Exam 3 First Set of Lecture Slides Flashcards
Why are small molecules needed?
Proteins naturally do not get into cells (but are starting to level off at around 32%)
What are some challenges to the pharmacy field?
- Move towards automation and mail order reduces need for retail positions
- More diseases and dosage forms increases the background knowledge needed
What is drug product performance?
The ability of the drug to elicit a therapeutic response and to stay in a safe therapeutic range during dosing regimens
What is the importance of drug product performance?
- If there is too little of a drug = not efficacious
- If too much of a drug = toxic effects
Drug product performance is…
a function of the drug, the formulation, and the body
What is the main goal of formulations?
Transfer new, promising therapeutic compound and develop a reproducible dosage form
The dosage form will go through different stages of what?
Formulation scale (from small batches on a bench to large batches in facilities)
What does reproducible mean?
Each dosage form contains the same amount of drug and has the same performance in the body
What has to be balanced?
The release of the dosage form and the way the body processes the medicine
What are some components of a typical blood level versus time curve?
Cmax: highest concentration of the drug in the blood
Tmax: the time it takes to get to Cmax
AUC: area under the curve
What can we not control?
disposition phase
What occurs during disposition?
distribution, metabolism, excretion
What primarily controls the removal of the drug from the body during the elimination phase?
metabolism and excretion
Where do we normally measure the blood/plasma levels?
in the arm
What is enterohepatic recycling?
Drugs that get secreted in the liver can get reabsorbed
What can we and cannot control?
We can control the dosage form but not what the body does to the drug
What is the absorption rate (kabs) defined by?
- the drug properties
- the excipient/drug composition of the formulation
- the physiological barriers between the GI tract and systemic circulation
When does absorption begin declining?
As disposition begins to increase
What are we trying to achieve with the dosage form design?
The margin of safety (don’t want to cause unwanted effects)
What is druggability?
the binding as well as the drug like properties that are favorable for product translation such as solubility
What is the difference between druggability and developability?
- discovery stage
- assesses the ability of NCEs to bind to the drug target
- in vivo models are used to assess
What is the difference between developability and druggability?
- refers drug product performance
- incorporates factors like biorelevant solubility and dissolution
- formulation factors related to ADME/T incorporated
What does the druggable genome refer to?
Genes that encode disease related proteins that can be modulated by drug like molecules → compare the genome of a healthy individual to a person that might have a disease
What is a druggable protein?
proteins that can bind drug like compounds with binding affinity below 10 mM (have to modulate the protein)
What is the process of druggability?
druggable genes are identified by pharmacogenomic methods → genes that encode disease related proteins and are modulated by drug like molecules are identified → druggable genes are converted to proteins with in silico methods so that binding cavities can be identified
What is a pharmaceutically tractable genome?
Genes that encode proteins which can be targeted by small molecular weight compounds, antibodies, and recombinant therapeutic proteins for pharmaceutical use
What is the goal when finding a drug candidate to a gene and the protein associated with the disease?
Want something to bind to the pocket and also mitigate the disease
What does druggability not infer?
That a compound will elicit a therapeutic response in a patient
What are the main indices of safe and efficacious use?
pharmacokinetics (what the body does to the drug) and pharmacodynamics (drug effect on the body)
What goes into consideration for the drug itself?
physicochemical properties and pharmacological efficacy
What goes into consideration when selecting a vehicle?
Properties are selected based on the ability to overcome physiological barriers and enable therapeutically relevant drug delivery from the site of administration
What is the trinity of formulation design?
- physicochemical properties of the drug
- physicochemical properties and composition of the formulation
- biological factors that influence performance (ADMET)
What are the 3 factors that govern drug performance in the clinic (need to be balanced)?
- physicochemical properties of the API
- physicochemical properties and composition of the formulation
- physiological barriers that influence the “targeted bioavailability” of the drug
What are some physicochemical properties of the drug that can affect absorption?
- solubility
- drug stability in solution (aka esters so if break down too fast = bad)
- lipophilicity (need some to get across the cell)
- molecular size and shape (big, long and extended = bad)
- pKa of ionizable groups (ionized has harder time)
- physical state of the drug
4.
What are the subsections of the physical state of the drug which is a physicochemical property that can affect a drug’s absorption?
- amorphous vs crystalline
- polymorphism
- hydrates/solvates
- liquid/gaseous
What are the 4 things that solubility depends on?
- molecular structure
- physical state
- composition of solvent
- measurement methods
What are the 2 physical states that solubility can depend on?
solid: amorphous (cotton candy is amorphous with sugar), crystalline, polymorphic form
liquid: predissolved in a solvent
What goes into consideration of the solvent composition?
- types of solvents
- co-solvent percentages
- solution components like salts and ions
- pH, temperature
What are the 2 measurement methods of solubility?
equilibration time and detection method
What is the partition coefficient?
The ratio of concentrations in 2 immiscible solvents (octanol and water) given as K = Coctanol/Cwater
What is the pH-partition hypothesis?
For drugs that are absorbed passively (transcellular mechanism), the permeability transport depends on the fraction of unionized drug at the intestinal pH.
What is the relationship between solubility and the partition coefficient?
As the partition coefficient (Ko/w) increases, the solubility decreases.
As we move down the stomach and the small intestine where the pH is different, how do the absorption of different molecules change?
The absorption of weak acids in the beginning of the duodenum and as we travel to the ileum, weak bases are absorbed
What is the difference in solubility of octanol and water?
The solubility of water in octanol is 4% but the solubility of octanol in water is 0.4%