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 U.S. 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)

Parenteral drugs are liquid formulations.

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

PAI Preapproval inspection; an FDA facility inspection performed in response to a biopharmaceutical com-pany's filing NDA. (See pre-license)

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 1,000 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 Process analytical technology; an FDA initiative that seeks to encourage industry to develop and use new analytical technology and multivariate analyses as part of risk management during process development, manufacturing, and quality control testing. PAT includes on-line, real-time analyses, process control tools, continuous improvement and knowledge management tools, and statistical tools.