Exam 2 (Polymers, Parenterals 1-6) Flashcards
What are the two types of polymer synthesis? What are examples of each?
Condensation polymerization - Two or more monomers that have different reactive functional groups interact with each other. Ex. Nylon
Addition polymerization - aka Free-radical polymerization. This involves initiation, propagation, and termination of the radical. Ex. polyacrylate, polystyrene.
What is the difference between Mn and Mw?
Mn - Number average. This is when you add the molecular weight of the compound, then divide by the number of monomers.
Mw - Weight average. Here, you divide by the molecular weight.
What is polydispersity?
Polydispersity is when the monomers are not homogenous.
If Mw»_space; Mn, then polydispersity (Mw/Mn)»_space; 1.
This means if it’s more homogenous, the polydispersity will be closer to 1.
What are these properties of polymers: glass transition temperature, structure, mechanical properties (stiffness, toughness, viscoelasticity, molten)
Glass transition temperature - The temp range where a polymer changes from a hard, rigid, or “glassy” state to a more pliable, compliant or “rubbery” state.
- T «_space;Tg = polymer is glass-like and rigid
- T»_space; Tg = polymer is rubbery and soft
Mechanical properties -
- Stiffness: this can be determined by stress/strain (slope), so the more stress needed to break the polymer, the stiffer it is. The more elongation at break, the less stiff it is.
- Toughness: this can be determined by the AUC. Higher AUC means it’s tougher.
- Viscoelastic: When polymers for neither purely elastic or fluid. These polymers show elastic and viscous behaviors
- Molten polymers or concentrates solutions can show Non-Newtonian flow (plastic, pseudoplastic, and dilatant).
What are some factors that affect Tg?
- Polymer length: Longer polymer, higher Tg
- Side chains: More side chains (bulkier), higher Tg
- Cross linking: More crosslinking, higher Tg
- Plasticizer: Lowers Tg
What is the definition of plasticizer and what is the function of them?
Plasticizer - molecules that increase the entropy and mobility of the polymer chains, thus lowering Tg.
ex. Water
What are some features of hydrogels?
Hydrogels - Crosslinked networks of hydrophilic polymers. These are essentially water soluble polymers (ex. jello).
- Chemical gels (covalently crosslinked)
- Physical gels (crosslinked via H-bonds, hydrophobic interactions, or complexations)
These swell rapidly when they are placed in water due to chain-water interactions, electrostatic repulsion, and osmotic forces. They retain a large amount of water in their structures.
What are the reasons for concern when it comes to biologics?
Inadequate controls increase the incidence of medication errors (incorrect ingredients, strengths of ingredients, contamination with pathogens, contamination with pyrogens).
What new law was imposed in 2004 in the USP 797?
A practice standard for compounding sterile preparations in pharmacy was imposed.
What was the idea behind the 2012 article, “Avastin Doesn’t Blind People, People Blind People”
The doctor used the medication left over from the first patient for the second patient, which caused infection that resulted in blinding people.
Humans are the ones making the mistake when it comes to biologic infection risk.
Why is the pharmacist so important when it comes to sterile products?
The pharmacist is THE health care professional that is responsible for doing the last check when approving or rejecting biologic formulas.
What is the distinction between USP chapters > 1000 or < 1000?
Chapters > than 1000 is just a recommendation (nice to have but you don’t have to)
Chapters < 1000 are enforceable.
What is the USP 797?
The law of compounding sterile preparations. Every pharmacist needs to know it and use it for any/all parenteral products.
What is a parenteral product in terms of pharmacy practice?
Products administered by injection. AKA all injectable products.
What are some considerations about parenteral products?
- Administration of the therapeutic agent requires an injury to the body
- Administration bypasses the body’s natural defense barriers
- Administration makes the body vulnerable
- Products must meet some stringent requirements
What are the 3 main requirements specifically for parenterals?
- Sterile
- Particle free
- Pyrogen free
(Pyrogen = bacteria endotoxins that produce fever)
What are the 5 risks when it comes to parenterals?
- Microbial contamination
- Excessive bacterial endotoxins
- Variability in the intended strength of correct ingredients
- Unintended chemical and physical contaminants
- Ingredients of inappropriate quality
What does it mean for something to be sterile and how do we achieve sterilization?
Sterile - Free of microbial organisms
Achieved by -
- Steam (autoclave)
- Filtration (bacteria retentive membrane)
- Dry heat (oven; used to make vial sterile)
- Gas (ethylene oxide)
- Irradiation (gamma rays; used to sterilize clothes/gloves/equipment)
T or F: Sterilization gets rid of pyrogens
False;
Why do we want parenterals to be particle free?
Foreign particles can trigger immune responses that can produce damage to the lungs and kidneys. Particles have killed people.
What’s the difference between septicemia and septic shock?
Septicemia - Infection of the blood
Septic shock - Acute reaction to bacterial endotoxins
What does the preposition,”for,” mean in terms of parenterals. Ex. Purduemycin for injection
“for” - don’t use it as is; you have to do something to it before injecting
Why do we worry about the size of the preparation? How many mL does something need to be in order to be considered a large volume parenteral?
If something goes wrong, and the volume is large, then that’s a large problem.
LVP - Large volume parenteral. Single dose injections packages in a container containing more than 100mL.
What is the preferred vehicle in parenterals?
Water
More specifically, there are 3 types of water used in parenteral products:
- WFI - Water for injection: Pyrogen free, non sterile, single use sealed container.
- SWFI - Sterile water for injection USP: Pyrogen free, sterile, packed in sealed containers not larger than 1000mL
- BWFI - Bacteriostatic water for injection USP: Pyrogen free, sterile with antimicrobial agent added
What is important about SWFI?
Although it is pharmacologically safe, sterile, particle and pyrogen free, we can never inject plain water directly into the blood stream (it will produce lysis of the cells).
What are 4 traits of the IV ROA?
- Very rapid
- Straight to the blood
- Good for irritant drugs (because it gets diluted in the blood immediately)
- Suitable for large volumes (careful of mistakes)
If something is good for IV, it can almost always be used for all other types of injections.
What’s the difference between requirements for parenteral v. intra-spinal injections?
Parenteral requirements: sterile, particle free, pyrogen free. (isotonic and phys. pH is recommended)
Intra-spinal injection: sterile, particle free, pyrogen free, isotonic, physiological pH, no preservatives.
Intra-spinal injections have much stricter requirements