Solid Oral Dosage Forms 1 Flashcards Preview

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Flashcards in Solid Oral Dosage Forms 1 Deck (17):

What are the clinically important features?

Contain the correct quantity of active ingredients
Release the contents for absorption as designed
Stable for the life of the product
Dispensed pack of medicines easily portable
Can be taken anywhere
Size suitable for swallowing
Strong enough to be handled without damage
Appearance to give patient confidence


How much does a tablet or capsule weigh?

Ampicillin 500mg:
Tablet weighs 750mg
Capsule weighs 700mg
Excipients added for processing and functioning


Sections of the PIL

1: What X is and what it is used for
2: Before you take X
3: How to take X
4: Possible side effects
5: How to store X
6: Further information- details of the active ingredient, quantity per dosage form, other ingredients, all the excipients


Other common ingredients in tablets

Cellulose microcrystalline
Silica colloidal anhydrous
Croscarmellose sodium
Sodium starch glycolate
Magnesium stearate


Other common ingredients in capsules

Pregelatinized starch
Dimethicone 350
Gelatin (shell)
Colouring agents (shell)


Powder properties

Particle size
Modifying bulk properties through processing and formulation


What does particle size affect?

Rate at which substances dissolve- surface area of powder is proportional to rate
Rate of sedimentation in suspensions (liquids)
Rate of powder flow
Type of powder packing- related to shape
Penetration into lungs- aerodynamic particle properties


Particle shape and size

Pharmaceutical particles are rarely regular shapes
The irregularity of a particle makes it difficult to assign a unique size
To describe them, need to use the minimum number of dimensions to provide useful information for the application involved


Sieve equipment

Simple test using a nest of sieves
Sieves are woven from wire (holes tend to be square) or are plates with perforations (holes tend to be round)


Sieve methods

Equivalent diameter: sieve diameter, ds
The particle diameter that passes through a square hole
Analysis range 45 to 1000 micrometres
Nest of sieves, 6 to 8, an aperture progression based on change in diameter
Place sample on coarsest and vibrate for specific time
Air jet sieving, one sieve at a time start with finest and remove the fraction under sized


Particle size reduction comminution

Objective: efficient processing of particles
Important for: powder mixing, manufacture of suspensions, powder flow, extraction of actives from raw materials, dissolution of actives, obtaining the correct dose in each unit


Bulk powder properties

Powders, mixtures of solid particles and air
Mass volume relationships: mass can be measured precisely, volume can be interpreted in several ways
Air is present between particles, in open pores on particles surfaces and inside closed pores on particles


Mixing solids

Unit operation which aims to treat two or more components so that each particle lies as nearly as possible in contact with a particle of each of the other components
If achieved it produces a perfect mix- when each particle lays adjacent to a particle of the other component


Mechanisms of powder mixing

Convective- groups of particles are transferred from one place to another
Shear- layers of material move or flow over one another
Diffusive- a dilated powder bed moves or flows


Is it mixed?

Take samples and determine composition
Results depend on sample size, composition of mixture, degree of mixing (mixer type and efficiency, mixing time)


Powder segregation (de-mixing)

Particle size effects- smaller particles have poor flow, larger particles flow better
Particle-density effects- denser particles acquire greater kinetic energy
Particle-shape effects- spheres flow better than irregular particles, they mix better but segregate more easily


Adhesive/interactive (ordered) mixtures

Mix of very small and large particles- small particles adhere strongly to surface of carrier particle e.g. powders for inhalation, small particles have a high specific surface area
Pharmaceutical mixtures show some degree of both ordered and random mixing