53 Questions
Which product has the capacity to absorb up to three times its weight in water?
Hydrophilic Petrolatum, USP
Which type of base is Hydrophilic Ointment, USP?
Hydrophilic
Which substance is obtained from the wool of sheep and contains not more than 0.25% water?
Lanolin, USP
Which type of base does not contain oleaginous components?
Water-Soluble Bases
What is the purpose of using antimicrobial preservatives in ointments and pastes?
To prevent microbial growth and maintain stability
Why are pastes not suited for application to hairy parts of the body?
Because of their stiffness and impenetrability
How is zinc oxide paste prepared?
By mixing 25% each of zinc oxide and starch with white petrolatum
Why is it challenging to sterilize terminal products like ointments?
Because steam cannot penetrate the ointment base effectively
What is the primary advantage of emulgel over conventional topical preparations?
It can incorporate hydrophobic drugs
What is the main function of antimicrobial preservatives in gels?
To prevent the growth of microorganisms
What distinguishes emulgel from conventional topical preparations?
It is a combination of an emulsion and a gel
Which component allows gels to be formulated to contain a drug substance, solvents, antimicrobial preservatives, and stabilizers?
Gelling agent dispersion
Why are certain products routinely tested for microorganisms?
Because of the way they are used
In which type of container are ophthalmic, nasal, vaginal, and rectal semisolid products almost always packaged?
Plastic tubes
Why are tubes considered superior to jars for packaging semisolid preparations?
They provide greater protection against external contamination
What is the purpose of the USP’s minimum fill test?
To ensure the proper content compared with the labeled amount
Topical ointments, creams, and gels are designed to deliver drugs locally.
False
The rate of drug movement across the skin layer depends on the drug concentration in the vehicle.
True
Ointments are always medicated and used for their physical effects only.
False
Ointment bases are generally classified into three groups by the United States Pharmacopeia.
False
A pharmacist may mix the components of an ointment using a mortar and pestle.
True
A stainless steel spatula should be used when the components of an ointment react with metal.
False
Liquid substances or solutions of drugs should be added to an ointment without considering the ointment base's capacity to accept the volume required.
False
Gummy materials, such as camphor, can be incorporated into ointments using pulverization by intervention.
True
Ointments are not effectively incorporated into bases because they soften greatly with the addition of water.
True
Ointment bases are selected based on the desirability of occlusion of the moisture from the skin.
True
Ointments can be prepared by two general methods: Fusion and Infusion.
False
An ointment is generally applied to weeping or oozing surfaces, while a cream is applied to dry, scaly skin.
False
Ophthalmic ointments provide extended residence time on the surface of the eye compared to ophthalmic solutions
True
Ophthalmic ointments are cleared from the eye faster than solutions
False
Ophthalmic ointments must meet the USP sterility tests and the test for metal particles
True
Each drug and other components used in ophthalmic ointments are rendered sterile separately and then incorporated in preparing the final product
True
What is the primary difference between ointments, creams, and gels?
The physical and chemical properties
Which type of semisolid dosage form has the capacity to absorb up to three times its weight in water?
Pastes
Why should systemic drug absorption be considered when using topical products for pregnant or nursing patients?
To prevent potential transfer of drugs to the fetus or nursing infant
In which type of container are ophthalmic, nasal, vaginal, and rectal semisolid products almost always packaged?
Metal tubes
What method is best suited for preparing medicated ointments containing beeswax, stearyl alcohol, and high molecular weight PEGs?
Fusion method
Which equipment is used for large-scale congealing of ointments after the fusion method?
Large steam-jacketed kettle
What is the purpose of passing the congealed ointment through an ointment mill or rubbing with a spatula or in a mortar?
To ensure uniform texture
What type of mills can be used on a large scale to force coarsely formed ointments through stainless steel or ceramic rollers?
Roller mills
What is the primary factor to consider when selecting the appropriate ointment base?
The release rate of the drug substance from the base
Which method is used for preparing ointments by mixing the components until a uniform preparation is attained?
Incorporation
What should be considered when incorporating large amounts of aqueous solutions into certain ointment bases?
They become less stable when mixed with water
Which characteristic makes some ointments generally more suitable for application to dry, scaly skin?
They are water washable
Why do creams usually require the addition of a preservative?
To prevent the growth of microorganisms and increase their shelf life
What is the primary purpose of gelling agents in the preparation of gels?
To render them jellylike and provide a translucent or transparent appearance
What is the main reason for shaking medicated gels before use?
To liquefy the gel and enable pouring
What is the significance of adding a suitable solvent with preservatives and other additives in gel preparation?
It helps in dissolving the drug and ensures its stability in the gel
What is the primary function of gelling agents in the preparation of gels?
To render the aqueous liquid vehicle jellylike
Why must creams usually require the addition of a preservative?
To extend the shelf life of creams and prevent microbial growth
What is the significance of gels thickening on standing and requiring shaking before use?
It creates a thixotropic property that enables liquefying before use
What is the main advantage of medicated gels prepared for administration by various routes?
They provide high rates of release of the medicament and rapid absorption
What is the primary reason for adding a suitable solvent with preservatives and other additives in gel preparation?
To dissolve the drug and ensure its uniform distribution in the gel
Study Notes
Hydrophilic Petrolatum, USP
- Formula for 1,000 g preparation: Cholesterol 30 g, Stearyl alc. 30 g, White wax 80 g, and White petrolatum 860 g
- Commercial products like Aquaphor and Aquabase can absorb up to three times their weight in water and are useful for incorporating water-soluble drugs into oleaginous ointment bases
Lanolin, USP
- Obtained from the wool of sheep and purified to contain not more than 0.25% water
- A waxlike substance that has been cleaned, deodorized, and decolorized
Water-Removable Bases (Water-washable)
- Oil-in-water emulsions (o/w) resembling creams
- Easily washed from skin and often called water-washable bases
- Can be diluted with water or aqueous solutions and absorb serous discharges
- Hydrophilic Ointment, USP is an example of this type of base
- Formula for 1,000 g preparation: Methylparaben 0.25 g, Propylparaben 0.15 g, Lauryl sulfate 10 g, Propylene glycol 120 g, Stearyl alcohol 250 g, White petrolatum 250 g, and Purified water 370 g
Water-Soluble Bases (Greaseless)
- Do not contain oleaginous components
Microbial Limit Test and Minimum Fill Test
- Conducted for both raw materials and finished products
- Used to determine the net weight or volume of the content of the filled containers
Packaging, Storage, and Labeling
- Ointments and semisolid preparations packaged in large mouth ointment jars or metal/plastic tubes
- Topical dermatologic products in jars or tubes, ophthalmic, nasal, vaginal, and rectal semisolid products in tubes
- Jars and tubes should be compatible and stable with the intended product
- Tubes are superior to jars due to being lightweight, inexpensive, convenient, and providing greater protection
Antimicrobial Preservatives and Metal Particles Test
- Antimicrobial preservatives like methylparaben, propylparaben, chlorobutanol, and benzalkonium chloride are used as needed
- The USP test for metal particles involves microscopic examination of a heat-melted ophthalmic ointment
Pastes
- Semisolid preparations intended for application to the skin
- Contain a larger proportion of solid material (e.g., 25%) than ointments and are stiffer
- Can be prepared by direct mixing or heat softening the base prior to incorporating solids
- Often use a levigating agent to render the powdered component smooth
- Remain in place after application and are effectively employed to absorb serous secretions
- Not suited for application to hairy parts of the body due to stiffness and impenetrability
- Examples include zinc oxide paste, prepared by mixing 25% each of zinc oxide and starch with white petrolatum
Test your knowledge of pastes, a type of semi-solid dosage form, with this quiz focused on Chapter 10 material. Explore topics such as antimicrobial preservatives, steam penetration, ointment base, and metal particles testing.
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