Biopharmaceutics, Generics, Compounding Flashcards

1
Q

What is the biopharmaceutical definition of what we commonly call a drug?

A

complex mixture of ingredients making a “finished drug product”

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2
Q

What are the different components that a finished drug product is comprised of?

A
  • Active pharmaceutical ingredient (API): aka “drug substance”; thing that actually causes the pharmacodynamic response
  • everything else (“excipients”)
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3
Q

What are the main different routes of biopharmaceutics?

A
  1. oral
  2. parenteral (IM/SQ/IV)
  3. topical vs transdermal
  4. intra-mammary (IMM)
  5. Intranasal (IN)
  6. rectal
  7. Buccal
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4
Q

What is the dosage form of oral meds & what are some things to consider?

A
  • solid (pills/tablets vs capsules), semi-solid (paste/suspension), oral soln, feed premix (powder/granular)
  • when & where is API released? how much API gets absorbed? what happens when it is absorbed? expiry dates?
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5
Q

What is the dosage form of parenteral meds & what are some things to consider?

A
  • usually soln (water-soluble), sometimes non-aqueous
  • sterility? how do you “inject” it? will it be irritating?
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6
Q

What is the dosage form of topical/transdermal meds & what are some things to consider?

A
  • cream, liquid, gels, patches
  • intended for local effect only, or is systemic absorption desired? how long does it stay there?
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7
Q

What is the dosage form of intramammary meds & what are some things to consider?

A
  • suspension
  • stay in teat/udder or systemic absorption? milk residues?
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8
Q

What is the dosage form of intranasal meds & what are some things to consider?

A
  • liquid, aerosolize/nebulize (convert liquid to fine particles)
  • how to ensure it gets inhaled? where does it go in respiratory tract?
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9
Q

What is the dosage form of rectal meds & what are some things to consider?

A
  • suppository
  • not common in vet med
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10
Q

What is the dosage form of buccal meds & what are some things to consider?

A
  • fast-dissolving tablet or paste
  • absorbed through cheek epithelium, avoids 1st pass (hepatic) metabolism, but make sure it isn’t swallowed! (in theory this increases bioavailability)
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11
Q

what is point of these “excipients”? why not just administer the active pharmaceutical?

A
  • just dosing the API wont maximize its efficacy or safety
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12
Q

What are some examples of how dosing just the API wont maximize its efficacy or safety?

A
  • how much reaches systemic circulation? where & when does the API get absorbed, & for how long?
  • stability of API (how long does it last in dose form)
  • oral: API’s taste awful (bitter) or irritate GI mucosa
  • parenteral: API is insoluble, or too rapidly absorbed
  • topical: API may not stay on skin
  • transdermal: API may not penetrate skin
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13
Q

What excipients do we add to oral pharmaceuticals & why?

A
  • binding agent -> delays DISAGGREGATION (breaks down tablet) & DISSOLUTION (solubilizes API); both are necessary to permeate intestinal cell
  • coating or capsule -> protect API from acid in stomach; decrease irritation in proximal GI tract; delay timing of absorption
  • flavouring agent - increase palatability
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14
Q

What excipients do we add to parenteral injection pharmaceuticals & why?

A
  • pH adjuster: make inj less irritating; increases solubility of API (smaller inj vol); enhances stability of API in soln
  • salt or chelating agent: alters API solubility; determines how long before API is released; vasoconstriction (impact on absorption?)
  • preservative : maintain sterility
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15
Q

3 big points in terms of formulating biopharmaceutics:

A
  1. formulation matters
  2. different forms of same API can have BIG difference
  3. messing w/ formulation changes drug product
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16
Q

What is a pioneer drug product?

A

innovators (original release)

17
Q

What is a generic drug product?

A

copies of pioneer drugs

18
Q

What is a compounded drug product?

A

when pharmacy makes up drug product but it’s not an approved formulation of drug

19
Q

what is point of generic drugs?

A
  • allows for more drug product availability
  • more competition = decreased prices
  • only once pioneer drug has expired
20
Q

How come pioneer drugs are more expensive?

A
  • v high cost for initial drug approval (have to perform all initial research & development (chemistry, clinical efficacy, & safety studies)
  • patent allows for “exclusive marketing”
  • when patent runs out - price typically drops
21
Q

How come generic drugs are cheaper?

A
  • “proven” safety & efficacy of pioneer drug
  • are not required to reproduce efficacy & safety studies that pioneer did
22
Q

What does generic drug need to be approved?

A

manufacturing & chemistry (Drug product quality):
- same requirements as pioneer drug
> potency (right strength or concentration)
> purity (API is legit, no excess impurities)
> stability, sterility, etc.

clinical efficacy & safety:
- generic drug must be same STRENGTH & DOSAGE FORM as demonstrate BIOEQUIVALENCE w/ pioneer product (it is assumed that equal plasma concentrations result in equal clinical efficacy & safety)
- if same strength, dosage form, & bioequivalent, generic & pioneer product are considered clinically interchangeable

23
Q

What is bioequivalence (BE)?

A

when RATE & EXTENT of absorption of 2 PHARMACEUTICALLY EQUIVALENT formulations of drugs (pioneer & generic) are sufficiently similar, w/in ALLOWABLE LIMITS, when administered under similar experimental conditions

24
Q

What does pharmaceutically equivalent mean?

A
  • 2 drugs that contain IDENTICAL AMTS (strength or concentration) of IDENTICAL MEDICINAL INGREDIENTS, in COMPARABLE DOSAGE FORMS (ex: if pioneer drug is a tablet, generic version cannot be a suspension or solution
  • does not necessarily contain same NON-MEDICINAL INGREDIENTS - provided they don’t influence absorption characteristics of active ingredient
25
Q

How do you prove bioequivalence?

A

Blood-lvl study
- 2 grps, 2 treatments (compare generic & pioneer products)
- each animal gets both products w/ washout period in btwn (10x half-life to avoid drug carry-over into next period)
-dosing same animal 2x reduces inter-individual variability
- collect multiple blood samples over time (early time: enough to capture absorption/Cmax & later time: @ least 3x half-life beyond Tmax)
- determine plasma concentrations (REQUIRES VALIIDATED ANALYTICAL METHOD)
- concentration-time profiles & PK modelling to estimate:
>extent of internal exposure: AUC
>peak exposure: Cmax
>rate of exposure: Tmax

26
Q

How do you interpret the results of blood-lvl study?

A

have lower & upper confidence intervals; if arm of lower is below 0.80, efficacy issue; if arm of upper is above 1.25, safety issue

27
Q

What is compounding?

A

combining or mixing multiple ingredients (@ least 1 of which is a drug) to create a final product in an appropriate dosing form

28
Q

why use compounded drugs?

A
  1. available formulations arent appropriate for specific patient (diluted formulations for v sm animals)
  2. improve client compliance (more palatable oral product; non-oral formulation)
  3. no approved drug product commercially available (requires bulk ingredient - “grey” zone; ex: cisapride)
    COST IS NOT A VALID REASON
29
Q

FDA rules on compounded drugs?

A
  • used to treat an UNMET therapeutic need or reduce animal suffering
  • dont cause harm to treated animal
  • dont result in therapeutic failures
  • dont result in violative drug residues (food animals)
    PRICE IS NOT VALID REASON
30
Q

Best to worst drug use order

A

approved (DIN) vet drug (on label) -> approved (DIN) vet drug (extra label) -> approved (DIN) human drug (ELDU) -> compounded drug: from approved (DIN) vet drug (ELDU) -> compounded drug: from approved (DIN) human drug (ELDU) -> compounded drug: from active pharmaceutical ingredients (ELDU)

31
Q

What are some concerns associated w/ compounding?

A
  1. PURITY of compounded drug
    - quality of drug
    - drug that is present (is supposed to be there)
    - no other drugs there (if not supposed to be there)
  2. POTENCY of compounded drug
    - “quantity” of drug
    - ACCURACY w/ label quantity
    - manufactured drugs: concentration must be w/in +/- 10%
  3. stability of compounded form
    - hydrolysis (if it comes dry - keep it dry)
    - oxidation (light or oxygen exposure; pink or amber colour change)
    - consistency (precipitates (organic vs aqueous solution); settling out)
    - expiry (beyond use) date (25% of time left on original expiry date; water-based cmpds - 14 days, oil bases cmpds - 180 days, NOT APPROPRIATE & NOT FOR LONG)
  4. pharmacokinetic changes due to formulation
    - absorption (oral, transdermal)
    - bioavailability
32
Q

ex of potency compounding mistakes

A
  1. testing meloxicam (12/19 did not meet label claim)
  2. Biodyl injectable supplement (incorrect [selenium] -> 100x potency -> 21 dead Eq)
33
Q

Ex of stability compounding mistake?

A

patients received epidural injs w/ preservative free methylprednisolone acetate leading to fungal meningitis

34
Q

ex of pharmacokinetic changes in product due to changes in formulation?

A
  • just b/c pharmacy can make gel or patch w/ API in it, does not mean that it will be absorbed
  • some APIs will not permeate skin
  • results can vary BTWN or even W/IN patients
  • products not uniform btwn pharmacies or batch-to-batch w/in pharmacy
  • explain transdermal products w/ client (HOW WILL YOU ASSESS EFFICACY?)
35
Q

What to tell your clients about compounded drugs?

A

DO: - explain why you are prescribing cmpd’d drug (for this SPECIFIC patient, different strength or route or administration is necessary (compared w/ approved drug) or no approved drug is available)
- have method of assessing efficacy of compounded drug
- get INFORMED CONSENT from client & DOCUMENT IN MEDICAL RECORD
DO NOT: - call it a “generic version” or “same thing”
- use it strictly b/c it is cheaper

36
Q
A