Administration and Formulation Flashcards
(26 cards)
What is the difference between administration and formulation of ocular drugs?
Administration refers to the process of instilling drops into the eye, while formulation refers to the type of drug and how it is made (e.g., drop, gel, ointment).
What are some alternative methods for delivering ocular medications, other than eye drops?
Alternative methods include intravitreal injections, slow-release surgical implants, and impregnated contact lenses. These are not available for entry-level optometrists.
What are the three essential points to consider before administering a drug to a patient?
Have basic clinical data about the patient.
Have a clear idea of why you want to use the drug.
Inform the patient about the consequences of using the drug.
What is the importance of obtaining consent and assent from the patient?
Consent is the patient’s formal permission to administer the drug, while assent refers to the patient’s agreement to comply or accept the treatment after it is explained to them
What are some of the principal concerns to discuss with the patient before instilling ocular drugs?
driving concerns after pupil dilation
topical anaesthesia, makes the eye vulnerable to foreign bodies
allergic reactions/ adverse effects, though rare, they can be ocular or systemic
What is the 4-D test in drug administration, and why is it important?
The 4-D test is a safety check before administering any drug:
Drug: Is it the right drug?
Dose: Is it the correct dose and concentration?
Date: Is the drug within its expiry date?
Dispose: Can the packaging be disposed of appropriately?
What is posology, and how is it related to drug administration?
Posology is the study of the dosages of drugs and determines the appropriate dose for the drug to be administered.
whta is the correct technique for instilling eye drops?
ensure the patient’s head is back and eye are horizontal
instil the drop into the lower fornix(space bet the eyelid and eyeball
ask the patient to close their eyes and occlude the puncta to reduce systemic absorption
wipe any excess soln w a tissue
Why is sterility important in administering ocular drugs?
Sterility prevents contamination and infection, particularly with multi-dose containers that may contain preservatives like benzalkonium chloride.
What are the two types of eye drop containers, and what is the difference?
Single-dose applicators (e.g., Minims®) are sterile and intended for one-time use.
Multi-dose bottles contain preservatives (e.g., benzalkonium chloride) to prevent contamination after opening.
What is the role of preservatives in multi-dose containers?
Preservatives like benzalkonium chloride are added to prevent microbial contamination but can be toxic to the ocular surface with prolonged use.
How should ocular drugs be stored for optimal stability?
Ophthalmic drugs should be stored in a cool, dark place to prevent deterioration. Some drugs require storage between 2°C and 8°C, while others should be kept below 25°C.
What is tonicity, and why is it important in eye drop formulations?
tonicity refers to the conc of solutes compared to the cell contents of the cornea. it is imp to ensure the solution is isotonic (around 0.9% NaCl) to avoid irritation or damage to the eye
What happens if eye drops are hypertonic or hypotonic?
hypertonic or hypotonic solns can cause discomfort such as stinging as the osmotic gradient causes fluid shifts between the eye and soln
What are common pH considerations in ocular drug formulations?
The pH of the solution should be close to the eye’s natural tear film, which is slightly alkaline (around pH 7.35). Eye drops outside this pH range can cause irritation.
What are viscosity-enhancing agents, and why are they used in eye drop formulations?
viscosity-enhancing agents(e.g. cellulose derivatives polyoxyl-40 stearate) help the drug stay in contact with the eye longer for better absorption and prolonged effect.
What is the purpose of using multi-dose bottles versus single-dose applicators for eye drops?
Single-dose applicators are sterile and prevent contamination but are intended for one-time use, while multi-dose bottles contain preservatives but risk contamination after repeated use.
How should you handle the disposal of drug containers after use?
Containers should be disposed of according to the manufacturer’s guidelines and local waste regulations, especially for multi-dose bottles containing preservatives.
What types of preservatives are used in multi-dose ocular drugs, and how do they work?
common preservatives include:
Benzalkonium chloride (detergent), which ruptures bacterial cell membranes.
Chlorhexidine acetate (antibacterial) and thiomersal (mercurial), which also target bacterial cell walls.
What is the significance of pH buffers in ocular drug formulations?
pH buffers (e.g., borates, acetates) help maintain the stability of the drug, ensure it is non-irritating, and prevent the drug from being too acidic or alkaline, which can cause discomfort.
Why should boric acid be used cautiously in ocular formulations?
Boric acid is commonly used for its buffering and anti-infective properties, but large quantities can cause contact sensitivity or rare toxicity.
What are examples of ocular inserts, and what are their advantages?
Ocular inserts (e.g., contact lenses impregnated with medication) offer sustained drug delivery and longer contact time with the eye, improving the therapeutic effect.
What are some common ocular formulations used in optometry?
Common ocular formulations include:
Minims® (single-dose applicators).
Paper strips for diagnostic dyes (fluorescein, lissamine green).
Multi-dose bottles, ointments, and gels.
How are eye ointments different from drops in terms of drug delivery?
Ointments and gels stay in contact with the eye longer than drops, which enhances drug absorption and prolongs therapeutic action.
