Page 120 - Medicinal Chemistry Self Assessment

Section 3 General Self Assessment Answers

2.4 Salts and Solubility

1. Some drug molecules can be formulated as either a potassium salt or hydrochloride salt. Evaluate all of
the acidic and basic functional groups in each of the drug molecules drawn below and fill in the grid with
the appropriate information.

Answer

Name of Functional Name of Functional Is the Hydrochloride
Name of Drug Group That Can Form Is the Potassium Salt Group That Can Form a Salt Acidic, Basic, or
Molecule a Potassium Salt Acidic, Basic, or Neutral? Hydrochloride Salt Neutral?
Arformoterol Phenol Basic Secondary amine Acidic
Baclofen Carboxylic acid Basic Primary amine Acidic
Irbesartan Tetrazole Basic Amidine Acidic
Ciprofloxacin Carboxylic acid Basic Secondary amine (NH) Acidic
component of piperazine

Aniline component (N) of Acidic
piperazine
Tetracycline Phenol Basic Tertiary amine Acidic
2. Each of these drug molecules will treat a particular ailment by either managing a symptom or
β-dicarbonyl Basic
modulating a biochemical pathway. In either case, the drug has to get to its biological target. Using your
Note: The ionized form of an acidic functional group is termed the conjugate base of that functional
group. The ionized form of a basic functional group is termed the conjugate acid of that functional group.
knowledge about functional group character, describe how both of the drugs get to their respective

biological targets. Consider the concepts of solubility, absorption, distribution, and route of administration
2. Each of these drug molecules will treat a particular ailment by either managing a symptom or modulating
a biochemical pathway. In either case, the drug has to get to its biological target. Using your knowl-
in your answer. [pH (stomach) = 1; pH (intestine) = 8; pH (plasma) = 7.4]
edge about functional group character, describe how both of the drugs get to their respective biological
targets. Consider the concepts of solubility, absorption, distribution, and route of administration in your

answer. [pH (stomach)=1; pH (intestine)=8; pH (plasma)=7.4]
Cl NCH 3
OH
O
O
N CH 2 OH
O
CONH 2

Scopolamine
Loperamide

3. Based on your structural evaluation, provide a rationale for why each of these drugs cannot be
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delivered via an oral route of administration, or why there is limited absorption of the drug when it is

administered orally.

PO 3 Na 2
H 2 N PO 3 Na 2
OH

Alendronate

Insulin