Aspirin Flashcards
What is aspirin prepared from?
What does it generally do?
Salicylic acid, from family, salicylates, to salicin, converted to salicylic acid in the body
mild analgesic (pain relief), anticoagulant (thin blood, prevent heart attack and strokes), lessen pain, swelling, fever
How do prostaglandins work?
What is the key enzyme in the synthesis of prostaglandins?
Pain receptors are stimulated by prostaglandins, from cells damaged by thermal, mechanical, or chemical energy
Prostaglandins mediate the inflammatory response by causing the dilation of blood vessels near the site of injury, which leads to swelling and increased pain
Prostaglandins have an effect on temperature regulation, causing increased temperature (fever)
key enzyme: cyclooxygenase (COX)
What is the synthesis of aspirin process?
salicylic acid and ethanoic anhydride to aspirin and ethanoic acid
concentrated sulfuric or phosphoric acid added to reactants, mixture is warmed gently
aspirin product must be isolated and purified from the mixture
product is first cooled causing crystals to form, suction filtered and washed with chilled water (aspirin has VERY LOW solubility in water AT LOW TEMPERATURE)
purification (recrystallization) involves dissolving the impure crystals in hot ethanol (solvent for impurities)
mixtures have a lower and less well-defined melting point
How does aspirin work?
stops the transmission of pain from SOURCE TO BRAIN by intercepting the pain stimulus at the source; prevent stimulation of nerve endings at the site of pain, inhibits cyclooxygenase, therefore inhibit production of prostaglandins from the site of injury
What are the negative effects of aspirin?
What is synergy?
negative: irritation or ulceration of the stomach and duodenum (small intestine), possibly leading to bleeding
not recommended for children under 12, linked with Reye’s syndrome (rare and potentially fatal liver and brain disorder)
Synergy: occurs when two or more drugs have an effect on the body that is greater than the sum of their individual effects (aspirin has more acute physiological effects when taken with alcohol, increases risk of hemorrhage (bleeding) in the stomach)
How is aspirin taken and transported into the body?
aspirin usually has a buffer coating which delays the activity of the aspirin until it is in the small intestine to help alleviate some of its side-effects
taken orally, transported in the plasma of the blood in an aqueous solution, LOW SOLUBILITY IN WATER (non-polar)
bioavailability can be increased by INCREASING ITS SOLUBILITY IN WATER through chemical modification)
- reacting aspiring with an ALKALI (NaOH or NaHCO3 so it forms an ionic salt)
