Oral Drug Delivery III: Formulation Factors and Excipients

These flashcards cover the functions and examples of various excipients used in oral drug delivery formulations, including diluents, surfactants, lubricants, disintegrants, and viscosity-enhancing agents.

What are excipients in the context of drug formulation?

Substances added to the formulation to facilitate the preparation, patient acceptability, and functioning of the dosage form as a drug delivery system.

What is the primary function of diluents?

To increase the bulk of potent drug substances.

What specific excipient change led to phenytoin toxicity in Australia in 1960?

The excipient was changed from calcium sulphate to lactose, which resulted in an undue increase in the bioavailability of the active drug.

Why does calcium sulphate decrease GI phenytoin absorption?

By forming a poorly soluble calcium-phenytoin complex by chelation

List at least four examples of diluents provided in the notes.

Lactose, Sucrose, Glucose, Mannitol, Sorbitol, and Calcium Phosphate.

What are the two structural components of a surfactant?

A hydrophilic (water-loving) head and a hydrophobic (water-hating) tail.

What are the four main functions of surfactants mentioned in the formulation?

Emulsifying agent, solubilizing agent, suspension stabilizer, and wetting agent.

Which surfactant examples serve as emulsifying agents?

Sodium Lauryl Sulfate, Lecithin, and Polysorbate 80.

What is the function of a surfactant acting as a wetting agent?

It improves the spreading of liquids on solid surfaces.

What is the function of lubricants during the manufacturing process?

To reduce friction between powder and metal surface in the manufacturing environment.

Name four examples of lubricants.

Magnesium stearate, stearic acid, polyethylene glycol, sodium lauryl sulfate, sodium stearyl fumarate, and liquid paraffin.

What is the specific function of disintegrants in oral dosage forms?

To break up capsules, tablets, and granules into primary powder particles to increase the effective surface area of the drug.

List three examples of disintegrants.

Starch, Cellulose, Crosslinked Polyvinyl Pyrrolidone, Sodium Starch Glycolate, and Sodium Carboxymethyl Cellulose.

What are the two main purposes of viscosity-enhancing agents?

To control the ease of pouring and to control the rate of sedimentation of dispersed particles in suspensions.

Give examples of suspending agents or thickeners.

Xanthan gum and Hydroxypropyl Methylcellulose (HPMC).

What are two examples of viscosity modifiers?

Glycerin and Propylene glycol.