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Chemistry in Medicine 2 - Coggle Diagram
Chemistry in Medicine 2
Aspirin 2
titrations
volumetric determination
of aspirin conc
aspirin =
WEAK ACID
titrated with strong alkali (NaOH)
phenolphthalein indicator
units
mol dm-3 (xRFM) = g dm-3
g dm-3 (x1000) = mg dm-3
reactions
Iron(III) Chloride
method
shake small amount aspirin
with deionised water
prepare similar solution salicylic
add drop iron(III) chloride solution
results
salicylic acid = immediate purple colour
aspirin = no colour (solution remains yellow)
no free -OH groups
if colour forms - recrystalise to purify + comparison w/ purified
Hydrolysis
method
boil
mix aspirin
with sodium hydroxide solution
in flask under
reflux
- 20 mins
cool
add
dilute sulfuric acid
until ppt salicylic acid finished
filter
recrystallise
from hot water
identify using:
= iron(III) chloride
= melting point
Titrations
(as an acid)
method
directly titrated using solution of NaOH
conc of aspirin sample determined
equation
using TLC to
check purity
1.
aspirin, salicylic acid + aspirin from tablet
dissolved in ethanol/dichloromethane
do not use water
aspirin does dissolve but partially hydrolysed
water does not evaporate off TLC
2.
using capillary tube - solutions from ^^ applied to TLC plate
3.plate run using
ethyl ethanoate
4.spots
developed
using
UV Light
Iodine
5.plate
placed in beaker
of
iodine crystals
6.
Rf value for aspirin using ethyl ethanoate = 0.45
different solvent = different Rf value
7.salicylic acid used
show whether present
as impurity in crude
using GLC to
check purity
always possibility for
"false positive"
compared to TLC
TLC
limited use
in identifying drugs
1 spot on 1D TLC can be 10 spots in GLC
TLC
very quick
to
compare simple drugs
TLC
not
used to
determine amount
uncertainty in value
GLC much MORE ACCURATE
Cisplatin
structure
complex of
Pt 2+
2 NH3 ligands
2 Cl- ligands
square planar
shape
cis-diamminedichloroplatinum (II)
(Pt(NH3)Cl2)
trans isomer
ineffective as
chemotherapy drug
2 DNA attacking ligands on OPPOSITE
side of molecule
∴ only able bind to DNA @ 1 site @ time
role
anticancer drug
cancer cells -
rapidly dividing cells
∴ cells need to replicate DNA
process of DNA replication stopped
cell die + growth of cancer stop
DNA replication -
process double stranded DNA molecule
copied to produce
2 identical DNA molecules
mode of action
molecule attached itself to DNA (of cancer cells)
simultaneously in 2 sites
prevents replicating further
stops growth of tumour
2 methods
1.
N atom
in guanine
bonds
to Pt
displacing water ligand
H2O bound
MORE LOOSELY
than Cl
Co-ordinate bonds
to platinum
lone pair - on N atom of 2 guanines
adjacent to each other in helix
2.
H atom
on 1 of ammonia ligands
forms
H bond
to N or O atom in guanine
very
expensive
treatment
HIGH COST of Pt
ability to bond to 2 DNA bases
GUANINE
ADENINE
unpleasant side
effects
weaken immune system
decrease in blood cell production
kidney damage
hair cells + gametes
killed
∴ less toxic
alternatives produced
Haemoglobin
globular protein
dissolves in water
structure
4 peptide chains
each with
HAEM GROUP
contain iron = in
polymorphic ring
oxidation state
+2
in tetradentate ligand
4 coordinate planar structure
1 Oxygen w/ lone pair
forms bond to iron (II) ion
equations
(double headed arrow)
CARBON MONOXIDE
bonds
200 times more strongly
w/ iron (II) than oxygen
prevents haemoglobin carrying oxygen
(once bonded - not released)
equation
(1 way arrow)
formed from:
faulty boilers
lack of O2
fuels burning with incomplete combustion
car exhausts
incomplete combustion
reduced by = catalytic converters
Blood Clotting
sequestering
D: formation of complex
so ion no longer available for reactions
polydentate ligand
(edta)
sequester metal ion
forming stable complex
prevents metal ion reacting w/ other ions
edta also used to REMOVE Ca2+ ions from
hard water
hard water = caused presence Ca2+ + Mg2+
softening water =
remove Ca2+ + Mg2+
using edta
ensure no limescale etc
calcium ion
essential for blood clotting
citrate ion
(sodium citrate)/
edta
chelates calcium ion
equation