Respiratory drug delivery changes

Schultz, R. K. Systemic drug delivery Issues and challenges in a changing environment, in Proceedings of Respiratory Drug Delivery VIII. Raleigh, NC Davis Horwood International Publishing, 2002. 

An excipient is defined as a material that is deliberately incorporated into the formulation to aid some physicochemical process, for example for a tablet, integrity, dissolution, bioavailability or taste excipients are typically chosen from among many compounds without pharmacological properties (e.g. lactose), although there are examples where pharmacokinetics change with the excipient used. There are specialized examples of excipients, for example propellants are excipients that assist in the delivery of inhaled drugs to the respiratory tract. For intravenous infusions or ophthalmic products, the excipients are usually pH buffers or... 

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