Semi-Solids

cream

FDA: an emulsion, semisolid dosage form, usually containing >20% water and volatiles and/or <50% hydrocarbons, waxes, or polyols as the vehicle. Generally for external application to skin or mucous membranes

gel

USP 1151: semisolid systems consisting of either suspensions make up of small inorganic particles or large organic molecules interpenetrated by a liquid

gel

FDA: a semisolid dosage form that contains a gelling agent to provide stiffness to a solution or a colloidal dispersion. May contain suspended particles

paste

USP 1151: semisolid dosage forms that contain one or more drug substances intended for topical application

paste

FDA: semisolid dosage form containing a large proportion (20-50%) of solids finely dispersed in a fatty vehicle. Generally for external application to skin or mucous membranes - no water

emolient

agent that softens or soothes irritation in skin or mucus membrane

protective

substance that protects injured or exposed skin surfaces from harmful or annoying stimuli

occlusive

substances that promotes retention of water in skin by forming hydrophobic barrier that prevents evaporation of moisture within the skin

humectant

substance that causes water to be retained because of its hygroscopic properties (water absorbing)

ointment bases

hydrocarbon, absorption, water-removable, or water-soluble

-chemically and physically stable under normal conditions and storage

-nonreactive and compatible with a wide variety of drugs

-typically odorless

-non-toxic, non-sensitizing, and non-irritating

easy application and non-greasy

-stays on skin until easy removal when desired

hydrocarbon (oleaginous) bases

Ideal choice of ointment base because they are inexpensive, non-irritating or reactive, are good emollients, protective, and occlusive, and stay on the skin to keep medicine in contact

disadvantages because patients often do not like the greasy feeling, it is difficult to wash off, does not absorb water so it is hard to incorporate liquid ingredients, and aqueous secretions of the skin cannot dissipate

anhydrous

type of absorption base that consists of a hydrocarbon with an emulsifier; forms water in oil emulsion when aqueous solution is added (able to absorb significant amounts of water and moderate amounts of alcoholic solution)

w/o

type of absorption base that contains water and is an emulsion - can absorb variable amounts of water and/or alcohol

absorption bases

ideal because they are emollients, protective, and occlusive, don't wash off easily to keep medicine in contact with skin, can absorb liquid, and some lanolin-types have composition somewhat like the sebaceous secretions of the skin and are thought to have superior emollient properties

disadvantages include poor patient acceptance because they may feel greasy or sticky, not easily removed with washing, bases containing wool wax or wool-wax alcohols may be sensitizing, bases with soap-type emulsions can have compatibility problems, and antimicrobial is required

hydrocarbon bases (examples)

Ex: white ointment

anhydrous absorption bases (ex)

Ex: hydrophilic petrolatum, polysorb, aquaphor, aquabase

w/o absorption bases (ex)

Ex: rose water ointment; hydrocream; eucerin

water-removable baes

oil-in-water emulsions and are classified as creams

ideal because they are non-greasy, can be removed from skin by washing, can add liquid to turn into a lotion once it reaches critical amount, absorbs water or alcohol, and allow dissipation of fluids from injured skin

disadvantages are that it is less protective, occlusive, or emollient, soap-type emulsifiers can have compatibility problems, have chemical stability problems with ingredients sensitive to hydrolysis, require a preservative, and may "dry out" due to evaporation of water (store in tight containers to minimize this) - add a humectant (2-5% glycerin and propylene glycol) to slow dehydration

water removable bases (ex)

Ex: hydrophilic ointment, soft water-washable base, dermabase, vanishing cream base

water soluble bases

greaseless ointment bases that are water-soluble. Most are polyethylene glycol- type ointment bases

advantages include easy washing in water, do not leave oil residue, and can absorb water or alcohol - as the amount of liquid added increases, the base thing out and dissolves

disadvantages are that they can be irritating, have little to no emollient properties, PEG-type bases may have compatibility problems with incorporated drugs that are subject to oxidation, and require a preservative

water soluble base (ex)

Ex: polyethylene glycol ointment

ointment base

absorption base

water-removable base

water-soluble base

fatty pastes

similar to ointments but thicker, less greasy, and more absorptive; better at absorbing secretions of the skin, making it useful for treating lesions that are weeping or oozing; less penetrating and stays in place on the skin better than ointment

Ex: zinc oxide

single-phase aqueous gel

carboxymethylcellulose sodium paste, USP; contains 16-17% sodium carboxymethylcellulose

animals

for ______________, pastes are an oral rather than topical dosage form, usually delivered by syringes

gels

may be used topically, introduced into body cavities, or used internally; can be single-phase or two-phase

magmas

_______________ have larger suspended particles than gels

single phase

type of gel that contain soluble macromolecules which are linear or branched-chain polymers dissolved molecularly in water; are classified into one of three groups: natural polymers (tragacanth), semisynthetic cellulose derivative (methylcellulose) , or synthetic polymers (carbomer)

two phase

type of gel that connected network of particulate association colloids; contain water insoluble particles that hydrate strongly (aluminum hydroxide, bentonite magma); thixotropic suspensions

gels

carbomer 934 aqueous jelly, carbomer 934, hydroxy alcoholic jelly, carbomer 934 alcoholic gel, poloxamer gel, and ephedrine sulfate jelly are types of ________

ointment pads

not ideal for manually preparing semi-solids with liquid ingredients because they absorb moisture and can tear if not working quickly

manual

_______________ methods of preparation primarily involve using a pill tile and a spatula or a mortar and pestle; surface must be clean and non-shedding; pill tile can be used for both particle size reduction and mixing ointment

mechanical

_______________ methods of preparation involve mixers from hand-held propellers to kitchen mixers to pattles or blades; used to prepare large quantities of ointment

levigation, fusion

drugs may be incorporated into an ointment base by ___________________ or _____________________

levigation

method of reducing particle size and homogenization with the base; select the levigating agent based on their hydrophilic/lipophilic properties appropriate for the drug

levigating agents

viscous, low surface tension liquid to enhance the wettability of the solid particles; must be compatible with the vehicle used

hydrocarbon and absorption

mineral oil, castor oil, olive oil, and Tween 80 are examples of levigating agents for ____________________________________ bases

water washable and water soluble

glycerin, propylene glycol, and polyethylene glycol (PEG) 400 are examples of levigating agents for ______________________________ bases

hydrophobic

for emulsion bases and a _______________ drug, mineral oil should be used as a levigating agent

hydrophilic

for emulsion bases and a ______________ drug, glycerin, alcohol, or propylene glycol should be used as a levigating agent

fusion

method of semi-solid compounding in which the waxy base is melted and the oil-soluble drugs dissolve, followed by adding the water phase in small quantities in which the drug is homogenized. Product filling should occur just before it solidifies because if it is too liquidy, sedimentation will occur and the semi-solid will no longer be uniform

plastic bag

two or more ointments can be combined by mixing in a ________________________

volatile

___________ solvents should not be used in levigating powders because the solvent will evaporate and leave crystals of the drug

aqueous, oil

when oil and aqueous phases are mixed together, heating the ______________ phase a few degrees higher than the _____________ phase before mixing because of their respective cooling rates

fusion

_____________ is the preferred compounding method for pastes, as levigation is difficult due to the high solid content

humectant (2-5%)

adding a ___________________ such as glycerin, PEG 300 or PEG 400, propylene glycol, or sorbitol to a cream will decrease rates of evaporation

cooled

when compounding a cream, the preparation should be ____________ before volatile oils or alcoholic solutions are added

surfactant

________________ is required for a good cream emulsion; 0.5 to 5%

lotions

______________ can be prepared form creams (o/w emulsions) by diluting the cream with water or aromatic water such as rose water. This may lower the concentration of preservatives, so the BUD should be shortened

10%

when compounding semi-solids, an excess of __________ should be made

aqueous

when working with ______________ systems, use heat for as short a time as possible and at a low temp as feasible

solvent, base

____________ and type of ___________ used should be noted on the face of the prescription or in the documentation table

quality control

observed and document the final weight, visual appearance, color, odor, viscosity, pH, homogeneity and phase separation, particle size distribution, and texture

headspace

minimising _______________ in a container is the best for decreasing the poss of water and the tendency toward rancidity

ophthalmic

sterility is not required for semi-solid preparations except for _________________ preparations

thin film

consult patients to use ____________________

30 days

BUD for an aqueous topical

ointment

USP 1151: semisolid preparations intended for external application to the skin or mucous membrane

ointment

FDA: semisolid dosage form, usually containing <20% water and volatiles and >50% hydrocarbons, waxes, or polyols as the vehicle. Generally for external application to the skin or mucous membranes

cream

USP 1151: oil-in-water emulsion or aqueous microcrystalline dispersions of long-chain fatty acids or alcohols that are water washable

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