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This blog mainly talks about QMS,cGMP,Regulatory Filings & Guidelines,Validation & Qualifications,Drug Stability,FDA 483s &Media Fill.
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Monday, 2 September 2013
Residual Solvents & Their Classifications
Residual Solvents & Their
Residual solvents in pharmaceuticals are organic volatile
chemicals that are used or produced in the manufacture of drug substances or
excipients, or in the preparation of drug products. The solvents are not
completely removed by practical manufacturing techniques. Appropriate selection
of the solvent for the synthesis of drug substance may enhance the yield, or
determine characteristics such as crystal form, purity, and solubility.
Therefore solvent may sometimes be a critical parameter in the synthetic
Residual solvents are potentially undesirable substances. Since
there is no therapeutic benefit from residual solvents, all residual solvents
should be removed from to the extent possible to meet product specifications,
good manufacturing practises, or other quality based requirements. Drug
products should contain no higher levels of residual solvents.Based on the
possible risk to human health, residual solvents are classified in to one of
the three classes as following:
Class 1 Solvents:
Solvents to be avoided
solvents are known human carcinogens (ex: benzene, carbon tetra chloride etc.).Solvents
in class 1 should not be employed in the manufacture of drug substances, excipients
and drug products because of their unacceptable toxicity or their deleterious
effect. However, if their use is unavoidable in order to produce a drug product
with a significant therapeutic advance, then their levels to be restricted.
Class 2 Solvents:
Solvents to be limited
Class 2 solvents are non-genotoxic animal carcinogens or
possible causative agents of other irreversible toxicity such as neurotoxicity
or teratogenicity. Class 2 solvents to be limited in pharmaceutical products
because of their inherent toxicity (ex: chloroform, methanol, toluene etc.).
Class 3 Solvents:
Solvents with low toxic potential
These are less toxic and possess lower risk to human health
than class I or Class II solvents (ex:ethanol,acetone).long term toxicity or
carcinogenicity not reported. Class 3 solvents have PDEs (permitted daily dose)
of 50mg or more per day.