title: Evaluation of Granulated Lactose as a Carrier for Dry Powder Inhaler Formulations 2: Effect of Drugs and Drug Loading.
abstract: Previously, granulated lactose carriers were shown to improve uniformity and aerosolization of a low-dose model drug. In the present study, the blending uniformity and aerosol dispersion performance were assessed for 2 model drugs salbutamol sulfate (SS) and rifampicin (RIF), blended at high loadings (10% or 30% drug) with granulated lactose carriers. The model drug powders differed in particle size distribution, morphology, density, and surface energies. Content uniformity of RIF blends was better than that of SS. Aerosolization studies showed that all blend formulations had acceptable emitted fractions (>70%). The SS blends showed low induction-port deposition (6%-10%) compared to RIF (5%-30%). This difference was greater at high flow rates. At 90 L/min, the low induction port deposition of SS blends allowed high fine particle fraction (FPF) of 73%-81%, whereas the FPF of the RIF blends was around 43%-45% with higher induction port deposition. However, SS blends exhibited strong flow rate-dependent performance. Increasing the flow rate from 30 L/min to 90 L/min increased SS FPF from approximately 20% to 80%. Conversely, RIF blends were flow rate and drug loading independent. It was concluded that the aerosolization of high drug-loaded dry powder inhaler formulations using granulated lactose, particularly flow rate dependency, varies with active pharmaceutical ingredient properties.
authors.affiliation: Division of Pharmaceutics, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712; Catalent Pharma Solutions, Research Triangle Park, North Carolina 27560.
authors.forename: Ping
authors.initials: P
authors.lastname: Du
authors.affiliation: Division of Pharmaceutics, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712; Catalent Pharma Solutions, Research Triangle Park, North Carolina 27560.
authors.forename: Ju
authors.initials: J
authors.lastname: Du
authors.affiliation: Division of Pharmaceutics, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712. Electronic address: hugh.smyth@austin.utexas.edu.
authors.forename: Hugh D C
authors.initials: HDC
authors.lastname: Smyth
mesh_terms: D000280:Administration, Inhalation; D000336:Aerosols / Q000737:chemistry; D000420:Albuterol / Q000008:administration & dosage* / Q000737:chemistry; D000904:Antibiotics, Antitubercular / Q000008:administration & dosage* / Q000737:chemistry; D001993:Bronchodilator Agents / Q000008:administration & dosage* / Q000737:chemistry; D004337:Drug Carriers / Q000737:chemistry*; D004339:Drug Compounding; D058995:Dry Powder Inhalers / Q000379:methods*; D007785:Lactose / Q000737:chemistry*; D010316:Particle Size; D012293:Rifampin / Q000008:administration & dosage* / Q000737:chemistry; D013499:Surface Properties
chemical_list: D000336:Aerosols; D000904:Antibiotics, Antitubercular; D001993:Bronchodilator Agents; D004337:Drug Carriers; D007785:Lactose; D000420:Albuterol; D012293:Rifampin
keywords: Aerosols; content uniformity; drug-excipient interaction; formulation; pulmonary drug delivery