Exam 3 Flashcards
what is a gel
semi solid dosage form
what does a gel consist of structure wise
a matrix formed by hydrogen bonds between..
- gel base/ gel base
- gel base/ active ingredient
- micelle/ micelle
- viscosity primarily due to hydrogen bonds not molecular weight
Can the organic matrix be altered? if so, by what
- temporarily by heat
2. permanently by alcohol
purpose of gels
- vehicle for topical, transdermal, IM or oral preparations
2. achieve high viscosity with low molecular weights
gel solubility
what should it be able to do
what is the exception
must be soluble in body fluids or able to melt @ body temp.
exception: hemostatic gelatin
examples of internal used gel
Amphojel tab/capsule
example of vaginal gel
metrogel (metronidazole)
examples of topical gels
hemostatic gelatin
americaine/ hurricaine (benzocaine)
campho-phenique (camphor/ phenol)
erygel (erythromycin)
examples of transdermal gels
clonidine, gabapentin, ketamine, lidocaine
indomethacin
prochlorperazine
scopolamine
examples of gels used topically for local effect
ketoprofen (PLO)
Transdermal gel dosing
should have what
should have.. 1. specific dose 2. by volume (mg/mL) 3. metering device 4. instructions should read .... ex: apply 1 mL to chest did orrr apply contents of1 syringe bid 5. CAREGIVER SHOULD WEAR GLOVES
Considerations for gel preparations
non organic based gels
- order of incorporation
2. topical
Considerations for gel preparations
organic based gels
- order of incorporation (lipo/hydro phase)
- shear forces
- micelles
- transdermal
(googled)
what is a PLO gel
Pluronic lecithin organogels (PLO gels) are lecithin-based organogels widely used in compounding pharmacies as a vehicle for enhancing the transdermal permeability of many therapeutic drugs.
when rx says to make PLO gel, what ingredients must you use
- drug prescribed (ofc.)
- Pluronic F127 (gel)
- Lecithin/ Isopropyl palmitate solution (oil/solution)
UBSOP policy for compounding transdermal gels
when compounding semi solid UNIT DOSE preparations, 1 extra dose of compound may be prepared
volume of deadspace in syringes for transdermal preparations we have to account for
- 0.1 mL x2 for the headspace of the syringes
- 0.1 mL of headspace in the syringe-to-syringe adapter
0.1+0.1+0.1=0.3
how to determine volume of Lecithin/ Isopropyl palmitate Solution to use when compounding transdermal gels
22% w/v
how to determine volume of plutonic F127 gel to be used when compounding transdermal gels
it is the qs media.
once mixing drug with the lecithin/ isopropyl palmitate solution. expel remaining air and note volume. subtract from total volume to DISPENSE, NOT total volume to prepare (which includes the deadspace volume
will end up with f127 volume needed to compound.
notes from transdermal gel compounding calculations
- calculate total volume to prepare ): prescribed volume + 1 extra +deadpsace volume
- calculate how many doses to prepare: total volume to prepare in proportion to 1mL/dose
- calculate drug amount
- calculate lecithin/ isopropyl palmitate solution: 22% w/v
- calculate F127 volume by subtracting volume of drug/ lecithin mix from TOTAL VOLUME TO DISPENSE (NOT PREPARED).
how to ensure tip contents transferred to main body of an ampule
- gentle tapping against work surface
- swirling
- gentle finger snap
how to safely handle ampule when using one
- ensure tip contents transferred to main body
- swab neck with alcohol swab
- wrap neck with alcohol swab or gauze pad when breaking
- use filter star or filter needle to withdraw
either pre filter or post filter
needles to use when using ampules
use a 0.5 micron filter needle when drawing liquid from ampule. then use switch needle to ensure filtered stuff doesn’t get back into the IV bag
pros and cons of ampules
pros: do not require preservatives
cons: contamination by glass shards upon opening, filtration required
define ophthalmic preparations
USP definition
essentially free from foreign particles, suitably compounded and packaged for installation into the eye (and ocular tissue surrounding the eye)
note: USP 797 “pharmaceutical compounding-sterile preparations” mentions ophthalmic preparations should be sterile
“…which include but are not limited to… inhalations, injections, powers for injection, irrigations, metered sprays, and ophthalmic and otic preparations”
purpose of ophthalmic preparations
administration of medication to the eye
lubrication
cleansing
local vs systemic effect of opthalmic preparations
local effect only? yes
systemic absorption:
always undesired
GI coupling: gets absorbed into nasolacrimal gland
epithelial absorption