Solid Oral Dosage Forms 1 Flashcards
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 Flow Packing Mechanical Mixing 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)
