Drug Development and Penicillins Quiz

<p>It increases b-lactam ring strain (A)</p> Signup and view all the answers

<p>Variations are restricted to the side chain (R) (D)</p> Signup and view all the answers

<p>Penicilloic acids (C)</p> Signup and view all the answers

<p>Penicillinase (C)</p> Signup and view all the answers

<p>Less active than other penicillins. (B)</p> Signup and view all the answers

<p>Hydrophilic groups at the α-position increase activity against Gram-negative bacteria. (C)</p> Signup and view all the answers

<p>2 (D)</p> Signup and view all the answers

<p>R-CO-OR (B)</p> Signup and view all the answers

<p>They affect absorption and plasma protein binding. (B)</p> Signup and view all the answers

<p>Penilloic acid (C)</p> Signup and view all the answers

<p>Has little effect on Gram-positive activity but lowers Gram-negative activity. (A)</p> Signup and view all the answers

<p>Hydroxamic acid (D)</p> Signup and view all the answers

<p>Presence of b-lactamases and efflux mechanisms. (C)</p> Signup and view all the answers

<p>Sulfur (S) (B)</p> Signup and view all the answers

<p>They are broken down by stomach acid. (A)</p> Signup and view all the answers

<p>Penilloic acid (B)</p> Signup and view all the answers

<p>Staphylococcus aureus. (B)</p> Signup and view all the answers

<p>Staphylococcus (A)</p> Signup and view all the answers

<p>Increased cell membrane permeability (C)</p> Signup and view all the answers

<p>It confers activity against Gram-negative bacilli. (C)</p> Signup and view all the answers

<p>It is a carboxylic acid. (C)</p> Signup and view all the answers

<p>To mask the polar carboxylic acid group (A)</p> Signup and view all the answers

<p>Degrade the antibiotic. (A)</p> Signup and view all the answers

<p>Carfecillin (D)</p> Signup and view all the answers

<p>It acts as a steric shield for the methyl ester. (C)</p> Signup and view all the answers

<p>It is metabolised to yield the active free drug. (D)</p> Signup and view all the answers

<p>It degrades and loses efficacy. (A)</p> Signup and view all the answers

<p>Ampicillin (C)</p> Signup and view all the answers

<p>It remains unhydrolysed in the body. (C)</p> Signup and view all the answers

<p>Carboxylic acid group (C)</p> Signup and view all the answers

<p>Inability of β-lactamase-sensitive penicillins to penetrate cell walls (A)</p> Signup and view all the answers

<p>It acts as a mechanism-based inhibitor of β-lactamases (A)</p> Signup and view all the answers

<p>They are not soluble in water. (C)</p> Signup and view all the answers

<p>Providing effective blood levels over a prolonged period (D)</p> Signup and view all the answers

<p>Semisynthetic penicillins (A)</p> Signup and view all the answers

<p>Most penicillins are weak acids with specific pKa values. (C)</p> Signup and view all the answers

<p>Semisynthetic penicillin (D)</p> Signup and view all the answers

<p>Narrow, intermediate, broad, or extended spectrum (D)</p> Signup and view all the answers

<p>Inhibiting transpeptidase activity (C)</p> Signup and view all the answers

<p>D-Ala-D-Ala (A)</p> Signup and view all the answers

<p>They lack a hydrophobic barrier (B)</p> Signup and view all the answers

<p>Preventing the action of penicillin (C)</p> Signup and view all the answers

<p>Presence of lactamase enzymes (C)</p> Signup and view all the answers

<p>Acyl side chain similar to D-Ala (D)</p> Signup and view all the answers

<p>It cannot bind to transpeptidase (D)</p> Signup and view all the answers

<p>Thicker walls do not form a barrier to penicillin (B)</p> Signup and view all the answers

<p>It irreversibly binds to bacterial enzymes (C)</p> Signup and view all the answers

<p>Hydrophobic outer membrane (A)</p> Signup and view all the answers

<p>Penicillin disrupts cell wall synthesis (B)</p> Signup and view all the answers

<p>High levels of transpeptidase enzyme (B)</p> Signup and view all the answers

<p>Is the main target for penicillin (B)</p> Signup and view all the answers

Penicillins can break down due to gastric acid (low pH) and the enzyme penicillinase.

A key intermediate in the degradation of penicillin, formed when penicillin interacts with stomach acid.

Acidified sodium salt of penicilloic acid.

The removal of a carboxyl group (COOH) from a molecule.

A product of penicilloate decarboxylation.

An enzyme that breaks down penicillin.

Stomach acid with a low pH.

The approximate acidity of human gastric acid.

Enzyme produced by microorganisms that affect penicillin.

Breakdown of penicillin caused by the interaction with the acidity of gastric acid.

Improving chemical stability for oral use, resistance to bacterial enzymes (beta-lactamases), and expanded drug activity.

Penicillins block a bacterial enzyme (transpeptidase) crucial for building the bacterial cell wall, creating irreversible binding and stopping cell wall formation.

Essential components for penicillin activity include the bicyclic system, amide, carboxyl group, and b-lactam ring, with specific spatial arrangements (cis for ring).

The carboxyl group, acting as the carboxylate ion, binds strongly, triggering the chemical reaction with the enzyme and causing the irreversible impact.

Penicillin structure permits modest changes only in the side chain "R", while essential core parts remain primarily constant

Bacteria that do not retain the crystal violet stain in the Gram staining process, making them appear pink or red under a microscope.

Effective against some bacterial strains that are resistant to the natural penicillin G. These strains often possess modified enzymes involved in cell wall synthesis.

Susceptible to degradation by acidic environments, such as the stomach.

Cannot be effectively absorbed through the digestive tract and thus must be administered by injection.

A type of penicillin with modifications that make it more resistant to breakdown by enzymes and better absorbed orally.

Enzymes produced by bacteria that can break down penicillin drugs, rendering them ineffective.

Changes in the structure of the side chain (represented by 'R' groups) can affect the penicillin's activity, absorption, and how tightly it binds to plasma proteins.

More hydrophobic groups on a penicillin generally lead to better activity against Gram-positive bacteria and worse activity against Gram-negative bacteria.

Penicillin targets the bacterial enzyme responsible for building the cell wall.

A short chain of amino acids essential for the formation of the bacterial cell wall.

Penicillin structurally resembles D-Ala-D-Ala, allowing it to bind to the bacterial enzyme and block its function.

The enzyme responsible for linking D-Ala-D-Ala chains in bacteria to form the cell wall.

Penicillin's binding to the transpeptidase enzyme prevents the formation of new cell wall, leading to bacterial death.

Protein channels in the outer membrane of Gram -ve bacteria that allow some molecules to pass through.

The outer membrane of Gram -ve bacteria is made of lipopolysaccharide, a complex molecule making it difficult for penicillin to reach its target.

Bacteria may produce very high levels of the transpeptidase enzyme, which can overcome the inhibitory effect of penicillin.

Bacteria's ability to survive the presence of penicillin due to factors like outer membrane barrier or enzyme activity.

Penicillin blocks the active site of the transpeptidase enzyme, preventing D-Ala-D-Ala molecules from binding, like an umbrella covering the entrance.

A molecule that is naturally involved in bacterial cell wall synthesis, chemically similar to penicillin.

A slightly modified penicillin, 6-methylpenicillin, is inactive despite being structurally similar to penicillin.

The combined effect of two drugs is greater than the sum of their individual effects.

A type of penicillin that is not broken down by β-lactamase.

Penicillin formulations designed for slow release, providing prolonged drug levels.

A substance that can act as both an acid and a base.

A measure of the acidity of a compound.

Penicillins are grouped based on their source, chemical properties, activity, and clinical use.

A penicillin derivative active against ampicillin-sensitive Gram-negative bacteria, including Pseudomonas, Klebsiella, and Enterobacter.

Inactive drug forms that need to be metabolized into their active form within the body.

A prodrug of ampicillin with an extended ester group, designed for oral administration.

A prodrug of ampicillin that undergoes enzymatic hydrolysis to release the active drug.

A prodrug of ampicillin with an extended ester group that increases its bioavailability.

Enzymes that catalyze the hydrolysis of esters, breaking them down into active drugs.

Penicillin derivatives with a carboxyl group at the alpha position, enhancing activity against Gram-negative bacteria.

A prodrug of carbenicillin, which is a carboxypenicillin with a phenyl group.

Prodrugs like pivampicillin and talampicillin can penetrate bacterial cell membranes better than ampicillin, enhancing their effectiveness.

The process by which prodrugs are converted into their active forms through enzymatic or chemical reactions.