Eye crazie (Exam 3)

Question 1

what are gels?

Answer 1

-semi-solid dosage forms

Question 2

Gels: consist of a matrix formed between hydrogen bonds between: (4 things **)

Answer 2

• gel base/gel base
• gel base/ active ingredient
• micelle/micelle
• viscosity primarily due to hydrogen bonds not molecular weights

Question 3

Gels & their organic matrix *

Answer 3

• may temporarily be interrupted by heat (viscosity can change with varying temps)
• may be permanently be destroyed by alcohol

Question 4

what is the purpose of gels?

Answer 4

• vehicle for topical, transdermal, IM or oral preps

- achieve high viscosity with low molecular weights

Question 5

Gels must be soluble in body fluids or able to melt at body temp, whats the exception?

Answer 5

hemostatic gelatin: used during surgical procedures, so in order to maintain its strength through the whole procedure - it cant be allowed to either melt at body temp or to dissolve in bodily fluids

Question 6

Where can i put some gel?

Answer 6

• used internally: Amphokel tablets/capsules: not suspension (aluminum hydroxide)
• used vaginally: metrogel (metronidazole)

Question 7

some examples of topical gels:

Answer 7

• hemostatic gelatin
• Americaine/hurricaine (benzocaine)
• campho-phenique (camphor/phenol)
• erygel (erythromycin)

Question 8

some examples of transdermal gels

Answer 8

-clonidine, gabapentin, ketamine, lidocaine, indomethacin, prochlorperazine, scopolamine

Question 9

gels used topically for local effect

Answer 9

-ketoprofen PLO

Question 10

gel dosing things *

Answer 10

need:
-specific dose - by volume (mg/ml)
apply 1 ml to chest tid or apply contents of 1 syringe bid
-caregiver should wear gloves!

Question 11

gel- extemporaneous prep considerations for non-organic based gels

Answer 11

• order of incorporation **v important- diverting from the plan can very easily render the product useless
• topical

Question 12

gel- extemporaneous prep considerations for organic based gels

Answer 12

• order of incorporation (lipo/hydro phase) = emulsion
• shear forces (help the formation of micelles)
• micelles
• transdermal

Question 13

administration dead space

Answer 13

-1 extra dose of compound: used to fill dead space of the storage and administration syringes

Question 14

USP def of ophthalmic preps

Answer 14

-essentially free from foreign particles, suitably compounded & packaged for instillation into the eye

Question 15

USP 797 def of ophthalmic preps*

Answer 15

basically they need to be sterile preparations

Question 16

what is the purpose of ophthalmic preparations*

Answer 16

• administration of medication to the eye (ocular tissues)
• lubrication (of the ball and socket joint)
• cleansing

Question 17

do ophthalmic preparations have local effect?*

Answer 17

yes!
but can have systemic absorption: always UNDESIRED = GI coupling (happens via lacrimal ducts connecting the eye to the back of the throat where tears drain into the GI system)
& epithelial absorption

Question 18

what is the capacity of the eye?*

Answer 18

• 1 gtt/eye (liquids)

- 50 mg/eye (ointments)

Question 19

dosage forms of eye drops(4)

Answer 19

• solutions: aqueous, ex: atropine 1% w/v
• ointments: white petrolatum & mineral oil, ex: tetracycline HCL 3% w/w
• suspensions: suspending agents, ex: prednisolone 1%
• gels: a solution which forms a gel upon administration, ex: timolol

Question 20

special considerations for ophthalmic preps*

Answer 20

• pH: 7.4 (ideal)
• tonicity: ~ 277 millimolar
• sterility? yes bish
• preservation: maybe, most times yes

Question 21

what are the tolerable ranges of pH for eye drop?

Answer 21

6-5-8.5 , if outside of this range = discomfort/stinging or can lead to corneal/tissue damage

Question 22

how is a tonicity/concentration measured?

Answer 22

via moles of solute particles per liter of solution

mole = avogadros # = 6.022 x 10^23

Question 23

**tonicity dictates colligative properties (4)

Answer 23

• osmotic pressure
• freezing point depression
• boiling point elevation
• vapor pressure
• colligative properties depend only upon the number of solute particles in solution, not the SIZE of those particles

Question 24

what is freezing point?*

Answer 24

the temperature at which a liquid freezes: unites = degrees C (absolute value)

Question 25

what is freezing point depression? *

Answer 25

-the number of centigrade degrees below the freezing point of water (zero C) at which a liquid freezes, units = C degrees

Question 26

what is the freezing point depression for water?

Answer 26

-freezing point is depressed 1.86 centigrade degrees for every mole of particles per liter of solution

Question 27

What 2 reasons could there be for the exception of hyper/hypo tonicity being unavoidable?*

Answer 27

• drug stability issues

- therapeutic dosing concerns

Question 28

what is the mM tolerable range for eye drops?*

Answer 28

200-600 mM

-outside of that range can cause discomfort, stinging and tissue damage

Question 29

what are the I values? or what is the pattern at least?*

Answer 29

non-electrolytes = 1.0
2-ion electrolytes = 1.8
-then add .8 to each on to add ions

Question 30

what is the I value?*

Answer 30

• works for most ionic salts in dilute solutions
• *exceptions: zinc sulfate, I = 1.4
• (moles of solute) X (the I value) = moles of particles in solution
• non-saturation at the indicated concentration is assumed!

Question 31

SCE method

Answer 31

-pH is not an issue (peep the lectures for that crazy math)

Question 32

Theorem “A”*

Answer 32

• if you add an isotonic solution (of any volume) to a second isotonic solution (of any volume), the resulting solution will also be isotonic.
• precipitation? drug degradation? reaction? miscible*

Question 33

V-values*

Answer 33

• the amount of H2O required for the dissolution of 300mg of drug which results in an isotonic solution
• assumptions: contribution of solute to the overall solution volume is negligible
• concentration: 300 mg/V-value

Question 34

USP method

Answer 34

-pH is not an issue (rest on ya sis)

Question 35

Sorensen Method

Answer 35

• pH IS an issue - pharmacist has direct control over product pH
• do thee phos and bi phos thing