ceutics quiz 2

what is the bronsted lowry acid base theory

acids are proton donors and bases are proton acceptors

are strong acids completely or partially ionized

completely so the equation uses a full arrow

what happens when a strong acid is ionized

the pKa is lowered and the molecule loses a proton

are weak acids completely or partially ionized

partially ionized so the equation has an equilibrium arrow

what happens when a weak acid becomes partially ionized

it has a higher pka than the strong acid

what is an acidic hydrogen

an H atom that can be released as a proton

what are some examples of acidic functional groups

carboxylic acids, sulfonamides, and phenols

what are some examples of basic functional groups

amines, imines, guanadines

what are conjugate acid base pairs

when an acid loses a proton it becomes a conjugate base

when a base accepts H+ it becomes a

conjugate acids

strong acids have

weak conjugate bases

weak acids have

strong conjugate base

sttrong bases have

weak conjugate acid

weak bases have

strong conjugate acids

the lower the pka

the stronger the acid

the higher the pka

the weaker the acid

weak an acids are partially unionized and their conjugate base is

partially ionized

weak a bases are unionized but their conjugate acid is

ionized

when a weak acids pH is less than pka it will be

unionized

when a weak acids pH is greater than pka it will be

ionized

when a weak bases pH is less than pka it will be

ionized

when a weak baes pH is greater than pka it will be

unionized

describe the ionized form

water soluble, permeable to the lipid membrane

describe the unionized form

lipophilic, absorbable form

when a weak base goes through the acidic stomach

ionization and water solubility increases

when a weak base goes through the alkaline intestines

unionization and lipophilicity increases

when a weak acid goes through the acidic stomach

it is unionized and lipid-soluble

when a weak acid goes through the alkaline intestine

it is ionized and water-soluble

what is a monoprotic compound

acids that can donate only one proton

what is a polyprotic compound

acids that can donate more than one proton and each loss of a proton is a separate step

what is an amphiprotic compound

a compound that can both donate and accept a proton; acid or base

what is the 2 unit rule that is to be considered when determining the net charge of polyprotic and amphiprotic drugs

if pH is:

greater than 2 units ABOVE pka it is ionized

if pH is:

greater than 2 units BELOW pka it is unionized

what is a pharmaceutical salt

a product of an acid reacting with a base

do salts donate or accept protons

both

what kind of bonds are responsible for forming salt ions

ionic bonds

what are the two products of an acid reacting with a base

a salt and water

why are salts important

provides increased dissolution, increased solubility and improved bioavailability

weak acidic drugs must react with what kind of base to form a salt

strong base

weak basic drugs must form with what kind of acid to form a salt

a strong acid

can reacting as weak acid and a weak base form a salt

no

what is a salt former/counterion

a substance that reacts with the drug to produce the salt

what is the counterion for acidic drugs

a strong base

what is the counterion for basic drugs

a strong base

why are salts primarily made

many drugs have poor water-solubility because of their lipophilicity even with good bioavailability, salts counter act with by improving solubility and dissolution rates

how do salts aid in increasing dissolution

by increasing pH and solubility is higher at the favored ionized form

what do basic drug salts do to their environment

increases acidity, lowering pH, and improving solubility because the ionized form is favored

what are buffers

a compound or mixture of compounds that resist changes in pH

a solution containing a buffer is called

a buffer solution

what three components form an acidic buffer

a week acid, a salt, and a strong base

what do acidic buffers do to the solution

neutralizes it by decreasing acid and increasing base

what are the main components of a basic buffer

a weak base, its salt, and a strong acid

what does a basic buffer do to a solution

neutralizes it by decreasing the base and HEAVILY decreasing the acid

what is the acidic buffer equation

pH=pka+log([salt]/[acid])

what is the basic buffer solution

pH=pka+log([base]/[salt])

what are three factors you should consider when selecting a buffer

your desired pH, the solubility and stability depend on pH, and the route of administration

what are the three main roles of salt formation

increasing solubility, dissolution, and bioavailability

what are the four main roles of pharmaceutical buffers

increasing solubility and stability, optimizing enzymatic activity, and enhancing patient comfort

what is drug stability

the extent to which a product retains within specified limits and throughout its period of storage and have the same properties and characteristics that it possessed at the time of manufacturing

what are the five types of drug stability

chemical, physical, microbial, therapeutic, and toxicologic

what is chemical stability

the API remains its chemical integrity and labeled potentcy within limits

what is physical stability

the original physical properties are retained

what is microbial stability

sterility or resistance to microbial growth is retained

what is therapeutic stability

the therapeutic effect remains unchanged

what is toxicologic stability

no significant increase in toxicity occurs

drug stability is one of the most important activities in what step of the drug manufacturing process

pre-formulation

what are the three stability studies conducted during pre-formulation

solid-state stability, solution-phase stability, and stability in the presence of excipients

what may a drugs chemical structure allow

the anticipation of the possible degradation reactions

in practice, pharmacists may consider what as a reason for lack of drug response or unexpected drug responses

drug stability

what are three common pathways for chemical drug degradation

hydrolysis, oxidation, photolysis

what may studying chemical stability aid in

selecting storage conditions, determining dispensing containers, and anticipating drug interactions

what is hydrolysis

drug molecules interact with water molecules to yield brekdown products

what is water used for in pharmaceutical products

either as an ingredient or as a contaminant

what are the most common form of chemical degradation

hydrolysis reactions

most hydrolysis reactions involve which functional groups

carboxylic acids such as esters and amides

how do you prevent hydrolysis

using non-aqueous solutions instead, film coating the tablets, supply the drug in a dry form, avoid humidity in tightly closed containers, use of buffers to maintain pH

what do oxidation reactions involve

an increase in the number of C-O bonds or bonds involving oxygen

OR

reduction of C-H bonds or bonds involving H

what are three functional groups that are susceptible to oxidation

aliphatic alcohols, aldehydes, and alkenes

what are some ways to prevent oxidation

replacing the air in the container with nitrogen, having a more acidic pH, add a chelating agent, store at low temps, anti-oxidants

what is photolysis

light induced degradation

what forms of light may cause photolysis

sunlight and artificial light

what nm of wavelength is the most damaging

300-400 nm

what functional groups are most susceptible to photodegradation

carbonyl, nitros, alkenes, aryl chloride, and phenols AND double bonded systems

what may change about the appearance of a drug when it is photodegradated

it may turn yellow or darken

what are some ways of preventing photolysis

appropriate packaging, dark storage, film coating on the tablets

what are the microbial preservative properties that are required

broad spectrum treating gram positive and negative bacteria, low toxicity, good solubility, stable in many pHs, compatible with excipients, nonvolatile/oderless/tasteless

what are some examples of microbial preservatives used in pharmaceutical products

alcohols, glycols, parabens, and quaternary ammonium salts

what is shelf life

the period during which a drug product post-manufacturing remains suitable for intended use

what are typical shelf lives

2-3 years

what is an expiration date

the date at which the manufacturer can still guarantee the full potency and safety of the drug

stability and expiration dating are based on

chemical reaction kinetics

what are chemical reaction kinetics

the study of the rate of chemical change and how it is influenced by the reactants, solvent, pressure, and temperature

what must molecules do inorder to react

collide