BACKGROUND: Exposure following oral inhalation depends on the deposition pattern of the inhaled aerosol, the extent and rate of oral and pulmonary absorption, as well as systemic distribution and clearance. For lipophilic inhaled compounds with low water solubility and high permeability, the extent and rate of pulmonary absorption can be assumed dependent on deposition pattern as well as dissolution rate. MATERIALS AND METHODS: A mechanistic model of airway deposition, mucociliary clearance, dissolution, absorption, and dissipation was applied to simulate systemic exposure of the novel selective glucocorticoid receptor modulator, AZD5423, when dosed to healthy volunteers using two different nebulizers and two different dry powder inhalers in combination with two different primary particle size distributions. Results from simulations were compared with observed pharmacokinetic data. RESULTS: Variations in systemic exposure (plasma concentration profile, AUC, and Cmax) resulting from variations in dose, deposition pattern, and dissolution rate could not be predicted solely from variations in delivered dose or predicted lung dose (as assessed using an anatomical mouth-throat model), suggesting incomplete pulmonary bioavailability. However, simulated systemic exposure well predicted observed systemic exposures for all tested formulations and devices. Furthermore, simulations of airway tissue exposure suggested that it was not directly linked to systemic exposure. CONCLUSIONS: Results support the initial hypothesis that systemic exposure of poorly soluble inhaled drugs is a complex but predictable function of dose, deposition pattern, and rate of dissolution. Furthermore, simulations indicate that local exposure for these types of drugs is not well correlated with systemic exposure. Hence, equivalence with respect to local exposure, and thus with respect to pharmacodynamic effect, cannot be fully inferred from systemic pharmacokinetic equivalence alone.
RCT Entities:
BACKGROUND: Exposure following oral inhalation depends on the deposition pattern of the inhaled aerosol, the extent and rate of oral and pulmonary absorption, as well as systemic distribution and clearance. For lipophilic inhaled compounds with low water solubility and high permeability, the extent and rate of pulmonary absorption can be assumed dependent on deposition pattern as well as dissolution rate. MATERIALS AND METHODS: A mechanistic model of airway deposition, mucociliary clearance, dissolution, absorption, and dissipation was applied to simulate systemic exposure of the novel selective glucocorticoid receptor modulator, AZD5423, when dosed to healthy volunteers using two different nebulizers and two different dry powder inhalers in combination with two different primary particle size distributions. Results from simulations were compared with observed pharmacokinetic data. RESULTS: Variations in systemic exposure (plasma concentration profile, AUC, and Cmax) resulting from variations in dose, deposition pattern, and dissolution rate could not be predicted solely from variations in delivered dose or predicted lung dose (as assessed using an anatomical mouth-throat model), suggesting incomplete pulmonary bioavailability. However, simulated systemic exposure well predicted observed systemic exposures for all tested formulations and devices. Furthermore, simulations of airway tissue exposure suggested that it was not directly linked to systemic exposure. CONCLUSIONS: Results support the initial hypothesis that systemic exposure of poorly soluble inhaled drugs is a complex but predictable function of dose, deposition pattern, and rate of dissolution. Furthermore, simulations indicate that local exposure for these types of drugs is not well correlated with systemic exposure. Hence, equivalence with respect to local exposure, and thus with respect to pharmacodynamic effect, cannot be fully inferred from systemic pharmacokinetic equivalence alone.
Authors: Jayne E Hastedt; Per Bäckman; Antonio Cabal; Andy Clark; Carsten Ehrhardt; Ben Forbes; Anthony J Hickey; Guenther Hochhaus; Wenlei Jiang; Stavros Kassinos; Philip J Kuehl; David Prime; Yoen-Ju Son; Simon Teague; Ulrika Tehler; Jennifer Wylie Journal: Mol Pharm Date: 2022-05-16 Impact factor: 5.364
Authors: Per Bäckman; Antonio Cabal; Andy Clark; Carsten Ehrhardt; Ben Forbes; Jayne Hastedt; Anthony Hickey; Guenther Hochhaus; Wenlei Jiang; Stavros Kassinos; Philip J Kuehl; David Prime; Yoen-Ju Son; Simon P Teague; Ulrika Tehler; Jennifer Wylie Journal: Mol Pharm Date: 2022-05-24 Impact factor: 5.364