Flashcards in Powders for Pharmaceutical use: API and excipients Part 2 Deck (25):
Why is flow important in powders?
1. Helps the industrial manufacturing process be more efficient
2. Can fill the tablet die and capsule more easily
3. If not, can get different tablet weights
What are the two problems that can occur if the flow isn't correct?
1. Poor flow can introduce air into the mix which can lead to:
Describe what capping is?
When the cap of a tablet breaks off due to poor flow
Describe what lamination is?
Break up of the tablet into many layers that usually occurs in the middle of the tablet due to gaps of air from poor flow
Describe the surface effects of adhesion and cohesion, and what are the forces involved for each of them?
1. Adhesion: the sticking of solid particles between two unlike particles
2. Cohesion: the sticking of solid particles between two alike particles
3. Van der waals and electrostatic
How do spheres influence the particle shape?
1. Have minimum inter-particle contact compared to flakes
2. Lower surface area per volume
How does being more dense influence the particle density?
1. Less cohesive (flow by gravity)
2. Due to them weighing more
Describe what main flow is?
1. Free flowing, first particle in is the first one out
2. Whole powder bed moves down
Describe what Funnel Flow is?
1. Cohesion on the side of the walls
2. Powder flows right down the middle
3. Causes erratic flow and poor filling
Describe what segregation is and used for?
1. Process by where different particle sizes in a powder separate
2. Generally poured into a heap that results in a segregation from a hopper
What are the four ways to improve flow?
1. Change particle size and size distribution:
- use sieves
- make granules flow better
2. Reduce inter particle forces
- Pour slowly
- Avoid moisture as it can cause cohesion
3. Add excipients
- Glidants such as magnesium sterate, talc, silicon dioxide
4. Change manufacturing equipment
- Vibrating hopper
Describe the role of compressibility?
1. Compresses to form a tablet from excipients and API
2. Most APIs tend to be relatively potent and require low doses
3. Nature of API has influence over quality of tablet
What are plastic materials in relation to tableting?
1. Deform by changing shape to bind together
2. On compression do not get new surfaces forming
3. Can add brittle excipient: lactose
What are elastic materials in relation to tableting?
1. Recovers their shape after tableting
2. If bonding is weak, capping will occur
3. Example: Paracetamol
What are brittle materials in relation to tableting?
1. Fragment on compression (not bind together)
2. Exposes new surface
3. Lead to high friability
4. Add excipient such as microcrystalline cellulose that has plastic properties
Why is measuring sticking important in compressibility?
1. If powder is sticky, it will adhere to the punch and die
2. Can lead to variable target weights
What are organoleptic properties?
1. In relation to tablets, relates to the sense of smell, touch, taste and visually
2. Considers: dryness, moisture, and stale fresh factors
How do you improve the organoleptic property of taste?
1. Use water insoluble derivatives
2. Add flavours:
- Citrus- mask sour
- Sweet- mask bitter
- Fruity flavour- mainly for children
How do you improve the organoleptic property of smell?
Use perfumes for topical products
How do you improve the organoleptic property of colour?
1. Mask colour changes
2. Aid tablet recognition
3. Should match taste and smell
What are the therapeutic consideration that should be taken when forming an oral form?
1. Length of therapy:
- Reduce frequency of dosing
2. Speed of onset:
- Fast: quick dissolution
- Long duration: sustained release
3. Age of patient:
- Children choke on tablets- use solution
- Elderly don't want to measure solution- use tablets
What is the purpose of the formulation stages?
1. The physicochemical properties of the API have been chosen and are suitable
2. Must move towards manufacturing, dosage form and making it into a medicine
3. This includes: quality control checks and excipients
Describe the initial formulation development and the purpose of it?
1. Uses small scale equipment such as those in labs to formulate small batches
2. Want to find out if the formulation is suitable for manufacture
3. If there is a way to improve its properties: using granules to improve flow
4. Can the dosage form be developed and scaled up on a large scale
What does the preliminary dosage form of formulation assess?
1. The physicochemical properties of the API
2. Chemical purity
3. Testing it against animals to see the pharmacokinetic properties to API alone
4. Stability when put under storage or specific packaging
5. Batch to batch variation
6. Marketing: can we sell the dosage form?