Flashcards in AP - Eye & Ear, Parenteral, Nasal & Pulmonary Drug Delivery Deck (42):
- stability (in solution, formulation and API itself)
- log P
- toxicity profile
- analytical assay
Auricular or Otic or Aural drug delivery means drug delivery to the...
Since drug is only applied to outer part of ear, drug is not absorbed ________.
systemically. Therefore, topical drug delivery rules apply.
In order to have a stable suspension, and want some interaction between a drug with average-low water solubility, and the solvent, you can add a ________.
Wetting agent - surfactant
What can modify viscosity?
Name a few flocculating agents.
- Electrolytes (sodium salts - acetate, phosphate)
- ionic surfactants
- polymeric agents
How do you prepare a suspension
Dissolve buffer in solvent. Add buffering agent, preservative and gelling agent (viscosity modifier) and mix to get uniform clear solution. Add the API last and mix thoroughly.
During suspension preparation, why is the API added last?
To ensure only API is suspended and not the other excipients such as gelling agent.
What are the stability tests for suspensions? (Three things)
- Particle size analysis (make sure it hasn't increased in size as this can cause local irritation)
- Degree of flocculation
Ocular drug delivery are used for...
Eye formulations are delivered ______
Solutions can be dispensed as _____ and _____
drops and irrigation solutions
Suspensions can be dispensed as ______
Particle size for eyes must be
Eye drops or anything administered to eyes MUST be
Buffering capacity for eye should have a pH of _____
Define parenteral drug delivery.
Administration of drug not through alimentary canal but rather by injection through an alternate route e.g. subcutaneous (under skin), IM (depot injections - oily solutions), IV (can be short acting/ long acting infusions), IA (infusions), IS (anti cancer, epidural), ID (vaccines), IC (adrenaline) e.t.c.
What are some reasons for using parenteral drug delivery?
1. If drug is not stable in GI tract and cannot go through any other route of administration e.g. insulin
2. GI enzymatic activity
3. Low absorption --> 1st pass metabolism
4. Variable absorption from patient to patient
Advantages of parenteral?
- Quick drug delivery
- Rapid onset of action
- Ideal alternative when oral therapy is not possible
- Accurate dosage
- Used for systemic and local effect
- Implants and depot for prolonged action
- Suitable for parenteral nutrition and for continuous medication
Disadvantages of parenteral?
- Patient compliance
- Administered by trained medical professionals
- Once administered, no way it can be altered --> nearly impossible to reverse the effects
- Stringent manufacturing and packing requirements leading to higher production costs
Types of parenteral formulations
- Solutions (can be dispensed individually as powders with a separate solvent)
- Suspensions (can be dispensed individually as powders with a separate vehicle)
What is the dose for small volume parenteral products?
0.1ml - 1.5ml
(single bolus injection suitable for i.m, s.c, i.v etc)
What is the dose for large volume parenteral products?
(usually for parenteral nutrition)
Choice of small volume or large volume depends on...
if you want it to act immediately (SVP) or over a long period of time (LVP).
Disadvantage of SVP?
- Fixed conc (manufacturer regulated)
- If frozen --> thawing --> can lead to altered product stability.
What are the excipients for injections?
- Solvents; aqueous - water for injection; aqueous miscible - propylene glycol, glycerol, PEG
- Solubilising agents e.g. surfactants
- Buffers; salts e.g. NaCl
- Viscosity modifiers e.g. methylcellulose
Water for injection is obtained by which process? ______ or _______ _______
Distillation or Reverse osmosis
Water for injection is free from _____, ______ and _______
particulates, pyrogens and bacteria.
Water for injection; quick production to utility to minimise _________
Water miscible solvents are used as co-solvents to increase _______/ _______.
Non aqueous are usually used for _______
intramuscular depot injections
Preservatives are used at much lower concentrations for parenteral injections than topical formulations. Why?
Because they are sterile manufactured or stabilised. Therefore, need to keep small amounts to maintain sterility.
What are buffer salts used for in parenteral drugs?
To stabilise the drug.
What is blood osmolality value?
280 - 303 milliosmoles.
Which is preferred hypertonic or hypotonic?
Nacl, dextrose and mannitol are all?
What are some buffers used in parenteral products?
Citrate (used for acidic)
Phosphate (used for ph 5-7)
If parenteral product is sterile, only need to add preservative if... ?
multi dose units are used
If a drug has poor water solubility what can you do?
- pH manipulation --> make it more acidic/ alkaline
- use co-solvents
- complexing agents
- NEED TO ANALYSE STABILITY OF FINAL PRODUCT BEFORE GOING AHEAD.
Particle size for suspension in injections is
What are some adverse effects following parenteral administration
- Haemolysis due to hypotonic formulations
- Pain (IM route due to pH or co-solvent conc)
- Phlebitis - pain, oedema