6. Ointments 1

What is the official definition of semi-solid preparations for cutaneous application?

Homogeneous-appearing preparations intended for local or transdermal delivery of active substances, or for emollient/protective action.

What are the four steps of percutaneous absorption?

1. Liberation, 2. Penetration, 3. Permeation, and 4. Resorption.

What is the difference between penetration and resorption?

Penetration is the diffusion of the active substance into the epidermis; resorption is the release of that substance into the systemic circulation.

Define a "Paste" in terms of its solid content.

A semi-solid product containing a high percentage of insoluble solids, usually 50% or more, finely dispersed in a vehicle.

How are ointments classified based on water interaction?

1. Hydrophobic, 2. Water-emulsifying, and 3. Hydrophilic.

What are the three types of flow behavior for ointments?

Plastic, Pseudoplastic, and Thixotropic flow.

What is a "Cremor" or "Cremum"?

An emulsion ointment with a soft consistency and a higher water content (creams).

What is a "Poultice" (Cataplasm)?

A soft, moist mass—often heated—spread on a cloth and applied to treat aching or inflamed body parts.

When must a mortar be used instead of a patendula?

A mortar must always be used for suspension-type ointments and all pastes.

A patendula is used for solution-type ointments and melting.

What is the rule for temperature when preparing O/W emulsion ointments?

The water phase must be at the same temperature or warmer than the melted fat phase.

What critical step must be performed after an O/W ointment has cooled?

Any water that evaporated during the heating process must be replenished before the ointment is filled into a container.

How should active ingredients be prepared for suspension-type ointments?

They must be used in "pulvis" (fine powder) form (160 - 63 μm) and incorporated via geometric dilution.

When should essential oils be added to an ointment?

Only after the system has cooled to prevent volatilization.

What is the standard shelf life for magistral (pharmacy-made) ointments according to FoNo?

They can usually be held for 6 months.

Which type of semi-solid preparation MUST always be dispensed in a tube?

Hydrophilic ointments

How are pastes typically dispensed?

In jars.

How are ointments classified based on their nature of effect?

1. Covering or protective ointments, 2. Wound ointments, 3. Penetration ointments, 4. Resorption ointments.

What are the three types of ointments distinguished by water absorption?

Hydrophobic, water-emulsifying, and hydrophilic.

What characterizes a "Hydrophobic Ointment"?

It can absorb only a small amount of water; common ingredients include paraffins, vegetable oils, animal fats, and waxes.

What is the primary base material for "Hydrophilic Ointments"?

A mixture of liquid and solid macrogols (polyethylene glycols).

What is the difference between Lipophilic and Hydrophilic Creams?

Lipophilic creams have a lipophilic external phase (W/O) and act as good occlusion barriers. Hydrophilic creams have an aqueous external phase (O/W).

What is the composition of a "Lipophilic Gel" (Oleogel)?

Usually liquid paraffin with polyethylene or fatty oil, gelled with colloidal silicon dioxide or aluminum/zinc soap.

Why are pastes often preferred for moist or chronic lesions?

They have high powder content making them porous (allowing perspiration to escape), they are less greasy, and they have good adhesive properties.

What is a major disadvantage of using pastes on the scalp?

They are difficult to remove from the hair.

How does the "Time of Onset" compare between different bases?

Hydrogel > O/W emulsion > W/O emulsion ointment base.

What is the role of a humectant (e.g., glycerin or propylene glycol) in O/W emulsion materials?

To prevent the material from drying out too quickly.

What is the difference in shelf life between official galenics and magistral preparations in FoNo?

Official galenics last 1 year, while magistral preparations (made in the size of the formula) last 6 months.

What is "Geometric Dilution" and when is it used?

It is a process of mixing the active ingredient with equal parts of the base in increasing amounts; it is used when incorporating 160 μm powder into suspension-type ointments.

What determines the temperature choice when mixing-emulsifying materials?

The material with the highest freezing point is the decisive factor to avoid "precipitation-freezing".

What is the purpose of a "Triple Roll Mill" in pilot-scale preparation?

It applies high shear force to homogenize the material as it passes between rotating rolls at different speeds.

Why must O/W emulsion ointments be cooled before filling into containers?

To ensure stability and allow for the replenishment of any evaporated water before final packaging.

What are the ideal site characteristics for a transdermal patch?

The site should be clean, not oily, hairless, and the skin must be intact/unbroken.

What are two key advantages of transdermal patches over oral forms?

1. They provide controlled/sustained release (avoiding peak plasma concentrations).

2. They avoid the first-pass metabolism and GI tract irritation.

For which patient populations are transdermal patches particularly versatile?

Patients who are sleeping, unresponsive, or unable to swallow.