Lab 6 Flashcards
APIs that are extremely lipophilic/hydrophobic are practically insoluble in water.
How can they be dissolved in water?
by using cosolvents or with pH modification
hydrophobic drugs can be solubilized with the use of SOLUBILIZERS and COMPLEXING AGENTS
Oral non-aqueous solutions of lipophilic APIs may be prepared in ___ and ____
fixed oils (peanut, corn, soybean, sesame, olive) and medium chain triglycerides
“oral non-aqueous solutions of lipophilic APIs may be prepared in fixed oils and medium chain triglycerides.”
these oral solutions may be flavored to improve taste, but generally are not appealing.
How are these solutions normally administered to combat this issue?
by mixing with food or filled in soft gelatin capsules.
soft gelatin capsules are what dosage form?
solid oral dosage form
give 7 examples of water-insoluble APIs
-Vitamin A
-Vitamin D
-Vitamin E
-Vitamin K
-CNS drugs (diazepam and barbiturates)
-hormones (progesterone)
SURFACTANTS can solubilize drugs by either ___ or ____
surfactants can solubilize drugs by either a DIRECT COSOLVENT EFFECT or UPTAKE INTO MICELLES
explain the structure of a surfactant molecule
contains a hydrophobic portion (the tail) and a hydrophilic portion (the head)
what is the function of surfactants
to solubilize poorly water-soluble drugs
the HEAD of a surfactant can be ____,____, or ____
CHARGED (anionic or cationic)
DIPOLAR (zwitter ionic)
NON-CHARGED (nonionic)
give the surfactant used in vitamin D2 formulation
cremophor
cremophor is a _____ surfactant used to solubilize ……..
NONIONIC surfactant used to solubilize a wide variety of hydrophobic CNS drugs (diazepam, barbiturates), and anticancer drugs
explain micelles are formed
when surfactant molecules are dissolved in water at concentrations above CMC (critical micelle concentration), they form aggregates known as micelles
micelles are formed when _____ molecules are dissolved in water at concentrations above CMC
SURFACTANT
explain the structure of a micelle
the hydrophobic tails flock to the INTERIOR to minimize contact with water.
the hydrophilic heads remain on the outer surface to maximize their contact with water
the hydrophobic drug is bound to the surfactant (micelle) and go to the interior of the micelle
the shape and size of the micelle formed depends on what FOUR things?
- the chemical structure of the micelle
- surfactant concentration
- presence of other surfactants, ions, and molecules
- pH
the ____ the cmc value of a given surfactant, the more stable are the micelles
LOWER
Precipitation is likely to occur if the preparation is diluted _____ the cmc concentration
BELOW
name 4 water-soluble organic solvents
-ethanol
-propylene glycol
-glycerin
-polyethylene glycol 400 (PEG 400)
name 6 water-insoluble solvents
-peanut oil
-corn oil
-soybean oil
-sesame oil
-olive oil
-medium-chain triglycerides
name a complexing agent
cyclodextrins
name 4 surfactants
Cremophor EL
Cremophor RH 40
polysorbate 20
polysorbate 80
heat is used to increase the ____ and does not affect the ____ of the substance
heat is used to increase the RATE OF SOLUBILIZATION and does not affect the intrinsic solubility of the substance
before using heat, what should you do??
check the properties of each ingredient to ensure that they do not degrade or evaporate
heat is used when preparing _____ solutions
HIGHLY CONCENTRATED
give 2 examples of highly concentrated solutions
simple syrup
sorbitol 70%
heat should NOT be used with ____ substances that __ during dissolution
exothermic substances that give off heat during dissolution
true or false:
when using heat, you should use the lowest temperature possible
TRUE
true or false:
hot plates (direct heat) are preferred over water baths
FALSE – water baths should be used for heating
when using heat, temperatures greater than ___ are usually not used
70 degrees celsius
____ or ____ are used to prepare drug loaded micelles.
which did we use in this lab?
heat or solvents
we used heat (water bath)
explain the process of using heat to prepare drug loaded micelles
heat stable oily ingredients (hydrophobic API, antioxidant, surfactant) are mixed together using heat
water is heated separately to ~65 degrees celsius then added slowly to the oily solution under constant stirring until a clear homogeneous solution is obtained.
heat-labile (destruction under heat) and water soluble ingredients are dissolved separately in water at room temp and added to the preparation just before making up the volume (QS) with the vehicle
the minimum amount of water required to make a clear solution is calculated using…..
SOLUBILITY INFORMATION
true or false
cremophor/oil micelles will not have some displacement volume
FALSE – they will have displacement volume
the preservative required is based on…..
THE WATER VOLUME USED IN SOLUBILIZING THE OIL (forming a micelle) and in dissolving the water soluble powders
(volume of color and flavor is almost insignificant)
what is the function of BHT (butylhydroxytoluene)
antioxidant – stabilizer
insoluble in water (it’s an organic compound)
