[PHA 619 LEC] Chapter 10 - Ointments, Creams, and Gels

Semisolid dosage forms intended for topical application. They may be applied to the skin, placed on the surface of the eye, or used nasally, vaginally, or rectally. They are used for both local and systemic effects.

Ointments, creams, and gels

It is designed to deliver drug into the skin in treating dermal disorders, with the skin as the target organ.

Topical dermatological product

It is designed to deliver drugs through the skin (percutaneous absorption) to the general circulation for systemic effects, with the skin not being the target organ.

Transdermal product

These are semisolid preparations intended for external application to the skin or mucous membranes. They may be medicated or not.

Ointments

Ointments used for the physical effects they provide as protectants, emollients, or lubricants

Unmedicated Ointments

They may be used for their physical effects or as vehicles for medicated ointments.

Ointment bases

What are the four groups of USP ointment bases?

- Oleaginous

- Absorption bases

- Water-removable

- Water-soluble

Oleaginous bases are also termed as?

Hydrocarbon bases

Ointment base with an emollient effect, protect against the escape of moisture, effective as occlusive dressings, and can remain on the skin for long periods without drying out. But, they are difficult to wash off.

Oleaginous bases

Examples of oleaginous bases

- Petrolatum

- White petrolatum

- Yellow ointment

- White ointment

When powdered substances are to be incorporated into hydrocarbon bases ______________ may be used as the levigating agent.

Liquid petrolatum

Liquid petrolatum is also known as?

Mineral oil

It is a purified mixture of semisolid hydrocarbons obtained from petrolatum. It is an unctuous mass, varying in color from yellowish to light amber.

Petrolatum, USP

Petrolatum dissolves at what temperature?

38 C to 60 C

Petrolatum is also known as?

- Yellow petrolatum

- Petroleum jelly

Example of commercial petrolatum

Vaseline

It is a purified mixture of semisolid hydrocarbons from petroleum that has been wholly or nearly decolorized. It has a lighter color and is considered more esthetically pleasing.

White Petrolatum, USP

White Petrolatum is also known as?

White petroleum jelly

Example of commercial white petrolatum

White Vaseline

What is the formula of yellow ointment, USP?

- Yellow wax (50 g)

- Petrolatum (950 g)

It is the purified wax obtained from the honeycomb of the bee, Apis mellifera.

Yellow wax

Yellow wax is obtained from the honeycomb of what bee?

Apis mellifera

Yellow ointment is also called as?

Simple ointment

Ointment prepared by melting the yellow wax on a water bath, adding petrolatum until the mixture is uniform, and then cooling and stirring until congealed. It has a slightly greater viscosity than plain petrolatum.

Yellow ointment, USP

It contains white wax (bleached and purified yellow wax) and white petrolatum in the formula.

White Ointment, USP

Ointment base that may be used as emollients, although they do not provide the degree of occlusion afforded by the oleaginous bases. They are not easily removed from the skin with water washing.

Absorption bases

What are the two types of absorption bases?

- Those that permit the incorporation of aqueous solution, resulting in the formation of water in oil emulsion (W/O)

- Those already water in oil (W/O) emulsions that permit the incorporation of small quantities of aqueous solution.

Examples of absorption bases

- Hydrophilic Petrolatum, USP

- Lanolin, USP

- Modified Lanolin, USP

It is prepared by melting the stearyl alcohol and white wax on a steam bath, adding the cholesterol with stirring until dissolved, adding the white petrolatum, and allowing the mixture to cool while stirring until congealed.

Hydrophilic Petrolatum, USP

Formula of hydrophilic petrolatum

- Cholesterol (30 g)

- Stearyl alchol (30 g)

- White wax (80 g)

- White petrolatum (860 g)

Examples of commercial hydrophilic petrolatum

- Aquaphor

- Aquabase

It is obtained from the wool of sheep (Ovis aries). It is a purified waxlike substance that has been cleaned, deodorized, and decolorized. It contains not more than 0.25% water.

Lanolin, USP

It is lanolin processed to reduce the contents of free lanolin alcohols and any detergent and pesticide residues.

Modified Lanolin, USP

Ointment bases that are oil-in-water emulsions, which are easily washed from skin and are water-washable bases. They can absorb serous discharges.

Water-Removable Bases

Example of water-removable bases

Hydrophilic Ointment, USP

In hydrophilic ointment, the stearyl alcohol and white petrolatum are melted together at about what temperature?

about 75 C

Ointment bases that do not contain oleaginous components. They are greaseless (completely water-washable). Large amounts of aqueous solutions are not effectively incorporated into these bases.

Water-soluble Bases

Example of water-soluble base

Polyethylene Glycol Ointment, NF

What are the two general methods of preparing ointments?

- Incorporation

- Fusion

Method of preparing ointments wherein components are mixed until a uniform preparation is attained. It involves mixing mortar and pestle, spatula, ointment mill, and unguator.

Incorporation

A device which allows a pharmacist to place the ingredients in a plastic ointment jar with a special lid that allows for a mixing blade to be used to mix the ingredients in the dispersing container.

Unguator

What techniques are performed before incorporating solids in ointments?

- Levigation

- Pulverization by intervention

In levigation, what is the external phase of mineral oil for bases?

Oil

In levigation, what is the external phase of glycerin for bases?

Water

What is the internal and external phase in O/W emulsion?

Internal - oil

External - water

What is the internal and external phase in W/O emulsion?

Internal - water

External - oil

What technique is used for incorporating a gummy material in ointments?

Pulverization by Intervention

These are used to force coarsely-formed ointments through stainless steel or ceramic rollers to produce ointments uniform in composition and smooth in texture, and free of entrapped air bubbles.

Ointment or roller mills

Method of preparing ointments wherein all or some of the components are combined by being melted together and cooled with constant stirring until congealed.

Fusion method

(True/False) In fusion method, heat-labile substances and any volatile components are added first.

False

- Added LAST

In small scale, fusion si conducted in?

Porcelain dish or glass beaker

In large scale, fusion is conducted in?

Steam-jacketed kettles

What are the two methods of manufacture for ointments with an emulsion base?

- Melting

- Emulsification

What are the USP compendial requirements for ointments?

- Microbial content

- Minimum fill

- Packaging, storage, and labeling

(True/False) In microbial content, topical applications are required to be sterile.

False

- Not required, but must meet acceptable standards for microbial content and must contain anti-microbial preservatives

Test used for determination of the net weight or volume of the contents of filled containers

Minimum Fill test

Ointments and other semisolid preparations are packaged either in?

- Large-mouth ointment jars

- Metal or plastic tubes

Semisolids are stored in?

Well-closed containers and in a cool place

In vitro drug release tests include ___________ studies to determine the drug's release profile from the semisolid product.

Diffusion cell

These are semisolid preparations containing one or more medicinal agents dissolved or dispersed in either a W/O or O/W emulsion or in another type of water-washable base.

Creams

Example of water in oil cream

Cold cream

Example of oil in water cream

Hydrophilic ointment, vanishing creams

Which from O/W and W/O is more easily removed?

Oil-in-water

They are usually formed from a fatty acid in the oil phase hydrolyzed by a base dissolved in the aqueous phase in situ during the preparation of creams.

Soap

Preparation of creams involve separating the formula components into what portions?

Lipid and aqueous

Emulsifying agents used in preparation of creams

- Nonionic surfactants

- Detergents

- Soaps

Where are APIs added in preparation of creams?

Phase in which the API is soluble

Gels are also called?

Jellies

These are semisolid systems consisting of dispersions of small or large molecules in an aqueous liquid vehicle rendered jellylike by the addition of a gelling agent.

Gels

Example of synthetic macromolecules as gelling agents

Carbomer 934

Example of cellulose derivatives as gelling agents

- Carboxymethylcellulose

- Hydroxypropyl methylcellulose (HPMC)

Examples of natural gums as gelling agents

Tragacanth

What carbomer yields the highest viscosity according to NF?

Carbomer 940

Gels in which macromolecules are uniformly distributed throughout a liquid with no apparent boundaries between the dispersed macromolecules and the liquid

Single-phase gels

Internal phase can also be called as?

- Discontinuous phase

- Dispersed phase

External phase can also be called as?

- Continuous phase

- Dispersion medium

A gel mass consisting of floccules of small distinct particles often referred to as magma

Two-phase System

It consists of a gelatinous precipitate of magnesium hydroxide. It is an example of a two-phase system.

Milk of Magnesia (or Magnesia Magma)

It refers to gels that thicken on standing; thus, it needs to be shaken before use to liquefy the gel and enable pouring.

Thixotrope

These are semisolid preparations intended for application to the skin and contain a larger proportion of solid material (such as 25%) than ointments, and therefore are stiffer.

Pastes

These are solid or semisolid adhesive masses spread on a backing of paper, fabric, moleskin, or plastic. They are applied to the skin to provide prolonged contact at the site.

Plasters

What is the adhesive material used in plasters?

Rubber base or synthetic resin

Plasters that provide protection or mechanical support at the site of application

Unmedicated plasters

What was the former term used to refer "adhesive plaster"?

Adhesive tape

Plasters that provide effects at the site of application, which may be cut to size to confirm to the surface to be covered.

Medicated Plasters

These are plastic masses containing gelatin, glycerin, water, and an added medicinal substance such as zinc oxide. They are applied to the skin for the long term. They are melted before application, cooled to slightly above body temperature, and applied to area with a fine brush.

Glycerogelatins

Percent of gelatin in glycerogelatins

15%

Percent of glycerin in glycerogelatins

40%

Percent of water in glycerogelatins

35%

Percent of added medicinal substance in glycerogelatins

10%

What is the most recent glycerogelatin?

Zinc Gelatin

- used in the treatment of varicose ulcers

- aka Zinc Gelatin Boot

Topical dermatologic products are packaged in?

Jars, tubes, or syringes

Opthalmic, nasal, vaginal, and rectal semisolid products are packaged in?

Tubes or syringes

Ointment jars are made of?

Clear or opaque glass/plastic

Ointment tubes are made of?

Aluminum or plastic

Plastic tubes that are soft and resilient, providing a good moisture barrier

Low density polyethylene (LDPE)

Plastic tubes that provides a superior moisture barrier but is less resilient

High density polyethylene (HDPE)

Plastic tubes that has a high level of heat resistance

Polypropylene (PP)

Plastic tubes that offer transparency and high degree of product chemical compatibility

Polyethylene teraphthalate (PET)

Plastic tubes that provide excellent moisture barrier because of the foil content, high durability, and product compatibility

Laminates