polyvinyl alcohol A synthetic polymer used as a fixative and an adhesive and as an emulsifying agent, thickener, and stabilizer. Specimens can
remain in PVA without damage for long periods of time.
postapproval changes Changes (scale-up, for example) made to a biopharmaceutical manufacturing process after the drug has been approved for marketing.
postmarketing surveillance Phase 4 clinical trials, which provide additional details about a product's safety (while the product is on the market) and
efficacy and may be used to evaluate formulations, dosages, durations of treatment, medicine interactions, additional indications,
and other factors.
posttranslational modification After a DNA sequence has been interpreted and a protein has been created, it may be modified by the addition of sugar (glycosylation)
or other molecules. This protein processing is done by the Golgi bodies after proteins have been constructed by ribosomes.
Performance qualification; Documented verification that all aspects of a facility, utility or equipment perform as intended in meeting predetermined
pre-license inspection An FDA facility inspection performed in response to a biopharmaceutical company's filing of a BLA; to confirm claims made
in the license application and assess the readiness and cGMP compliance of the manufacturing plant.
precipitation Process causing a solid to settle out of solution (as in centrifugation) by the action of gravity or by a chemical reaction;
a reaction between a soluble antibody and a soluble antigen, resulting in the formation of a substance (known as a precipitate)
that separates, in solid particles, from a liquid.
preformulation An exploratory activity that begins early in biopharmaceutical development, involving studies designed to determine the compatibility
of initial excipients with the active substance for a biopharmaceutical; physicochemical and bioanalytical investigation in
support of promising experimental formulations.
preparative chromatography Chromatography methods used in manufacturing rather than analytical applications, larger in scale and intended to purify a
product; also called process chromatography. Chromatographic methods were first used in analytical laboratories, and only later in the 20th century were they adapted
to industrial separations use. (Contrast with small-scale analytical chromatography.)
Mouse prion protein computer model
preservative A chemical additive that prevents spoilage by killing or inactivating microorganisms. Also stabilize molecules such as when
using antioxidants or sulfhydyls to stabilize proteins. (Contrast with bacteriostatic agent, which prevents microbes from
multiplying but does not kill them).
primary recovery The early steps in separation and purification of a biopharmaceutical, in which a complex biological solution containing the
protein of interest is concentrated and clarified, usually by means of filtration, centrifugation, or extraction (precipitation);
and the protein of interest is isolated from residual debris, cells, and other macromolecular materials.
prion Believed to be the smallest, simplest infectious particle consisting of a hydrophobic protein (no nucleic acid, DNA, or RNA),
suggested as a possible model for the causal agent of scrapie and related diseases, called TSEs. (Term originally derived
from proteinaceous infectious particle.)
Proline, an imino acid often grouped with the 20 naturally occurring amino acids.
process analytical technology (PAT) A system for designing, an-alyzing, and controlling manufacturing through timely measurements (i.e., during processing) of
critical quality and performance attributes of raw and in-process materials and processes with the goal of ensuring final
product quality. [ICH Q8]
process control 1. The means by which a process is monitored and operated, and is designed to maintain critical parameters within set ranges
determined to be safe. 2. A consistent process that follows predictable statistical trends and is monitored using control
charts, is said to be in a state of 'statistical control'.