Lecture 5 Ointments, Creams, and Gels Flashcards

1
Q

What are the three layers of skin in order?

A

Epidermis, Dermis, and Hypodermis

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2
Q

What is a topical?

A

Preparations applied to the skin either for their physical effects or for the specific effect of a medicinal agent.

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3
Q

What is occlusive?

A

Forming a hydrophobic seal to keep the moisture there.

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4
Q

What are the uses of dermatologicals?

A

To protect skin or mucous membranes from chemical or physical irritants in the environment and to permit rejuvenation of the skin. To provide hydration of the skin or an emollient effect. To provide a vehicle for applying a medication either for local or systemic effects.

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5
Q

What are the factors of drug penetration?

A

Amount of pressure and vigor of rubbing, surface area covered, condition of the skin(abraded, dry, eczema), base used, and occlusive dressing use.

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6
Q

What are ointments?

A

Semisolid preparations intended for the external application to the skin or mucous membranes. Soften or melt at body temperature, Should spread easily and be non-gritty, Semisolid plastic flow characteristics, Definite yield value, resistance to flow drops as applications continues.

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7
Q

What are desirable properties of ointments?

A

Chemically and physically stable under normal conditions of use and storage, nonreactive and compatible with a wide variety of drugs and auxiliary agents, free from objectionable odor, nontoxic, nonsensitizing and nonirritating, aesthetically appealing, easy to apply and nongreasy, remains in contact with the skin until removal is desired then is easily removed.

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8
Q

What are the four ointment bases?

A

Oleaginous, absorption, water-removable, and water-soluble.

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9
Q

What is a oleaginous base?

A

Hydrocarbon base; water insoluble.
Emollient effect; prevent escape of moisture
Can remain on skin for prolonged periods without drying out; difficult to wash off
Not water washable
Can’t absorb water
Oily, occlusive, lack cosmetic appeal

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10
Q

What are the advantages of oleaginous bases?

A

Inexpensive
Nonreactive
Nonirritating
Good emollient, protective and occlusive properties
Not water-washable, so they stay on the skin and keep incorporated medications in contact with the skin

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11
Q

What are the disadvantages of oleaginous bases?

A

Poor patient acceptance because of their greasy nature.
Not removed easily with washing.
Cannot absorb water and can only absorb limited amounts of alcoholic solutions.

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12
Q

What are some examples of oleaginous bases?

A

Hydrocarbons(mineral oils, petrolatums, paraffins, waxes), Animal/vegetable fats/oils (castor oil, cottonseed oil, olive oil), Synthetic esters (glyceryl monosterate, butyl stearate, isopropyl lanolate, cetyl alcohol, stearyl alcohol), Petrolatum, White petrolatum, yellow ointment, white ointment.

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13
Q

What are the two types of absorption bases?

A

Those that permit the incorporation of aqueous solutions resulting in the formation of water in oil emulsions. (ex: hydrophilic petrolatum)
Those that are water in oil emulsions that permit the incorporation of additional quantities of aqueous solutions. (ex: lanolin)

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14
Q

What are the advantages of absorption bases?

A

Moderately good protective, occlusive and emollient properties, do no was off easily, so they hold incorporated medications in contact with the skin, can absorb liquids.

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15
Q

What is the main differences between absorption bases and ointments?

A

Absorption bases are sensitizing(irritating to the skin) because they have surfactant because they are emulsions. They also contain water so microbial growth can occur so antimicrobials need to be added.

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16
Q

What are the two main ways to prepare ointments?

A

Incorporation and fusion

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17
Q

What equipment do you use when compounding ointments?

A

Ointment slabs or pads, spatulas, small-scale ointment mills.

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18
Q

Account for excess when compounding ointments. T/F

A

True

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19
Q

When incorporating solids in ointment compounds what should you consider?

A

Should be solubilized or the particle size should be reduced as far as possible.
Auxiliary agents, levigating agents and solvents, can be added to facilitate making a smooth, elegant product.
If possible, select a fine powder.

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20
Q

When choosing a levigation agent for ointment what should we consider?

A

Levigating agents are usually chosen to be similar to the ointment base.
Melted ointment base may be used.

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21
Q

What are common levigating agents used in ointments?

A

Mineral oil - oleaginous, absorption, W/O emulsion bases

Glycerin/propylene glycol/water - O/W emulsion bases, water-soluble bases

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22
Q

How should fusion be performed while compounding ointments?

A

Heat highest melting point material first
Water phase a few degrees higher
W/O: add water slowly
O/W: add oil slowly

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23
Q

What are some examples of antimicrobial preservatives used in topical preparations?

A

Methylparaben and Propylparaben (usually used together), phenols, benzoic acid, sorbic acid, and quarternary ammonium salts.

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24
Q

What is the beyond use date for non-aqueous formulations?

A

6 months or 25% of the time remaining on the expiration date

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25
What is the beyond use date for everything but non-aqueous formulations?
No later than the intended duration of therapy or 30 days, whichever is ealrier
26
What are the differences between creams and lotions?
Lotions are going to have more liquid.
27
What is a cream?
A semisolid preparations containing one or more medicinal agents dissolved or dispersed in either a water in oil emulsion or an oil in water emulsion base or in another type of water-washable base. Semisolid, pseudo plastic flow Won't flow under force of gravity but small force will initiate flow.
28
What are creams typically used for?
topical skin products and product used rectally and vaginally. Often preferred to ointments because they are easier to spread and remove.
29
What is petrolatum (yellow or petroleum jelly)?
Purified mixture of semisolid hydrocarbons obtained form petroleum, unctuous mass, varying in color from yellowish to light amber. Melts at 38 to 60 degrees C. May be used alone or in combination with other agents as an ointment base.
30
What is white petrolatum?
Purified mixture of semisolid hydrocarbons that has been decolorized. More esthetically appealing than petrolatum, but used for same purposes.
31
What is yellow ointment?
Its a simple ointment that is slightly more viscous than plain petrolatum. 95%w/w Petrolatum and 5%w/w yellow wax(from honeycomb)
32
What is the difference between white and yellow ointment?
White ointment is made with white wax that is bleached and purified yellow wax.
33
What are the characteristics of absorption bases?
They may be used as emollients, but don't provide the degree of occlusion of oleaginous bases. not easily removed from the skin with water washing. Useful as adjuncts to incorporate small volumes of aqueous solutions into hydrocarbon bases. Oily, occlusive, lacks cosmetic appeal.
34
What are the disadvantages of absorption bases?
Some bases in this class have poor patient acceptance Not easily removed with washing May be sensitizing Can have compatibility issues related to the emulsifying agent May have chemical stability issues with bases that contain water and ingredients sensitive to hydrolysis Those that contain water may be subject to microbial growth
35
What are some examples of absorption bases?
Hydrophilic Petrolatum, USP Aquaphor Aquabase Lanolin, USP
36
What are the ingredients of Hydrophilic petrolatum?
Cholesterol (holds on to water and is the emulsifying agent) Stearyl alcohol )holds on to water) White wax White petrolatum
37
What is Lanolin?
Obtained from the wool of sheep Purified wax-like substance that has been cleaned, deodorized and decolorized contains not more than 0.25% water Modified Lanolin, USP has been processed to reduce the contents of free lanolin alcohols and any detergent and pesticide residues.
38
What are water-removable bases?
Water-washable bases Oil-in-water emulsions resembling creams (water is external phase) Easily washed from the skin May be diluted with water or aqueous solutions Can absorb serous discharges
39
What are examples of Water-Removable bases?
Hydrophilic ointment, vanishing cream, Dermabase
40
What are the advantages of Water-Removable Bases?
Nongreasy Can be removed from the skin by washing Can absorb some water or alcohol Will allow dissipation of fluids from injured skin.
41
What are the disadvantages of water-removable bases?
Less protective, less emollient, a less occlusive than hydrocarbon or absorption bases Can have compatibility issues with certain emulsifying agents May have chemical stability issues with bases that contain water and ingredients sensitive to hydrolysis Those that contain water may be subject to microbial growth May dry out due to evaporation of water.
42
What are the ingredients of a hydrophilic ointment (Water-removable base)? Don't need to know
``` Methylparaben - preservative Propylparaben -preservative (two work more efficiently) Sodium lauryl sulfate - surfactant Propylene glycol Stearyl alcohol White petrolatum Purified water ```
43
What are water-soluble bases?
No hydrocarbon components Contain no oleaginous components Completely water washable, greaseless Soften greatly with addition of water so not able to incorporate large amount of aqueous solutions effectively
44
What are the advantages of water-soluble bases?
Soluble in water, so easily removed by washing Leaves no oil residue Can absorb some water and alcohol
45
What are the disadvantages of water-soluble bases?
Irritating, little to no emollient properties PEG-type bases may have compatibility problems with drugs that are sensitive to oxidation Those that contain water may have the compatibility and stability problems associated with water and require a preservative
46
What is polyethylene glycol a polymer of?
Ethylene oxide and water
47
What is an example of a water-soluble base?
Polyethylene Glycol Ointment polyethylene glycol 3350 polyethylene glycol 400
48
What are important considerations when selecting an appropriate base?
Desired release rate of the drug substance from the ointment base Desirability of topical or percutaneous drug absorption Desirability of occlusion of moisture from the skin Stability of the drug in the ointment base Effect of the drug on the consistency of the ointment base Desire for a base that is easily removed from the skin Characteristics of the surface to which it is applied
49
What are the two ways you can prepare ointments?
Incorporation and Fusion
50
What are examples of gelling agents?
``` Synthetic Macromolecules (ex: Carbomer 934) Cellulose Derivatives (ex: Carboxymethylcellulose and hydroxypropyl methylcellulose) Natural Gums (ex: Tragacanth) ```
51
How much excess should you have to compensate for loss during compounding?
Either 10% or stated amount
52
What is a gel?
Semisolid systems consisting of dispersions of small or large molecules in an aqueous liquid vehicle rendered jellylike by the addition of a gelling agent. May also contain drug substances, solvents, preservatives and/or stabilizers May be prepared for various administration routes including the skin, eye, the nose, the vagina, and the rectum.
53
What different types of gels are there?
Single-phase gels and Two-phase gels
54
What is a single-phase gel?
Gels in which the macromolecules are uniformly distributed throughout a liquid with no apparent boundaries between the dispersed macromolecules and the liquid.
55
What is a two-phase gel?
magmas (Like suspensions); gel mass consisting of floccules of small distinct particles
56
What are phenomena's that are associated with gels?
syneresis, swelling, imbibition, thixotrophy
57
What is syneresis?
When the interaction between particles of the dispersed phase becomes so great that on standing, the dispersing medium is squeezed out in droplets and the gel shrinks.
58
What is swelling?
The taking up of a liquid by a gel with an increase in volume.
59
What is imbibition?
The taking up of a certain amount of liquid without a measurable increase in volume
60
What is thixotrophy?
A reversible gel-sol formation with no change in volume or temperature.
61
Topical ointments, creams, and gels can be designed to deliver a drug systemically by the addition of what to the vehicle?
Penetration enhancers
62
What are examples of penetration enhancers?
Dimethyl sulfoxide (DMSO), ethanol, propylene glycol, urea, dimethyl acaetamide, sodium lauryl sulfate, the poloxamers, Spans, Tweens, lecithin, terpenes, and others.
63
What is a cmommonly compounded transdermal preparation which aids in the rapid penetration of many active drugs through the skin?
Pluronic Lecithin Organogel (PLO) - Consists of Pluronic (Poloxamer) F127 gel (usually 20% or 30% concentration)mixed at a ration of approximately 1:5 with a mixture of equal parts of isopropyl palmitate and lecithin.
64
Ointment, Gels, and Suspension are the only forms that are used for topical drug delivery. T/F
False
65
Ointment bases are prepared by two main methods with a usual set of components to ensure product integrity. T/F
True