ABSTRACT
Prefiltration can be described simply as any filtration step incorporated into a
manufacturing process prior to the final filtration. The usual purpose in conducting
pharmaceutical filtrations is to remove objectionable particles from a fluid drug
preparation. In effecting such a purification there is a concern for the rate at which the
filtration takes place, and the extent to which it proceeds before the retained particles
block the filter’s pores sufficiently to render further filtration so slow as to be impractical.
An adequacy of particle removal is the principle goal. The rate of filtration and
throughput are secondary considerations. Nevertheless, the accrual of particles on the
final filter relative to its porosity and extent of filter surface determines the ongoing rate
of filtration as well as its ultimate termination.
