective effects of (R)-enantiomers but not (S)-enantiomers of β2-adrenergic receptor agonists against acute colitis: The role of β2AR

The outcomes of ulcerative colitis (UC) treatment remain unsatisfactory. Salbutamol is a β2-adrenergic receptor (β2AR) agonist that is frequently used to treat human airway diseases, and it is a chiral drug with (RS)-isomers. However, the effects of (RS)-enantiomers of this drug on acute ulcerative colitis remain unknown. The present work determined and compared the effects of different chiral β2AR agonists in acute colitis. Acute colitis was established in mice with 3% dextran sulfate sodium and the mice were orally administered different salbutamol isomers. Body weight loss, colon length, disease activity index (DAI), and colon histopathology were assessed. Inflammatory cytokine levels were detected by ELISA. Colonic biopsies were collected from colitis patients. 16S rDNA amplicon sequencing was carried out to assess the composition and relative abundance of the gut microbiome. The expression of M1 and M2 macrophage markers in the colon were assessed by immunofluorescence staining and Western blotting. The results revealed that (R)-salbutamol prevented body weight loss and colonic shortening, decreased the DAI and histopathological scores, and reduced splenomegaly and inflammatory cytokine levels significantly better than (RS)-salbutamol and (S)-salbutamol. (R)-salbutamol downregulated levels of inflammatory protein in LPS-induced human colon tissue specimens. Furthermore, (R)-salbutamol ameliorated gut dysbiosis and macrophage polarization in mice with colitis. The β2AR antagonist ICI-118551 reversed the effect of (R)-salbutamol in ameliorating acute colitis. Taken together, (R)-salbutamol ameliorated the mice with acute colitis, which can serve as a new candidate or lead compound for UC treatment.

Efficacy and safety of tratinterol hydrochloride tablets in bronchial asthma: a randomized double-blind and multicenter clinical trial

PURPOSE

The aim of this study was to investigate the efficacy and safety of tratinterol hydrochloride in bronchial asthma (BA) treatment.

METHODS

Patients enrolled in this study were distributed randomly into a treatment group (tratinterol hydrochloride) and an active control group (procaterol hydrochloride) and were treated for 2 weeks after running-in. The end points were changes in pulmonary function and clinical symptoms after administration. Safety indices were physical examinations, laboratory testing and spontaneous reporting.

FINDINGS

We enrolled 732 subjects, -365 in the treatment group and 367 in the active control group. Forced expiratory volume (FEV₁), significantly increased in both group after treatment (P < 0.05). Least-squares (LS) means were -0.03/in the full-analysis set (FAS) and -0.02 in the per-protocol set (PPS) set, and 95% confidence intervals (CIs) for these sets were -0.09 to 0.03 and -0.08 to 0.04, respectively. Forced expiratory volume (FVC), morning peak expiratory flow (PEF) and asthma scores were significantly different with pretreatment (P < 0.05). There was no difference in asymptomatic days or frequency of relief medicine use (P > 0.05). No serious adverse events occurred.

IMPLICATIONS

Tratinterol hydrochloride was effective, safe and not inferior to procaterol hydrochloride in treating BA.

Randomized, Multicenter Clinical Study of Tratinterol Hydrochloride Tablets for the Treatment of Bronchial Asthma

PURPOSE

The aim of this study was to determine the efficacy and safety profile of tratinterol hydrochloride tablets in the treatment of bronchial asthma.

METHODS

This multicenter, randomized, double-blind clinical research study was completed at 6 centers in the People's Republic of China from March 2009 to June 2010, and a randomized trial of procaterol hydrochloride tablets produced by Otsuka Pharmaceutical Co Ltd was conducted. The study was approved by the Medical Ethics Committee of the First Hospital of China Medical University. The clinical trial registration number is 2007L04263.

FINDINGS

A total of 223 patients were selected for this study, with 112 patients in the treatment group and 111 in the control group. The lung function of the 2 groups after treatment significantly increased in all (P < 0.05); however, there was no significant difference in the changes between the 2 groups (P > 0.05). The occurrence of related adverse events at varying degrees in the control group was higher than in the treatment group.

IMPLICATIONS

It is safe and effective to use tratinterol hydrochloride tablets to treat bronchial asthma.

Pharmacotherapy for exercise-induced asthma: allowing normal levels of activity and sport

Exercise-induced bronchoconstriction (EIB) is experienced by the majority of an estimated 300 million individuals who have asthma, a condition that affects all ages and is increasing globally. Respiratory water loss with dehydration of the airways causing mediator release and airway narrowing is considered the cause of EIB, the severity of which will be increased if the inhaled air is cold or polluted. Adequate control of asthma is essential to minimize or prevent EIB and permit normal levels of physical activity and sport. This is important because exercise is a necessary component of daily living, assists in obtaining and maintaining a healthy body and has been demonstrated to benefit asthmatics. Inhaled glucocorticosteroids and inhaled β(2)-adrenoceptor agonists (IβA) are the pharmacological agents of choice to manage asthma and minimize EIB, assisted when necessary, by other drugs including leukotriene receptor antagonists and chromones. Tolerance from daily use of IβA is of concern and more flexible drug therapy needs to be considered. Optimal use of inhalers to deliver drugs effectively requires closer attention. Pharmacogenetics may hold the key to future drug therapy.

Detrimental effects of albuterol on airway responsiveness requires airway inflammation and is independent of β-receptor affinity in murine models of asthma

BACKGROUND

Inhaled short acting β2-agonists (SABA), e.g. albuterol, are used for quick reversal of bronchoconstriction in asthmatics. While SABA are not recommended for maintenance therapy, it is not uncommon to find patients who frequently use SABA over a long period of time and there is a suspicion that long term exposure to SABA could be detrimental to lung function. To test this hypothesis we studied the effect of long-term inhaled albuterol stereoisomers on immediate allergic response (IAR) and airway hyperresponsiveness (AHR) in mouse models of asthma.

METHODS

Balb/C mice were sensitized and challenged with ovalbumin (OVA) and then we studied the IAR to inhaled allergen and the AHR to inhaled methacholine. The mice were pretreated with nebulizations of either racemic (RS)-albuterol or the single isomers (S)- and (R)-albuterol twice daily over 7 days prior to harvest.

RESULTS

We found that all forms of albuterol produced a significant increase of IAR measured as respiratory elastance. Similarly, we found that AHR was elevated by albuterol. At the same time a mouse strain that is intrinsically hyperresponsive (A/J mouse) was not affected by the albuterol isomers nor was AHR induced by epithelial disruption with Poly-L-lysine affected by albuterol.

CONCLUSIONS

We conclude that long term inhalation treatment with either isomer of albuterol is capable of precipitating IAR and AHR in allergically inflamed airways but not in intrinsically hyperresponsive mice or immunologically naïve mice. Because (S)-albuterol, which lacks affinity for the β2-receptor, did not differ from (R)-albuterol, we speculate that isomer-independent properties of the albuterol molecule, other than β2-agonism, are responsible for the effect on AHR.

Solid-state characterization of two polymorphic forms of R-albuterol sulfate

R-albuterol (levalbuterol) is a drug used for asthma therapy and some formulations of it are in solid dosage forms. The aim of this work was to describe and characterize two polymorphic modifications of R-albuterol sulfate by means of typical structure-sensitive analytical techniques such as X-ray powder diffraction, FT-IR spectroscopy, visual and microscopic inspection, and DSC. Substantial differences were observed between the solid-state properties of the crystals, confirming the existence of at least two polymorphic forms for R-albuterol sulfate: Form I and Form II.

Effects of (R)- and (S)-isomers of beta-adrenergic agonists on eosinophil response to interleukin-5

BACKGROUND

Racemic beta2-adrenergic receptor agonists (beta2-agonists) are used frequently to treat patients with asthma. Potential differences in the biological activities and clinical efficacies among racemic beta2-agonists and their isomers are controversial, and research into these possible differences is limited.

OBJECTIVE

We hypothesized that the (S)- and the (R)-isomers of beta2-agonists have opposing effects on the activation of inflammatory cells.

METHODS

Isolated human eosinophils were pretreated with 1:1 racemic (R,S)-, (R)- or (S)-albuterol, isobutyl methylxanthine (IBMX), and stimulated with IL-5. The kinetics of superoxide production were examined by reduction of cytochrome c, and the effects of pharmacological agents on superoxide production were monitored for 180 min.

RESULTS

(R,S)-albuterol inhibited IL-5-induced superoxide production. This inhibition was enhanced by a cyclic adenosine monophosphate (cAMP) phosphodiesterase inhibitor, IBMX, and was reversed by the selective beta2-adrenergic receptor antagonist, ICI 118, 551, verifying the involvement of both cAMP and the beta2-adrenergic receptor. In addition, (R)-albuterol alone, similarly to (R,S)-albuterol, significantly inhibited IL-5-induced superoxide production up to 60 min (P<0.05, n=4), but the inhibition was lost with longer incubation. In contrast, (S)-albuterol with IBMX did not inhibit IL-5-induced superoxide production before 60 min, but it significantly enhanced IL-5-mediated superoxide production after 60 min (P<0.05, n=4). When both were present as racemic (R,S)-albuterol, the inhibitory effect of (R)-albuterol was not affected by (S)-albuterol.

CONCLUSION

When incubated with IL-5-activated eosinophils, (R)-albuterol shows anti-inflammatory effects and (S)-albuterol shows pro-inflammatory effects in the presence of IBMX. The kinetics of these effects are different, and when used simultaneously, (R)-albuterol predominates. When marked usage of the (S)-isomer is anticipated, racemic (R,S)-albuterol should be used clinically with caution.

[Chiral switch: towards a better benefit-risk ratio?]

The chirality of drugs has emerged as a major theme in drug design, discovery, development and intellectual property. Single enantiomers offer some advantages and two options are available: the switch from an existing racemic drug to the single enantiomer or the development of an enantiomerically pure chiral drug. At present, the second possibility is systematically considered. The possibility of chiral switch has led to innovative drugs. However, this opportunity may be limited by several factors: the spontaneous interconversion of the two enantiomers, the pharmacokinetic profile or the selective toxicity of the most active enantiomer, and the difficulty of demonstrating the clinical superiority of one enantiomer over the racemate. Finally, the small size of the market, the policies of the drug agencies and/or the patent problem also limit the development of enantiomers. All these factors have led the pharmaceutical industry to develop new galenic forms rather than enantiomers when the patent of the racemate is expiring.