Compatibility and aerosol characteristics of formoterol fumarate mixed with other nebulizing solutions.
BACKGROUND
Patients with chronic obstructive pulmonary disease (COPD) are often given admixtures of nebulizable drugs to minimize the time of administration in treatment regimens.


OBJECTIVE
To evaluate the physicochemical compatibility and aerodynamic characteristics of formoterol fumarate 20 microg/2 mL when mixed or sequentially nebulized with budesonide inhalation suspension 0.5 mg/2 mL, ipratropium bromide 0.5 mg/2.5 mL, cromolyn sodium 20 mg/2 mL, or acetylcysteine 10% (100 mg/mL).


METHODS
The admixtures were prepared in triplicate and analyzed for physicochemical compatibility at 0, 15, 30, and 60 minutes after mixing at room temperature. Physical compatibility was determined by visual examination and measurements of pH, osmolality, and turbidity. Chemical stability was evaluated using compendial or in-house-validated high-performance liquid chromatography (HPLC) assay methods. The aerodynamic characteristics of the admixtures or sequentially nebulized drugs were determined from aerosols generated from a Pari LC Plus nebulizer, using an 8-stage cascade impactor followed by HPLC analysis of the deposited drug.


RESULTS
The admixtures remained clear, colorless solutions with no precipitation, except for cloudiness observed in the formoterol/budesonide combination due to budesonide suspension. The pH, osmolality, and turbidity for all admixtures were within the initial values (< or = 3%), and there were no significant changes (< or = 2%) in potency of the active components throughout the 1-hour study period. Due to increased drug volume or reconcentration in the nebulizer cup, the respirable fraction/delivered dose increased significantly (p < 0.05) for the mixed or sequentially nebulized drug. However, the fine particle fraction (FPF), mass median aerodynamic diameter, and geometric standard deviation generally remained unchanged for all admixtures, with the exception of FPF for the formoterol/budesonide combination.


CONCLUSIONS
Our results indicate that admixtures of formoterol with budesonide, ipratropium, cromolyn, or acetylcysteine are physically and chemically compatible. However, admixing or sequential nebulization significantly increased the amount of drug delivered compared with single drug nebulization. The clinical implications of the in vitro data in patients with COPD have not been determined.
Akapo
Samuel
S
Analytical Development, Dey L.P., 2751 Napa Valley Corporate Dr., Napa, CA 94558, USA. samuel.akapo@dey.com
Gupta
June
J
Martinez
Eloisa
E
McCrea
Chithra
C
Ye
Liwen
L
Roach
Mark
M
D000111:Acetylcysteine / Q000008:administration & dosage / Q000737:chemistry; D000336:Aerosols; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage / Q000737:chemistry*; D001993:Bronchodilator Agents / Q000008:administration & dosage / Q000737:chemistry*; D019819:Budesonide / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid; D004205:Cromolyn Sodium / Q000008:administration & dosage / Q000737:chemistry; D004344:Drug Incompatibility; D004355:Drug Stability; D004983:Ethanolamines / Q000008:administration & dosage / Q000737:chemistry*; D005100:Expectorants / Q000008:administration & dosage / Q000737:chemistry; D000068759:Formoterol Fumarate; D006801:Humans; D006863:Hydrogen-Ion Concentration; D009241:Ipratropium / Q000737:chemistry; D009330:Nebulizers and Vaporizers; D009994:Osmolar Concentration; D010316:Particle Size; D029424:Pulmonary Disease, Chronic Obstructive / Q000188:drug therapy; D013997:Time Factors
D000336:Aerosols; D018927:Anti-Asthmatic Agents; D001993:Bronchodilator Agents; D004983:Ethanolamines; D005100:Expectorants; D019819:Budesonide; D009241:Ipratropium; D004205:Cromolyn Sodium; D000068759:Formoterol Fumarate; D000111:Acetylcysteine