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Powder Inhalation Aerosol Studies I: Selection of a Suitable Drug Entity for Bronchial Delivery of New Drugs

1977; Elsevier BV; Volume: 66; Issue: 9 Linguagem: Inglês

10.1002/jps.2600660912

1520-6017

Z.T. Chowhan, Adriana Amaro,

Advanced Drug Delivery Systems

Micronized powders of 7-methylsulfinyl-2-xanthone car- boxylic acid and its sodium salt with similar particle-size distributions were used in formulating powder inhalation aerosol dosage forms. Large differences between the two micronized powders were observed in the distribution on plates of the air sampler. The micronized powders were highly cohesive, the sodium salt being slightly more cohesive than the carboxylic acid. The absorption and desorption isotherms obtained at 23 and 37° indicated considerable moisture uptake following equilibration under different relative humidities and the occurrence of hysteresis of moisture content for the sodium salt–lactose blend and the empty gelatin capsules. The carboxylic acid–lactose blend gained only a small amount of moisture. The drug distribution to the lower plates of the air sampler from the sodium salt blend was reduced to a negligible amount after equilibration at high relative humidities during the moisture absorption experiment. There was no significant change in the drug distribution to the lower plates of the air sampler for the carboxylic acid–lactose blend equilibrated up to 93% relative humidity at 23° and up to 100% relative humidity at 37° during the moisture absorption experiment. During the moisture desorption experiment, essentially no change in the drug distribution to the lower plates of the air sampler was observed for the sodium salt blend at 23 and 37° and the carboxylic acid blend at 23°. At 37°, the drug delivery from the carboxylic acid blend appeared to improve during the desorption experiment. These data suggest that studies of this nature may be useful in the selection of appropriate drug species for designing powder aerosol dosage forms during early phases of the drug development program.