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Pharmaceutics II, Semisolids, (test 1)


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Name 7 semi-solid dosage forms?
1. ointments

2. creams

3. gels

4. pastes

5. lotions

6. topical solutions

7. liniments
What should meds do for skin disease?
should penetrate the skin and be retained in it
Semi-solid dosage forms are usually not intended for what?
systemic admin. of drugs (typically just want a local effect)
Semi-solid dosage forms have ? and ? uses.
OTC and prescription
Which term is broader, topical or dermatological?
When can the term "topical dosage form" be used?
it can be used when the application of a delivery system is on the:


What is a dermatological dosage form?
refers to products that are applied only to the skin or the scalp, and an external use only label is used to denote such restricted use
What is the largest of the body organs?
The skin has how many layers? Name them.
1. epidermis

2. dermis

3. subcutaneous layer
Anatomically, skin is a ? organ.
Define stratum corneum?
- aka "horny layer"

the outer layer of epidermis, functions as a protective phys. and chem. barrier

-it is composed of 40% protein, 40% H2O, lipid mainly triglycerides, free FAs, cholesterol, and phospholipids
What is on the surface of the skin?
an acidic film (pH 4-6.5) of emulsified material of a mix of sebum, sweat, and desquamating epidermal cells covers the stratum corneum (it provides little resistance to drug penetration)
The stratum corneum acts as what?
a selective barrier...a semipermeable membrane
Passive diffusion thru the stratum corneum depends upon what 3 things?
1. conc. of drug

2. aqueous solubility

3. oil-water partition coefficient
What kind of drugs are good candidates for diffusion thru the stratum corneum?
drugs with both aqueous and lipid solubility
Drugs that pass thru the stratum corneum may also be able to pass thru what?
the deeper dermis layers or to the blood
What is percutaneous absorption?
the absorption of subst.s from outside the skin to positions beneath the skin, including entrance to the blood stream.
Before a drug has percutaneous absorption what has to happen?
it has to diffuse out of it's vehicle ( cream, oint., gel, etc)
6 factors that affect drug penetration into the skin?
1. physiochemical prop.s of the drug

2. the vehicle/base

3. method of application

4. contact time

5. the skin conditions

6. multiple application
Explain how the physiochemical prop.s of a drug affects it's penetration into the skin?
1. drugs must have a greater affinity for the skin than the vehicle

2. biphasic solubility (ex. has to partition bn water and oil)...solutes with 100-800 molecular can permeate skin (1mg/mL solubility O/W)

3. drug concentration increases amount of drug absorbed per surface area
What does biphasic solubility have to do with a drugs penetration of the skin?
solutes with 100-800 molecular can permeate skin (1mg/mL in O/W)
Explain how the vehicle/base affects a drugs ability to penetrate into the skin?
veh.s that increase hydration at the stratum corneum enhance percutaneous absorption (ex. oleagionous vehicles and occlusive bandages)
What does oleaginous mean?
having the qlty or nature of oil
Describe how the method of application affects a drugs ability to penetrate into the skin?
rubbing in leads to greater absorption
Describe how contact time affects the ability of a drug to penetrate into the skin?
greater contact time leads to more absorption
Explain how the skin conditions can affect a drugs ability to penetrate into the skin?
1. Stratum corneum (thin vs. thick), the thinner the SC the greater the percutaneous absorption

2. hydration of the skin, hydrated SC has an affinity for both lipohilic and hydrophilic compounds

3. surface area of application, more drug is absorbed when the substance is applied to a greater area
Who tends to have a thinner SC?
infants and the elderly
Explain how multiple applications affects a drugs ability to penetrate into the skin?
better than single bolus
Name 3 semi-solid dosage forms intended for topical application?
1. ointments

2. creams

3. gels
oint.s, creams, and gels are intended for application to where?
1. skin

2. eye

3. nasal membrane

4. vagina

5. rectal
Topical dermatological vs. transdermal delivery?
1. topical dermatological = deliver drug into the skin (local effect)

2. transdermal = del. drug thru the skin
Effects of topical dermatological vs. transdermal?
1. top. derm. = treats dermal disorders

2. transderm. = for systemic effect (not a local effect)
Give an example of a transdermal med.?
nicotine patches...drug delivered thru skin and has a systemic organ is not the skin.
Oint. base may be used for what?
their physical effects or as vehicles for medicated ointments
Name two general types of ointments?
1. non-medicated

2. medicated
3 uses for non-medicated ointments?
1. used alone as emollient (moisturizing effect hydrates the skin and prevents loss of water) or lubricating...ex. vaseline

2. used as a base for prep. of medicated oints.

3. as occlusive (aids in prevention of loss of water) to enhance drug absorption
Two types of medicated ointments?
1. antifungal

2. steroids
2 phases of an emulsion?
1. aqeous

2. oil phase
When using the abbr. "W/O" to describe a 2 phase material which is the internal phase and which is external?
Water is internal, oil is external...general form = internal/external
Which is less greasy O/W or W/O?
O/W bc water is external phase
4 main groups of ointment bases?
1. oleaginous (aka hydrocarbon bases)

2. absorption bases

3. water removable bases (O/W type)

4. Water soluble bases
What are the oleaginous (hydrocarbon bases) made out of?
petrolatum (petroleum)
The 2 types of absorption oint. bases?
1. anhydrous

2. W/O type (aka hydrous)(water in oil, so greasy)
An ex. of a water removable (O/W type) oint. base?
Are Oleaginous bases hydrophilic or hydrophobic?
Oleaginous bases have a ? effect.
2 disadvantages of oleaginous bases?
1. difficult to wash with water

2. greasy and stain clothing
Concerning oleaginous bases, mineral oil is a ? agent.
An advantage of oleaginous bases?
occlusive (prevent the escape of water from SC, swells, helps permeation of drug) (ex. good for eczema)
Upon aging what don't oleaginous bases do?
dry out or change
Oleaginous bases are retained on the skin for how long?
long periods of time (can be uncomfortable)
Name 4 oleaginous bases?
1. petrolatum USP

2. white petrolatum USP

3. yellow ointment USP

4. white ointment USP
petrolatum is aka what?
yellow petrolatum = petroleum jelly
petrolatum usp is a mixture of what?
semisolid hydrocarbons obtained from petroleum
petrolatum usp has a high degree of what?
compatibility with a variety of medicaments
Color of petrolatum usp?
yellowish to light amber
MP of petrolatum usp?
38-60 degrees celsius.
Commercial name of petrolatum usp?
White petrolatum usp is the same as what?
petrolatum usp, just decolorized
White petrolatum usp is what kind of mix?
wholly or partially decolorized, purified mixture of semisolid hydrocarbons from petroleum
White petroleum jelly = ?
white soft paraffin
What is white petrolatum usp used for?
the same purposes as petrolatum but it is more esthetically pleasing due to it's color
Is white petrolatum usp washable?
not water washable, it is occlusive
White petrolatum is aka?
white petroleum jelly
Commercial name of white petrolatum usp?
white vaseline
All oleaginous bases involve what?
Yellow ointment usp is aka?
simple ointment
What is yellow oint. usp composed of?
petrolatum with 5% yellow beeswax (ex. yellow wax = 50g and petrolatum = 950g)
Explain how yellow ointment is prepared?
1. melt wax in water bath

2. add petrolatum until the mix is uniform or melt them together

3. mix and allow to congeal
Viscosity of yellow ointment usp vs plain petrolatum?
has slightly greater viscosity
What is white oint. usp composed of?
white petrolatum and 5% white beeswax (ex. white wax = 50g and white petrolatum = 950g)
How is white oint. prepared?
1. melt wax in water bath

2. add white petro. until the mix is uniform or melt together

3. mix and allow to congeal
The 2 types of absorption bases?
1. Anhydrous (absorbs water to become W/O)

2. hydrous (is W/O already and can absorb more water)
Anhydrous absorption bases absorb water to become what?
W/O emulsion
8 notes about anhydrous absorption bases?
1. emollient

2. occlusive

3. anhydrous

4. absorbs water

5. not water washable

6. greasy and stain clothing

7. ex. hydrophilic petrolatum

8. ex. anhydrous lanolin (lanolin usp)
Hydrophilic petrolatum is an ? ? base.
anhydrous absorption
Components of hydrophilic petrolatum usp?
1. Cholesterol = 30g (emulsifying agent)

2. Stearyl alcohol = 30g (emulsifying agent)

3. white wax = 80g

4. white petrolatum = 860g
Procedure for preparing hydrophilic petrolatum?
1. melt stearyl alc. and white wax on steam bath

2. add cholesterol till dissolves completely

3. then add white petrolatum and mix

4. remove from heat, stir until mix congeals
Commercial product of hydrophilic petrolatum usp?
Aquaphor products (takes up to 3 times of water per weight)
What is lanolin?
wool fat/ refined wool fat
What is anhydrous lanolin usp?
an anhydrous absorption base
Where does anhydrous lanolin usp come from?
sheeps wool (also contains sterols and aliphatic alcohols)
Anhydrous lanolin is a ? ? substance.
purified wax-like substance
Anhydrous lanolin usp mixes with up to how much water?
with up to twice its weight in water
What is Modified Lanolin USP?
another type of anhydrous lanolin...has less lanolin alcohols...less detergents and pesticide residues
Are hydrous absorption bases written W/O or O/W?
Absorption bases are ? and are w/o emulsions that can absorb what?
they are hydrophilic and can absorb more water
w/o absorption bases are aka what?
hydrous absorption bases or hydrated emollient base
8 notes about hydrous absorption bases?
1. emollient

2. occlusive

3. contain water to start with

4. absorb addnal water

5. greasy and stain clothing

6. hydrous lanolin

7. cold cream (typically) (w/o), cleansing creams

8. commercially eucerin and nivea cream
When you wash your face with a cleansing cream that is a hydrous absorption base what are you doing to it?
as you wash you change it from w/o to o/w
Two commercially available forms of hydrous absorption bases?
eucerin and nivea cream
4 notes about hydrous lanolin.
1. it is a hydrous absorption base

2. wool fat (anhydrous lanolin) with 25-30% water added becomes "lanolin"

3. addnal water may be incorporated

4. hydrous wool fat
5 notes about cold cream (cleansing cream)?
1. w/o emulsion

2. some ex. = petrolatum rose water ointment, nivea cream, eucerin

3. both hydrous and anhydrous bases not used often for drugs

4. w/o system more difficult to deal with than o/w

5. decreased pt. compliance due to greasiness
Explain how a cleansing cream works?
1. application of the w/o emulsions helps dissolve and remove cellular debris and lipophilic sebum

2. addn. of large qty of water produces a phase inversion

3. w/o ---> o/w

4. o/w emulsion is water washable
Water removable bases are what kind of emulsions?
Water removable bases are aka?
"water washable bases" creams
The external phase of water removable bases is what?
Water removable bases can be diluted with what?
water or aqueous solutions
Are water removable bases (water washable bases) greasy?
Water removable bases must be what? Why?
preserved...b/c has water as external phase and water promotes bacterial growth unless preserved
Water removable bases could be called cosmetically ?.
An example of a water removable base (water washable base)?
hydrophilic ointment
The 3 phases of water removable bases?
1. oil phase

2. emulsifier

3. aqueous
Describe the oil phase of water removable bases?
(internal phase)...typically petrolatum and/or liquid petrotlatum with a higher MW alcohol, like cetyl or stearyl alcohol
What can emulsifying agents do to skin?
they can damage/dry skin (esp. soaps and detergents...anionic and cationic surfactants)...nonionic surfactants to a lesser extent
Which phases are involved in hydrophilic ointment?
1. oily phase

2. aqueous phase

3. emulsifying agent
The two preservatives in hydrophilic ointment?
1. methylparaben

2. propylparaben

(both are o/w type)
In hydrophilic oint. which phase is external and which is internal?
external = aqueous

internal = oily
Propylene glycol is a humectant. What does this mean?
it has hydrophilic prop.s and a stabilizing effect on the water content in a material, minimizes water loss in a finished product...So it absorbs moisture
Water soluble bases contain only what?
H2O soluble components
Water soluble bases may include what?
gelled aqueous solutions
Are water soluble bases water washable?
Do water soluble bases contain any lipids?
no, lipid free
Are water soluble bases ever greasy?
Water soluble bases have no ? component.
Water sol. bases are for ? or ? substance incorporation.
are for nonaqueous or solid substance incorp.
2 disadvantages of water soluble bases?
1. Nonocclusive and may dehydrate SC

2. High drug solubility in the base may lead to poor bioavailability
The major component of water soluble bases.
PEG (polyethylene glycol)
An example of a water-soluble base?
PEG ointment NF
PEG ointment NF is a polymer of what?
ethylene oxide and water
Are there only a few or many grades of PEG ointment NF?
many grades...depends upon the avg. molecular weight
The avg. molecular weight of PEG range?
The greater the molecular weight of PEG the ? ? it is.
more viscous
Give an example of a general formula for PEG.
PEG 3350 400g

(3350 = MW)
(400g = Qty used)
Besides PEG ointment NF what else may be qualified as a water-soluble base? What are they referred to as?
aqueous gel vehicles containing water, propylene glycol and or PEG and gelled with a carbomer or a cellulose derivative...referred to a gels
2 steps of ointment preparation?
1. incorporation = mix together

2. fusion = all or some components of an ointment melted together and cooled with constant stirring until congealed, add non-melting substances as the ointment is being cooled and stirred
What is "levigating" in terms of solid incorporation into an ointment?
levigating a powder is a reduction of particle size in suspending agent compatible with the ointment base...example, levigation with MO or propylene glycol
A solid (or levigated solid) is mixed with an ointment base using what?
geometric dilution (a method of mixing where you gradually add drug to levigated oint. base)...use a mortar and pestle or 2 spatulas and slab in small scale
Solids may be dissolved in a solvent before what?
incorporation into base (use mortar)
Give an example of a "gummy material"?
How are gummy materials incorporated?
they are dissolved in solvent then solvent is spread and allowed to evaporate, leaving a thin film
Fusion involves ?, ?, ?, and ?.
is involves Melting, Mixing, Cooling, and Congealing
What is added last to an ointment base?
heat sensitive and volatile substances
What may be added to a congealed base?
solutions and levigated solids
In a lab one may carry out the process of fusion using what? What does the industry use?
lab = dish or beaker

industry = steel=jacketed kettles
During Fusion you heat both the ? phase and the ? phase seperately to ? degrees C then add ? to ? phase.
During Fusion you heat both the oleaginous phase and the aqueous phase seperately to 75 degrees C then add the aqeous phase to the oily phase
What is a cream?
a semisolid dosage form containing one or more medicinal agents dissolved or dispersed in either o/w emulsion or an w/o emulsion or water washable bases. (includes topical, vaginal, rectal, etc)
Which is easier to spread and easier to remove, creams or ointments?
Pharmaceutical creams are classified as what in the USP? What are they described under?
classified as water-removable bases and describe under ointments
2 kinds of cream?
1. Vanishing (o/w emulsion)

2. Cold cream (w/o emulsion)
Cold cream (w/o emulsion) is aka what?
cleansing cream
Vanishing cream (o/w) contains a large percentage of what?
water and stearic acid or other oleaginous components
Upon application what happens to vanishing creams?
water evaporates ("vanishes") leaving a thin residue film of the stearic acid or other oleaginous component
How does the USP define gels?
as a semisolid being either a suspension of small inorganic particles or a large organic molecule interpenetrated in a liquid medium
Gels are rendered ? like by the addition of a ? agent.
rendered jelly like by the addn of a gelling agent
Gels are often not ? and spread ?.
not tacky, spread easily
Gels are easily removed from the ?.
Color of most gels? What does this result in?
clear...resulting in consumer perception of a safer, purer and non-irritating product, thus rendering better compliance
What sticks to skin better, creams or gels?
What is a gelling agent?
a polymer used to provide the structural network that is the essence of the gel system
4 types of gelling agents?
1. cellulose derivatives

2. polysaccharides (natural)

3. acrylic polymers (synthetic)

4. Colloidal dispersed solids
Which type of gelling agents are natural and which are synthetic?
polysacchs. are natural and acrylic polymers are synthetic
2 examples of cellulose derivatives that may be used as gelling agents?
1. methylcellulose

2. hydroxypropyl methylcellulose (HPMC)
4 examples of polysaccharides that may be used as gelling agents?
1. xanthan gum

2. tragacanth

3. alginates

4. carrageenan
example of an acrylic polymer that may be used as a gelling agent?
carbomer that form gels at concentrations as low as 0.5%
2 examples of colloidal dispersed systems that may be used as gelling agents?
1. silica

2. clays
2 ways of classifying gels?
1. by the nature of solvents

2. by the number of phases that comprise them
2 types of gels classified by the nature of their solvents?
1. Hydrogels (a water-based gel)(aqueous)

2. Organogels (a non-aqueous solvent system)
2 types of gels classified by the number of phases that comprise them?
1. single phase (more typical)

2. two phase called magma (ex. milk of mag)
Name 6 miscellaneous semi-solids?
1. lotions

2. pastes

3. plasters

4. liniments

5. collodions

6. glycerogelatin
What are lotions?
suspensions of solids in an aqueous medium
What are lotions intended to be applied to?
broken skin with no friction
How are lotions prepared?
by triturating the ingredients to a smooth paste and then adding the remaining liquid phase with trituration...on a large scale high-speed mixers or colloid mills produce better dispersion
An example of a lotion?
calamine lotion, USP
Components in Calamine lotion, USP?
Calamine 80g
Zinc Oxide 80g
Glycerin 20ml
Bentonite Magma 250ml
Calcium Hydroxide qs 1000ml
The USP def. of pastes?
usp defines pastes as semisolids dosage forms that contain one or more drug substances intended for topical application
Pastes are prepared by ? or ?.
by fusion or incorporation
Pastes have no ? agent.
no levigating agent
Pastes contain a larger percentage of ? ? than ointments. This makes them ? and stiffer.
a larger percentage of solid material...makes them thicker and stiffer...they are essentially ointments with more powder
Pastes will not do what after application?
will not soften and flow
Pastes should not be applied to what?
hairy parts
Pastes are used to absorb what?
serous secretions
An example of a paste?
triamcinolone acetonide dental paste (kenalog in orabase)
How can some ointments be packed?
in a jar or tube
Jars may be what?
transparent or light resistant
Weight of packaged ointment?
range from 0.5oz-1 pound
Which ointment should be packed in tubes?
ophthalamic, nasal, vaginal, and rectal
What do jars and tubes need to be compatible with?
the cream
Benefits of a tube?
they are light, cleaner, inexpensive, convenient, and compatible with most products from 1.5-120g
Tubes can be made of what material?
aluminum or plastic

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