Drug-Like Properties: Solubility, Permeability and Metabolic Fate · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Potent means little until the body sees it

Science · Chemistry · ages 23-24
Name ______________________   Date ____________

  1. Which form of a drug slips through membranes easily?

    • The charged form
    • The neutral form
    • The buffered form

  2. What does adding a polar group usually do to solubility?

    • Lifts it
    • Lowers it
    • Leaves it unchanged

  3. Like dissolves like: polar groups welcome water while greasy parts refuse it.

    Circle one:   True   False

  4. Blood at pH 7.4 versus stomach near pH 2: why must you state the compartment?

    • pH shifts the neutral fraction hugely
    • pH changes the drug dose
    • pH picks the target

  5. An acid has a pKa far below gut pH. What do you predict for absorption?

    • No dissolution at all
    • Strong absorption, mostly neutral
    • Poor absorption, mostly charged and stuck

  6. Your lead is cleared in minutes at an exposed amine. What is a sound fix?

    • Add more amines
    • Block the site with fluorine or add nearby bulk
    • Raise the dose tenfold

  7. Excellent potency alone makes a compound a good drug candidate.

    Circle one:   True   False

  8. A team keeps boosting potency while half life stays five minutes. What is your advice?

    • Switch to a salt form only
    • Push potency further
    • Stop: this is a metabolism problem needing a structural shield
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Potent means little until the body sees it W1-mt_HGnGjBCLM6-s1

  1. The neutral form · Neutral species cross fatty membranes; charged ones stall.
  2. Lifts it · Polar groups welcome water, aiding dissolution.
  3. True · Matching polarity is the first solubility rule.
  4. pH shifts the neutral fraction hugely · The same pKa gives different neutral shares at different pH values.
  5. Poor absorption, mostly charged and stuck · High pH above the pKa leaves the acid charged.
  6. Block the site with fluorine or add nearby bulk · Shielding the soft spot slows oxidation without touching the target fit.
  7. False · Solubility, permeability, and clearance decide with potency, not after it.
  8. Stop: this is a metabolism problem needing a structural shield · No potency level survives clearance that fast.
Worksheet · LightMySky