Fun facts
TCA: The compound is structurally related to acetic acid in which all three hydrogen atoms of the methyl group are substituted by chlorine. TCA is widely used in research labs for precipitation of macromolecules. Although TCA is extremely corrosive and potentially dangerous, it is used as a chemical peel to remove the outer skin layer in doctor's office. Patients often feel burning sensation from the application. The procedure, a controlled injury to skin cells, is intended to remove the dead skin and regenerate new skin tissue.
PEG: The petroleum polymers find quite versatile applications in medical, industrial, commercial, and consumer products. PEGs, available over a wide molecular weight range of 300 to 10,000,000 g/mol, can be used as an excipient, laxative, and drug carrier in medical applications. PEG-8000 is used in research labs for precipitation of macromolecules. Protein or lipid PEGylation is employed in pharmaceutical manufacturing. Many personal hygiene and food/drink products also contain PEG. The polymers, being biologically inert, are considered safe by the FDA.