physical state The form that matter takes, whether solid, liquid, gas, or plasma.
placebo A fake treatment (often the same formulation used for the real product, but without the active ingredient) administered
to the control group in a controlled clinical trial so that the specific and nonspecific effects of the experimental treatment
can be distinguished. The experimental treatment must produce better results than the placebo to be considered effective.
polyethylene glycol (PEG) A polymer that varies in consistency from liquid to solid depending on its molecular weight (indicated by a number following
the name). PEGs are used as surfactants in industry (for foods, cosmetics, and pharmaceuticals) and in biomedicine as dispersing
agents, solvents, ointment and suppository bases, vehicles, and excipients.
polysorbates Complex mixtures of polyoxyethylene ethers used as emulsifiers or dispersing agents in pharmaceuticals.
precipitation Process causing a solid to settle out of solution by the action of gravity or by a chemical reaction, which forms a substance
(precipitate) that separates as solid particles in the liquid.
preservative A chemical additive that prevents spoilage by killing or inactivating microorganisms; an additive that prevents microbial
contamination, usually employed in multi-dose containers.
protein collapse Mild denaturation, in which a protein's native structure falls out of equilibrium.
proteolysis Separation (cleavage) of peptide bonds in proteins by proteases (enzymes that recognize and cut specific peptide bonds)
or other means.
residue An amino acid when referred to as part of a polypeptide chain.
shear Tearing force, such as that caused by blending or stirring.
shelf life The period of time during which a drug can be stored without significant loss in quality, safety, or efficacy.
size-exclusion chromatography (SEC) Also gel-filtration or gel-permeation chromatography; an analytical method that uses porous particles to separate molecules
of different sizes. Molecules that are smaller than the pore size can enter the particles and therefore have a longer path
and longer transit time than larger molecules that cannot enter the particles. SEC can separate biological molecules and help
scientists determine the molecular weights and molecular weight distributions of polymers.
spectroscopy Study of the molecular absorption of light. Different wavelengths and types of light can tell different things about the
molecules' identity and condition. Proteins are often studied using fluorescence and infrared spectroscopy. Fluorescence spectroscopy
induces molecules to emit light by the application of laser energy. Fourier-transform infrared (FTIR) spectroscopy uses a
mathematical logarithm to interpret the vibrations of functional molecular groups and highly polar bonds. It can produce a
biochemical "fingerprint" illustrating the vibrational features of all sample components, and it can be used to learn about
stability Ability to maintain constant characteristics in the presence of forces that threaten to disturb them; resistance to change.
stabilizer A chemical additive that helps maintain solution or drug stability.
sublimation Passing directly from a solid to a vapor state without first melting into a liquid.
surfactant Any substance that changes the nature of a surface, such as by lowering the surface tension of water.
delivery Controlled delivery that is engineered to release the active ingredient over an extended period in a well-defined and reproducible
targeted delivery Drug delivery that is specifically directed to the therapeutic molecule's site of action by one of various means such as
a monoclonal antibody that targets a specific kind of receptor or surgery in which a drug formulation is injected into a particular
location, such as the liver.
tertiary structure The three-dimensional folding of polypeptide chains in a protein molecule.
transdermal delivery Drug delivery across the skin, accomplished without breaking the skin. For large molecules like proteins and peptides, this
is possible only through iontophoresis.
transmucosal delivery Drug delivery across mucosal membranes, such as the nasal lining, the inside of the mouth, or the rectal wall.