Evaluating the Delivery of Nebulized and Metered-Dose Inhalers in an in vitro Infant Ventilator Lung Model

• Published in: The Annals of pharmacotherapy 1999-02, Vol.33 (2), p.144-148
• Main Authors: Avent, Minyon L, Gal, Peter, Ransom, J Laurence, Brown, Yvonne L, Hansen, Charles J, Ricketts, William A, Soza, Felicia
• Format: Article
• Language: English
• Subjects: Albuterol - administration & dosage; Beclomethasone - administration & dosage; Biological and medical sciences; Bronchodilator Agents - administration & dosage; Chromatography, High Pressure Liquid; Evaluation Studies as Topic; Humans; In Vitro Techniques; Infant; Medical sciences; Models, Biological; Nebulizers and Vaporizers; Pharmacology. Drug treatments; Respiratory system; Ventilators, Mechanical - standards
• ISSN: 1060-0280; 1542-6270
• DOI: 10.1345/aph.17426

OBJECTIVE: To evaluate drug delivery to the lungs of nebulized and metered-dose inhalers (MDIs) in an in vitro infant lung model. METHODS: An in vitro lung model was modified to study drug delivery. A 1000 mL intravenous bag filled with 500 mL deionized water was attached to a 3.5 mm (12 cm length) endotracheal tube. An inline Marquest Whisper Jet infant circuit nebulizer system delivered 2.5 mg/3 mL albuterol sulfate inhalation solution (Ventolin nebules) at a flow rate of 5 L/min. An Aerochamber (Monaghan) was placed at the endotracheal tube for the delivery of the MDIs. Albuterol MDI (Ventolin) 10 inhalations and beclomethasone MDI (Beclovent) 20 inhalations were delivered. A Servo 900C (Siemens-Elma) was used at the following ventilator settings: positive inspiratory pressure 30 cm H2O), intermittent mandatory ventilation 40 breaths/min, positive end expiratory pressure 4 cm H2O, inspiratory time 0.4 sec. Each formulation was run at least 10 times and assayed in duplicate by HPLC. An unpaired Student's t-test was used to analyze the statistical significance of the data. RESULTS: There was a significantly greater percentage of drug delivery with MDI albuterol (1.96 ± 0.50) as compared with nebulized albuterol (1.26 ± 0.37) (p = 0.002) or beclomethasone diproprionate (0.51 ± 0.24) (p = 0.001). CONCLUSIONS: Albuterol MDI provides a more efficient delivery of drug to the lung as compared with nebulized albuterol and MDI beclomethasone diproprionate.