Pre-Midterm Flashcards
8 advantages of Solid Dosage Forms
Unit dose
Cost of shipping
No breakage or leakage
Masking taste less difficult
More portable
Require less space per dose
Good physical and chemical stability
Elegant distinctive appearance which has a high patient acceptability
Disadvantages of a solid dosage form
Potential bioavailability problems
Potential irritant effect on GI mucosa
Occasional difficulty in formulation
Manufacturing can be more technical or
specialized
What are the Physical Properties of Solids
a) Particle size
b) Mixing powders
What are the Types of compounded powders
Bulk powders for internal use
Other bulk powders
Dissolution rate:
the rate at which the particle dissolves.
By increasing the surface area, one may increase the bioavailability for some poorly soluble drugs, because there is often a direct relationship between dissolution rate and bioavailability and drug absorption.
Suspendability
the ability of particle to remain undissolved but uniformly dispersed in a liquid vehicle.
Accuracy of dosage form
there must be uniform distribution of drug substance in a powder mixture or dosage form, and to ensure batch-to-batch uniformity.
Penetrability
the ability of particle to reach their intended location, e.g. to be inhaled deep into the respiratory tract particles should be 1-5 μm.
Non-grittiness
do not want solid particle in dermal products to feel “gritty”. Finer particles allow for a smoother texture and better appearance and flow. This is also important for oral products such as chewable tablets.
Chemical stability
refers to degradation reactions (e.g. oxidation and hydrolysis). Smaller particles have an increased surface area, leaving them more exposed and vulnerable to reactions with oxygen, water and light.
Flowability
effect on flow properties of powders and mixing of powders and granules. This is important in the manufacturing of tablets and capsules.
Compressibility
effect on adhesion and “sticking” together when compressing granules into tablets. This is important in the manufacturing of tablets and capsules.
the larger the mesh#
the smaller the particles
Monodisperse powders
powders containing particles of uniform size, RARE
Polydisperse
particle size varies a great deal
Comminution
Comminution is the mechanical process of reducing particle size of a solid substance to a finer state of subdivision.
Small-scale comminution
Most commonly involves the use of a mortar and pestle and is done by
the pharmacist or technician.
trituration
the process of grinding a drug in a mortar to reduce its particle size
levigation
the process of mixing a powder with a liquid or semi-solid vehicle (the levigating agent), in which the powder is insoluble, to form a smooth paste
pulverization by intervention
particle size reduction with the aid of an additional material, which can be later, removed
lSpatulation
blending powders with a spatula on a tile or paper
Advantages (of powders as a dosage form)
Flexibility in compounding.
Suitable for infants and young children who cannot swallow tablets or capsules.
Rapid onset of drug action because disintegration is not required.
Can be applied to many body cavities such as ears, nose, tooth socket, and throat.
Relatively good chemical stability.
Disadvantages of powders
Potential for misunderstanding of the correct method of
use that can lead to inaccurate dosing.
Undesirable for bitter or unpleasant tasting drugs
Dentifrices
dental cleaning powders, denture powders
