Pharmaceutical Semisolids Overview
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Questions and Answers

Define semisolids.

A system that is not pourable and does not flow under low shear stress at room temperature.

List 5 semisolid dosage forms.

  1. Ointments 2) Creams 3) Gels 4) Pastes 5) Collodions

Define ointment.

Semisolid preparations incorporated into a hydrocarbon base intended for external application, usually containing less than 20% water and greater than 50% hydrocarbon.

Define creams.

<p>Semisolid with a relatively fluid consistency formulated as either water-in-oil (W/O) or oil-in-water (O/W) emulsions, usually containing greater than 20% water and less than 50% hydrocarbons.</p> Signup and view all the answers

Define gels.

<p>Semisolid consisting of suspensions made up of either small inorganic molecules or large organic molecules interpenetrated by a liquid.</p> Signup and view all the answers

Define paste.

<p>Semisolid dosage form consisting of a large proportion, 20-50%, solid finely dispersed in a fatty vehicle.</p> Signup and view all the answers

Define collodions.

<p>A thick solution composed of pyroxylin dissolved in a mixture of alcohol and ether.</p> Signup and view all the answers

What are the indications of an emollient?

<ol> <li>Softens the skin 2) Soothes irritation in skin or mucous membranes.</li> </ol> Signup and view all the answers

What are the indications of a protective semisolid?

<p>Protects injured or exposed skin surfaces from harmful or annoying stimuli.</p> Signup and view all the answers

What are the indications of an occlusive semisolid?

<p>Retention of water in the skin by forming a hydrophobic barrier preventing moisture evaporation.</p> Signup and view all the answers

What are the indications of a humectant?

<p>Causes water retention due to its hygroscopic properties.</p> Signup and view all the answers

What are the indications of medicated semisolids?

<p>Provide a vehicle for applying a medication for local or systemic effects.</p> Signup and view all the answers

Give an example of a local and a systemic effect medicated semisolids might be used for.

<ol> <li>Local - Topical antibiotic 2) Systemic - Nitroglycerin ointment for treating angina.</li> </ol> Signup and view all the answers

What are the desirable properties of a semisolid base?

<ol> <li>Chemically and physically stable 2) Nonreactive and compatible 3) Odorless 4) Non-toxic, non-sensitizing, and non-irritating 5) Aesthetically appealing 6) Easily removed.</li> </ol> Signup and view all the answers

What are the four general classes of ointment bases?

<ol> <li>Hydrocarbon 2) Absorption 3) Water-removable 4) Water-soluble.</li> </ol> Signup and view all the answers

Hydrocarbon bases will not absorb water.

<p>True</p> Signup and view all the answers

What indications are hydrocarbon bases good for?

<ol> <li>Emollient 2) Occlusive 3) Protective.</li> </ol> Signup and view all the answers

What is one disadvantage of hydrocarbon bases?

<p>Leave an oily feeling.</p> Signup and view all the answers

What are three advantages of hydrocarbon bases?

<ol> <li>Inexpensive 2) Non-irritating 3) Non-reactive.</li> </ol> Signup and view all the answers

Hydrocarbon bases are soluble in water.

<p>False</p> Signup and view all the answers

How would you remove a hydrocarbon base?

<p>With mineral oil, then warm water and soap.</p> Signup and view all the answers

What are the two classes of absorption bases?

<ol> <li>Anhydrous 2) Water in oil emulsions.</li> </ol> Signup and view all the answers

Describe anhydrous absorption bases.

<ol> <li>Contain emulsifiers that form W/O emulsions when water is added 2) Have the highest absorption of water.</li> </ol> Signup and view all the answers

Describe water in oil emulsion absorption bases.

<ol> <li>Contain water 2) Have a lower capacity for absorption of water because they already contain water.</li> </ol> Signup and view all the answers

Anhydrous bases cannot absorb water.

<p>False</p> Signup and view all the answers

What indications are anhydrous bases appropriate for?

<ol> <li>Emollient 2) Occlusive 3) Protective.</li> </ol> Signup and view all the answers

What problem do the emulsifying agents in anhydrous bases cause?

<ol> <li>Irritation 2) Sensitivity 3) Sticky 4) Reactivity leading to compatibility problems.</li> </ol> Signup and view all the answers

Anhydrous bases are insoluble in water.

<p>True</p> Signup and view all the answers

Anhydrous bases can be washed off with water.

<p>False</p> Signup and view all the answers

What is the difference between anhydrous and W/O bases?

<ol> <li>W/O bases contain water, so they only absorb a limited amount of water 2) W/O bases may have stability or microbial problems.</li> </ol> Signup and view all the answers

Absorption bases have better occlusive properties than hydrocarbon bases.

<p>False</p> Signup and view all the answers

How can absorption bases be used with hydrocarbon bases?

<p>Can be used as a supplement to incorporate small volumes of aqueous solutions into hydrocarbon bases.</p> Signup and view all the answers

O/W bases can absorb water.

<p>True</p> Signup and view all the answers

What are two disadvantages of O/W bases?

<ol> <li>Less emollient, protective and occlusive properties 2) Can dry out.</li> </ol> Signup and view all the answers

What is one advantage of O/W bases?

<p>They are non-greasy.</p> Signup and view all the answers

O/W bases may have _____________, ______________ or _________________ problems.

<ol> <li>Compatibility 2) Stability 3) Microbial.</li> </ol> Signup and view all the answers

O/W bases are soluble in water.

<p>False</p> Signup and view all the answers

O/W bases are water-washable.

<p>True</p> Signup and view all the answers

O/W bases can absorb some _________ or _________.

<ol> <li>Water 2) Alcohol.</li> </ol> Signup and view all the answers

O/W bases will allow the ____________________________________.

<p>Dissipation of fluids from injured skin.</p> Signup and view all the answers

Water soluble bases can absorb water.

<p>True</p> Signup and view all the answers

What properties do water soluble bases not possess?

<ol> <li>Emollient 2) Occlusive.</li> </ol> Signup and view all the answers

What is one advantage of water soluble bases?

<p>Do not leave an oil residue (non-greasy).</p> Signup and view all the answers

Water soluble bases may have _______________, ___________________ or _______________ problems.

<ol> <li>Compatibility 2) Stability 3) Microbial.</li> </ol> Signup and view all the answers

What is one disadvantage of water soluble bases?

<p>Irritating.</p> Signup and view all the answers

Water soluble bases are water washable.

<p>True</p> Signup and view all the answers

The term cream used to be used for ______________, but is now used for __________________ or __________________ or __________________.

<ol> <li>Either O/W or W/O bases 2) O/W bases 3) Microcrystalline dispersions of long chain fatty acids 4) Alcohols in water.</li> </ol> Signup and view all the answers

What are four things to consider when choosing a base?

<ol> <li>Desired action 2) Systemic vs. local effect 3) Desired action of base 4) Physiochemical properties (solubility, compatibility, stability).</li> </ol> Signup and view all the answers

What are the two ways to compound semisolid dosage forms and which is the most common?

<ol> <li>Incorporation (most common) 2) Fusion.</li> </ol> Signup and view all the answers

Define levigation.

<p>Reducing particle size by triturating or spatulating with a small amount of a viscous liquid or melted base in which the solid is not soluble.</p> Signup and view all the answers

When would you not use levigation?

<ol> <li>Solid has fine particle size 2) Quantity of solid is small 3) Ointment base may become soft after 4) Final product is a stiff ointment or paste.</li> </ol> Signup and view all the answers

Define levigating agents.

<p>Somewhat viscous liquids with low surface tension.</p> Signup and view all the answers

What are four examples of the most common levigating agents?

<ol> <li>Glycerin 2) Propylene glycol 3) Mineral oil 4) PEG 400.</li> </ol> Signup and view all the answers

What types of bases are propylene glycol, PEG 400 and glycerin used as levigating agents in?

<ol> <li>O/W 2) Water soluble.</li> </ol> Signup and view all the answers

What types of bases is mineral oil used as a levigating agent in?

<ol> <li>Hydrocarbon 2) Absorption 3) W/O.</li> </ol> Signup and view all the answers

What are three examples of the less common levigating agents?

<ol> <li>Cottonseed oil 2) Castor oil 3) Tween 80 (polysorbate 80).</li> </ol> Signup and view all the answers

What is the general rule for choosing a levigating agent?

<p>Choose something chemically similar to the base.</p> Signup and view all the answers

What levigating agent would you choose for an oily base?

<p>Mineral oil.</p> Signup and view all the answers

What levigating agent would you choose for a water removable base?

<p>Glycerin, propylene glycol, or PEG.</p> Signup and view all the answers

What are the determining factors for the amount of levigating agent you should use?

<ol> <li>Quantity and property of the solids 2) Levigating agent 3) Ointment base 4) Desired consistency.</li> </ol> Signup and view all the answers

What is the general rule for the amount of levigating agent you should use?

<p>The minimum amount necessary to lubricate the powder (usually less than 5%).</p> Signup and view all the answers

What do you do with crystalline agents that are difficult or impossible to levigate?

<p>Dissolve the solid ingredient in a solvent and incorporating the solution into the base.</p> Signup and view all the answers

What are the two categories of solvents?

<ol> <li>Water miscible 2) Lipophilic.</li> </ol> Signup and view all the answers

What types of liquids are hydrocarbon bases able to absorb?

<ol> <li>Miscible with oils (reduces viscosity) 2) Limited alcoholic solutions.</li> </ol> Signup and view all the answers

What types of liquids are anhydrous absorption bases able to absorb?

<ol> <li>Large amounts of water 2) Lesser amounts of alcohol 3) Miscible with oils (reduces viscosity).</li> </ol> Signup and view all the answers

What types of liquids are W/O emulsion bases able to absorb?

<ol> <li>Variable amounts of water 2) Variable amounts of alcohol 3) Miscible with oils (reduces viscosity).</li> </ol> Signup and view all the answers

What types of liquids are water removable bases able to absorb?

<ol> <li>Limited amounts of water 2) Limited amounts of alcohol 3) Some oil (more if you add polysorbate 80).</li> </ol> Signup and view all the answers

What types of liquids are water soluble bases able to absorb?

<ol> <li>Lose viscosity with very limited amounts of water or alcohol 2) Some oil (prior levigation with glycerin or propylene glycol).</li> </ol> Signup and view all the answers

What are four things you could do if the solution is not absorbed into the base?

<ol> <li>Change to another base in the same base class 2) Add an emulsifier 3) Add alcohol to water soluble PEG bases 4) Spatulate.</li> </ol> Signup and view all the answers

How could you add aqueous liquids to hydrophobic bases?

<p>Use a minimum amount of hydrophilic base first.</p> Signup and view all the answers

What is pulverization by intervention used for?

<p>Incorporation of gummy materials.</p> Signup and view all the answers

What is the process of pulverization by intervention?

<ol> <li>Dissolve material in a solvent 2) Allow solvent to evaporate producing a thin film 3) Spread other ingredients on top of the film.</li> </ol> Signup and view all the answers

How do you make ointments that do not mix well by incorporation?

<p>Fusion.</p> Signup and view all the answers

Explain the fusion method.

<ol> <li>All or some chemicals are combined by being melted together and cooled 2) Other compounds are added during cooling 3) Heat liable and volatile substances are added when the temperature is proper.</li> </ol> Signup and view all the answers

What are the characteristics of pastes?

<ol> <li>Contain a larger proportion of solid 2) Stiffer and less greasy 3) Remain in place and absorb serous secretions.</li> </ol> Signup and view all the answers

Semisolids are required to be sterile.

<p>False</p> Signup and view all the answers

How do you minimize microbial content in semisolids?

<ol> <li>Environmental control 2) Add preservatives 3) Good manufacturing practice.</li> </ol> Signup and view all the answers

Study Notes

Semisolids Overview

  • Semisolids are non-pourable, retaining shape without flowing when subjected to low shear stress at room temperature.

Semisolid Dosage Forms

  • Common forms include ointments, creams, gels, pastes, and collodions.

Ointments

  • Comprised of less than 20% water and more than 50% hydrocarbons.
  • Designed for external applications in a hydrocarbon base.

Creams

  • Formulated to have a relatively fluid consistency as either water-in-oil (W/O) or oil-in-water (O/W) emulsions.
  • Contain more than 20% water and less than 50% hydrocarbons, utilizing waxes or polyols.

Gels

  • Comprise suspensions of small inorganic or large organic molecules interspersed with liquid.

Pastes

  • Contain a high proportion (20-50%) of solid particles evenly dispersed within a fatty vehicle.

Collodions

  • Thick solutions made from pyroxyline dissolved in a mixture of alcohol and ether.

Indications for Semisolids

  • Emollients: Soften skin and soothe irritation.
  • Protective semisolids: Shield injured skin from harmful stimuli.
  • Occlusive semisolid: Retain moisture by forming hydrophobic barriers.
  • Humectants: Hydroscopically retain water.
  • Medicated semisolids: Serve as vehicles for local or systemic drug delivery.

Types of Ointment Bases

  • Four general classes: hydrocarbon, absorption, water-removable, and water-soluble bases.

Hydrocarbon Bases

  • Do not absorb water, beneficial for their emollient, occlusive, and protective properties.
  • Disadvantages include leaving an oily residue.
  • Examples include mineral oil, which can be removed with warm water and soap.

Absorption Bases

  • Classified into anhydrous and water-in-oil emulsions.
  • Anhydrous bases have the highest water absorption capacity and may cause irritation or stickiness.

Water-in-Oil (W/O) Emulsion Bases

  • Contain water and have limited additional water absorption capacity.

Oil-in-Water (O/W) Bases

  • Can absorb some water and alcohol; less emollient and can dry out.
  • Non-greasy construction is an advantage.

Water-Soluble Bases

  • Absorb limited amounts of water and alcohol; do not leave an oily residue but may be irritating.

Choosing Ointment Bases

  • Consider desired action, systemic versus local effects, properties of the base, and physico-chemical properties like solubility and compatibility.

Compounding Methods

  • Two primary methods: incorporation (most common) and fusion.
  • Levigation involves reducing particle size using a viscous liquid where solids are insoluble.

Levigating Agents

  • Agents such as glycerin, propylene glycol, mineral oil, and PEG 400 are used based on compatibility with the base.
  • Choose similar chemical agents for effective results.

Handling of Solutions

  • If a solution does not absorb into the base, options include changing the base, adding emulsifiers, or incorporating solvents.

Microbial Control in Semisolids

  • Minimize microbial content through environmental control, preservatives, and good manufacturing practices.
  • Sterility is not typically required unless for ophthalmic uses.

Fusion Method

  • Involves melting chemicals together, cooling, and adding heat-sensitive ingredients at the proper temperature.

Characteristics of Pastes

  • Pastes are less greasy, stiffer, and designed to remain in place while absorbing secretions.

Understanding Semisolid Properties

  • Key desirable properties include stability, non-reactivity, and aesthetic appeal, ensuring product effectiveness and safety.

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Description

This quiz covers the essential aspects of semisolids, including definitions, common dosage forms, and specific examples like ointments, creams, gels, and pastes. Learn about their compositions, uses, and therapeutic indications in pharmaceutical applications.

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