Sulphonamide Flashcards
What is chemotherapy?
The drug treatment of parasitic infections and cancer, where infective parasites are destroyed without harming the host.
Who reported the antibacterial activity of prontosil?
Domagk in 1932.
What are sulphonamides?
Antibacterial agents that act against cell metabolism as antimetabolites.
What is the significance of the para-amino group in sulphonamides?
It is essential for activity, with R1=H being a requirement.
What is a prodrug?
A compound that is metabolized into an active drug form in the body.
What is the first synthetic antibacterial agent?
Sulfanilamide.
Fill in the blank: The sulphonamide group is essential for __________.
activity.
What is the relationship between pKa and sulphonamide activity according to Bell & Roblin?
Maximal activity is found in sulphonamides with pKa values between 6 and 7.4.
What type of agents are sulfonamides classified as?
Competitive enzyme inhibitors and bacteriostatic agents.
True or False: Dihydropteroate synthetase is present in human cells.
False.
What is the mechanism of action of sulfonamides?
They mimic para-aminobenzoic acid and inhibit dihydropteroate synthetase.
What is the role of N-acetylation in sulfonamide metabolism?
It increases hydrophobic character and reduces aqueous solubility.
What is the main application of sulfanilamides?
Treatment of urinary tract infections and other infections.
Fill in the blank: Sulfadiazine and its metabolite are more __________ soluble.
water.
What is the consequence of poor water solubility in sulfonamides?
Crystallization in urine, leading to kidney damage.
What is co-trimoxazole?
A combination of sulfamethoxazole and trimethoprim.
What is the purpose of combining sulfamethoxazole and trimethoprim?
To achieve sequential blocking in the same biosynthetic pathway.
What is the primary action of sulfasalazine?
Used in the treatment of inflammatory bowel disease (local action).
What is the activation mechanism of sulfasalazine?
Activated by gut bacteria to mesalazine and sulfapyridine.
Fill in the blank: Sulfonamides are __________ agents.
bacteriostatic.
What is the effect of adding PABA to sulfonamide treatment?
It can reverse the antimicrobial efficacy of sulfonamides.
What does the Henderson-Hasselbalch equation relate to sulphonamides?
It relates pKa to ionization and activity at different pH levels.
What is sulfadoxine used for?
As a long-lasting antibacterial agent, often in combination with pyrimethamine.
What is the activation process of sulfasalazine?
It is activated by gut bacteria to mesalazine (5-aminosalicylic acid) and sulfapyridine.
Why is sulfasalazine used as a prodrug?
Direct administration of salicylic acid as anti-inflammatory is irritating.
What are the two main components produced from sulfasalazine?
- Mesalazine (5-aminosalicylic acid)
- Sulfapyridine
What is mesalazine?
5-aminosalicylic acid
What is sulfapyridine?
A component activated from sulfasalazine.
What is the role of sulfonamides in relation to sulfasalazine?
Sulfones are related compounds.
What enzyme is thought to be inhibited by sulfasalazine?
Dihydropteroate synthetase
In what condition is sulfasalazine used as a treatment?
Leprosy
