organic In chemistry, any molecule containing carbon atoms is considered an organic molecule (from the Greek for "work"). Organic chemistry is the chemistry of life because carbon interacts in myriad ways with a large number of other elements to form complex molecules (RNA, DNA, amino acids, proteins, and so on) that perform the intricate actions that make life "work."

organism A single, autonomous living thing. Bacteria and yeasts are organisms; mammalian and insect cells used in culture are not.

orphan drug A US product that treats a rare disease affecting fewer than 200,000 people.

osmolarity The concentration of osmotically active particles in a solution (expressed in osmoles of solute per liter of solution). Osmosis is flow through a semipermeable membrane under the influence of an osmotic gradient. Osmotic pressure is the pressure that must be applied to a solution to prevent osmosis. Osmotic shock is a rapid change in osmotic pressure on a cell or virus, usually causing it to discharge its contents.

outsourcing Having research, laboratory testing, clinical trials, or manufacturing done by another firm, usually called the contract organization. (See contract giver; sponsor; quality agreement)

Oligonucleotides are used in a broad array of biopharmaceutical applications. The Waters UPLC Oligonucleotide Analysis Solution provides high resolution chromatographic performance and flexible detection options for clear analytical information.

oxidation Chemical reaction in which a compound or atom loses valence electrons; due to reaction with an oxidizing agent (e.g., oxygen, peroxides, metal ions, or others). Many proteins are prone to oxidation on exposure to air (such as oxidation of the Met amino acid into methionine sulfide or sulfone). (See also redox)

P

PA projection approximation; an ion is modeled by a collection of overlapping hard spheres with radii equal to hard sphere collision distances. The orientationally averaged geometric cross section is determined by averaging the geometric cross section over all possible collision geometries.

PAI Preapproval inspection; an FDA facility inspection performed in response to a biopharmaceutical company's filing an NDA. (See prelicense inspection)

parenteral delivery Drug delivery by injection; subcutaneous, intra-muscular, and intravenous delivery are most common. Drug must be sterile.

particle filtration Particle filtration is used to filter macro particles, which are visible to the naked eye and range in size from 50 μm to 1000 μm. Examples of particles in this size range include beach sand, granular activated carbon, human hair, mist, pollen, milled flour, and precipitates formed during bioprocessing.

passage number When cells are cultured, the passage number is a theoretical number of cell generations, or how many times the cells have been "passaged" in vitro.

PAS Pre-approval supplement; a regulatory submission to FDA used for biologics and biopharmaceuticals when major changes to the process, facility, or quality control system are desired. The sponsor must wait for full FDA review and approval before any product manufactured may be placed in distribution. Often, a PAS or a CBE-30 may be part of a comparability protocol, and the type of submission required for a given package of changes is negotiated with FDA by RA personnel.

PAT See process analytical technology.

PCR Polymerase chain reaction; a process that exponentially amplifies (reproduces) a short piece of DNA having a specific nucleotide sequence, making possible many research and clinical applications involving that DNA (used extensively in forensics). PCR may be qualitative or quantitative (qPCR).

peak An individual component of a mixture that is washed out of the chromatography column during elution (the elution fraction). The sharp rise in the line graph of a chromatogram that represents this phenomenon.