Parental formulations Flashcards
Define Parental route of administration
A sterile preparation intended for administration by injection, infusion or implantation
What tissues can the parental route be given too?
Muscle, soft tissue, organ, anatomical space, vascular system
Advantages of Parental route of administration
- Rapid effect - emergency
- Effective, predictable response
- Good if oral route unavailable
- Drug may not be absorbed orally or is metabolised by GI tract/ liver
Disadvantages of Parental Route
- Painful
- Expensive to manufacture
- Patient compliance low—needle phobia
What is the difference between large and small volumes of parental injections?
Large: 100—1000ml
Small: < 100ml
Describe parental injections
- · small volumes (<100ml)
- · Various routes: IV, IM, SC
- · Drug and excipients in vehicle
- · Sterile solution or emulsion
Describe parental infusion
- · Large volumes (100– 100ml)
- · Delivered IV
- · Sterile solution or emulsion
- · No preservatives (one usage)
Describe concentrates for injection/ infusion
- · Sterile concentrated solutions that need to be diluted before administration
- · Patient specific doses
- · Diluted with water or 0.9% w/v NaCl solution
Describe powders for injection/ infusion
- · Dry, solid sterile powder sealed in final container
- · Instable in aqueous solution
- · Diluted before administration
Describe gels for injection
- · Sterile gel
- · Enhanced viscosity allows for modified release of drug
Describe implant
- · Sterile solid preparation
- · Allows for release of drug over extended time period
What is a clean room?
Manufacturing room where concentration of particles are tightly controlled as well as parameters: temp, humidity
Describe Particulates control
- · Don’t want MCP (carry bacteria) or inert particles (lodge in BVs)
- · Solutions: No visible particles and low subvisable particles
- · Suspensions: particles permitted bar IV
- · Emulsion: droplet size < 3 uM
Describe sterile control
- · No pyrogens/ microorganisms (these by pass defence system and go into blood stream)
- · Terminally sterilised or anespetically prepared
What excipients are required in parental products?
- · preservative
- · Antioxidant
- · Suspending agent
- · buffer
What is needed in the vehicle?
· co– solvent: aids solubility of poorly soluble drugs (ethanol)
· Solubilizing agents: aids dissolution
· Water for injection
· O/W emulsion (for water in sol drugs)
· Oils (intramuscular injections)
Why are preservatives required?
To prevent microbial growth. Co-solvents can also be effected
Why are buffers needed and why is PH so important?
- Stability and solubility is pH dependent. Also determines ionisation.
- Buffers maintain pH
What is plasma pH and what is the pH requirement of a drug?
Plasma pH: 7.4
PH needs to be between 3 and 9
(3= pain, 9= necrosis)
Why are suspending agents needed?
Ensures drug stays suspended in vehicle and it is uniform/ even so the correct dose is administered
What is Tonicity? What is the requirement?
The ability of an extracellular solution to make water move in or out or a cell by osmosis.
0.9% saline isotonic with plasma. Osm (280 –295)
What is osmosis?
The movement of water from an area of low solute concentration to high solute concentration through a semi perm membrane
What happens if a hypertonic solution is administered?
Solution has higher solute conc and osmotic pressure. Water driven out blood cells causing them to shrink
What happens if an isotonic solution is administered?
Solute concentration same in blood plasma. Same osmotic Pressure. No net flow of water.
What happens if a hypotonic solution is administered?
Solute concentration and osmotic pressure lower than blood cells therefore water moves into the cells and cell lysis occurs.
Add dextrose or NaCl
Describe Ampoules
- · Small volumes <1—10ml
- · Glass or plastic
- · Single use—unpreserved
- · Open necked, sealed after filling
Describe Vials
- · Volume: 5 –100ml
- · Glass with reusable plastic cap
- · Multiple use—preservative
Describe pre-filled syringes
· small volumes: 0.5—20 ml
· Glass or plastic base
· Convenient, affordable, accurate, sterile, safe
Describe infusion bags/ bottles
- · volume 100 –1000 ml
- · Glass bottles, collapsible plastic bags
- · Single use
What tests are carried out for parental products?
uniformity of weight, Uniformity of content, Test for pyrogens , Test for sterility - membrane filtration, direct inoculation, Particulate test—light obscuration particle count test, microscopic particle count, LAL test
Describe IM injections
- · 90 into muscle
- · Solution, emulsion, suspension
- · Rapid absorption
- · <4 ml
Describe SC injections
- · 45 into SC below dermis
- · Solution, emulstion, suspension
- · Slower absorption
- · <1 ml
Describe IV injections
- · 25 into vein
- · Solutions, emulsions
- · Fastest absorption
- · <1ml—litres
Describe IA parental injections
- · into artery
- · Immediate effect on peripheral organs
- When vein isn’t available. Cancer treatments. Causes arterial spasms
Describe inradermal
- · 10—15 into skin between dermis and epidermis
- · 0.1– 0.2 mL
- · Used for diagnostic testing
Describe intrathecal injections
- · Into the spine in the CSF in the subarachnoid space between 2 inner protective membranes
- · Up to 10 mL
- · Used to treat bacterial meningitis
Describe Intra Cisternal
- · Into the cisterna magna
- · Antibiotics into CSF
Describe Epidural
- · Injections / infusions
- · Peridural space between the dura and the vertebrae
Describe intra-bursal / intraarticular
- · Into the synovial fluid of joint cavities
- · Aqueous solution/ suspension
- · Local effect
Describe ophthalmic
· Around or in eye
· Subjunctaval, intravitreal, intracameral
Describe intra cardiac
Directly into cardiac muscle/ ventricle. Rapid local effect
What controls are involved in parental administration
Temperature, pH, mixing, time, light, concentration
What are physical complications?
- · Mixing of drugs prior to administration
- · Insolubility, colour change, precipitation, gas formualtion
What are Chemical complications?
Oxidation, reduction, hydrolysis, photolysis, increase in toxicity, drug degradation, pH changes, packaging incompatibility
What are Error complications?
- · Wrong drug
- · Wrong route
- · Wrong dose
- · Wrong time
What are contamination complications?
- Microbial: bacteria, fungi, virus.
- Source: air, water
- Particulate: dust, glass, fibres
- Source: packaging, enviroment
What are clinical complications that may occur through parental route of administration
Thrombus, Vein irritation, leakage of IV med into extravascular tissue,