WORLD OF GENERIC DRUGS MODULE

Residual Sovents

Residual solvents are often listed in the ANDA. By definition, residual solvents are organic liquids or gases used in the synthesis and purification of drug substances. These solvents fall into three classes:

• Class I-- benzene (2 ppm) and carbon tetrachloride (4 ppm) are to be avoided.
• Class II-- methylene chloride (600 ppm), methanol (3000 ppm), pyridine (200 ppm), toluene (890 ppm), N,N-dimethylformamide (880 ppm), and acetonitrile (410 ppm) are commonly used.
• Class III-- acetic acid, acetone, isopropyl alcohol, butanol, ethanol, and ethyl acetate have daily exposures of 50 mg or less per day.