Objectives
• Identify
water and alcohol as commonly used solvents
• Explain
the relationship between the properties of solvents and their use in cosmetics
and external medications
• Identify
cosmetics and external medications where water is the solvent
• Identify
cosmetics and external medications where alcohol is the solvent
Solvents
• All
products that are solutions contain a solvent that dissolves important
components into the product.
• Water
is the most common, but there are many other solvents like Ethanol, turpentine,
kerosene and isopropyl alcohol. These
other solvents are organic solvents.
Organic solvents
• In
broader society, “organic” usually means a non-harmful part of nature with a
little human interference as possible
• The
scientific definition of “organic” means a substance that contain carbon-based
compounds
• Organic
solvents are ALWAYS harmful
Types of solvent
• Water
is used in substances that need to flow well (low viscosity)
– Hair
gel, moisturiser
• Alcohol
evaporates quickly and leaves the substance behind on the skin
– Deep
heat, nail polish, nail polish remover
Dissolution rates
• Plan
and conduct an investigation to compare the rates that capsules, tablets
and enteric coated tablets dissolve.
• What
variables will we need to control?
Review
• Identify
water and alcohol as commonly used solvents
• Explain
the relationship between the properties of solvents and their use in cosmetics
and external medications
• Identify
cosmetics and external medications where water is the solvent
• Identify
cosmetics and external medications where alcohol is the solvent
Homework
• Use
a variety of resources to research about subdermal implants. Use your research to prepare a 2
minute presentation.
• Your
presentation needs to describe one particular type of subdermal implant. In particular:
– How
does it work?
– What
is it used for?
– What
problems can occur?
• It
is advisable to use visual aides,
• This
is not a formal assessment task but you will be marked by your classmates.
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