Effect of Spacer Construction on Dose Delivery

Drug dehvery from a spacer is critically dependent on the factors outlined above, including the volume and shape of the spacer, valves, and spacer material. The influence of these factors can be illustrated with reference to three of the more commonly used spacers. 

NebuChamber is a 250-mL metal spacer with high-resistance valves and no dead space between the valves. 

Babyhaler is a 350-mL plastic spacer with low-resistance valves and a 40-mL dead space between inlet and outlet valves. 

The comparaflve efficiency of these spacers has been documented in vitro (38) and in vivo (24,34,35) by collecting the dose delivered to a filter in front of 

---