Pharmaceutics Exam 3 (Lecture 31- Compounding Ophthalmics)

What are the 4 types of ophthalmic delivery routes?

1. Topical

2. Intravitreal

3. Subretinal

4. Subconjuctival

Intravitral Drug Delivery

Into Vitreous Humor

Subretinal Drug Delivery

Administered all the way in the back of the eye

Subconjunctival Drug Delivery

Administer Under the Conjuctiva

Advantages of Topical Drug Delivery

• Applied to direct sight of action (high local drug concentration)

• Minimizes possible side effects

• Easy to self administer

Disadvantages of Topical Drug Delivery

• low drug retention due to low tear volume

• Lots of spillage

• Can be inaccurately administered by the patient

• must be sterile

• Can cause local side effects (pain, blurred vision, irritation)

Layers of Tear Film

1. Lipid Layer

2. Aqueous Layer

3. Mucus Layer

4. Cornea

What layers of the eyes must the drug pass through?

ALL LAYERS

What chapter is ophlalmic drugs regulated by?

USP 797: Compounding Sterile Preparations

How is By Use date (BUD) determined in Ophthalmic Drugs?

1. Sterility Testing

2. Aseptic Preparation

3. Post-Manufacturer Steralization

How many categories in Compounding Sterile Preparations (CSP)?

3 categories

Category 1 CSP

• Least environmental Control

• BUD of < 12 hours at room temp

• BUD of < 24 hours in fridge

Category 2 CSP

• More environmental control

• BUD of > 12 hours at room temp

• BUD of > 24 hours in fridge

• Still less than # on table

Category 3 CSP

• Sterility Testing

• More requirements

• Sterile Garb

• Sporadical disinfectants

• envirnmental monitoring

• Longer BUD

Factors to Consider when compounding Ophthalamics

1. Sterility (proper sterilization and aseptic technique)

2. Tonicity (0.6-2% NaCl, 0.9%=ideal)

3. pH, Buffering (Ideal pH=7.4, Tolerate pH 3.5-8.5, useful 6.5-8.5)

4. Need preservative (must be used if product used > 24 hours)

5. viscosity

6. inherent toxicity of API

7. Solubility

8. Stability

9. Free from particulates/ need clarity

10. Packaging and storage

What is most common vehicle in Ophthalmics?

Sterile Water for injection

What is not used in Ophthalmics?

Alcohol

Auxiliary Agents in Ophthalmics

• Buffers

• Tonicity Agents

• Perservatives

• Antioxidents

• Viscofiers

• Clarifying/wetting agents

• Drug permeability enhancers