ceutics parenterals 1

drug delivery involves delivering a drug at ________________ rate to desirable site to treat disease

therapeutically effective

compare and contrast pharmacokinetics and pharmacodynamics in drug preparation

kinetics= what body does on drug

-where?how much? how often?

dynamics= what drug does to body

-effects of drug

both: plasma concentration

goals of drug delivery

1. low degradation

2. target Site deployment (less side effects)

3. therapeutic Window drug level

4. Predictable controllable release rates

5. patient Compliance by reducing dose frequency

DS W PC

7 factors influencing route of administration of drug delivery

1. ease (difficulty swallowing? nausea?

2. site of action (local vs systemic)

3. onset of action (oral?sublingual?IV?)

4. duration of action (controlled, immediate, IV..)

5. metabolism/excretion

6. quantity of drug (small vs large)

7. toxicity

ESOD M QT

how does difficulty swallowing/ nausea impact route of administration choice

difficulty swallowing= avoid solid in favor for liquid

nausea= avoid oral routes

t/f: drugs meant for systemic administration still have specific sites of action

true

local use vs systemic use

local= site specific application

systemic= absorption into blood then to target

do liquids or tablets have faster onset of action?

liquids= meds more available for absorption

do sublingual or oral tablets have quicker onset of action?

sublingual=> med bypasses stomach, goes straight to bloodstream

examples of topical medications with quick onsets of action

-applied to skin

-inhaled into lungs

-instilled into eye

duration of action

The length of time the concentration of a drug in the blood or tissues is sufficient to elicit a response. (in therapeutic level)

how long do CR/ER drugs last? IR?

CR/ER: 12-24hrs

IR: 4-6hrs

which drug route allows for sustained duration

IV infusion

which injections last longer? IM/SC or IV?

IM/SC

how does quantity of drug impact choice of drug route?

small amount of API= tablet with a lot of diluent

large quantity= use IV (diluted in blood)

which method is used to deliver a large amount of drug systemically

IV injections/infusions

first pass effect

The initial metabolism in the liver of a drug absorbed from the gastrointestinal tract before the drug reaches systemic circulation through the bloodstream.

how does age and disease affect choice of drug delivery

older patients usually have less effective drug metabolism and elimination

= usually given lower dose

= potential accumulation and toxicity

toxicology

study of toxic effects of drugs on body

t/f: very little difference exists in the therapeutic vs toxic blood level

true

what is parenteral administraton

injection or infusion by means of a needle or catheter inserted into body

greek definition of parenteral

para= outside

enteron= intestine

parenteral route of administration bypasses the _________

alimentary canal

to ensure sterility, parenterals are prepared using...

1) aseptic technique

2) special clothing (gown,mask..)

3) laminar flow hoods

ASL

what are the 5 routes of parenteral drug administration

1.IV= into vein

2. IM= into muscle

3. SC= under skin

4. ID= into skin

5. IP= into peritoneal cavity

advantages of IV route

1. Fastest method for giving systemic drugs

2. Provides fluids, electrolytes, nutrition

3. Provides higher concentration of drug to bloodstream (serious bacterial infections)

4. Continuous amount of needed medication (no fluctuations)

5. Infusion rate can be adjusted

what is the fastest route for giving systemic drugs

IV

which route is preferable for continuous amounts of medications with no fluctuations

IV

disadvantages of IV route

1. Injury from needle insertion

2. Potential for introducing toxic agents, microbes, pyrogens

3. Impossible to retrieve once given

compare rate of onset and duration for SC, IM, and IV

SC: longer onset and longest duration (low blood supply)

IM: longer than IV (higher blood supply)

IV: fastest onset and shortest duration (into blood)

T/F: IM/SC can be used for medications not active orally

true

parenteral preparations are usually what dosage forms?

solutions and suspensions

which route of drug administration must be free of air bubbles and why?

IV; introduction of air and matter might cause embolism, vessel blockage, or painful rxn

IV injections must be given at what angle

15-20

describe the proper needle length, gauge, angle, and volume for IM injection

22-25 gauge, 1/2 to 1 inch, 90 degree angle, less than 3mL

T/F: absorption of IM drugs is predictable and used for emergency situations

false. IM absorption is unpredictable and not recommended for unconscious patients (IV is predictable and preferred)

t/f: IM injections can be used to give antibiotics, vitamins, iron, and vaccines

true

which route is used for TB skin test

ID; upper forearm

which route is used for allergy skin tests

ID; usually on back

where are ID injections given

into capillary-rich layer just below epidermis (local anesthesia, diagnostic tests, immunizations)

which injection route is used for epi, heparin, sumatriptan, and vaccines

subcutaneous

which angle, gauge, length, and volume of needle should be used for SC injections

45 degree angle, 25-26 gauge, 3/8 to 5/8 inch, less than 1.5mL

why should less than 1.5mL be used for SC injections

to avoid pressure on sensory nerves causing pain and discomfort

which factors may influence the choice of parenteral route of administration

onset or duration of action, setting where drug is to be administered

describe the types of vehicles used for parenteral drugs

-viscous, water-miscible vehicles (ex: aqueous gelatin, polyvinylpyrrolidone)

-water-immiscible, water-repelling agents (ex: vegetable oil)

parameters manipulated in the design of parenteral controlled forms

1. route of administration

2. drug delivery systems

3. particle size

4. chemical modification of drug

t/f: parenteral medications often need coadministration of vasoconstricters

true (lowers blood flow to increase drug duration at specific site)

3 classifications of parenterals based on mode of delivery

1. injectables (solutions/suspensions)

2. implants

3. infusion devices (pumps)

summarize the 3 types of solutions made for parenteral injections

1. aqueous (high viscosity)

2. aqueous complexed formulations (IM)

3. oil solutions (IM)

example of viscous, water miscible vehicles for parenterals

gelatin or polyvinylpyrrolidone

example of water-immiscible vehicles and water-repelling agents for parenterals

water-immiscible: vegetable oils

water-repelling: aluminum monostereate

what are high viscosity solutions used for in parenterals?

1. molecular weight >750Da

2. water soluble drugs

3. with gel agents/ viscosity enhancers

how are complexed aqueous formulations given

IM (aq)

how is drug release for oil solutions in parenterals controlled

controlled by partitioning of drug out of oil into surrounding into aqueous medium

how are oil solutions/suspensions in parenterals administered?

IM (oil)

how can aqueous suspensions be given

IM or SC

for aqueous parenteral suspensions, solid concentration should be? particle size?

concentration: 0.5-5%

size: <10 micrometers

compare length of drug action of oil suspension, aqueous suspension, and oil solution

oil suspensions have longest drug action. drug particles must dissolve then partition from oil solution to aqueous medium

penicillin G procaine in vegetable oil is an example of

oil parenteral suspension

release of water soluble drugs can be slowed by presenting it as what form of parenterals?

oil suspension

what is a microsphere and how is drug released controlled

-matrix of drug in polymer

- first order process, dissolution/degradation of matrix

small matrices release drugs at a ___slower?faster?___ rate

faster

examples of polymers used in microspheres

polylactic acid, polylactide coglycolide

microsphere vs microcapsule

microsphere: drug matrix-> dissolution (first order)

microcapsule: drug centrally located within shell-> dissolution or diffusion; for potent drugs

for potent drugs, are microspheres or microcapsules preferred

microcapsules (steroids, peptides, antineoplastics)

-> more controlled release

polymers used for nanoparticles/nanospheres

polyacrylic acid, polyglycolic acid

what are nanoparticles used for

targeted therapy (cancers)

niosomes

closed vehicles formed in aqueous media from NONIONIC surfactants (similar to liposomes)

liposomes are? which lipids are used?

-spherical vesicle of lipid bilayers enclosing aqueous compartment (water soluble drugs)

- phospholipids, sphingolipids, glycolipids, sterols

liposomes can be given by which routes

IM and SC, can be IV for targeted delivery (cancers)

type 1 vs type 2 scFV conjugation to liposomes

type 1: scFv directly attached onto liposome (sterically hindered0)

type 2: scFv conjugated via flexible spacer (ex: PEG)

these are immunoliposomes with drug inside

properties of resealed erythrocytes for drug delivery

-biodegradable, biocompatible,nonimmunogenic

-circulate intravascularly for days, carry large amounts of drugs

-easy drug loading

-damaged= removed by liver

t/f: resealed erythrocytes can carry large amounts of drugs and stay in circulation for days

true

what factors may influence the choice of an injectable parenteral DDS

1. size of formulation

2. loading of drug

3. action and setting where drug is to be targeted or delivered