ABSTRACT
Sterile formulations, by necessity, must be as simple as possible. Safety considerations limit the number and choices of additives to use in formulations besides the active and, if stability is sufficient, a vehicle. The ideal parenteral formulation would contain the active ingredient and water and nothing else. In reality, the author is unaware of any sterile formulation that contains only active ingredient in a ready-to-use 2-year stable aqueous solution. Formulations that contain only the active ingredient typically are freeze-dried with the therapeutic dose of the active sufficient to produce an elegant cake that is constituted with a diluent vehicle prior to administration. Most sterile formulations contain at least one additive besides the active ingredient and a majority of formulations contain two or more additives. This chapter will describe the types and purposes of additives (solutes) and vehicles used in sterile formulations. References 1 through 8 provide reviews and listings of approved additives in marketed sterile product formulations including a valuable Food and Drug Administration Web site.
