Powder-based medicines

What is a bulk powder?

Multiple doses of powder packed i one container.

Why are some powders reconstituted before dispensing?

To improve stability when drug is unstable in water

Advantage of wrapped powders over bulk powders

More accurate dosing and better moisture protection

Why are powders often more stable than liquid medicines?

Less chemical degradation and minimal microbial growth

Hygroscopic

powders absorb moisture from the air

Deliquescent

powders absorb enough water to dissolve

caking

powders sticking together due to moisture

Why is powder flow important?

poor flow causes inaccurate or inconsistent dosing

factors affecting powder flow

particle size, shape ,moisture and surface charge

What can cause powder separation?

movement during transport or pouring

What is geometric mixing?

Mixing small and large quantities by progressively adding equal volumes

Why equalise particle size before mixing?

To reduce separation and improving dose uniformity

What is granulation?

Binding powders together to form larger granules

Advantages of granulation?

Improved flow, reduced separation, better packing

Two types of granulation

Wet granulation and dry granulation

What is used as a binding agent in wet granulation?

Water-soluble polymers (PVP)

What are polymers?

High molecular weight substances made of repeating monomers

What is a tablet?

A single dose of compressed powder or granules

Advantage of tablets over powders

better stability and easier handling

What are dispersible tablets?

Tablets dissolved in water or on the tongue for rapid action

What are immediate release tablets?

tablets that disintegrate quickly in the stomach

What are delayed-release tablets?

Tablets that resist stomach acid and dissolve in the intestine

What coating is used for delayed release?

enteric coating

What are extended-release tablets?

tablets releasing drug slowly over 8-24 hours

What is a capsule?

An edible shell containing a unit dose of medicine

Two main types of capsules?

Hard capsules and soft capsules

Materials commonly used for capsule shells

Gelatin and HPMC

structure of a hard capsule

two pieces: cap and body

What can hard capsules contain?

Powders, granules, semi-solids or non-aqueous liquids

Advantage of hard capsules

easy to swallow, easier to manufacture than tablets

What are soft capsules mainly used for?

Oils, liquids and semi-solids

What are soft capsules easier to swallow?

smooth and flexible

GWP

good working practice

Why is GWP important?

ensures accuracy, avoid contamination and ensures traceability