Chapter 11A - Extraction, purification & identification of medicinal molecules

Component of a substance/ mixture that produces a chemical or biological effect

A set of liquids that do not mix w/ each other (insoluble)

A compound w/ healing properties

Technique used to seperate liquids w/ significantly different boiling points

Method of seperating compounds based on a difference in solubility in the two solvents

Distillation by injection of water vapour to lower the boiling point of substances & hence minimise decomposition

• represents bonds coming out of the page

Bonds going into the page

• initial mixture (desired compound + impurities) dissolved in a solvent & placed in a seperating funnel • immiscible solvent added & contents shaken • impurities w/ similar polarity to 2nd solvent will transfer • two solvents seperated by opening funnel tap & collecting each layer • desired product extracted via solvent evaporation

• to isolate oils • contain large hydrocarbon chains • largely non-polar

Hexane: very non-polar Acetone (propanone): Quite non-polar Ethanol: Quite polar Water: Very polar

• process is slow & requires large volumes of solvents at industrial scales • ineffective removal of impurities w/ similar polarity to desired compound • desired product often highly impure

• mixture heated to vaporise the substance w/ lowest boiling points • vapours transferred to condenser where they are cooled & collected as a liquid • liquid w/ highest boiling point remains in distilling flask • boiling chips help distribute the heat • heating mantle must be used instead of a bunsen to minimise risk of explosion when heating fuels

• some molecules (oils) are heat sensitive • can be damaged w/ high temperatures required for vaporisation • hinder medicinal properties

• water vapour is pumped through the distillation apparatus into mixture to be distilled • reduces the temperature required to vapourise the substace in the mixture • process repeated to maximise purity of desired product

Substance that can be used to treat/cure an ailment

• solvent extraction • distillation • HPLC - quantitative/qualitative • MS, IR and H and C-NMR

• relatively large molecules • contain polar molecules (enable some medicines to dissolve/absorbed by bodies) • Contain rings - saturated or aromatic

• give lots of flat surfaces providing plent of receptor binding points • easily modified through addition of functional groups (helps bind compound to specific receptors)

• bind to specific receptors in the body • must have correct structures & properties to align w/ receptors & maximise electrostatic interactions