Cold water extraction

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Cold water extraction is the process whereby a substance is extracted from a mixture via cold water. It is a type of fractional crystallization.

The process generally involves taking a mixture of substances, dissolving them in warm water, and then rapidly cooling the mixture. The insoluble compounds precipitate out of the water, while the soluble ones stay dissolved. The solution can then be separated by filtration or decantation.

This process works by exploiting the differences in solubility (with respect to temperature) of different substances in a mixture. It is commonly used to separate out opiate-derived drugs that have been mixed with common non-opiate-based analgesics, such as are found in Codeine/Paracetamol(Acetaminophen) formulations, Zaldiar and Vicodin.[1]

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  1. ^ Cone EJ (June 2006). "Ephemeral profiles of prescription drug and formulation tampering: evolving pseudoscience on the Internet". Drug Alcohol Depend. 83 Suppl 1: S31–9. doi:10.1016/j.drugalcdep.2005.11.027. PMID 16458455.