BACKGROUND: Nebulized drugs for asthma treatment are often mixed together in order to simplify inhalation regimens, although not recommended. We therefore evaluated aerosol characteristics and physicochemical stability of the admixture of an inhaled corticosteroid suspension with a beta2-agonist solution. METHODS: An 8-stage cascade impactor was used to measure the particle size distribution of admixture of Pulmicort® Respules® (budesonide, 0.5mg/2mL) with Meptin® Inhalation Solution Unit (procaterol hydrochloride, 30μg/0.3mL) from a jet nebulizer, PARI LC Plus®. Concentration of each drug was assayed with high-pressure liquid chromatography. Physicochemical compatibility was also assessed up to 24 hours after mixing. RESULTS: With regard to budesonide, impactor parameters such as mass median aerodynamic diameter (MMAD) and respirable mass (RM) were comparable between admixtures and single-drug preparations (2.92 ± 0.03 vs 2.99 ± 0.14μm, 146.8 ± 2.9 vs 147.6 ± 8.2μg, respectively). On the other hand, delivery rates of procaterol increased when admixed with budesonide suspension, resulting in significantly higher RM (15.1 ± 0.8 vs 10.2 ± 0.5μg, p < 0.01). Variations from initial concentration in the percentages of drug remaining at any time point were less than 10%, and there were no appreciable changes in pH of the admixtures for up to 24 hours. CONCLUSIONS: There is a possibility that admixture might influence of aerodynamic characteristics of procaterol, but not budesonide. In vivo data will be needed for the clinical implications of our findings.
BACKGROUND: Nebulized drugs for asthma treatment are often mixed together in order to simplify inhalation regimens, although not recommended. We therefore evaluated aerosol characteristics and physicochemical stability of the admixture of an inhaled corticosteroid suspension with a beta2-agonist solution. METHODS: An 8-stage cascade impactor was used to measure the particle size distribution of admixture of Pulmicort® Respules® (budesonide, 0.5mg/2mL) with Meptin® Inhalation Solution Unit (procaterol hydrochloride, 30μg/0.3mL) from a jet nebulizer, PARI LC Plus®. Concentration of each drug was assayed with high-pressure liquid chromatography. Physicochemical compatibility was also assessed up to 24 hours after mixing. RESULTS: With regard to budesonide, impactor parameters such as mass median aerodynamic diameter (MMAD) and respirable mass (RM) were comparable between admixtures and single-drug preparations (2.92 ± 0.03 vs 2.99 ± 0.14μm, 146.8 ± 2.9 vs 147.6 ± 8.2μg, respectively). On the other hand, delivery rates of procaterol increased when admixed with budesonide suspension, resulting in significantly higher RM (15.1 ± 0.8 vs 10.2 ± 0.5μg, p < 0.01). Variations from initial concentration in the percentages of drug remaining at any time point were less than 10%, and there were no appreciable changes in pH of the admixtures for up to 24 hours. CONCLUSIONS: There is a possibility that admixture might influence of aerodynamic characteristics of procaterol, but not budesonide. In vivo data will be needed for the clinical implications of our findings.