Contact lens care regimens Flashcards
Directly contribute to product efficacy
Active ingridients
Additional ingredients to produce a usable product
Excipients (non active ingredients)
chemical agent that gives form or consistency to the drug preparation but with limited use in ophthalmic preparation:
Excipients - non active drug ingredients
Non-active agent that dissolves the active form of the drug, controlling its viscosity and aids the transport of the active drug:
ophthalmic vehicle
non-active ingredients (Excipient):
- Water
- Salts
- Viscosity enhancing agents
- Buffer systems
- Measure of the relative amounts of hydrogen ions
- Method of expressing the strength of acids and bases (acids <7>bases)
pH
Is a molecule that includes a positively charged hydrogen ion (H+) as part of its chemical structure and can transfer this ion to another molecule
ACID
- Is a molecule that has a negatively charged hydroxide group (OH-) within its chemical structure and can accept hydrogen ion from an acid
BASE
Average pH of tearfilm:
7.4
pH range of contact lens solutions:
6.5 - 8.0
One or more chemical compounds that when dissolved resist drastic changes in pH
Maintains the Ph of contact lens solutions
Buffer
buffer systems:
Borate - boric acid (B&L) / sodium borate (Alcon optisoft)
Citrate - sodium Citrate / Citric acid (Alcon optifree)
Phosphate - Sodium phosphate / phosphoric acid (Allergan)
A chemical term which describes a solution’s total salt concentration
Usually expressed in milli-osmoles per kilogram (mOsm/kg)
Osmolality
average tear film osmolality
302 mOsm/kg
Describes a solution’s effect on the “tone” or shape of a cell
Tonicity
