Compounding II Flashcards
Equipment used for HDs should be
dedicated to HD and sanitized after use
Calibration of equipment
Equipment must be calibrated regularly to confirm accuracy
Metal spatulas should not be used with
metal ions
When measuring volume, select a device
that has a capacity equal to or slightly larger than the amount being measured to get the most accurate measurement
Measurements should be made in the
metric system
Graduated cylinder
Same diameter from the top to the bottom, provides more accurate measurements
Conical cylinders or beakers
Have wide mouths that make it easier to stir mixtures with a glass stirring rod.
The wider the mouth, the lower the accuracy
A graduated cylinder should not be used to measure volumes
less than 20% the graduates capacity
Parenteral syringes
hypodermic syringes
Syringes are most accurate for
measuring small volumes.
Especially useful for viscous liquids
If a patient requires a very accurate dose, should use a syringe
Luer locks
Make secure, leak free connections between syringes, catheters, and IV lines
Injection (hypodermic) syringes come with
cannulas (needles) attached
Choosing the correct syringe size
Do not use the exact syringe size needed. Select the closest syringe size above the one needed.
Pipettes
Thin plastic or glass tubes used to measure small volumes
Volumetric pipette
Draws up a set volume only, which is the volume that the pipette can hold.
Mohr pipette
Graduated and is used to measure different volumes
Class III Torsion balance
Also called class A balance
-Older type of balance
-Have to calculate minimum weighable quantity (MWQ)
-Have a sensitivity requirement
MWQ=SR/acceptable error rate (0.05 or 5%)
Electronic balance
-Called analytical balance or scale
-Top loading
-Simple to use and has a higher sensitivity
Glass mortars are used for
Liquids and mixing compounds that are oily or can stain
Wedgewood mortars
Have a rough surface and are preferred for grinding dry crystals and hard powders
Porcelain mortars
Have a smooth surface. Preferred for blending powders and pulverizing gummy consistencies
Spatulas
Used to mix and transfer ingredients.
The flat part can be used to flatten and grind down ingredients.
Stainless steel and plastic most common
Ointment slabs
Ingredients are mixed on the compounding/ointment slab
Can also be used to form pulls (pill tiles)
Disposable ointment slabs can be used as a work surface if the water content of the mixture will not cause the paper to tear
Powder sieves
Sifters similar to those used in baking.
Ensure a uniform particle size
Ointment mills
Draws ointment between rollers that grind and homogenize (make uniform) the ingredients
Homogenizers
Also called an electronic mortar and pestle
Can be used to mix ointments, creams, or other semi-solid preparations
Ointment mills and grinders
reduce the particle size, which increases the SA and rate of drug absorption
Electric mixing equipment
Ointment mill
Homogenizer
Grinder
Hot plate with magnetic stirrer
The stirrer has a rotating magnet under the ceramic plate, which causes the stir bar to spin.
Hot plates are used without the stir bar to heat only (a glass stirring rod can be used to mix manually)
Heating devices
-Water bath when temp needs to be carefully controlled
Soft delivery vehicles are often
dispensed in a disposable plastic mold.
Refrigeration helps it retain shape
Capsule shells are made from
Gelatin- pork derived
Hypromellose- plant derived
000 capsule size
largest
5 capsule size
smallest
Tube-sealers
heat and squeeze the ends of tubes shut. The end looks similar to the end of a toothpaste tube
Ingredients that are recommended for use in compounding will be listed in either
USP-NF
Food Chemicals Codex (FCC)
If ingredients are not manufactured at an FDA registered facility
a certificate of analysis (CoA) should be obtained that confirms the specifications and quality.
Expiration dates are important to
ensure that the product retains potency and is non-toxic
What do you do if an ingredient does not have an expiration date?
Assign a date that is no more than 3 years.
Label with the date of receipt and assigned expiration date.
Salad dressing chemistry
Quickly settles back into two distinct parts because the “tension” between the two surfaces is high.
Surfactants
Lower the tension between two surfaces and keep the phases from quickly separating
Surfactant does what?
Surfactant= surface acting agent
Lower the surface tension (interfacial tension) between two ingredients (or phases) to make them more miscible (easier to mix together)
Surfactants are amphiphilic
they have both a lipophilic and hydrophilic end
How do surfactants help ensure a consistent dose?
By ensuring that the drug is dispersed
Types of surfactants
Wetting agents
Emulsifiers
Suspending agents
Levigating agents
Foaming agents
Glycols and gels
Wetting agents
Surfactants
- Reduce the surface tension between a liquid and a solid
-Levigating agents can be referred to as wetting agents
Fine powder that will be incorporated into a suspension
Wetted with a wetting agent and stirred into a thick paste before being added
Emulsifiers
Surfactants
An emulsion is 2 or more liquids not blended together (immiscible).
Emulsifiers are added to keep the liquid droplets dispersed throughout the liquid vehicle.
Suspending agents
Surfactants
A suspension is a solid dispersed in a liquid
-Suspending agents are added to keep the solid parts from settling.
-Suspensions still must always be shaken to redisperse the solid particles.
A suspending agent can also be
Dispersants (Dispersing agents)
Plasticizer- makes the preparation easier to mold or shape
Levigating agents
Make particles smaller
Levigation uses a levigating agent (also called levigant) to aid in the grinding.
Commonly used levigating agent for lipophilic (oil-soluble) compounds
Mineral oil
Commonly used levigating agent for aqueous (water-soluble) compounds
Glycerin
Propylene glycol
Foaming agent
Surfactant
-Helps foam to form (soap) by lowering the surface tension of water.
Anti-foaming agent
Simethicone
What agents are used as delivery vehicles and surfactants?
Polyethylene glycol (PEG)
Poloxamer (P in PLO gel)
Have both hydrophilic and hydrophobic parts
Poloxamer is useful for
Topical drug delivery
Ora plus
Suspending agent
-Keeps particles suspended to prevent settling.
Ora-Sweet is added to provide flavor.
Emulsion
Liquid in a liquid
What must be considered when selecting the surfactant to use in an emulsion?
The hydrophilic-lipophilic balance
-Is the emulsion water in oil w/o or oil in water o/w?
HLB
Scale from 0-20
Surfactants with a lower HLB (<10) are more lipid soluble, used for w/o emulsions
Surfactants with higher HLB (>10) are more water soluble, used for o/w emulsions
What type of emulsion would PEG form (HLB value 11.4)
Oil in water (o/w)
What type of emulsion would Span 65 be used for? HLA value 2.1
Water in oil (w/o)
What type of emulsion would Tween 85 be used for? HLA 11
Oil in water (o/w)
Stability
The extent to which a product retains throughout its period of storage and use (shelf life), the same properties
What is a common cause of drug degradation
Reactions involving functional groups
What three types of chemical reactions cause most drugs to become unstable and degrade?
Oxidation-Reduction
Hydrolysis
Photolysis
Oxidation- reduction
Oxidation- loses electrons
Reduced- Gains electrons
Color change with oxidation
Epinephrine becomes amber-colored (yellow/orangish)
Other compounds turn pink/reddish
Carmelization
Oxidation reduction reaction
Alcohol functional group is oxidized and water is removed (evaporates)
Which molecular structures are most likely to oxidize?
Hydroxyl (OH) bonded directly to aromatic ring
How can oxidation be prevented?
Light protection
Adequate storage
Chelating agents
Antioxidants (free radical scavengers)
pH control
Chelating agents
Used to chelate metal ions that have an unshared electron. These are free radicals that catalyze oxidation chain reactions.
Chelating agents prevent this reaction from occurring.
Example- agents with ED in them (EDTA, EDetate)
Antioxidants inhibit
Free radicals, prevents oxidation
Example- ascorbic acid (vitamin C), tocopherols (vitamin E)
Hydrolysis
Occurs when water causes the cleavage of a bone.
Dessicants are sometimes used to soak up any moisture that enters the container.
Which compounds are likely to be hydrolyzed?
Ester- carbonyl group bonded to OR group
Amide- Carbonyl bonded to nitrogen
Lactam- beta lactam ring
How should hydrolysis be prevented?
Protect from moisture
-Light protection
-Adsorbents/desiccants
-Lypophilized (freeze dried) powders
-Hygroscopic (water absorbing) salt
-Prodrug form
-Control temp and pH
Hydrolysis occurs more rapidly at
higher temps
Hydrolysis reaction prodrug
Aspirin is hydrolyzed into salicylic acid
Photolysis
Many drugs are sensitive to UV light exposure. Need to be protected from light.
Which compounds are likely to be degraded by light exposure?
Ascorbic acid
Nitroprusside
Phytonadione
Buffers
Excipients that maintain the pH in adequate range
Binders
Excipient
Allow the contents of a tablet to stick together.
Provide stability and strength
Diluents and fillers for tablets/capsules
Lactose, mannitol, sorbitol
Starches
Calcium salts
Cellulose powder
Diluents and fillers for topicals
Petrolatum
Mineral oil
Waxes
Disintegrants
Oral products have to be dissolved to be absorbed in the small intestine
Alginates and cellulose- absorb water and cause the tablet to swell and release water
Disintegrants examples
Alginic acid, cellulose
Polacrilin potassium
Starches
Lubricants
Also called glidants
Improve powder flowability
Lubricant examples
Magnesium stearate
Preservatives should not be used in
neonates
Preservative examples
Chlorhexidine
Povidone iodine
Sodium benzoate/benzoic acid, benzalkonium chloride
Sorbic acid/ potassium sorbate
Methyl/ethyl/propyl parabens
EDTA
Thimerosal
Cetylpyridinium chloride
Buffers used to maintain acidic pH
HCL
Acetic acid
Citric acid
Buffers used to maintain alkaline pH
Sodium hydroxide
Boric acid
Sodium bicarb
Buffers used to maintain neutral pH
Sodium biphosphate
Potassium phosphate
Ionized compounds are more
polar, which makes them more soluble
Hydrophilic solvents
Water
Alcohol
Glycols
Purified water
Has been treated
-distilation
-Deionization
-Reverse osmosis
What type of water is used for reconstitiution?
Distilled
Sterile water is free from
bacterial endotoxins (pyrogens)
Alcohols have high _______with water
miscibility
They can be used to dissolve solutes that would be insoluble in water alone
Benzyl alcohol is used as a
Solvent
Preservative
Fragrance
Glycols
Polyethylene glycol (PEG)
-Surfactant, solvent, lubricant
Water soluble and water-miscsible
When PEG is linked to a protein drug (pegylated)
increased half life
Polybase
PEG mixture used as a suppository base.
It is a good emulsifier
Mineral oil is the ingredient in
baby oil
Emollient
Softens and soothes the skin
Moisturizers
Occlusive ointments
Petroleum jelly (white petrolatum)
Theobroma oil (Cocoa butter)
Waxes
Form protective barrier to prevent the loss of water
Humectants
Pull water from atmosphere to moisturize skin
-Glycerin, glycerol, PEG
Ointments
0-20% water
80-100% oil
Best for extremely dru, thick skin
Creams
Half oil and water
Best for normal and dry skin
Lotions
Most water, best for oily skin
Common ointments
Petrolatum
Polybase
Aquaphor
Aquabase
Oleaginous ointments
Contain no water
-Vaseline
-White petrolatum
Lotions have a small amount of
alcohol added to solubilize the ingredients
Aqueous solutions of poloxamers are
liquid when refrigerated and form a gel at room temperature
Gel examples
PLO gel
Poloxamers
Suppository bases
Polybase
Cocoa butter
Hydrogenated vegetable oils
Gelatin
Adsorbent examples
Magnesium oxide/carbonte
Kaolin
Coatings examples
Shellac
Gelatin
Gluten
Emulsifiers examples
Type of surfactant
-Acacia, PEG
Enteric coating examples
Cellulose acetate phthalate
Gelling (thickening) agent , stabilizer
Gelatin
Cellulose
Benzonite
Agar
Algintes
Gums- guar, xanthine, acacia
Carbomer
Starches
Poloxamer
Humectant ex
Glycerin
Glycerol
Propylene glycol
PEG
Wetting agents/Levigating agents examples
Mineral oil
Glycerin
Aspartame should be avoided in
PKU
Contains phenylalanine
Sorbitol should be avoided in
IBS
