Exam 2 Flashcards
if a drug is formulated in a solution, suspension, and a tablet, which would have the best chemical stability?
tablet, less degradation of drug so least reactive
optimize the absorption rate of drug, increase the ease of administration by the patient, control the rate and site of drug absorption, mask the taste of therapeutic agent, improve chemical stability of drug
solid dosage forms designed to do all these things
increased stability (solid dosage forms have longest shelf life), ease of packaging/storage/dispensing, convenience and accurate dosing, little to no taste/smell of drug
advantages of solid dosage forms
solubility (drug must dissolve from solid dosage form), not suitable for some patients (pediatric/geriatric, patients have difficulty swallowing solid dosage forms - dysphagia), solid dosage forms not suitable for some routes of administration (IV, transdermal, ophthalmic, otic), some drugs lose their activity in solid form (therapeutic proteins, several biological products)
limitations of solid dosage forms
evaluate the impact of physiochemical characteristics of the drug (API) and excipients (solubility, dissolution rate, permeability, drug-excipient compatibility, stability), suitability and therapeutic activity of final drug product (quality, stability, marketability, patient acceptance, cost)
performulation studies
drug particles in some solid products are often micronized, this process increases….
dissolution rate of the drug (decrease the particle size)
purity (efficacy and safety), organoleptic properties (color, odor, taste), presence of polymorphs (crystal forms), surface properties (wettability), particle size and size distribution (monodisperse - uniform particle size vs polydisperse - different particle sizes)
solid-state properties
which has faster dissolution rate, higher solubility, but lower stability?(amorphous or crystalline)
amorphous structures
what is the function of a wetting agent in solid dosage forms?
increase contact between drug particles and liquid
what is used to measure the wetting of a substance by a liquid?
contact angle, lower angle number greater contact
a hygroscopic drug is one that…
adsorbs moisture from the environment
will take in moisture from the air until it gets saturated, want a drug that will not be this at low relative humidity, also need to take into consideration the amount of water being taken up (% weight change)
hygroscopicity
stability issues, physical changes, dosing accuracy, microbial growth, packaging challenges
problems due to hygroscopicity
methods to prevent problems due to hygroscopicity
moisture-resistant excipients, incorporate desiccants or moisture barriers, appropriate packaging materials, implement appropriate storage and handling practice
particles are measured in ___________ but this can be a challenge with irregular particles, use __________
diameter, equivalent sphere
examples of physical stability problems
capsules stick to each other, solvent from a solution evaporates, tablet dissolves slower than its specifications
excipients for solid dosage forms
diluents, binders, disintegrants, lubricants, glidants, opacifiers
a diluent is added to solid dosage formulations to…
act as a filler
glidants/lubricants are added in the manufacture of solid dosage forms to…..
reduce friction among particles
some excipients can perform more than one function, pre-processed and co-processed excipients, provide multiple functionalities to the formulation
multifunctional excipients
mannitol-calcium silicate co-processed excipient
chewable properties, flowability, compressibility
simple and convenient to use (solid unit dosage form), quick and safely manufactured into convenient doses for dose accuracy, carried in portable packages (improving compliance), can disguise unpleasant tastes with film coating, easily identified by markings, shape, and color for safety
tablet features
not all drugs suitable for oral use, some drugs deactivated by the liver (first pass metabolism), may not be suitable for emergencies (slow onset of action, need for patient cooperation), not suitable for patients that can’t swallow, some drugs poorly absorbed by GI tract, pill-cheeking
drawbacks to tablets
may affect drug product performance, makes powder blend more compact and affects tablet hardness
compression
disintegrate slowly, results in slower rate of dissolution, reduces rate of systemic drug absorption, affecting the clinical response
excessive compression may cause tablets to do these things
segregation of drugs from excipients (different particle sizes, density), friction between particles and between particles and equipment (clumping, sticking to equipment, poor flow)
problems with powders