Preparation and evaluation of single and co-engineered combination inhalation carrier formulations for the treatment of asthma

Design of Inhalable Solid Dosage Forms of Budesonide and Theophylline for Pulmonary Combination Therapy

Corticosteroid resistance poses a major challenge to effective treatment of chronic obstructive pulmonary diseases. However, corticosteroid resistance can be overcome by co-administration of theophylline. The aim of this study was to formulate the corticosteroid budesonide with theophylline into inhalable dry powders intended for pulmonary combination therapy. Four types of spray-dried powders were prepared: (i) budesonide and theophylline co-dissolved and processed using a 2-fluid nozzle spray drier, (ii) budesonide nanocrystals and dissolved theophylline co-dispersed and processed using a 2-fluid nozzle spray drier, (iii) dissolved budesonide and dissolved theophylline processed using a 3-fluid nozzle spray drier, and (iv) budesonide nanocrystals and dissolved theophylline processed using a 3-fluid nozzle spray drier. Spray drying from the solutions resulted in co-amorphous (i) and partially amorphous powders (iii), whereas spray drying of the nanosuspensions resulted in crystalline products (ii and iv). Even though budesonide was amorphous in (i) and (iii), it failed to exhibit any dissolution advantage over the unprocessed budesonide. In contrast, the dissolution of budesonide from its nanocrystalline formulations, i.e., (ii) and (iv), was significantly higher compared to a physical mixture or unprocessed budesonide. Furthermore, the spray-dried powders obtained from the 2-fluid nozzle spray drier, i.e., (i) and (ii), exhibited co-deposition of budesonide and theophylline at the same weight ratio in the aerodynamic assessment using the New Generation Impactor. In contrast, the depositions of budesonide and theophylline deviated from the starting weight ratio in the aerodynamic assessment of spray-dried powders obtained from the 3-fluid nozzle spray drier, i.e., (iii) and (iv). Based on these results, the powders spray-dried from the suspension by using the 2-fluid nozzle spray drier, i.e., (ii), offered the best formulation properties given the physically stable crystalline solid-state properties and the co-deposition profile.

Novel alternatives to reduce powder retention in the dry powder inhaler during aerosolization

Dry powder inhalers (DPIs) are used predominantly for the treatment of pulmonary diseases by delivering drugs directly into the lungs. The drug delivery efficiency is typically low and there is significant drug retention inside the DPI. An innovative 'green' initiative aimed at minimizing drug wastage via channeling the residual drug into the useful inhaled therapeutic fraction was pioneered. Drug retention could be minimized via coating the drug capsule and delivery device with pharmaceutically acceptable force-control agents. This coating reduces the adhesion between the drug particles and the internal surfaces of the DPI, which in turn increases the fine particle dose by as much as 300%.