the medicine Flashcards
what is rational design
the strategy of creating new molecules with a certain functionality, based upon the ability to predict how the molecules structure will affect its behaviour
what are catecholamines
class of neurotransmitters and hormones that play crucial roles in the NS
3 main categories are:
dopamine
noradrenaline
epinephrine (adrenaline)
what do beta recpetors do
three types beta 1,2&3
control vasodilation
stimulate cardiac and smooth muscle
what do alpha receptors do
two types alpha 1 and alpha 2
intestinal relaxation
vasoconstriction
pupil dlation
what is Analytical characterisation
Evaluating the success of a combinatorial synthesis by determining the yield and the purity of the compounds.
how to seperate single conounds
purification by conventional techniques (e.g. chromatography)
determination of the yield by weighing the substances
confirmation of purity by elemental analysis or NMR spectroscopy
how to seperate compound mixtures
highly sensitive methods are required
mass spectroscopy coupled with H/uPLC or capillary electrophoresis (CE)
what are the two mehtods for Determining the most bioactive substance in a mixture, High Throughput Screening
On Bead screening
Deconvolution
What is On Bead screening
Compounds are covalently attached to the solid support
The solid-bound library is treated with a labelled biological target (receptor)
Selection of the labelled beads (highly automated methods) followed by structural characterisation
Requirement: Solid support/ linkers have to be water soluble
What is deconvolution
Preparation of sets of sub-libraries (each contains compounds, with one single known building block; the remaining positions contain all possible variations
Screening of the sub-libraries provides the mixture with the highest bioactivity.
Iterative deconvolution/ deconvolution by positional scanning
what % of compounds are abondended each year due to poor solubility?
40%
Describe lead selection of medicines
A lead chemical series for optimisation (application of rational design)
Probability of Success increased by identifying a back-up series
Probability of Candidate Selection is low
Probability of Success for a precedented mechanism is low and lower still for an unprecedented mechanism
Even after Candidate Selection still a long way from becoming a medicine
what is the BCS
Biopharmaceutical Classification System
a system used to classify drug substances based on their solubility and permeability characteristics. It is widely used in the pharmaceutical industry to guide the development of oral drug products.
what is class 1 of the BCS
high solubility
high permeability
rapid dissolution
what is class 2 of the BCS
low solubility
high permeability
what is class 3 of the BCS
high solubility
low permeability
what is class 4 of thr BCS
low solubility
low permeability
what is the BDDCS
Biopharmaceutical Drug Delivery Classification.
sha
what is class 1 of the BDDCS
minimal drug effects on the gut and liver
what is class 2 of the BDDCS
effects predominate in the gut by uptake, and efflux transporters can effect liver
what is class 3 of the BDDCS
absorptive transporter effects predominate (can be modulated by efflux transporters)
what is class 4 of the BDDCS
absorptive and efflux transporter effects could be important
what classes of the BDDCS have low permiability / metabolism
3 and 4
what classes of the BDDCS have high permiability / metabolism
1 and 2
what classes of the BDSCS have high solubility
1 and 3
what classes of the BDDCS have low solubility
2 and 4
describe relative difficulty in formulation design
most to least
poor permeability
high first pass metabolism
poor chemical stability
low solubility
instability in GI fluids
high dosage
describe Overview of Pharmaceutical Product Development
lead optimisation
preclinical evaluation
Safety/ tolerability Phase I, PoC in humans
Phase IIb/ Phase III studies
Post-marketing studies
what is efficacy
Efficacy refers to the ability of a drug or medical intervention to produce the desired therapeutic effect under ideal or controlled conditions. It is a measure of the extent to which a treatment is effective in achieving its intended purpose
what are 4 reasons for failure of clinical trials
efficacy
safety
commercial viability
other (formulation problems)
what is commercial viability
Commercial viability refers to the likelihood or feasibility of a product, service, or business endeavor being successful and profitable in the marketplace. It is an assessment of whether a particular business venture has the potential to generate sufficient revenue to cover its costs, achieve profitability, and sustain its operations over the long term.
benefits of an IV bolus dose
The correct dose will result in the correct
and optimal clinical outcome
what is an IV bolus dose
An IV bolus dose involves the direct injection of one
entire dose (i.e. the bolus) into the venous
circulation.
This results in the TOTAL dose being administered
and entering the systemic circulation.
The bioavailability is therefore 100 %
tell me about an IV bolus dose
As we inject a BOLUS dose into our patients, the starting concentration in the blood is the
highest and the drug will eventually distribution out to the circulation and be eliminanted.
Essentially we see a DECLINE in drug levels
what does T1/2 mean bolus dose
half life
it describes the time required for a quantity to reduce to half its initial value.
what does C0 mean bolus dose
initial conc, where the graph intercepts the y axis
what does kel mean bolus dose
elimination rate constant
linked to degredation
what does Cl mean bolus dose
clearance
tells you about elimination
what does Vd mean bolus dose
volume distribution
bolus dose
conc time graph
what can you calculate?
Once you calculate the gradient and intercept (basic
maths), you are then able to calculate other important
pharmacokinetics terms
what kinetics is bolus dose based on
1st order
define initial concentration
the concentration (e.g. mg/mL) or mg/L) in the body (blood)
following dosing of a drug (in mg) into the volume of the blood (in mL or L). This is
sometimes referred to as C0 (the concentration at time zero)
define volume distribution
the volume (mL or L) within which you dose (in mg) the drug
define elimination rate constant
a constant terms (like the degradation rate constant when
looking at zero or first order degradation). This is not useful on its own but it used to
convert into something which is more clinically useful. The term is referred to as kel
define clearence
this has been discussed previously. The term is referred to as Cl. This is a useful
indicator of the amount of drug removed from the body by the kidney or liver
define half life
the most important term clinically. It can be calculated from the both of the above
and is the time taken for a 50 % drop in drug levels in the body. The terms is referred to as
t1/2
whats ADME
ADME pharmacokinetics is an acronym that stands for Absorption, Distribution, Metabolism, and Excretion. It’s a set of processes that describe what happens to a drug within the body after administration
conc eq
mass(dose) / volume
Cl
clearance two equations
Cl = Kel X Vd
Cl = Dose / AUC (Area under curve)
describe half life relationships
0.693 X Vd / Cl