Class quiz Flashcards
Why is protein aggregation a major concern in pharmaceutical formulations, and what conditions can lead to it?
Concern
- can reduce drug
- loss of biological activity
- trigger immune response
Causes
- high temp
- pH =~ pI
- mechanical agitation (shaking)
- surface adsorption
- oxidative stress
Difference between topical vs transdermal delivery
Topical
- nose, mouth, eye
- treats area of application only
Transdermal
- skin (patches)
- drug is absorbed into the bloodstream
Major barrier in transdermal delivery
Stratum corneum
Polymorphs have the same _____ but different _____
Chemical compound
Solubility, melting point, stability, bioavaiability
What is the difference between amorphous and crystalline drug forms, and how does this affect drug dissolution?
Crystalline
- organized, repeating 3D lattice structure
- more stable, lower energy
- slower dissolution rate
Amorphous
- random arrangement
- less stable, higher energy
- faster dissolution (better bioavailability)
Purpose of using cryoprotectants in lyophilized drug formulations
Prevent damage to proteins or drug structure
Help maintain physical stability and biological activity of the drug
Reduce aggregation or denaturation
Eg. glycerol, sorbitol
What are disulfide bonds? How are they important?
Covalent bonds formed between two sulfur atoms on cystine amino acids within a protein
- Help maintain functional 3D conformation
- Prevent denaturation and folding
Why are inhalers designed to optimize the aerodynamic diameter of drug particles?
To ensure particles reach the deep lungs; 1–5 µm is ideal for effective deposition
- 5 µm = stuck in throat; <1 µm = exhaled
What is the main mechanism of action of Paclitaxel (Taxol) in cancer treatment?
Paclitaxel binds tubulin, stabilizes microtubules, blocks mitosis, and triggers apoptosis in cancer cells.
What is the role of glidants in tablet formulation?
Glidants improve powder flow by reducing interparticle friction, ensuring smooth tablet manufacturing.
What is bioavailability and what factors affect it?
Bioavailability is the fraction of drug that reaches systemic circulation. Affected by first-pass effect, solubility, route, formulation, and patient factors.
Why is lyophilization (freeze-drying) often used for protein-based drugs?
Lyophilization removes water to improve stability, shelf-life, and prevent degradation of protein-based drugs.
What is the main advantage of using transdermal patches for drug delivery?
Transdermal patches provide controlled drug release and bypass first-pass metabolism for better bioavailability.
What is the role of ionizable lipids in LNP formulations for mRNA delivery?
Ionizable lipids stabilize and protect mRNA, assist in encapsulation, and support cellular uptake and release into the cytoplasm.
How does pH-dependent solubility affect drug absorption in the GI tract?
Drugs dissolve differently at varying GI pH levels. Weak acids absorb better in stomach, weak bases in intestine. Solubility influences bioavailability and site of absorption.
What is the function of disintegrants in oral tablets? Give examples.
Disintegrants help break tablets apart for better dissolution and absorption.
Ex. Explotab
What is the purpose of enteric coatings on oral dosage forms?
To prevent drug release in the stomach and ensure release in the intestine, protecting the drug and reducing gastric irritation.
Where does the first-pass effect primarily take place?
In the intestines and liver, where drugs are metabolized before reaching systemic circulation.
What are two common mechanisms of protein degradation in formulations?
Deamidation (loss of amide groups) and oxidation (affecting methionine/cysteine) can reduce protein stability and activity.
What is the purpose of surfactants like Polysorbate 80 in protein drug formulations?
To reduce surface tension, prevent aggregation, and stabilize proteins by minimizing surface adsorption.
What are the key components in a polymer-drug conjugate system?
Backbone: biocompatible carrier
Linker: cleaves at target site
Drug: active only after release
(+ targeting moiety if needed)
What are linkers in drug delivery systems, and give two examples of release mechanisms.
Linkers cleave at target site to release drug.
Examples:
- pH-sensitive (e.g., hydrazones)
- Redox-sensitive (e.g., disulfide bonds)
What are liposomes, and how do they improve drug delivery?
Liposomes are lipid vesicles that protect drugs, improve solubility, and allow controlled/targeted release, reducing side effects.
