New techniques for studying airway drug pharmacokinetics for asthma therapeutics

A review of the pharmacokinetics of M3 muscarinic receptor antagonists used for the treatment of asthma

Introduction: There is solid evidence that in patients with poorly controlled severe asthma despite the use of ICS and LABA, the addition of LAMAs, such as tiotropium, significantly increases the time to the first severe exacerbation and provides a modest but sustained bronchodilation. However, only a very limited number of pharmacokinetic studies with these agents have been performed in asthmatic patients.Areas covered: The pharmacokinetic profile of inhaled tiotropium, umeclidinium and glycopyrronium in healthy volunteers and that of inhaled tiotropium and umeclidinium in asthmatic patients have been reviewed.Expert opinion: In asthmatic patients, LAMAs are rapidly absorbed into the systemic compartment and demonstrate bi-exponential elimination (rapidly declining plasma concentrations followed by slow apparent terminal elimination). Apparently, the severity of asthma does not change the pharmacokinetics of LAMAs. The limited information available is focused on the plasma pharmacokinetic profile of these drugs and, consequently, although suitable for establishing a systemic safety profile, it does not tell us much about possible therapeutic efficacy of LAMAs in asthmatics because quantification of systemic plasma values is neither at the airways, which are their site of action nor representative of their transport to this site.

Pharmacokinetics and pharmacodynamics of inhaled corticosteroids for asthma treatment

The differences in the pharmacokinetic (PK) characteristics of inhaled corticosteroids (ICSs) critically influence the profile of each of them, but also the significant differences in glucocorticoid receptor selectivity, potency, and physicochemical properties are critical in defining the pharmacodynamic (PD) profile of an ICS. The PK and PD properties of ICSs used in asthma and the importance of their interrelationship have been reviewed. The differences among the ICSs in PK and PD must be considered when an ICS should be prescribed to an asthmatic patient because a better understanding of the PK/PD interrelationship of ICSs could be important to better fit with the between-patient variability and within-patient repeatability in the response to ICSs that often complicate the therapeutic approach to the asthmatic patient. The role of the device in influencing the PK profile of an ICS must be always considered because it is crucial. Also patient-related factors and disease severity affect pulmonary deposition of ICS.