Delivery of CNS drugs Flashcards
(37 cards)
What is Lipinski’s Rule of 5?
A set of criteria to evaluate druglikeness based on molecular properties:
* Hydrogen bond donors ≤ 5
* Hydrogen bond acceptors ≤ 10
* Log P ≤ 5
* Molecular weight ≤ 500 Daltons (≤ 300 Da for hydrophilic molecules, ≤ 1kDa for lipophilic molecules)
* Must be unionised.
Lipinski’s Rule helps predict the absorption and permeation of drugs.
What is the maximum volume for intranasal delivery?
Max 200 uL.
This volume is crucial for effective drug absorption in the nasal cavity.
What is the pH range for intranasal delivery?
pH 4 – 7.4.
This range helps ensure drug stability and absorption.
What does the term ‘tonicity’ refer to in intranasal delivery?
Tonicity range is 300 – 700 mOsmol.
Proper tonicity is important to prevent irritation of the nasal mucosa.
What device feature is crucial for intranasal drug delivery?
A nozzle that bypasses the nasal vestibule (hair).
This helps in delivering the drug more effectively to the nasal cavity.
What is Spray Content Uniformity (SCU)?
The amount of drug delivered per pump.
SCU is important for ensuring consistent dosing.
Name one thermoreversible gel excipient used in drug formulation.
Pluronic F127.
It can be combined with other materials like Chitosan or HPMC.
Other thermoreversible gels are Poloxamer 407 and 188
What is the main way for drugs to cross the skin in transdermal delivery?
Via intercellular lipidic domains.
This pathway is critical for effective transdermal absorption.
What is a common antioxidant used in drug formulations?
DL-alpha-tocopherol. (a synthetic form of Vit E)
It is often used to stabilize formulations.
What is the maximum molecular weight for a drug to be considered suitable for intranasal delivery?
≤ 450 Da.
Less than the 500 Da for gut abdorption. This ensures better absorption rates in the CNS.
Fill in the blank: The maximum Log P for a drug according to Lipinski’s Rule is _______.
≤ 5.
A higher Log P indicates increased lipophilicity.
What type of polymer is used in transdermal delivery systems?
Co-polymer membrane - Ethylene-vinyl acetate copolymer.
This material helps control drug release rates.
Name a key consideration for the delivery device in intranasal drug delivery.
Reproducibility of pump spray weight.
Consistent delivery is essential for therapeutic effectiveness.
What is the function of sodium acetate, citrate, and phosphates in injections?
Buffer
These components help maintain pH stability in the formulation.
What is the typical concentration of benzyl alcohol used as a preservative?
1-2% w/v
Benzyl alcohol is commonly used to prevent microbial growth.
What is the function of chlorbutanol in injections?
Preservative
Chlorbutanol helps to extend the shelf life of the product.
What concentration range is typical for methylparaben as a preservative?
0.1 – 0.18
Methylparaben is part of a group of preservatives known as parabens.
What is the primary function of propylparaben?
Preservative
Propylparaben is used to prevent the growth of mold and bacteria.
What concentration of phenol is typically used as a preservative?
0.2 – 0.5
Phenol is effective against bacteria and fungi.
What is the function of thiomersal in injections?
Preservative
Thiomersal is used to prevent bacterial contamination.
What is mannitol classified as in injections?
Tonicity adjusting agent / cryoprotectant
Mannitol helps to stabilize the formulation during freeze-drying.
What is the typical concentration of sodium chloride used as a tonicity adjusting agent?
0.9% w/v
Sodium chloride helps to match the osmolarity of body fluids.
What is the function of ethanol in injections?
Solvent
Ethanol is used to dissolve other ingredients in the formulation.
What are glycerin/glycerol used for in injections?
Solvent/tonicity adjustment
Glycerin can also provide moisture to the formulation.
