Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIOT3002 > part 1 > Flashcards

part 1 Flashcards

1
Q

drug administration methods: speed of onset

A

I/V: 30-60 seconds (FASTEST)
Inhalation: 2-3 mins
Sublingual: 3-5 mins
I/M: 10-20 mins
S/C (subcutaneous): 15-30 mins
Rectal: 5-30 mins
Oral 30-90 mins (SLOWEST)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Duration of action

A
  • Dependant upon whether effects are local or systemic (ADME)
  • Half-life of drug, 1st pass effect - enzymatic susceptibility
  • Type of formulation administered (e.g. uncoated tab v CR tab)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Patient factors

A
  • Is patient conscious?
  • Fear (or phobia) of a particular route
  • Age of patient?
  • Any surgery?

e.g. Age, disease

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

oral drug requirements

A

Oral Drug MUST be in solution before it can be absorbed and exert its biological effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Enteric coating

A
  • To prevent disintegration in stomach at low pH
  • In drugs that irritate the mucosal lining
  • In drugs that break down under acidic conditions

Delays release of drug until it reaches s. intestine

Delays onset of action thus therapeutic response

Protects drug from degradation: - improves oral bioavailability compared to conventional uncoated
tablets.

Protects mucosal lining of stomach from effects of drug (aspirin) – ulceration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

E.C. Formulations

A

Granules contained within a rapidly dissolving hard gelatin capsule or rapidly disintegrating tablet.
Enable to pass through pyloric sphincter even when closed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

ELIMINATES

A

E.C granules/ pellets exhibit a gradual but continual release of drug from stomach to duodenum

Avoids complete dose release of drug as seen with E.C tablets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Bioavailability

A

Aqueous solution > aqueous suspensions > hard gelatin capsules > uncoated tablet > coated tablet

Tablets go through high compression force -> slower in dispersing the drug particles from the tablet after administration (excipients and drugs are compressed together)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Buccal & Sublingual

A

buccal: a medicine given between the gums and the inner lining of the mouth cheek
sublingual: under the tongue

Very rapid effect

100 % bioavailability – No 1st pass effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Capsules

A

Soft gelatin- drug is dispersed or dissolved in non-toxic, non aqueous vehicle

Drug released is dependent on dissolution of flexible shell -> vehicle disperses, drug is dissolved in GI
fluids -> releasing drug -> rapid absorption (depending on the solubility of drug, solution: faster,
suspension: slower)

Factors affecting bioavailability:
- Solubility of drug in vesicle
- P.S of drug
- Nature of vesicle (hydrophilic or lipophilic)
Digestible/non-digestible oil
Digestible oil (lipophilic drug): can be absorbed via fat absorption process
Non digestible oil/less lipophilic drug: bioavailabilty depends on drug partitioning out of oil
phase

Hard gelatin- Provided shell dissolves rapidly in GI fluid, drug is released rapidly and efficiently

Bioavailability dependent upon rapid dissolution of gelatin shell AND Rate of penetration of GI fluids
into encapsulated mass

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Dissolution of HGC

A

table …

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Excipients

A

To aid in preparation (Binders- Bind the tablet ingredients together)

Patient acceptability (mask taste eg. Sweeteners)

Aid functioning of dosage form as a delivery system (Disintegrants -> so drugs can disintegrate in the
body)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

oral administration summary

A

Aqueous solution: solution of drugs in GI fluids -> absorption from GIT to blood -> first pass into
the liver -> systemic circulation

Aqueous suspension: suspension of fine particles of drug in GI fluids -> dissolution -> solution of
drug in GI fluids -> absorption from GIT to blood -> first pass into the liver -> systemic circulation

Hard gelatin capsule and uncoated tablet: disintegration -> granules -> deaggregation -> suspension of fine particles of drug in GI fluids -> dissolution -> solution of drug in GI fluids -> absorption from GIT to blood -> first pass into the liver -> systemic circulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Eye – drops, suspn, gels, oint

A

LOCAL EFFECT ONLY

Dosage forms must be: STERILE (free of foreign particles, free of pathogens)

be Isotonic and pH neutral

ALL formulation is lost in 10-20 min (Improve duration of action using gels or ointments)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Parenteral products

A

Intradermal (diagnostic tests)

Subcutaneous S/C (e.g. insulin)

Intramuscular I/M (e.g. vaccines)

Intravenous I/V (e.g. infusions, drugs, EMERGENCIES)

Intra-arterial I/A (EMERGENCY)

FYI: parenteral = administered or occurring elsewhere in the body than the mouth and alimentary canal.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Why use the parenteral route?

A
  • To ENSURE adequate delivery
  • To TARGET delivery e.g. to organ or malignancy
  • Oral route unavailable…unconscious, elderly
  • Low or NO oral bioavailability
  • For Unstable drug (pH) in the stomach
  • To give a LOCAL effect (anaesthesia)
  • To give a rapid effect
  • To give sustained effect
  • To assure compliance – administered by trained personnel
  • In EMERGENCIES!!!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Potential issues with the parenteral route

A

DISADVANTAGES: - Dosage forms MUST be sterile
- Costs - drug prep & administration
- Effects (adverse) are almost immediate – no way back!

18
Q

Formulation of Parenteral Products

Factors to consider:

A

Factors to consider:
1) Route
2) Volume of injection
3) Vehicle
4) Osmotic pressure (isotonic: 0.9% w/v NaCl)
5) Use of preservative
6) pH – transfer across biol. membranes
7) Stability of components

19
Q

Role of vehicle

A
  • must mix with the circulating blood (miscible)
  • must NOT precipitate from solution
20
Q

Properties of vehicle

A
  • pharmacologically inert (must not interfere with drugs effect)
  • non-toxic (non-sensitizing, non-irritating)
  • maintain solubility of drug
  • chemically and physically stable (inert)
  • unaffected by pH changes
  • must be an aqueous solution (e.g. water for injection)
21
Q

Hypotonic and Hypertonic solutions

A

Injection of Hypertonic solution results in rapid EFFLUX (goes out) of H2O
- Cell shrinks and becomes crenate
- REVERSIBLE
- When osmotic pressure returns to normal - cell swells

Injection of Hypotonic solution results in rapid INFLUX of H2O
- Cell (r.b.c) swells and bursts
- IRREVERSIBLE
- Severity dependent on no. of cells affected

22
Q

Rectal route – suppository / gel

A

Useful where drug is inactivated by GI fluids (drug is ineffective when taken orally due to incompatibility with GI fluids) or by 1st pass effect

Useful if patient is: sedated, vomiting, can’t swallow or not safe to swallow

systemic effect: e.g. paracetamol supp., hydrocortisone supp.

local effect: e.g. laxative effect

23
Q

Skin

A

Topical/Local effects - Creams, ointments, pastes

Systemic effects - Transdermal patches

24
Q

Nasal – sprays, drops, inhalations

A

Sprays generally used for systemic effects (steroid nasal spray)

Drops generally for local effects (decongestants)

Must use preservatives

25
Q

Respiratory route

A

M.D.Inhalers/Turbohalers/Nebulisers

ONLY 10-20% reaches the lung – 80% in oropharynx, then swallowed!

Nebulisers
- Converts drug solution into a continuous fine aerosol mist

26
Q

Drug Repurposing:
Overview on drug discovery and development

A

Drug discovery: screening compound libraries, rational drug design

Lead optimization: in vitro testing (in vitro models, pharmacodynamics)

Pre clinical testing: ADME, EFFICACY, SAFETY, TOXICITY, GLP STUDIES

Manufacturing: Cgmp

Clinical trials: phase I, II, III

Regulatory approvals: TGA, FDA, EMA

Phase IV trials

27
Q

Drug Repurposing:
Challenges of drug development (NCE)

A

1) High risk of failure, but high rewards
2) Very costly- R&D cost ($2,558 million)
3) Highly regulated process (regulatory hurdles)
4) Long time to enter the market (15 years)
5) Rapidly changing of healthcare landscape
6) Very competitive

28
Q

Challenges leads to:

A

1) Fewer products approvals
2) Drying product pipelines
3) Fewer Partnerships, licencing, mergers and downsizing

29
Q

Patent cliff

A

The patent expires, emergence of generic market causes drop in sales. (generic competition)

30
Q

Drug repurposing (3)

A

Studying drugs that are:
1. Currently in clinical development
2. Discontinued compounds that failed regulatory approval due to lack of efficacy
3. Existing approved drugs

to see if they are safe and effective for treating other diseases.

31
Q

Two Major Approaches

A
  1. Known molecules new target/mechanism (‘Off Target’) (Compound targeting different receptor)
  2. Known target/mechanism new indication (‘On Target’) (Compound targeting the same receptor but having a new indication)
32
Q

Benefits

A

Lower development risk
- Because the safety and toxicity profile is established, …..

Lower commercial risk
- The success rate is lower for NCE and higher for repurposed drug
- Increase productivity: allow companies to recoup lost time/cost for clinical failed
candidate

Shorter time to the market
- It can enter the development path at an more advance stage -> estimated to accelerate development time frame by 15-20% -> increased productivity

Lower cost development
- Most of the pre clinical testing and some early clinical testing has been done -> may not need to repeat again -> cheaper -> more patient can have assessed to and be able to afford repurposed drugs

33
Q

Target diseases that isn’t favourable for a NCE

A

Rare diseases, acute diseases (infection), neglected diseases where people have no means to pay for treatments.

34
Q

Drug repurposing vs NCE

A

Generics: low risk, low return
NCE: high risk, high return
Repurposing: low risk, high return

35
Q

Barriers to Drug Repurposing

A

Intellectual Property issues:
- Licensing
- Prior art issues (any evidence that your invention is already known. If an invention has been described in the prior art, a patent on that invention is not valid)
- Relying on ‘use’ patents (With the generic drugs in the market, how do you make sure doctors will prescribe branded drugs?)

Other issues:
- Previous studies may not meet regulatory current requirements
- Having access to discontinued candidates and their data

36
Q

Issues for Repurposed Drugs

A
  • Market exclusivity and possible generic competition
  • Perception of a ‘dirty’ molecule with multiple targets
37
Q

Drug Product Life Cycles

A

Goals of Approved Product Life Cycle Management (existing drugs):

  • Extend marketing period without generic competition
  • Increase the market size
    Life cycle management strategies (new drugs) [ways to earn more money]:
  • New formulations (having in different dosage forms)
  • New dosing strengths (having multiple strength for the same drug)
  • Broader patient populations (more patients will purchase)
  • Paediatric indications (more chances of people purchasing the drug)
  • Combination therapies (patients “forced” to buy 2 drugs instead of 1)
38
Q

Repurposing Strategies

A

Strategy 1: Virtual Discovery
* Apply analysis technology/methodology to screen published data to identify repurposing opportunities

Strategy 2: Favoured Target
* Rescreening drugs/candidate compounds against new targets

Strategy 3: Model Insight
Applying specific insight about a target’s role in a new indication

Strategy 4: Agnostic Screening
* End-point screening to discover new uses for both on- and off target effects of existing drug

39
Q

Examples of Repurposed Drugs

A

Viagra
Thalidomide

40
Q

Vaccines
1st and 2nd Generation Vaccine Technology

A
  1. Inactivated Vaccines
    - Inactivated (or killed) vaccines generally induce the weakest immune responses and recipients often require a “booster” vaccination.
  2. Live Attenuated Vaccine
    - Virulence of the live organism is attenuated
    - Often the most successful vaccines
    - Immunity produced is often lifelong
    - Carry the greatest risk
  3. Subunit Vaccines
    - Use parts of an organism (antigens) that are known to stimulate the immune system.
    - Antibody-mediated immune response
41
Q

New Vaccine Strategies

A

Vaccines are not available for many diseases of public health importance

  • DNA Vaccines
    Benefit: Low cost and ease of manufacture at large scale
    Good stability, no cold-chain required
    Challenges: Although very effective in various animal models, immunogenicity a problem in
    humans. Activation of oncogenes
  • Viral vectored vaccines
    Viral vector vaccines use live viruses to carry DNA into human cells.
    Advantages: May be easy to genetic manipulate, Encode multiple antigens
    Challenges: increasing cancer risk, Immunity to the virus in the population affects vaccine
    efficacy, induces apoptosis and increasing inflammation
42
Q

Challenges of Vaccine Development
???? confusing

A

Challenges of Vaccine Development
1. Efficacy
Suitable animal models
2. Safety
Vaccines are usually injected into healthy infants, children and adults.
3. Regulatory hurdles
Regulatory hurdles more stringent than for therapeutic proteins or small-molecule drugs
4. Manufacturing issues
Translating bench scale production procedure to a cGMP process.

BIOT3002 (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions