Preclinical Pharmacodynamic And Pharmacokinetic Studies Of Glycopyrronium Bromide

Chronic obstructive pulmonary disease(COPD)is a chronic disease mainly characterized by airflow limitation,which is related to inflammatory response of lung to noxious particles or toxic gases.According to WHO,COPD is the 4th cause of death in the world and smoke is a major risk in COPD developing.Smoke,released when tobacco burned,contains more than 3800 kinds of known chemical substances.Most of them are harmful and can induce inflammation in the airway.Recently,scientists have a new understanding that in addition to bronchodilator,anti-inflammatory maybe another mechanism of anticholinergics in treatment of asthma and COPD.Glycopyrrolate Bromide(Glyco),is a quaternary ammonium cholinergic receptor antagonist,which can inhibit gastric secretion and regulation of gastric motility,was used for the treatment of early gastric and duodenal ulcers,chronic gastritis,gastric acid hypersecretion embolism.It is found that Glycopyrrolate has a high selectivity for the M3 receptor in the previous studies and which is being developed as a dry powder inhalation in treatment of COPD.In order to study a dry powder inhalation of glycopyrrolate,we firstly observed the effect of glycopyrrolate on airway resistance increase caused by acetylcholin.Data suggested that glycopyrrolate can antagonize contraction of isolated smooth muscle of guinea pig induced by cholinergic agonist.In addition,it can inhibit cholinergic agonist-induced increase in airway resistance and decrease in lung compliance in guinea pigs.Furthermore,Glycopyrrolate inhibited antigen-induced asthma exacerbations in sensitized guinea pigs.All these results indicated that glycopyrrolate can inhibit bronchial contraction and airway resistance increase induced by acetylcholine,thus it has a therapeutic effect on asthma and COPD.Since inflammation is one of the important factors of airway remodeling in COPD,we further observed the effect of glycopyrrolate on acute airway inflammation induced by cigarette smoke or LPS.It is suggested in our results that glycopyrrolate can reduce neutrophils and other inflammatory cells infiltration,inhibit TNF-α,IL-1β,KC and other inflammatory cytokines expression,increase GSH levels,and reduce the expression of MMP-9 in alveolar cells.Meanwhile,the pathology results indicated that glycopyrrolate significantly reduced inflammatory cell infiltration,alveolar wall thickening,and pulmonary interstitial edema.The above results suggested that glycopyrrolate can inhibit airway inflammation in COPD.Based on these,we further investigated the mechanism of glycopyrrolate on suppression of airway inflammation.Data from our experiment suggested that glycopyrrolate suppressed an increase in JNK phosphorylation and NF-κB protein expression,but had no effect on increase in ERK and p38 phosphorylation induced by cigarette smoke.Such results indicated that glycopyrrolate play an anti-inflammatory effect through inhibiting CSE-induced JNK phosphorylation and then blocking NF-κB signaling pathway.Finally,we carried out a study to investigate pharmacokinetics of glycopyrrolate powder aerosol administrated by airway spray in beagle dogs.The results suggested that the developed LC-MS/MS method of quantifying glycopyrrolate in dog plasma met the requirement of pharmacokinetic study.In the dose range 44-176μg,Cmax and AUC were in a dose dependent manner.Local drug concentration in lung tissue was significantly higher than plasma,and the drug in plasma was cleared rapidly.These features of the drug are benefit for it to play a therapeutic role in the lung locally and had less systemic side effectsAbove all,this study laid emphasis on pharmacodynamics,mechanisms and pharmacokinetics of glycopyrrolate to prove the possible of glycopyrrolate to become a new anticholinergic drug for COPD,which provide important data for the clinical evaluation of glycopyrronium bromide.