Pharmaceutical biotechnology I Flashcards
State a drug in liquid form that is extremely volatile?
Amyl nitrite (for vasodilation)
Oral liquid drugs cannot be formulated into a tablet form. State an exception.
Nitroglycerlin
which is formulated into sublingual tablets that
disintegrate within seconds after placement under the tongue
What does micronization of drug powders lead to?
Micronization of drug powders can lead to changes in crystallinity and
particle surface energy which cause reduced chemical stability.
Particle size also affects the taste, color, flow characteristics and
sedimentation rates of the drug powders.
What techniques could be used to improve drug solubility?
Micronizing, complexion and solid dispersion techniques
State some chemical and physical characteristics of a drug?
➢Physical description
➢Particle size and surface area
➢Solubility
➢Dissolution
➢Partition coefficient and pKa
➢Crystal properties: polymorphism
➢Stability
➢Organoleptic properties(colour, taste, smell and texture)
Desrcribe polymorphism
Many drug substances can exist in more than one form with different
molecular packing arrangements in the crystal lattice. This property is
termed polymorphism.
Polymorphic forms usually exhibit different physicochemical properties,
including melting point and solubility
What areas does pharmaceutics cover?
➢To investigate the basic physical chemistry for the effective design of dosage forms
(physical pharmaceutics)
➢To study the relevant body systems and how drugs arrive there following
administration (biopharmaceutics)
➢To design and formulate medicines (dosage form design)
➢The manufacture of these medicines on a small (compounding), intermediate (pilot-
scale) and large (manufacturing) scale
➢The avoidance and elimination of microorganisms in medicines (pharmaceutical
microbiology, sterilization), and
➢To perform testing of products (physical testing, drug release, stability testing).
What is a drug?
It is a single chemical entity present in the medicine used for diagnosis, prevention or cure of a disease.
WHO definition: any substance or a product that is used or intended to be used to modify or explore the physiological systems or pathological states for the benefit of the recipient
Why is the direct use of active drug substance rare?
- API handling and accurate dosing can be difficult or impossible, its administration is impractical
- Some APIs are chemically unstable, e.g. light sensitive, moisturesensitive or oxygen sensitive.
- Some APIs can be degraded at the site of administration, e.g. pH sensitive APIs in the stomach (pH 2)
- Some APIs may cause local irritations or injury at the site of
administration
What does it mean by ‘dosage form’?
Dosage form = drug (API) + excipient(s)
What are excipients?
Excipients 輔料 are often referred to as “inactive ingredients” because, in drugs,
they comprise everything except the active pharmaceutical ingredients (APIs).
* Functions of excipient range from helping to guarantee the stability and bioavailability of the API to the drug product’s manufacturability to its texture
and taste, e.g. antioxidants, binders, coatings, colorants / colors, disintegrants,
emulsifiers / surfactants, fillers & diluents, flavoring agents, lubricants & glidants, plasticizers, preservatives, solvents, suspension & viscosity agents, sweeteners
What is bioavailability?
bioavailability = the extent a substance or drug becomes completely available to its intended biological destination(s)
What are pre clinical studies for?
preformulation , formulation, preclinical drug’s safety and effectiveness.
What are clinical studies for?
to assess safety and efficacy
Why are dosage forms needed?
To provide the mechanism for the safe and convenient delivery of accurate dosage
(tablets, capsules, syrups…)
- To protect the drug substance from the destructive influences of atmospheric oxygen or
humidity (coated tablets, sealed ampules) - To protect the drug substance from the destructive influence of gastric acid after oral
administration (enteric-coated tablets) - To conceal the bitter, salty, or offensive taste or odor of a drug substance (capsules,
coated tablets, flavored syrups) - To provide liquid preparations of drug substances, either as dispersions (suspensions) or
as clear preparations (solutions) - To provide rate-controlled drug action (various controlled-release tablets,
capsules and suspensions) - To provide optimal drug action from topical administration sites
(ointments, creams, transdermal patches, and ophthalmic, otic, and nasal
preparations) - To provide for insertion of a drug into one of the body’s orifices (rectal or vaginal suppositories)
- To provide for placement of drugs directly in the bloodstream or body tissues (injections)
