Parenteral Products I Flashcards
IV qualities
Very rapid
Straight to blood
Good for irritant drugs
Suitable for large volumes
Least forgiving
Drug must be dissolved
Parenteral Routes of admin
IV
IM
SubQ
Intradermal
Intraperitoneal (IP)
Intraspinal - VERY delicate
Parenteral products needs
Right potency
Properly labeled
Sterile
Free of particles
Free of pyrogens
Isotonic
Physiological pH
Intraspinal injections needs
Has the right potency
Is properly labeled
Is sterile
Is free of particles
Is free of pyrogens
Is isotonic
Has physiological pH Has no preservatives
Common aqueous isotonic vehciles:
0.9% (w/v) NaCl Solution (Normal saline)
5% (w/v) Dextrose Solution (aka D5W)
Sterile solutions: all are sterile but
Not all are isotonic
Components of parenteral products: Vehicles
Water miscible solvents (cosolvents)
-Ethyl alcohol
Polyethylene glycol (PEG)
-Propylene glycol (PG)
Used to solubilize drugs
Can also slow down hydrolysis reactions
Often for IM injection
But also used in IV preparations
Water miscible solvents - cosolvents
PEG can be used IV at concentrations as high of 40% (v/v)
Ethyl alcohol can be used up to 10% (v/v)
Oils as injectables
Straight liquid oil IV is a BIG NO
Oil emulsion is ok for IV injection
Oil is distributed into small droplets that are even smaller than RBCs
No risk of embolism
Solution is NOT emulsion
Oil based solutions for IM injection are acceptable and do exist
Emulsions
Emulsion CONTAINS oil, but is not oil
Some emulsions (P.N.) are administered by IV route
Antimicrobial Preservatives
Used for multi dose preparations
Benzyl Alcohol 0.9% is the most common preservative
Parabens: Combination of methyl and propyl parabens, 0.18% and 0.02%
Cresol
Compatibility issues
T/F: antimicrobials are not very effective in non-aqueous (oil base) formulation
True
Parenteral preps-antimicrobial
ONLY preps intended for multiple use are allowed to contain an antimicrobial preservative (in the US)
Big points on antimicrobial preservatives
If you are going to be punching holes in a sterile container to administer the drug contained in it more than once, you need some type of antimicrobial preservative
Any sterile product intended for multi dose MUST contain antibacterial preservative
Single dose = single use
Preservatives recall:
Benzyl alcohol 0.9% is the most commonly used
Generally safe - some people are allergic
DO NOT USE benzyl alcohol in neonates - can produce gasping syndrome
Do not use preps containing antimicrobial preservatives in neonates
Preps intended for the intra-spinal route of admin MUST BE FREE of antimicrobial preservatives
pH buffers
Address solubility and or stability issues with the drug
Use at lowest concentration as necessary
Common buffers:
Citrates - some caution. Safe by IV, very irritating by IM or SC routes
Acetates
Phosphates - considerable caution. Potentially fatal DANGER (look for phosphate and calcium together)
Keep in mind pH
Citrate can be injected IV no problem - IM or subq irritating
-Phosphate and calcium combined have a strong tendency to precipitate and the result can be fatal
Caution: phosphate and calcium need to be given together in PN preps
Buffers: more
Buffers are used to force the pH to remain at a fixed value
Unbuffered solutions are quickly diluted into physiological pH
That is why you want buffers as dilute as possible, so the physiological pH takes over asap
Antioxidants and Chelating agents
-Antioxidants
Metabisulfite salts - low pH
Bisulfite - intermediate ph
Sulfite - high pH
Ascorbic acid
-Chelating agents
Most common: sodium EDTA
Enhance antioxidant’s effect
Sequester trace metals
