OPHTHALMICS, EAR, AND NASAL PREPARATIONS Flashcards
What are Ophtalmics?
Sterile products for instillation into the eye
-can be solutions, suspensions, ointments, emulsions, gels
and ophthalmic inserts
-we want an local effect not systemic
When are Ophtamlics used?
used include anti-inflammatories, antibiotics, vasoconstrictors, miotics (Glaucoma), anesthetics, antifungals, antivirals, mydriatics (relax the pupil before eye testing), and cycloplegics (to relax ciliary muscle)
Pros and Cons:
Pros:
▪ Convenient
▪ Noninvasive
▪ Self-administration
▪ Reduced systemic side effects
Cons:
▪ Low bioavailability
▪ Inability to reach a posterior segment of the eye
▪ Low drug retention and frequent administration bc of the low volume administered
The human eye:
The cornea, lens, & vitreous body don’t have blood vessels
-> Oxygen and nutrients are transported to nonvascular areas by aqueous humor
Tear volumes:
-Normal tear volume: 7-8 μL
-non-blinked state: 30 μL
-blinked state: 10 μL
-quantities must be small with high concentration, Drops vary in size but approx. 50 μL
How can Opthalmics be sterilized?
Most common: Autoclave (terminal after preparing)
if not possible -> Filtration
-Dry Heat, Gamma Radiation, Ethylene Oxide
-Sterility Test has to be performed: Direct inoculation and membrane filtration
When and which preservatives are used?
When single-dosed, not needed; avoid after surgery
-Multiple-dose: preservatives can be irritating, so only use those:
Benzalkonium chloride (BAK), Benzethonium chloride, Chlorobutanol, Phenylmercuric acetate or nitrate, Thimerosal
-make sure it is effective against certain bacteria like Pseudomonas
What are the ideal pH and Viscosity range for Opthamlics?
-protect against pH change
-Ideally: 7.4, basic is more preferred than acidic (irritating)
-Optimum viscosity: 15-25 cp obtained by adding Viscositx agents:
MC: Methylcellulose, HPMC: Hydroxypropyl methylcellulose, HEC: Hydroxyethylcellulose
Gelling agent -> PVP: Polyvinylpyrrolidone, PVA: Polyvinyl alcohol
What are the antioxidants and how to obtain ISOTONICITY for Opthamlics?
Antioxidants to prevent oxidation
-EDTA chelating agents, Sodium bisulfite, Thiourea
Isotonicity: 0.6-2.0 % NaCl or its osmotic equivalent
What are different ophthalmic drugs?
-Solutions: most common
-Suspensions: Fine particle size <10 µm - Shake before use
-Emulsion: Shake before use
-Ointments: More viscous allowing the drug to stay longer in the eye -> melt at room temperature and release the drug
-Inserts: Gel-polymer with multiple layers for extended-release f.e. Pilocarpine for Glaucoma 20-40 µg/h in 7 days
-Contact lens: Corrective, Cosmetic, or therapeutic
How are ophthalmics packaged?
Glass or Plastic: 2 to 30 mL, sometimes with a small syringe
What is the BUD for compounded Ophthalmics?
Nonpreserved aqueous: 14 days
Preserved aqueous: 35 days
What are the requirements for Ophthalmic Ointments?
-extended residence time on the eye
-must not be irritating to the eye
-must melt at room temperature, for comfort and drug release
-USP sterility test and metal particle test
What is the correct method of Ointment Application?
- Wash hands
- tube should not touch eyelid
- head should be tilted back, eyelid should be gently pulled
downward - insert a thin ribbon into eye sack
Advice for patients:
-blurred vision, better at bedtime
-If multiple medications are to be given wait 5-10 min so that one doesn’t dilute the other one
-eye drops first before the ointment
-NEVER eardrops for eyes
Contact Lenses:
-Soft lenses use a hydrogel such as a hydroxyethyl methacrylate (HEMA), hard ones out of plastics
-silicone hydrogels for extended wear due to high oxygen
permeability
-Multipurpose Solutions for Rinsing AND Enzymatic cleaning, Disinfection & Neutralization for cleaning
How is the backside of the eye treated?
-Intravitreal injections
-Iontophoresis (still research) - charged drugs with electrical current to push it to the back of the eye
What are Otic or Aural preparations?
For delivery of drugs into the ear canal for localized action
Barriers: Tympanic membrane, middle ear
What are the indications and dosage forms?
Dosage forms: Drops or solution; suspensions, ointments, and foams (for longer retention)
Indication: removal of excessive cerumen (earwax), ear infection, pain
Why may there be sterile and nonsterile ear meds?
-If there is a chance of entrance into the inner ear, due to eardrum rupture or after surgery sterile products should be used
Which drug is used to remove Cerumen from the ear?
The most often used OTC drug for earwax removal is Debrox
-earwax is a lipid so for removal, a surfactant is needed
-Carbamide peroxide (6.5%) dissolved in glycerin and propylene glycol (increasing the viscosity so that it stays longer in the ear)
-carbamide peroxide releases oxygen which disrupts the wax -> easy removal
Which vehicles are used in the formulation of ear drops?
To increase viscosity and the retention in the ear
▪ Propylene glycol
▪ Polyethylene glycol (Low MW)
▪ Glycerin
▪ Mineral oil
▪ Olive oil
When formulating an otic suspension, which property should be paid attention to?
pH bc it could be irritative
ideal range is 3 to 3.5
How should ear drops be administered?
-wash hands
-Shake if it is an emulsion or suspension
-warm the bottle for 3 min
-tilted position or lie down
-to children 3 or less: downwards
-4 or older: ear upward and backward
-keep on taking the drug for 3 days after the symptoms
