Exam 1 Devilliers

How does Aqueous Solubility affect the bioavailability of drugs

If the drug can be given as a salt the solubility will be increased leading to improved dissolution

How does dissolution rate affect the bioavailability of drugs

Faster dissolution rate = more bioavailable

How does partition coefficient affect the bioavailability of drugs

Drugs with high partition-coefficient value can easily permeate through biological membrane. (hydrophobic)

How does permeability affect the bioavailability of drugs

low permeability means low bioavailability

How does ionization constant affect the bioavailability of drugs

Ionized drugs are not absorbed as efficiently as un-ionized drugs are.

How does polymorphism affect the bioavailability of drugs

Different polymorphs may have different solubilities which affects bioavailability.

Shelf life: more soluble (less stable) forms may transform into the less soluble form

How does crystallinity affect the bioavailability of drugs

crystalline solids usually less soluble, and therefore less bioavailable than their amorphous counterparts.

How does particle size affect the bioavailability of drugs

Smaller particle size means more surface area means more dissolution meaning more bioavailable

How does particle morphology affect the bioavailability of drugs

Irregular particle shapes have more surface area therefore are more bioavailable

How does surface area affect the bioavailability of drugs

Higher surface area means higher dissolution rate meaning more bioavailable

How does hygroscopicity affect the bioavailability of drugs

(the tendency of a solid substance to absorb moisture from the surrounding atmosphere)

The high hygroscopicity causes issues such as alterations to their physicochemical properties, which in turn cause difficulties in subsequent downstream formulation processes, instability during their shelf life, and, eventually, adverse effects on their bioavailability

higher hygroscopicity = less bioavailable

why the oral route is the most popular route for drug administration?

Most convenient

Most cost effective

Great flexibility in dosage regimen

different parts of the GI tract?  

Buccal, Esophagus, Stomach, Duodenum, Small Intestine, Large intestine,

 barriers to oral drug delivery?

—> Drug needs to remain in solution & not precipitate

—> Resist pH of GI tract

—> Resist enzymatic degradation

—>Diffuse across mucous layer without binding to it

—>Must survive liver enzymes before systemic circulation

the difference between buccal and sublingual drug delivery?  

Buccal is cheek, sublingual is under tongue

Buccal tablets are often harder designed to dissolve slowly

Buccal delivery advantages

—> Avoid first pass metabolism and GI elimination

—>Seems to work for patients

—> You can control the permeability

—> Alternative for orally inefficient drugs and noninvasive delivery of protein drugs

Buccal delivery disadvantages

—> Holding dose in mouth is inconvenient

—> if any is swallowed it’ll be treated as an oral dose and subject o first pass metabolism

—> Only accommodates small doses

the advantages and disadvantages of compressed tablets as an oral drug delivery system?

Accuracy in dosing

Blandness of taste

sugar coating

Enteric coating

film coating

Variable release rates

Chewable

Elegant

Efficient-Versatile-Practical

What is the difference between compressed and molded tablets and why are compressed tablets preferred over molded tablets?

What is the purpose of tablet coating?

—> Enhance permeability

—> Mask unpleasant taste

—> Increase stability

—>Increase mechanical integrity

—> Enhance appearance & elegance

—> Protect patient from stains

—>Modify drug release profile

—>Avoid side effects

—>Identity product

—>Avoid incompatibility of active drug substances by physical separation into the core and coat

CT

Compressed tablet

SCT

sugar coated tablet

FCT

film coated tablet

ECT

enteric coated tablet

MCT

multiple compressed tablet

layered

DT

dispensing tablet

(for compounding I think)

What are the two commonest tablet coatings and how are they different? (sugar and film)

What is an enteric tablet coating and why is some tablets coated by enteric coating?

Prevents release during exposure to the stomach to protect the drug or the stomach

Coat with pH sensitive polymers that do not dissolve under acidic conditions

Which properties of drugs can change the passive diffusion of drugs across intestinal membranes?

Size, pka