“Ampicillin an Amoxicillin NH2” The amino group on these two drugs will exist in what form at physiological pH?
NH3+
“Ampicillin an Amoxicillin NH2” The amino group on this molecule will exist as a cation at physiological pH, what character will it impart?
String inducer that will result in oral activity, polarity that expands the G- spectrum
“Ampicillin and Pen G” Which molecule would have a broader G- spectrum and why?
A: Ampicillin, because of the NH2, which will be NH3+ at physiological pH making the molecule polar (B: Pen G)
“Ampicillin an Amoxicillin NH2” The NH2 (NH3+ in vivo) makes this group polar, does it have G+ activity?
Yes, despite this polar group, the molecule is lipophilic as a whole, so it retains G+ activity
“Ampicillin an Amoxicillin” Would this drug be useful for treating Haemophilus influenza meningitis, why or why not?
Yes, because it has a polar NH2 (NH3+ in vivo) group
Why should reconstituted vials of Ampicillin be used within 2 hours?
Conc. ampicillin can form high molecular weight aggregates by nucleophilic attack of its primary amino group on the carbonyl carbon of the beta-lactam bond of another molecule. Aggregates are antigenic
“Ampicillin and Amoxacillin unlabeled” What are these molecules?
A: ampicillin B: Amoxacillin
Ampicillin forms a Zwitterion, what result does this have?
Incomplete absorption from the intestine and stomach
Why does Ampicillin have a greater incidence of Diarrhea compared to other B-lactams?
Broader spectrum and incomplete absorption because it is a zwitterion
“Amoxacillin para OH” What effect does the para-OH group have on Amoxicillin’s character?
Increases acidity of the molecule providing for better absorption and enhanced blood levels
“Penicillin Pharmacophore” Lipophilicity of R provides good activity against G____, but not against G_____.
Good activity against G+, but not against G-
“Carbenicillin –COOH” The alpha-COOH is highly ionized and provides for extended spectrum against what organism?
Pseudomonas (relatively poor and large doses are required)
“Carbenicillin and Ticarcillin” Ticarcillin or carbenicillin is more potent and why?
Ticarcillin (though only somewhat), because it is a biosteric analog of Carbenicillin
“Ampicillin and Amoxicillin” A B-lactam with an NH2 group, like ampicillin or amoxicillin, provides more G- coverage, can it also treat Pseudomonas?
No, not polar enough
“Ticarcillin” What is the drug?
Ticarcillin
“Carbacilillin” What is this drug?
Carbenicillin
“Carbenicillin and Ticarcillin” Why are drugs with a –COOH on the alpha carbon acid liable?
Even though the COOH is electron withdrawing, it undergoes acid-catalyzed decarboxylation to the acid labile Pen G
“Carbenicillin and Ticarcillin” Can drugs with a –COOH on the alpha carbon be given orally, why or why not?
No, because they are acid-liable
What is the advantage of the indane ester group on this product (Indane Carbenecillin)?
-COOH is protected from hydrolysis in the acidic stomach, so it has increased acid stability but retains a broad spectrum activity
“Indane Carbenecillin” What are the cons to using this product?
Too Low of blood levels to treat systemic infections, more effective antimicrobials available
“Indane Carbenecillin” What is this product used for?
Mild urinary tract infections by G- bacteria including Pseudomonas
What is this structure?
Urea
“Ureidopenicillins” What are these structures called?
Ureidopenicillins (note the urea containing rings)
“Ureidopenicillins” The bulky side chain of Ureidopenicillins is thought to mimic a longer segment of the peptidoglycan chain, wht benefit does this have?
Provides more points of attachment to the enhanced antibacterial properties
“Ureidopenicillins” Why do these molecules have enhanced G- activity?
Heterocyclic nature of the peiperazindione and imidazolidinone increase polarity and thus G- activity
“peiperazindione and imidazolidinone” What are these potential R groups called?
A: Peiperazindione B: Imidazolidinone
“Ureidopenicillins” The larger G- spectrum of piperacillin, mezlocillin and azlocillin allow for activity against what clinically relevant bacteria when given intravenously?
Klebsiella, Seratia and Pseudomonas
What is this drug?
Piperacillin
What is this drug?
Mezlocillin
What is this drug?
Azlocillin
“Penicillin Pharmacophore” (True/False) The –COOH group is essential for activity.
True
“Penicillin Pharmacophore” (True/False) An aquaphilic R group enhances G+ activity.
False, should say lipophilic
“Penicillin Pharmacophore” (True/False) An electron withdrawing group for R' or R" will enhance oral activity.
True
“Penicillin Pharmacophore” (True/False) A thienyl group for R enhances anaerobic coverage.
True
“Penicillin Pharmacophore” (True/False) An Cα in a ring, reduces activity against Staph aureus producing beta lactamases.
False, should say “Enhances activity”
“Penicillin Pharmacophore” (True/False) Incorporation of the Cα into a five membered ring (isoxazole derivatives) is not sufficient for beta lactamase resistance since there is not sufficient steric hindrance.
True
“Penicillin Pharmacophore” (True/False) A methyl group at the -C5 of the isoxazole ring is beneficial but not required for activity against Staph aureus producing beta lactamases.
False, it is required
“Penicillin Pharmacophore” (True/False) An amino group for R" broadens the spectrum (i.e.) increases G- activity but not against Pseudomonas.
True
“Penicillin Pharmacophore” (True/False) For an aminopenicillin, a para–OH group increases DOA and increases GI side effects.
False, should say “Decreases side effects”
“Penicillin Pharmacophore” (True/False) Prodrugs of aminopenicillins enhance oral activity and decrease GI side effects.
True
“Penicillin Pharmacophore” (True/False) A –COOH for R" will extend the spectrum to include more G- including pseudomonas aeruginosa but only if given in large doses.
True
“Penicillin Pharmacophore” (True/False) The piperazindione and imidazolidinone are responsible for extending spectrum to include pseudomonas, Klebsiella and Seratia.
True
“Sulbactam and Clavulinic Acid” What is the purpose of these molecules?
To be used in combination with Penicillins to extend their spectrum to include B-lactamase producing bacteria
“Sulbactam and Clavulinic Acid” Do these suicide inhibitors protect against B-lactamases of Staph aureus?
Yes
“Sulbactam and Clavulinic Acid” Do these suicide inhibitors protect against B-lactamases of Pseudomonas?
No
“Sulbactam and Clavulinic Acid” Why are these suicide inhibitors more accessible to the bacterial B-lactamases than that of a B-lactam antibiotic?
No steric hindrance from a side chain
“Sulbactam and Clavulinic Acid” What are these two drugs?
Left: Sulbactam Right: Clavulinic Acid
“Ampicillin and Amoxicillin” (True/False) Amoxicillin has less CNS effects but more gastrointestinal effects than Ampicillin due to the para-OH.
