T2 - Biopharmaceutics E2 Flashcards
What is pharmaceutics?
The science of preparation of drugs, dosage forms and drug delivery systems taking an account of the physicochemical properties, pharmacokinetics and pharmacodynamics of the drug
What is biopharmaceutics?
The interrelationship between the physicochemical properties, the dosage form, and the route by which a drug is administered, on the rate and extent of drug release from the dosage form and its subsequent absorption in the body
What is pharmacokinetics?
The mathematical and descriptive expressions of how the body handles the drug after its administration, through absorption, distribution, metabolism, and excretion
What is absorption?
Mass transfer process that involves the movement of unchanged drug molecules from the site of absorption to bloodstream
What is distribution?
The reversible mass transfer of drug molecules from the systemic circulation to other parts of the body
What is metabolism/biotransformation?
Represents drug elimination through enzyme-catalyzed chemical reactions, removal of a drug chemically
What is excretion?
The physical removal of the drug from the body into bile, urine, feces, sweat, and air
How is a drug released in a solution?
Drug molecules are administered in a dosage forms, but must be in its free form
Do all drugs undergo ADME?
No, depends on the route the products are administered
What are the main routes of administration?
- Enteral
- Parenteral
- Topical
What is enteral?
Through the GI tract
What are examples of enteral routes?
- Oral
- Buccal
- Rectal
What are the advantages of oral routes?
- Convenient: portable, safe, no pain, easy to take
- Cheap: no need to sterilize, compact, multi-dose bottles
- Availability of variety of dosage forms
What are the disadvantages of oral routes?
- Inefficient: high dose, low solubility
- First pass effect
- Effect of food and GI motility
- Local effect
- Patient needs to be conscious to swallow
What is the first pass effect?
- Drug is absorbed orally are transported to the blood to the live
- Drugs which are extensively metabolized will be metabolized in the liver during absorption
How can oral route drugs affect food and GI motility?
- Effects drug absorption
- Absorption of some drugs is slower with food, some have higher bioavailability after food
What is local effect?
Antibiotics may kill normal gut flora and allow overgrowth of fungal varieties
What is a buccal and sublingual drugs?
Drugs that are held in the mouth under the tongue
What is the difference between buccal and sublingual drugs?
- Buccal: harder tablets designed to dissolve slowly (4hrs)
- SL: softer tablets (2 min disintegration)
What are the advantages of buccal and sublingual routes?
- First-pass metabolism is bypassed
- Bioavailability is higher
- Rapid absorption due to good blood supply to the area of absorption, especially if drug is lipid soluble
- pH in mouth is relatively neutral so drug is more stable
What are the disadvantages of buccal and sublingual routes?
- Holding the dose in the mouth is inconvenient
- If any part of the dose is swallowed that portion is subject to first pass metabolism
- More suitable for drugs with small doses
- Drug taste may need to be masked
What are rectal route drugs?
Drugs given in the rectum usually suppositories or enemas
What are advantages of rectal route drugs?
- Reduced first pass effect bypasses the metabolism in the liver
- Useful for patients unable to take drugs orally or with younger children
What are the disadvantages of rectal route drugs?
- Erratic absorption
- Not well accepted
What are erratic absorption?
Absorption for suppositories is often incomplete and erratic
Enemas may be more reliable
What is parenteral?
Not through the alimentary canal and commonly refers to injections
What are example routes of parenteral?
- IV
- IM
- SC
- ID
What are the types of intravenous routes?
- Rapid (IV bolus) iv injection
- Slow longer iv infusion
What are the advantages of IV routes?
- Rapid onset
- Plasma concentration can be precisely controlled using IV infusion administration
- Total dose is delivered: 100% bioavailability
- Larger doses or poorly soluble drugs may be given by IV infusion in a larger volume over an extended time period
What are the disadvantages of IV routes?
- May cause tissue damage at the site of injection
- Maybe toxic: due to rapid response
- Requires trained personnel
- Expensive
Why is IV drugs expensive?
- Sterilization
- Pyrogen testing
- Larger volume of solvent means greater cost for prep
- Transport
- Storage
What are the advantages of intramuscular routes?
- Larger volumes than SC
- Easier to administer than IV
- A depot or sustained release effect is possible with IM injections such as procain and penicillin
What are the disadvantages of IM?
- Trained personnel required to administer
- Absorption can be rapid from aqueous solution
- Absorption is sometimes erratic for poorly soluble drugs
- Irritating drug may be painful
What is subcutaneous routes?
- Injecting the interstitial tissue beneath the dermis
- Upper arm, thigh, lower abdomen or upper part of the back
How does SC differ from IM?
- Blood supply is less than muscular
- Absorption is slower
How does SC differ from oral routes?
More rapid
What is intradermal routes?
- Injection into the dermis
- Mainly for diagnostic agents, vaccines, or desensitization
- A little faster than SC
What is topical?
Applying a drug mainly at the site of desired action intended for local actions
What are examples of topical routes?
- Dermatologic
- Inhalation
- Ophthalmics
- Otic
- Transdermal patches
What topical drugs are used for local action?
- Ear drops
- Eye drops or ointments
- Antiseptic creams or ointments
- Sunscreen
What topical drugs are used for systemic actions?
- Transdermal
- Inhalation
What are the functions of transdermal drugs?
- Slow absorption
- Cuts through abrasions or thin skin sites and absorption can be relatively fast
- Transdermal patches that can provide prolonged or controlled drug delivery (nicotine patches)
What is an inhalation drug that has a local effect?
Bronchodilators
What is an inhalation drug that has a systemic effect?
General anesthesia
What is the function of inhalation drugs?
- Used for local effect
- Used for systemic effect
- Rapid absorption bypassing the liver
- Some doses are swallowed and undergo first-pass metabolism
