Parenteral formulation Flashcards
Why are more and more drugs being administered parenterally?
- Clinical need in particular medical situations for rapid, assured high blood and tissue levels
- Oral administration
> Very inefficient or unreliable absorption from the GIT
> Destruction or inactivation in the GIT
> Extensive mucosal or first-pass metabolism following oral administration
Provide FOUR advantages of Parenteral Route of Drug administration
- Rapid onset
- Predictable effect
- Predictable and nearly complete bioavailability
- Avoidance of the gastrointestinal tract (GIT), hence the problems of variable absorption, drug inactivation, and GI distress
- Reliable drug administration in very ill or comatose patients
Provide THREE disadvantages of Parenteral Route of Drug administration
- Frequent pain and discomfort of injections
- Psychological fears associated with “the needle”
- Incorrect drug or dose is often harder or impossible to counteract when it has been given parenterally rather than orally
How to define parenteral preparations?
Parenteral preparations are sterile preparations intended for administration by injection, infusion or implantation into the human or animal body
What are some quality aspects of parenteral dosage forms?
- Pyrogen free
- Sterile
- Free from visible particulate matter
- Container-closure integrity
- Injection site tolerability
- Physical and chemical stability
- The formulation containing the fewest number and the simplest excipients possible
- Highest level of purity for the active drug substance and excipients
- Detailed dosing and administration instructions including evaluation of compatibility with coadministered drugs
What are the types of injections? How are they prepared?
Solutions, emulsions or suspensions. They are prepared by dissolving, emulsifying or suspending the active substance(s) and any added excipients in Water for injections, in a suitable, sterile non-aqueous liquid or in a mixture of these vehicles
For solutions, emulsions, and suspensions (types of injections)
A) Which one is used for injections and do not show any evidence of phase separation?
B) Which one for injection may show a sediment which is readily dispersed on shaking to give a suspension which remains sufficiently stable to enable the correct dose to be withdrawn?
C) Under suitable conditions of visibility, are clear and practically free from particles
A) emulsions
B) suspension
C) solutions
What are the FIVE official types of injections?
- [Drug] Injection
- [Drug] for Injection
- [Drug] Injectable Emulsion
- [Drug] Injectable Suspension
- [Drug] for Injectable Suspension
What does the physiochemical properties of the drug depend on?
If the dosage form is a SOLUTION, SUSPENSION,EMULSION or POWDER
What are the excipients used in injections?
- Vehicle
- Buffering agent
- Solubilising agent and surfactant
- Preservative
- Antioxidant
- Chelating agent
- Inert gas
- Protectant
- Tonicity adjustment agent
What are the SEVEN factors/criteria to consider when creating a basic formulation of injection?
- Volume
- Vehicle
- Stability
- Tonicity
- Preservative
- Sterility
- Safety
What is volume dependent on? When must volume be made isotonic?
- Usually depends on the solubility of the medicament (active ingredient)
- Route of administration
- The volume also influences other aspects of formula
> LARGE VOLUME must be made isotonic
- IV injections of doses greater than 15mL may not contain a bactericide
What are the routes of parenteral administration?
- Subcutaneous route
- Intramuscular route
- Intravenous route
- Specialised route –> intradermal, intrathecal, intracardiac, intra-articular
For Intravenous route (IV route);
A) What is the volume required
B) Where is it injected
C) Benefit of it?
D) Danger of it?
E) What will a rapid drug administration do?
F) Where is risk of thrombosis increased
A)
- 1mL or less to 500mL or even more
B)
- Injected directly to the vein
- Immediate total access to bloodstream
C)
- Extremely rapid and predictable response, avoid irritation to other tissue
D)
- Antidoting very difficult, if not impossible, in most cases
E)
- May cause drug shock (excessive drug concentration at the target organ)
F)
- Increased at extremity sites (wrist or ankle) or patients with impaired circulation
For intramuscular route (IM);
A) Volume required?
B) Where are the injection sites?
C) Why is the drug slowly absorbed?
D) How can it be controlled to produce long-acting products?
E) What can result from faulty technique?
A)
- Rarely greater than 2mL, should not exceed 4mL at one site
B)
- Principal injection sites are the gluteal (buttocks), deltoid (upper arm), and vastus lateralis (lateral thigh) muscles
C)
- Forms a depot in the muscle mass
D)
- Dissolution and absorption
E)
- Muscle or neural damage