title: Effect of compression pressure on inhalation grade lactose as carrier for dry powder inhalations.
abstract: BACKGROUND
  This study focused on the potential effects of compression forces experienced during lactose (InhaLac 70, 120, and 230) storage and transport on the flowability and aerosol performance in dry powder inhaler formulation.
  
  
  METHODS
  Lactose was subjected to typical compression forces 4, 10, and 20 N/cm(2). Powder flowability and particle size distribution analysis of un-compressed and compressed lactose was evaluated by Carr's index, Hausner's ratio, the angle of repose and by laser diffraction method. Aerosol performance of un-compressed and compressed lactose was assessed in dispersion studies using glass twin-stage-liquid-impenger at flow rate 40-80 L/min.
  
  
  RESULTS
  At compression forces, the flowability of compressed lactose was observed same or slightly improved. Furthermore, compression of lactose caused a decrease in in vitro aerosol dispersion performance.
  
  
  CONCLUSIONS
  The present study illustrates that, as carrier size increases, a concurrent decrease in drug aerosolization performance was observed. Thus, the compression of the lactose fines onto the surfaces of the larger lactose particles due to compression pressures was hypothesized to be the cause of these observed performance variations. The simulations of storage and transport in an industrial scale can induce significant variations in formulation performance, and it could be a source of batch-to-batch variations.
authors.affiliation: Department of Quality Assurance, Shrimati Kishoritai Bhoyar College of Pharmacy, Nagpur, Maharashtra, India.
authors.forename: Neha Sureshrao
authors.initials: NS
authors.lastname: Raut
authors.affiliation: Department of Quality Assurance, Shrimati Kishoritai Bhoyar College of Pharmacy, Nagpur, Maharashtra, India.
authors.forename: Swapnil
authors.initials: S
authors.lastname: Jamaiwar
authors.affiliation: Department of Quality Assurance, Shrimati Kishoritai Bhoyar College of Pharmacy, Nagpur, Maharashtra, India.
authors.forename: Milind Janrao
authors.initials: MJ
authors.lastname: Umekar
authors.affiliation: Department of Quality Assurance, Shrimati Kishoritai Bhoyar College of Pharmacy, Nagpur, Maharashtra, India.
authors.forename: Nandkishor Ramdas
authors.initials: NR
authors.lastname: Kotagale
keywords: Aerosolisation; compression pressure; dry powder inhalation; lactose; particle size