Development of Dry Salbutamol Sulfate Powder with High Inhalation Performance Independent of Inhalation Patterns

Abstract

While dry powder inhalations are commonly used to treat pulmonary diseases, their clinical performance depends on patient inspiratory flow patterns. The purpose of this study was to develop a new powder with high and stable therapeutic performance for various patients. We applied the supercritical antisolvent (SCF) method to salbutamol sulfate (SS) to prepare a bulky SS particle (SS-SCF). Tests of in vitro inhalation performance with a human inspiratory flow simulator revealed SS-SCF to be less susceptible to inspiratory flow patterns than milled SS. When inspired, the unique structure seemed to be broken resulting in small fragments that could be delivered to the lungs. However, stability tests under physical stress showed tolerance for transportation and handling. In addition, optimization of the concentration of the SS solution applied to SCF method improved the in vitro inhalation performance of SS-SCF. These results indicated that a unique bulky SS powder prepared by the SCF method was useful for dry powder inhalation.Key words dry powder inhalation; inspiratory flow pattern; supercritical fluid drying; twin stage liquid impinger; inhalation performanceThe most common treatment for pulmonary diseases like asthma and chronic obstructive pulmonary disease (COPD) is inhalation therapy. Dry powder inhalants (DPIs) have become common in the field of inhalation therapy because they are free from environmentally damaging propellants and easy to use with small portable devices.1,2) With passive DPIs, because the aerosolization is activated by inhalation, handling is easier than that with pressurized metered dose inhalers (pMDIs). Many studies have investigated the therapeutic performance of dry powders influenced by particle size, morphology, surface roughness, crystallinity, and so on. [3][4][5] In addition, inspiratory flow patterns and inhalation devices have a significant impact on particle dispersion. [6][7][8] The clinical performance of inhalable drugs is susceptible to inspiratory patterns. 9,10) Numerous studies have shown the influence on inhalation performance of inspiratory patterns. 8,11,12) For stable therapeutic performance, not only drug administration guidance for patients but also the development of new formulations whose inhalation performance is independent of inspiratory flow patterns is needed.We previously constructed a human inspiratory flow simulator, and evaluated the influence of human inspiratory flow patterns and inhalation device type on the in vitro inhalation performance of dry salbutamol sulfate (SS) powders physically mixed with coarse lactose monohydrate powders, revealing that the effect of inspiratory flow patterns depended on the particle diameter of the active pharmaceutical ingredient (API).13) Peak flow rate (PFR) most affected in vitro inhalation performance among three critical parameters selected for the characterization of human inspiratory flow patterns; flow increase rate (FIR), inspiratory flow volume (area under the curve corresponding to inspiratory flow volume, AUC...

Supercritical Fluid Technology: An Emphasis on Drug Delivery and Related Biomedical Applications

“…Further, the formulation is tolerant to physical stress, but the particles can break down upon inhalation. [ 125 ] During the processing of proteins for inhalation formulation, conditions should be optimized in the SCF technology to yield the end product with no significant change in protein conformation. [ 23a , 126 ] In addition, poorly soluble proteins are also facilitated to increase their solubility in the supercritical atmosphere, suggesting the new path for bioavailability improvement in formulating protein powders.…”

Assessment of inhalation flow patterns of soft mist inhaler co-prescribed with dry powder inhaler using inspiratory flow meter for multi inhalation devices

“…In some commercial inhalers, the required flow rate is determined to release the drug particles from an inhaler [ 9 ]. As the measurement method of inhalation flow rate, we previously reported the inhalation flow pattern monitor system [ 5 , 10 , 11 ]. In clinical practice, In check ® and whistles for some devices are available [ 12 ].…”