MedChem

Exam 1

MOA penicillins

inhibit cell wall synthesis

MOA for cephalosporins

inhibit cell wall synthesis

MOA for vancomycin

inhibit cell wall synthesis

MOA for tetracyclines

inhibit protein synthesis

MOA for oxazolidinones

inhibit protein synthesis

MOA for chloramphenicol

inhibit protein synthesis

MOA for polymyxins

alter cell membrane function

MOA for daptomycin

alter cell membrane function

MOA for sulfonamides

inhibit metabolic compound synthesis (antimetabolite)

MOA for Isoniazid

inhibit metabolic compound synthesis (antimetabolite)

MOA for fluoroquinolones

inhibit nucleic acid synthesis

MOA for Rifamycins

inhibit nucleic acid synthesis

result of low solubility in sulfonamides

crystalluria

sulfonamides antibacterial pKa is

6.7-7.4

sulfonamides are more soluble in their

ionized form

sulfonamides have an increase in solubility if there is an

increase in urine pH

a microbial metabolic product (or synthetic analog of the metabolite) that kills or inhibits growth of another microorganism

antibiotic

no antibiotic is effective against

all bacterias

depends on comparative distribution, bioavailability, and cytology

selective toxicity

UTI, burns, ophthalmic infections, prophylaxis of rheumatic fever, Crohn’s disease and ulcerative colitis, AIDS

uses of sulfonamides

functional group of sulfonamide

SO₂ NH₂

Sulfonamide antibacterial agent with antibacterial pKa of (7.4)

Sulfamethazine

the pKa of sulfonamides refers to loss of hydrogen from the

N1 nitrogen (So₂- N-H)

negative charge on a sulfonamide nitrogen is usually unstable unless the charge can be stabilized by

delocalization

sulfisoxazole (pKa 5) is almost as

acetic acid (pKa 4.8)

sulfanilamide causes severe kidney damage due to crystallization in the kidney because neither the parent sulfonamide nor its acetylated metabolite are

water soluble

water solubility is greater for the

ionized forms of sulfonamides

if urine pH < pKa for the sulfonamide functional group there is very little ionized form =

low solubility

sulfonamides are

acidic

if U is greater than I

not soluble

increase urine flow-increase fluid intake =

force fluids

methods to increase amount of sulfonamide dissolved in urine

force fluids, raise urine pH, use sulfonamides with lower pKa, mix sulfonamides to reach total dose

to increase the amount of sulfonamide dissolved in urine by raising urine pH

increases ionization=increases solubility

increasing amount of sulfonamide dissolved in urine by mixing them to reach total dose

solubilities are independent of one another = triple sulfas

essential for life for protein and nucleic acid (DNA/RNA) synthesis

folate coenzymes

bacteria can not use folic acid from the host due to lack of

permeability

use of sulfonamides takes advantage of differences in (selective toxicity)

biochemistry and cytology