Device design nasal formulations

Nasal drug delivery devices can be divided into multidose and unit-dose/bi-dose systems. Multidose systems consist of a container mounted with a mechanical pump dispenser that is designed to deliver multiple doses from one container (Fig. 1). The various requirements of the customer and of the formulation are respected in the design and performance of the delivery systems. Unit-dose and bi-dose systems are becoming increasingly attractive to the pharmaceutical industry. In particular, therapies that require precise performance in their delivery system employ these single/ dual-use disposable systems. 

It should be assumed that the regulatory authorities will question as much, if not more, the nasal delivery device, rather than the formulation per se. They will critically examine for equivalence between the nasal device used in clinical trials and that proposed for the market. As the nasal device is usually more complicated in design than the formulation, and is manufactured by a third party, it is absolutely essential to work closely with the device provider. Among the key questions to ask of the supplier are the following ... 

When a nasal spray is supplied in a squeeze bottle instead of one with a pump atomizer, a viscous spray might be difficult to nebulise. So, in the design of a spray formulation, viscosity has to be considered together with the intended type of container and atomising device. 

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