Pharmaceutics Flashcards
What is a pharmaceutic?
A branch of pharmacy which includes the study of formulation of drugs into dosage form.
What is a drug?
A chemical entity obtained from various sources which has a therapeutic effect on the body.
List 5 physical pharmaceutic properties
- Rheology
- Diffusion
- Aggregation
- Percolation
- Surface tension
List 5 biological pharmaceutic properties.
- Nanoparticle flow
- Diffusion in vivo
- Movement in tumours.
- Bio-adhesion
- Particle interaction in lung.
What is dosage form?
When drugs are combined with other inert substances (eg. excipients) and converted into suitable forms of administration to the body (eg. tablet).
List the 4 forms of dosage administration to the body and give an example of each.
- Solid - tablet (unit dose) or granules (fine dose)
- Liquid - syrup (mono-phasic) or suspensions (di-phasic).
- Semi-solid - suppositories (internal) or creams (external).
- Other - inhalers (gaseous).
What is an API?
Active Pharmaceutical Ingredient is a chemical compound used for diagnosis, treatment and prevention of disease.
What is an excipient? Give 3 examples.
Substances that give a particular shape to the formulation to increase stability. eg. colouring, flavouring, antioxidants.
What is biopharmaceutics? Why is it studied?
Relationship between physiochemical properties in dosage form and the observed therapeutic effect. The therapeutic effect is studied at the absorption site.
Give 5 examples of factors that are studies in biopharmaceutics.
- Rate of drug release from product.
- Rate of dissolution at adsorption site.
- Availability of drug at site of action.
- Protection and stability of drug within product.
Give 2 examples of causes of drug instability and how it can be improved?
- Chemical degradation by hydrolysis or deamidation.
- Improved by pH, solvent choice, temperature.
Give 2 examples of factor affecting rate of dissolution at adsorption site.
- Environmental - agitation, composition, etc.
- Other - polymorphism, particle size
When manufacturing dosage forms, give the 7 key factors involved.
- Amount/type of diluent.
- Type of tablet manufacture
- Granule size & distribution.
- Compression force
- Humidity
- Storage conditions’
- Age of dosage form
What is a vehicle?
The binding agent for the product eg. aqueous, miscible, immiscible.
Give 2 examples of diluents.
Organic - starch
Inorganic - Dicalcium Phosphate Divalent
What is a lubricant? How is it different than a binder?
Lubricants ensure good flow of granules to reduce sticking whereas binders promote cohesive compactness.
Why are surfactants used?
Wetting agents that enhance or reduce adsorption.
What is a negative to using colourants?
May decrease the dissolution rate of a drug.
Why is wet granulation generally better?
It improves the wettability of poorly soluble drugs by incorporating hydrophilic properties resulting in a greater rate of dissolution.
What is colloidal dispersion? How are particles seen?
Where there is a dispersed phase (very fine particles) and a dispersion medium (continuous phase). Particles seen through electron microscope, pass through filter paper but not a semi-permeable membrane).
Give 6 properties of colloidal dispersion properties.
- Shape
- Diffusion
- Light scattering
- Viscosity
- Gel formation
- Electric properties
What is course dispersion?
Same as colloidal dispersion but particles can be seen through normal microscope but do not pass through filter paper.
What is bioavailability?
The transfer of a drug from its site of administration into body with general circulation. It is characterised by rate of transfer and amount transferred.
What are the different factors affecting drug adsorption?
- Physiological - cell membrane is semi-permeable so highly charged and large molecules cannot cross.
- Physiochemical - surface area of the drug (crystal or amorphous), hydration & solubility.
- Dosage form - inert ingredients eg. diluents or type eg. solution.
Outline the rotating basket apparatus.
- 22 mesh cylindrical basket
- 100rpm speed
- Closed compartment
- 1L capacity, partially immersed in water bath.
- Mesh basket placed into glass cylinder 2cm from bottom and rotated by variable speed motor
- All metal parts are stainless steel.
Outline the rotating paddle apparatus.
- Paddle instead of basket
- Paddle attached vertically to motor.
- 50rpm
