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Okay, opium is a material that has been
used since ancient times,
particularly for its medicinal properties,
for instance as a painkiller.
And opium is the crude material that's
obtained
from the seed heads of the poppy, papaver
somniferum.
Somniferum is Latin for bringer of sleep,
and one of the
effects of taking opium is to become
sleepy so it would help people sleep.
The way opium was obtained is that the
seed heads are scored and the latex
exudes from those cut marks, and that
latex, when it's dried, is opium.
Paracelsus, who we'll meet again in a
lecture on toxicology, went one better -
he improved opium by extracting it with
alcohol and this
gives a liquid, which was given the name
laudanum, and that was used medicinally.
In most countries, of course, opium
production is illegal.
Currently, the major illegal producer of
opium is Afghanistan.
Other countries that produced opium in the
past, such as Burma
and Thailand and Laos, now produce much
less of the stuff.
Now, what is it in opium that has these
effects,
and the answer is, it is a chemical called
morphine.
So we can say that morphine has been used
as a painkiller for thousands of years, and
in
fact it is still used as a painkiller and
even today it is one of the most
effective.
So because there is still clinical demand
for morphine, there not only are the
illegal producers, there's also the legal
producers. And the biggest legal producer
is in fact the Australian State of
Tasmania, and opium poppies are grown in
fields in Tasmania which apparently cause
to some problems to the local wallabies.
One of the uses of opium is for
gastrointestinal problems.
So if you have a bad stomach upset, you
have eaten something
you really shouldn't, one way to cure
those problems is by taking opium,
and opium was used in this way up to a few
decades ago.
Even when I was a child, when I had a
stomachache, my parents would give
me a spoonful of something called Kaolin
and
morphine, and I can tell you it tastes
disgusting.
Now, one thing you learn after having a
spoonful of Kaolin
and morphine is to be careful what you eat
in future.
One person who we know took opium is the
poet, Samuel Taylor Coleridge,
and one of the poems that he's best known
for is the poem, Xanadu, which
starts "In Xanadu did Kublai Khan stately
pleasure dome decree".
According to the story, Coleridge came up
with
this poem while under the influence of
opium,
but before he could write it down, he
was famously interrupted by the man from
Porlock.
So what we have in the poem Xanadu is only
a part
of what he dreamed about while he was in
this influence of opium.
In his own words, he says, "This fragment,
with a good deal more, not
recoverable, composed in a sort of Revery
brought on by two grains of Opium
taken to check a dysentery, at a Farm
House between Porlock and Linton, a
quarter of a mile from Culbone Church, in
the fall of the year, 1797."
Well, that was a long time ago, but
even now we can still find medicines
containing opium.
Okay, here's a packet from some Thai
stomach medicine, and if you look at the
ingredients carefully, you see "Opium
Tincture, 0.60 millilitres".
While that's not very much opium, I might
be a little bit more worried
about the Antimony Potassium Tartrate
that's also in there.
Well, opium has also inspired composers,
here's the composer Hector Berlioz, and it
is believed that his Symphonie Fantastique
was composed under the influence of opium.
So if you want to know what it's like to
take opium, but
you don't actually want to take opium,
you could just listen to Symphonie
Fantastique.
Opium has also caused wars.
There were two opium wars between the
British and the Chinese
in the 19th century, the primary cause
being trade in opium.
Opium or morphine may also have affected
the Second World War.
Hermann Goering, who was Head of the German
Airforce during that war, was addicted to
morphine.
He'd become addicted after his doctor had
prescribed some for him, and it's possible
that some of the odd decisions taken
by the Luftwaffe were influenced by that
addiction.
So we know opium, that's what is the crude
material that comes from the plant,
and we know morphine, that is the active
ingredient in that crude material.
The third member of this trio is heroin.
What is heroin?
Heroin is a semi-synthetic.
It was invented by a chemist working for
the well-known
pharmaceutical firm Bayer in Germany, and
chemically it is diacetylmorphine.
Bayer is also the company that gave us
aspirin, and in fact they used the same
chemistry
to convert morphine into heroin as to
convert the
starting material they were using,
salicylic acid, into aspirin.
They were very impressed by heroin, it
made people feel strong.
It was more potent than morphine and this
word, "Heroin", was dreamt up by their
marketing department.
The idea was take heroin and feel like a
hero.
Of course, very quickly, the awful side
effects of heroin were discovered.
It was taken off the market and country
after country banned it.
In many countries, heroin is totally
banned.
In a few countries, including the United
Kingdom, heroin may still
be used medicinally if prescribed by a
doctor.
For instance, if you have a terminal
cancer patient who is suffering great
pain, a U.K. doctor may prescribe them
heroin to ease their symptoms.
The fact that heroin is available in
some countries to doctors can be very
unfortunate.
Here's the case of Harold Shipman, he was a
British family doctor and
also a serial killer, and he would murder
old ladies
who were in his charge by administering
them a lethal dose of heroin.
Because all of these ladies were old, they
were already in poor health and Dr.
Shipman
was a respected local doctor, there was
very
little suspicion and there was no
investigation of him
until he made a mistake. It's only when he
forged
a will for one of his victims that there
was an investigation and he was caught.
It is not known how many people Harold
Shipman killed.
Statistically, it's been estimated it could
be well over 200 people, making him
one of the most prolific serial killers of
all time, and he did it with heroin.
How does heroin work?
Why is it better than morphine?
Well, on the left you see the structure of
morphine and this
is treated with a chemical called acetic
anhydride to convert it into heroin.
Now, originally heroin meant this
compound here.
Nowadays, the term heroin refers to the
illegal drug,
which is pretty much always going to be
impure.
So the term used for the pure compound is
the chemical term diacetylmorphine, which
may be shortened to diamorphine.
The chemical used for this transformation,
acetic anhydride, is
nowadays controlled in many of the
countries where morphine is produced
and also in the nearby countries where the
processing may occur.
Now how does diamorphine work, why is it
so much more effective than morphine?
And the answer is, this derivatization of
morphine result in a
chemical that is transported faster through the
body and into the brain.
So those two acetyl groups that are added
simply
speeds up the transport of the molecule
within the body.
The two acetyl groups will be rapidly
cleaved off by metabolic processes to
release morphine.
So the actual action on the brain is just
the action of the
morphine, but the faster transport to the
brain means that a much
higher concentration will be obtained in a
shorter time.
A consequence, of course, of this rapid
cleavage of these acetyl groups
is that if the urine for instance of a
user is analyzed, diamorphine
itself is unlikely to be detected, but
morphine will be detected.
Well chemists, of course, have made many, many
derivatives of morphine and some of
them will have similar properties, some of
them have different properties.
So one analog of morphine is etorpine, and
this is a very powerful tranquilizer.
So if, for instance, there's a wild animal
on the
loose escaped from the local zoo and it
has to
be shot by someone with a dart gun to make
it fall asleep, then that dart would
probably contain etorpine.
If you've seen the Jurassic Park movies,
there's
one of them where they tranquillize a
Tyrannosaurus Rex,
and they probably did that, or would have
done that, with a really big dose of
etorpine.
Now, etorpine was discovered by a research
group in a university, and there's
a story about how they realized that this
material was a very powerful tranquilizer.
Apparently this research group would have
afternoon tea together, and one day
the guy whose job it was to make the tea
couldn't find the spoon to stir the tea.
So he took one of the spatulas or stirring
rods
from the lab and used that to stir the tea,
but didn't realize that that stirring rod
wasn't
clean - it had traces of etorpine on it.
So after drinking the tea, the whole
research group fell asleep and
when they woke up, they realized the
discovered a really potent tranquilizer.
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Now, back to heroin, we have said that
heroin nowadays refers to the illegal
drug, which will be impure and it will
have all sorts of impurities in it.
Some of these will be related compounds,
for instance, if the acetylation
reaction is not done properly, there will
be left over morphine in the heroin.
There may also be codeine and thebaine, and
these are
morphine-like alkaloids which are also
produced by the poppy plant.
The codeine may be acetylated in the same
process by which
morphine is acetylated and therefore,
acetyl codeine may also be present.
So these are closely related compounds
which
are likely to be in the heroin sample.
The poppy plant also produces other
alkaloids
which are not related to morphine, such
as papaverine and noscapine and these may
be detected in the heroin sample too.
In addition, the heroin may have been
cut, that is, diluted, with
inert or less active materials, such as
sugar or caffeine or barbiturates.
So, if a sample of heroin is seized, it
can be
analyzed chemically, it can be analyzed by
GC or by HPLC. And the
composition of different samples of heroin
that have been seized can be compared
and then you can see whether the samples
came from the same source,
therefore they would have the same
composition,
or whether they come from different
sources.
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