Paracetamol Case Studies

Fever

• regulated rise in body temperature

• controlled by the hypothalamus

COX 1

constitutive

• make PGs

• maintaining homeostasis

COX 2

inducible

• activated by tissue damage or inflammatory cytokines

COX 3

a variant of COX 1, mainly in the brain

COX 1 Inhibition

reduces:

stomach protection

clotting

COX 2 Inhibition

reduces:

inflammation

pain

swelling

Paracetamol Functional Groups

phenol (hydroxyl and aromatic ring) and amide

Paracetamol pKa

9.5

IR Absorption Spectrophotometry

test to prove paracetamol structure, when supported by melting point analysis

Paracetamol

• very weak acid

• phenolic OH proton is the only acidic group

• amide practically neutral

Acesulfame Potassium

an artificial high intensity sweetener to enhance sweetness

Sorbitol Liquid

sugar free sweetener to improve taste

Carmoisine

pink colouring agent

Xantham Gum

used as suspending agent, increasing viscosity to reduce the rate of sedimentation

Dispersible Cellulose

like xantham gum, may be used as a suspending agent

Purified Water

solvent used in Calpol

Glycerol

cosolvent used in Calpol

• dissolves preservatives as they are not readily soluble in water

Surfactant

reduces surface tension allowing two substances that do not normally mix to interact

Oral Suspension

liquid containing one or more active ingredients suspended in a suitable vehicle

• doses easier to adjust

• faster onset

• more palatable

Capsule or Tablet

a solid preparation usually containing a single dose of active substance intended for oral administration

Elixir

• homogeneous

• clear liquids

• contain alcohol as solvent and preservative

• more physically stable

• no shaking before use

Suspension

• heterogeneous

• cloudy or opaque

• primarily use water-based vehicles

• used when drug is insoluble or unstable in dissolved form

Paracetamol Metabolism

glutathione mediated, mostly glucuronidation and sulfation

NAPQI

toxic metabolite of paracetamol metabolism

Sulfation

paracetamol metabolism in neonates