O Rx - Lecture 1 - Intro

Front 1

TQ: What are the systemic effects of topically administered ocular drugs?

How can they be reduced?

Back 1

Through conjunctival capillaries --> nasal mucosa
--> pharynx or GI system after swallowing
If absorbed directly into bloodstream, does not have benefit of being “weakened” by GI system/liver

Nasal Lacrimal Duct Occlusion (NLDO)

Front 2

What is YOUNG'S RULE for pediatric dosing?

Back 2

Young’s Rule: ped dose = adult dose x (age in years / age + 12)

Front 3

TQ: What is CLARK'S RULE for pediatric dosing?

Back 3

Clark’s rule: ped dose = adult dose x (weight in kg / 70)

(1 kg = 2.2 lbs)

Front 4

Young's Rule is based on ________.

Clark's Rule is based on ________.

Back 4

Young = Age

Clark = Weight

Front 5

In pediatrics, ________ therapy is unpredictable therefore making ________ therapy favorable.

Back 5

Topical less favorable than Oral

Front 6

Tear film (TF) layer which prevents evaporation of aqueous layer?

Name 2 disease which interfere with this layer.

Back 6

Lipid layer (pH 7.4)

1) MGD
2) Blepharitis

Front 7

Tear film layer which comprises 95% of TF thickness?


Decreased in __________ disorders (lipid problems) and in __________ disorders

Back 7

Aqueous Layer

Evaporative and Hyposecretion (usually do to inflammation) disorders

Front 8

What is the HYDROphilic tear film layer made of glycoproteins secreted by GOBLET cells in the conjunctiva?

Back 8

Mucin Layer


True mucin deficiency is rare; associated with conjunctival scarring and/or destruction

Front 9

What is the volume of the TF?

Capacity?

Standard eye-drop ?


Increasing drop size increases __________ absorption but not __________ absorption

Back 9

8 to 10 MICROliters


Capacity = 30 mcl

Standard eye-drop = 50 mcl

Systemic NOT ocular

Front 10

Name 5 Factors that might influence Topical Drug Penetration.

Back 10

1) Nasolacrimal Duct Occlusion
2) Tilt head backwards to reduce drainage
3) Separate multiple drop instillation by 10 or more minutes
4) Ocular surface disruption may enhance penetration
5) Excessive lacrimation may dilute drug and reduce penetration

Front 11

Corneal penetration provides over __________ of drug penetration to A/C.

Back 11

80%

Front 12

Sclera and conjunctiva provide __________ of penetration of drug to AC - majority is carried away by __________.

Back 12

< 20%

Vasculature

Front 13

INTACT Superficial corneal epithelium (squamous cell layer) is __________ and therefore resists __________ drug penetration.

An example of this is __________.

__________ may act as drug storage depot because it is HYDROPHILIC.

Back 13

LipoPHILIC

HydroPHILIC

NaFl

Stroma

Front 14

__________ produces enzymes that detoxify and remove drugs from the eye.

Back 14

Ciliary Body

Front 15

__________ reversibly can absorb lipophilic drugs.

Back 15

Iris epithelial pigment granules

Front 16

____________ is the most metabolically active, and most prone to damage from drugs or toxins. It acts as a partial barrier between anterior and posterior segments.

Back 16

Anterior lens capsule

Front 17

____________ compounds can slowly pass into and through the lens cortex.

Back 17

LIPOphilic

Front 18

(____________) ____________ drugs don’t pass blood-retinal barrier easily to reach vitreous.

These drugs may be ____________ into the vitreous and remain there for 24 hours or more.

Back 18

(ORAL) HYDROphilic

Injected

Front 19

____________ in RPE impair movement of drugs from blood into retina and vitreous.

Blood-retinal barrier
is similar to BBB because retina is ____________ derived.

____________ drugs cross much more easily in both directions.

Many drugs are toxic to the retina and/or optic nerve.

Back 19

Tight junctions

Neural

LIPOphilic

Front 20

How are drugs removed from the eye by the bloodstream?

Retinal vessels – ____________

Uveal vessels – ____________

Episcleral vessels – Through ____________, through ____________, through ____________

Back 20

Retinal vessels – Active transport

Uveal vessels – Bulk transport

Episcleral vessels – Through AQUEOUS, through TM, through CANAL of SCHLEMM

Front 21

What is a compound that is changed metabolically to an effective drug form at or near the receptor site?

May involve the addition of chemical structures to help penetration.

____________ was the first successful example.

Back 21

Prodrug

PROPINE (dipivalyl epinephrine)

Front 22

The “opposite” of prodrugs, what is an effective form of drug that is rapidly and predictably transforms into an inactive form?

Give 2 examples.

Back 22

Site - specific drug


LOTEMAX and ALREX - these cause fewer side effects than older STEROIDS

Front 23

What was designed to kill or inhibit growth of microorganisms in multiple-dose containers?

Back 23

Preservatives

Front 24

- Quarternary surfactant
- Very effective antimicrobials
- Long shelf life – very stable
- Significantly disrupts lipid layer of tear film (takes a long time to re-distribute and normalize)
- Use is associated with corneal epithelial disruption, conj disruption, and possibly intra-ocular tissue changes in long-term use of meds containing BAK
- Increases penetration of drugs
- Most toxic to the cornea but if you need a drug to penetrate than it would be great

What COMBO is it used in?

Back 24

BAK / BAC / Benzalkonium Chloride

ZYMAR

Front 25

What preservative is a DIGUANIDE and does not disrupt cornea as much as BAK?

Back 25

Chlorhexidine

Front 26

TQ: What preservative has a high incidence of contact sensitivity (allergy mediated) developing over time and how will it present?

___________ is most common in this group.

Not commonly used in “name-brand” drugs today.

Back 26

Mercurials

With a puffy eye

Thimerosal

Front 27

Which preservative is a weak antimicrobial with fairly short shelf-life?

Does not disrupt tear film or cornea to any significant degree.

Usually combined with ___________ to increase effectiveness

Back 27

Chlorbutanol

EDTA (Ethylene diamine tetra acetic acid)

Front 28

Which oxidative preservative dissipates into water and sodium chloride when exposed to light?

Which oxidative preservative is converted to hydrogen peroxide and then oxygen and water once in the eye?

What is another name for oxidative preservatives?

They are used extensively in ___________ and ___________.

Back 28

Stabilized oxychloro-complex (Purite, Allergan)


Sodium perborate (Ciba)

“disappearing preservatives”

AT preparations and CL solutions

Front 29

Drug vehicles are also known as ___________ and is the ___________ ingredient in most drops and ointments.

The vehicle can significantly change what 4 things?

**Be able to recognize agent on pages 32-34.**

Back 29

"carriers"

Inactive

1) Penetration
2) Contact Time
3) Lipophilic/hydrophilic profile
4) Side effects of medications

Front 30

What are the 5 types of preservatives we learned?

Which one is most used today?

Back 30

1) BAK
2) Chlorhexidine
3) Mercurials
4) Chlorbutanol
5) Oxidative Preservatives *