Feasibility of drug delivery to the respiratory tract by a mechanical micro spray pump.

A hand actuated, propellant free spray device is being developed which may be suitable for medical inhalation therapy. The purpose was to evaluate the feasibility of the mechanical micro spray pump to produce a fine spray whose droplets were suitable for inhalation. The physical and technical requirements have been achieved using an air blast nozzle which has been improved by changing the geometry and therefore the dynamic properties within the spray nozzle. The generation of particles above 50 mum in diameter was suppressed and the injection time of the spray increased. These features resulted in a finer and more uniform spray. In-vivo experiments were conducted, where 15 mul per stroke of a 99mTc labeled saline solution was delivered to test persons. The activity was measured by gamma-scintigraphy. It was observed that without and with a spacer, a respective thoracic deposition of 8 %vol and 13 %vol was achieved on average.

A mechanical micro spray pump: an alternative to propellant driven devices?

An account is given on the development of a purely mechanical Micro Spray Pump (MSP) which is capable of delivering aqueous drug solutions to the respiratory tract. In-vitro, deposition characteristics of two solutions, food dye and salbutamol sulphate, at different dosage levels and various flow rates were determined. A theoretical flow model was employed to understand deposition pattern in the Twin Impinger. In-vivo experiments where a 99mTc marked isotonic saline solution which nebulized by the MSP showed bronchial deposits on average of 8% and in a single experiment with spacer even up to 25%. The MSP prototype proves to be a feasible alternative non-propellant driven device to deliver drugs to the respiratory tract.

Feasibility of a low dosage dynamic powder dispenser for drug delivery to the lungs.

Inhalation of drugs offers the opportunity to treat diseases of the respiratory tract. A manually operated prototype, called Dynamic Powder Dispenser (DPD), for dispensing a predetermined amount of powdered drug has been developed. This device actively disperses powder from a chamber through a mouthpiece ready for inhalation. The DPD is a multi-single dose device which delivers drugs actively and does not require breath actuation. This DPD which insufflates dry powder into the respiratory tract can be considered as a counterpart to an MDI. The respirable fraction was found in-vitro in the range of 10% and 25% for salbutamol and terbutaline, respectively.