option D

• Addiction

  Occur when the body quickly adapts to the presence of the medication and experiences negative effects in its absence
• Tolerance

  Decreased absorption of the drug with prolonged usage
• Slower, time-released method

  1. Oral ingestion or skin patch

  2. Keeps levels of medicine in the body lower and more consistent

  3. Avoid dependency
• Target cells


  Identified by 3D receptors
• If the drug passes by cells that do not contain the receptor, it will not bind to the cell and have a medicinal effect
• Bioavailability

  Fraction of the administered dose that reaches the target site
• Bioavailability can be affected by administration, polarity, and functional groups
• Oral ingestion


  Acidity of the stomach or small intestine may destroy some of the drug, the drug may not be completely absorbed or it might even be absorbed by the bacteria in the small intestine
• Polarity


  May also affect the bioavailability
• Drugs must have both polar and nonpolar functional groups to be absorbed by the body and at the cellular level
• If the drug is not very polar, it might bind to food particles instead, preventing it from being absorbed
• Drugs are sometimes required to be taken either with food or on an empty stomach, depending on the drug, for better absorption (and higher bioavailability)
• Therapeutic window


  Effective window where the dosage of the drug is most active
• Effective dose (ED50)


  Minimum dose required to have an effect on 50% of the population
• Toxic dose (TD50)


  Upper limit of the therapeutic window, the dose where a serious toxic effect is observed for 50% of the population
• Therapeutic index (TI)


  Calculated using the LD50 and ED50, magnitude is an indication of the "safety" for the dosage of the drug
• Recrystallisation


  1. Improve the purity of a product

  2. The solid organic product is collected using a vacuum, and any impurities will remain dissolved and flow through the funnel
• Purity testing


  • Melting point and IR spectroscopy
  • Melting point: impure samples will have a lower MP than the theoretical temperature
  • IR spectroscopy: determine if the sample tested contains the types of bonds and functional groups expected, can also identify bonds present in the impurities
• Analgesics


  Medicines that provide relief from pain (analgesia)
• Analgesics


  • Aspirin, acetaminophen/paracetamol and opiates
• Aspirin


  • Pain reliever, fever reducer and anticoagulant
  • Can irritate the stomach, leading to ulcers if overused
  • Causes the blood to thin, which can be a problem for some people who have clotting issues
  • Improves circulation for people with diabetes
• Prostaglandins


  • Cause the sensation of pain, swelling and sometimes fever
  • Aspirin works by stopping the enzyme that produces prostaglandins, which is called cyclooxygenase (known as COX)
• Aspirin does not have a specific target site, but rather acts to inhibit the production of prostaglandins throughout the body, so any and all pain, swelling or fever will be treated
• Aspirin


  • Slows down the clumping of platelets, so instead of coagulating, they anticoagulate
  • Can also be taken as a prophylactic, or preventative measure of a blockage
• Aspirin can be chemically modified to a salt to increase its solubility in aqueous solutions, although this doesn't affect its bioavailability
• Sodium acetylsalicylate


  More soluble in water than the aspirin molecule, as ions have a stronger attractive force to the dipoles in water molecules than the intermolecular forces of the carboxyl functional group
• Aspirin and alcohol


  Synergistic effect, aspirin has a higher medicinal effect when taken in combination than they would when taken separately
• Penicillin is produced when the fungi are under stress, not under regular growth conditions
• Scientists provide penicillin with lactose sugar, rather than glucose sugar that the fungus prefers as a food source
• Temperature, pH and other nutrients added to the batch also ensure that the fungi are under stress
• Different strains of fungi produce different penicillin molecules
• Penicillin


  • Key feature is the beta-lactam ring, important for the action of penicillin in preventing the growth of bacteria
  • Different side chains for the R-group give rise to differences in physical properties, such as polarity, and thus bioavailability and action
• The R-group isn't the beta-lactam ring
• Different R groups lead to different physical properties, bioavailability and action, but they don't need to be memorized (in data booklet)
• Penicillin


  • Act on bacterial cell walls (peptidoglycan)
  • Polymer made of sugars and amino acids, also known as murein, that is sandwiched between two lipid layers
  • A bacterium would not have the rigid structure required to function and rupture
• Cell walls


  Cross-linked, providing additional structure and rigidity
• Transpeptidase (PBP)


  Allows for trans-linking of the cell wall
• The beta-lactam ring binds to PBP, interferes with the action of the enzyme, and doesn't allow the cell wall to be cross-linked
• Penicillinase/beta-lactamase


  Enzymes that destroy the beta-lactam ring, rendering the penicillin ineffective
• Opiate types


  • Morphine
  • Codeine
  • Diamorphine (heroin)