Basics Of Medicine Design Flashcards
What are the important things to consider when manufacturing a medicine?
Must be chemically and physically stable
Must have preservation against microbial contamination
Should have uniformity of dose
Must be acceptable to users
Must have suitable packaging and labelling
What are the principle objectives of medicine design?
To achieve a predictable therapeutic response to a drug included in a formulation ( medicine)
To be able to manufacture the medicine on a large scale with reproducible product quality.
What is preformulation?
This is when the fundamental physical and chemical properties of potential drug molecules are determined.
The first learning phase is preformulation.
It is undertaken on lead compounds or potential new drugs
Will indicate the feasibility of potential new dosage forms including stability,poor in Vivo dissolution and hence bioavalibility
Includes stability of potential excipients
What is bioavalibility?
The rate and extent of drug absorption - the amount of an administered drug which reaches the systemic circulation in an unaltered form.
What are the oral routes of drug administration?
Tablets, capsules,
Suspensions, solutions
Emulsions
Buccal,gingival,sublingual
What are the parenteral routes of administration?
Intravenous, intramuscular, subcutaneous injections or solutions/suspensions/ emulsions
Uses a hollow needle
What is the rectal route used for?
Suppositories and enemas.
Normally for local rather than systemic, with some exceptions.
What other routes of administration are there?
Respiratory, usually for respiratory problems IE inhalers
Gases, aerosols or ultra fine particles
Topical - applied to the skin, normal local but cane by systemic IE nicotine patches
What should be considered when deciding on a route of administration?
Bio pharmaceutical considerations IE ADME
Therapeutic considerations IE indication, site of action, duration, onset of affect.
Drug factors - the physics chemical factors
What are the drug factors to consider?
Particle size and surface area
Solubility
Dissolution
Partition coefficient - ability to dissolve in lipids
PKA - the degree to which the drug is ionized/unionized
What is polymorphism?
Different polymorphs can be produced by manipulation of the conditions of particular formation during crystallisation IE temp, cooling rate,choice of solvent
Only one form of a pure drug substance is stable at a given temperature and pressure
The other forms are described as meta stable and will convert at different rates to the stable form.
Different polymorphs have different physical properties, and can exhibit different behaviours during processing.
What is the requirement for stability and potency in regards to shelf live?
Should have a shelf life of approximately 3 years, and should not fall below 95% of its original potency.
The product should look and perform as it did when manufactured.
What destabilisation can occur that are due to chemical stability?
Hydrolysis Oxidation Dimerisations Isomeric change Photodegredation Excipients compatibility
What degradation is attributed to physical stability?
Sorbitol of drug to containers Precipitation of drug Crystal ripening Creaming and cracking Change in mechanical properties Polymorphic change
What is cGMP is required during preformulation?
A written stability testing programme, the results of which will determine storage conditions and expiration date.
