Term
| What are the semisolid dosage forms? |
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Definition
Semisolid dosage forms pertain to the use of ointments, creams, gels, lotions, and similar preparations as drug delivery systems.
Topical agents |
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Term
| Are semisolids used for local or systemic effects? |
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Definition
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Term
| If a semisolid doesn't have a therapeutic drug, what can it be used for? |
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Definition
| They could be used for a sun protectant or lubricant |
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Term
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Definition
Ointments are semisolid preparations intended for external application on the skin or mucosal surfaces.
They primarily consist of the drug and a base (vehicle). |
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Term
| List the four categories of ointments |
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Definition
1. Oleaginous base (aka. Hydrocarbon base)
2. Absorption base
3. Water-removable base
4. Water-soluble base |
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Term
| Describe oleaginous bases |
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Definition
-Immiscible with water
-Difficult to wash
-Occlusion, prevents water escape |
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Term
| Give three examples of oleaginous bases |
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Definition
| Petrolatum, white ointment and yellow ointment |
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Term
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Definition
| These bases allow the absorption of water or aqueous drug solutions resulting in the formation of water-in-oil (w/o) emulsions. |
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Term
| List some properties of absorption bases |
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Definition
-Emollient effects (though not as much as oleaginous)
-Difficult to wash
-W/O |
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Term
| Give two examples of absorption bases |
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Definition
| Hydrophilic petrolatum and lanolin |
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Term
| List properties of water removable bases |
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Definition
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Term
| Give an example of a water removable base |
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Definition
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Term
| Define water-soluble base |
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Definition
These bases do not contain any oleaginous components, and are mostly used for incorporation of solid substances.
aka Greaseless base |
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Term
| Give an example of a water soluble base |
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Definition
| Polyethylene glycol (PEG) |
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Term
| What are the two general methods to make an ointment? |
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Definition
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Term
| Define incorporation (in preparing an ointment) |
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Definition
| Ointment ingredients in smaller quantities (drug, excipient etc.) are incorporated into the larger quantity (base). |
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Term
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Definition
An electronic mortar and pestle for ointments.
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 dispensing container. |
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Term
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Definition
A process of mixing the solid material in an insoluble vehicle to make a smooth dispersion
Reduces solid particle size |
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Term
| If an ointment is w/o, what is usually the levigating agent during preparation? |
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Definition
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Term
| If an ointment is o/w, what is usually the levigating agent during preparation? |
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Definition
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Term
| How do you add aqueous drug to oleaginous base? |
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Definition
| The solution is first incorporated into a minimum amount of hydrophilic base and the mixture is then added to the hydrophobic base. |
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Term
| Define the fusion method of preparing an ointment |
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Definition
| All or some of the ointment ingredients are combined in a porcelain dish or glass beaker, by melting together and cooled with constant stirring until congealed |
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Term
| If using the fusion method, do you add volatile oils and heat sensitive ingredients when adding the rest? |
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Definition
| No, wait until it has cooled down |
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Term
| How are ophthalmic preparations different from other ointments? |
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Definition
| Ointments and other semisolid dosage forms (discussed later in this notes) must meet USP tests for microbial content, minimum fill, packaging, storage, and labeling. For ophthalmic ointments, additional tests for sterility and metal particle contents must be met. |
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Term
| List some antimicrobial preservatives that can be put in ophthalmic ointments? |
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Definition
methyl- or propyl-paraben
phenols
benzoic acid
sorbic acid
quaternary ammonium salts |
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Term
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Definition
| Creams are semisolid emulsion preparations containing the drug dissolved or dispersed in a suitable base (usually o/w emulsion; rarely w/o). |
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Term
| How is a cream immediately distinguishable from an ointment? |
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Definition
| Creams have a creamy appearance as a result of reflection of light from the emulsified phases. This distinguishes them from simple ointments which are translucent. |
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Term
| When are creams used, and why is this better than using an ointment? |
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Definition
Creams find applications in topical skin products and in products used rectally and vaginally.
Creams are preferred to ointments because they are easier to remove, and are better for acne because they dry out the skin. |
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Term
| For what use are ointments better than creams? |
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Definition
| Ointments hydrate the skin, so they are better than creams for dry skin |
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Term
| Define gels (aka jellies) |
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Definition
| Semisolid systems consisting of dispersions of molecules in an aqueous vehicle rendered jellylike by the addition of a gelling agent. |
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Term
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Definition
Synthetic macromolecules such as carbomer 934
Cellulose derivates such as carboxy- or hydroxypropyl-methylcellulose
Natural gums (e.g. tragacanth, pectin) |
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Term
| What happens if you leave a gel standing too long? |
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Definition
| Gels thicken on standing, forming a thixotrope, and must be shaken before use to liquefy the gel and enable pouring (e.g. milk of magnesia). |
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Term
| List some semi-solid dosage forms other than ointments, creams, or gels |
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Definition
| Pastes (zinc oxide paste for diaper rash), lotions (antimicrobial), plasters (salicylic acid plaster used on the toes for removal of corn), and glycerogelatins (zinc gelatin for varicose ulcers) |
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Term
| How are semisolids packaged? |
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Definition
Jars, tubes or syringes.
The packaging material is first tested for compatibility and stability with the intended product.
May include a special applicator |
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Term
| How are ointments in jars packaged? |
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Definition
| Jars are filled by carefully transferring the weighed amount of semisolid into the jar with a spatula. The semisolid is packed avoiding entrapment of air. Ointments prepared by the fusion method (heating) may be poured directly into the jar to congeal inside it. |
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Term
| How are ointments in tubes packaged? |
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Definition
| Tubes are filled with the semisolid from the open back, opposite to the cap end. Ointments prepared by the fusion method may be poured directly into the tubes. The bottom of the tube is flattened, folded, and sealed with a crimping clip. |
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Term
| How are ointments in syringes packaged? |
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Definition
| Syringes are filled either by drawing the semisolid into the barrel using the plunger or by removing the plunger and filling through the back end of the syringe. The plunger is then reinserted. |
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Term
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Definition
| Metal Particles in ophthalmic ointments |
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Term
| On hairy skin, are ointments or creams more appropriate? |
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Definition
| Creams are better on hairy skin |
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