Option D - Medicinal Chemistry Flashcards
(149 cards)
1
Q
List the possible ways of administration of drugs and examples of medicines for each.
A
- oral - mouth - tablets
- inhalation - breathed in - asthma medications (bronchodilators).
- skin patches - absorbed from skin into the blood - hormone treatments.
- suppositories - inserted into the rectum - digestive illnesses treatments
- eye/ear drops - come on - eye/ear infections (who would’ve expected).
2
Q
List the types of injections with the corresponding level of tissue the substance is injected into.
A
- intramuscular - muscle (wow)
- subcutaneous - subcutaneous tissue
- intravenous - veins
- intradermal - epidermis
3
Q
Define bioavailability of a drug and state its significance.
A
Amount of a drug that reaches the bloodstream.
(higher in intravenous)
Important to consider in choosing dosage.
4
Q
Define the first-pass effect.
A
Initial metabolism/alteration of a (orally ingested usually) drug that occurs in the liver after it is absorbed from the gastrointestinal tract and before it enters the systemic circulation.
(reduction in the amount of active drug entering the bloodstream)
5
Q
State the advantages for drug solubility of both water and lipid solubility.
A
- water solubility: crucial for circulation in the aqueous solution in the blood.
- lipid solubility: helps in the passage of drug through membrane.
6
Q
Define and thus distinguish tolerance and addiction.
A
Tolerance - a person given a repeated dose of a drug responds with a reduced response to the drug of the same dose.
Addiction - occurs when a patient requires a drug to feel normal and suffers from withdrawal symptoms if the drug is not taken.
7
Q
Define the therapeutic index (TI) of a drug and list its formula.
A
Ratio comparing the dose of a drug required to produce a therapeutic response (ED50) to the dose that causes toxicity (TD50)
TI = TD50 / ED50
8
Q
State the correlation between the TI of a drug and its safety.
A
Higher TI -> safer drug.
9
Q
Define the ED50.
A
Effective dose 50%
Dose of a drug required to produce a therapeutic effect in 50% of the population/experimental subjects.
10
Q
Define LD50.
A
Lethal dose 50%
Dose of a drug lethal/ causing death in 50% of the population/experimental subjects.
11
Q
Define TD50.
A
Toxic dose 50%
Dose of a drug required to produce a toxic effect in 50% of the population/experimental subjects.
12
Q
Distinguish the TI testing in animals vs in human subjects.
A
TI (animals) = LD50/ED50
TI (humans) =TD50/ED50
13
Q
List the stages of drug development.
A
- Identify target molecule within the body.
- Find lead compound with desired pharmaceutical activity.
- Optimize the lead compound by synthesizing and testing chemically related analogues.
- Combinatorial chemistry to produce and test candidate medicines.
- Laboratory testing
- Animal testing
- Determine TI
- Human trials (three phases)
- Evaluate drug effectiveness based on real medication vs placebo in phase III.
- Post-marketing surveillance programs.
- Adverse reaction monitoring.
14
Q
Define the prostaglandins.
A
Chemical stimulating the pain receptors, released from damaged cells, which mediate the inflammatory response.
15
Q
State the principle of functioning of prostaglandins.
A
Causing blood vessel dilatation near the injury site, leading to swelling and increased pain
impact body temperature regulation potentially causing fever.
16
Q
Define the major principle of painkiller action mechanism.
A
Interception or blockage of the pathway between the source of pain and the receptors in the brain, disrupting the transmission of pain signals.
17
Q
State the category of drugs aspirin belongs.
A
non-steroidal anti-inflammatory drugs (NSAIDs)
mild analgesics
18
Q
State the bulk of aspirin mechanism of action.
A
Prevention of the stimulation of the nerve endings at the site of pain and inhibition of the release of prostaglandins from the site of injury.
Gives relief to inflammation and fever as well as pain.
19
Q
State why mild analgesics are known as non-narcotics.
A
Because they do not interfere with the functioning of the brain
(as strong analgesics do).
20
Q
State the historical predecessor of aspirin and the active ingredient in it.
A
chewing willow bark
active: salicin
21
Q
State the current active ingredient in aspirin and what changed.
A
Ester derivative of salicylic acid
(by Bayer).
Changed alcohol group into an ether which made it more palatable and less irritating substance.
22
Q
State the name of the property of a drug reducing fever.
A
Antipyretic
23
Q
State the process of synthesis of aspirin.
A
Salicylic acid (2-hydroxybenzoic acid) esterificated in a condensation reaction with usually ethanoic anhydride to form aspirin.
24
Q
State the current use of aspirin.
A
anticoagulant - heart
attacks/strokes
antipyretic - mild analgesic
25
State and describe the production process of aspirin.
1. Concentrated sulfuric/phosphoric acid is added to the reactants.
2. Gentle warming of the mixture.
3. Isolation and purification of aspirin from the mixture.
4. Cooling to induce crystal formation (crystallization), followed by suction filtration and washing with chilled water which helps remove soluble acids without losing the (not
very soluble) aspirin.
5. Recrystallisation - impure crystals are dissolved in a minimal volume of hot ethanol, which is a better solvent for impurities than for aspirin, creating a saturated aspirin solution.
6. Crystallization of aspiring first through slowly cooling and filtration of the impurities and unreacted salicylic acid in the solution.
26
Describe how is the purity of aspirin determined.
Through melting point determination
as pure substances exhibit well-defined melting points which would be altered by the presence of impurities.
27
State the melting point of pure aspirin vs salicylic acid.
aspirin 138-140 degrees
salicylic acid 159 degrees
28
State the purpose of IR.
Infrared spectroscopy.
Aids in identifying the functional groups within a molecule through the absorption of specific wavenumbers of infrared radiation.
29
State the possible potential risk of aspirin.
- dangerous for individuals with difficulty clotting blood or post surgery when clotting is necessary.
- stomach and duodenal irritation, possible bleeding.
- allergic reactions especially in those prone to asthma.
- not for kids under 12 (Reye's syndrome).
30
State and define the effect of consuming aspirin with ethanol.
Synergistic
Means the physiological effects intensify when taken with ethanol
which means it may increase bleeding of the stomach lining elevating the risk of ulcers.
31
Define, state another name and list the practical use of soluble aspirin.
Formulations containing the salt of the acid, formulations containing various coating and buffering components.
For example: reacting aspirin with an alkali to form an ionic salt (NaOH for example).
Dispersible aspirin.
Delay of its activity until its in the small intestine to help alleviate some of its side-effect or because it has low solubility in water (is largely a non-polar molecule) increasing its solubility and thus bioavailability.
32
Describe the basics about the discovery of penicillin and its consequence.
Alexander Fleming (in only 1928)
observed that fungus Penicilium notatum inhibited bacterial growth.
Birth of antibiotics and in 1940s an isolation of penicillin as an antibacterial agents by Florey and Chain.
33
Describe the structure of penicillin.
Dipeptide formed from two amino acids: cysteine and valine.
Nucleus thiazolidine (a five-membered ring containing a sulfur atom) attached to a beta-lactam (four-membered ring containing a cyclin amide group).
34
State the role of the beta-lactam ring in penicillin.
Responsible for its antibacterial properties because by specifically inhibiting (acetylating irreversibly) the transpeptidase that catalyzes the final step in cell wall biosynthesis, the cross-linking of peptidoglycan.
35
State the chemical structure of the beta-lactam ring and its consequence.
Bond angles reduced to about 90 degrees, despite that because of the sp2 and sp3 hybridized atomic orbitals the atoms would seek to form bonds with angles 120 and 109.5 respectively.
Puts a strain on the bonds - weakening them -> the ring will easily break.
36
State the biological mechanism behind the bacterial resistance to penicillin problem.
Resistant bacteria produce an enzyme - penicillinase (or beta-lactamase) opening penicillin's four-membered ring and making it inactive.
37
State a possible strategy to combat antibiotic resistance on the example of penicillin.
Synthesis of different penicillin forms resistant to penicillinase (like oxacillin replacing methicillin) which retain the beta-lactam ring but have different side chains protecting against enzyme binding.
38
State a disadvantage of penicillin.
Its broken down by the stomach acid and thus has to be administered intravenously
(but that's dealt with by the modifications of the side chains).
Also allergic response to it.
39
Describe the mechanism of action of penicillin.
Disruption of the formation of bacterial cell wall by inhibition of the key enzyme in that process - transpeptidase.
The high reactivity of the amide group in the ring causes it to bind irreversibly near the active site of the enzyme as the ring breaks thus inactivating the enzyme as it prevents polypeptide cross-links from forming between the mucopeptide chains.
The cell wall is unable to support the bacterium and thus it bursts and dies.
40
Define opiates and its origin.
Strong analgesics derived from unripe seed pods of opium poppy.
41
State the principles on which opiates work.
They cross the blood-brai barrier by binding temporarily to the opioid receptors in the brain which will block the transmission of impulses between brain cells that would signal pain.
42
State the correlated to their function structural feature of the opiates.
Phenylamine chemical moiety.
Gives molecule rigidity and allows it to interact strongly with the opioid receptors.
43
List the most popular drugs derived from opium.
- morphine
- codeine
- diamorphine (heroine)
44
State the utilization of morphine.
- powerful analgesic
- narcotic - sleep inducing
45
- used in cough mixtures
- narcotic - sleep inducing
- less powerful than morphine analgesic
46
State how morphine and codeine are interconvertible.
morphine -> codeine
by replacing -OH by and ether group -OCH3 (methoxy)
achieved by reacting morphine with CH3I in KOH
47
State the utilization of heroin (diamorphine).
Metabolized in the brain rapidly into morphine and binds to the opioid receptor and thus its effects but much more powerful.
48
State why is heroine more powerful than morphine.
The acetylation of morphine substitutes the both hydroxyl group with ester groups reducing the polarity of the molecule.
Thus increases lipophilicity and its ability to cross the blood-brain barrier.
49
State the reaction of formation of heroin.
morphine + ethanoic anhydride in an acetylation reaction.
50
State the reactions in which morphine can be converted into codeine and diamorphine.
Morphine -> Codeine is achieved through methylation.
Morphine -> Diamorphine is achieved through esterification.
51
State the possible side effects of using morphine and its derivatives.
- constipation
- suppression of the cough reflex
- constriction of the pupil in the eye
- narcotic effects.
52
List the narcotic effects od morphine and its derivatives.
- induces a sense of euphoria
- depresses nervous system - sedation
- vasodilation
- high dosages - coma or death by suffocation
- quickly growing dependence and withdrawal symptoms
53
State the utilization of methadone.
Reduces drug cravings and prevents symptoms of withdrawal.
Effective treatment for opioid dependence.
54
State how the human body combats viruses.
Producing specific antibodies as an immune response and developing immunity in case of repeated infections.
55
State the ability of viruses that makes them hard to treat.
Ability to alter their genetic material and thus fool the antibodies.
56
Define prophylactic treatment of viruses.
Vaccine treatment stimulating the human body to create antibodies.
57
State the use of antiviral medication to fight of viruses.
Interference in some way with the viral life cycle so as to prevent the release of new viral particles from the cell.
58
State the ways in which the antivirals work.
- altering cell DNA do that the virus cannot multiply.
- blocking of the enzyme activity within the host cell to prevent the virus from reproducing.
59
State an example of an antiviral drug and its mechanism of working.
Amantadine.
Cage-like structure causes changes in the cell membrane to prevent the entry of virus into the host cell.
60
State the cause of flu.
Influenza A and B -
spherical viruses with RNA as their genetic material.
61
State how the flu is built work and relate it to their function.
contain two major proteins:
- hemagglutinin (H) - glycoprotein enabling the viral particles to "dock" within the host cell before it enters.
- neuraminidase (N) - enzyme catalyzing a cleavage reaction which allows the new viral particles to escape from the host cell and spread infection. It will snip off sialic acid (carbohydrate) from the glycoproteins on the surface of the host cell membrane.
62
State the principle on which Oseltamivir (Tamiflu) and Zanamivir (Relenza) function.
They are antiviral medications
the neuraminidase inhibitors.
63
Distinguish structurally the oseltamivir and zanamivir.
OSELTAMIVIR:
Functional groups:
- alkenyl
- ether
- primary amino
- carboxyamide
- ester
Drug action:
Neuraminidase inhibitor
Administration:
orally
Resistance to drug:
Some rare strains of flu virus have shown resistance.
Counter-effects:
nausea, vomiting
ZANAMIVIR:
Functional groups:
- alkenyl
- ether
- primary amino
- carboxyamide
- carboxylic acid
- hydroxyl (3)
Drug action:
neuraminidase inhibitor
Administration:
inhalation
Resistance to drug:
No resistance reported
Counter effects:
possible asthma
64
Define AIDS.
Acquired immune deficiency syndrome caused by the human immunodeficiency virus (HIV) and transmitted through sexual or parenteral exposure to fluids such as blood, semen, mucus containing HIV.
65
State the mechanism of action of AIDS.
1. infection of vital white blood cells CD4+ T cells.
2. binding to specific receptor proteins on the cell surface and cell penetration.
3. release of viral RNA into the cell.
4. control of the synthesis of DNA from the viral RNA by the reverse transcriptase.
5.viral particles produced within the host cell and released in large numbers when the cell dies.
66
Define a retrovirus.
A type of virus using RNA as its genetic material.
67
State the principle of HIV infection.
Destroys helper CD4 T cells that should be defending the body against the virus.
68
State the possible treatment for AIDS and describe its mechanism.
Antiretroviral drugs
but they just suppress symptoms work by stopping:
- binding and fusion of the virus of the receptor on the CD4 cell membrane.
- reversing transcription of viral RNA to DNA in the host cell.
- integration of viral DNA into the host chromosome.
- release of new viral particles by budding from the host cell surface.
69
Distinguish structurally morphine and codeine and diamorphine.
CODEINE:
Functional group:
- arene
- ether (2)
- alkenyl
- hydroxyl (1)
- tertiary amino
Obtained from:
- Raw opium (0.5%)
- Usually prepared from morphine.
MORPHINE:
Functional group:
- arene
- ether
- hydroxyl (2)
- tertiary amino
Obtained from:
- Raw opium (10%)
DIAMORPHINE (heroin):
Functional group:
- arene
- ether
- alkenyl
- ester (ethanoate)(2)
- tertiary amino
Obtained from:
- Found in opium, but usually obtained by reaction of morphine.
70
List the radiations with their corresponding interaction and detector effects in compounds.
- X-rays - inner shell electron transitions - bond distance/angles.
- UV-Vis radiation - molecular orbital electron transitions - electronic levels.
- IR radiation - molecular vibrations - functional group present.
- microwave radiation - molecular rotations - bond length.
- radiowaves - nuclear spin transitions - atoms and their connectivity.
71
State the use of infrared spectroscopy.
Because it doesn't have enough energy to cause electron transitions.
It will cause molecular vibrations of certain groups of molecules about their bonds thus identifying the groups.
72
Define the nuclear medicine.
Medical specialty using radioactive materials, radiopharmaceutical to diagnose and treat different illnesses and diseases.
73
Define the alpha radiation.
Ejection of particles from the nucleus that carry a charge of 2+ and have a mass of 4 atomic mass units (are equivalent to a nucleus of helium 4 (top) 2 (bottom) 𝛂)
74
State the effect of the emission of an alpha particle.
Decrease in the mass number of a radionuclide by 4 and the atomic number by 2.
238- top
92 - bottom U -> 4 top, 2 bottom 𝛂 + 234 top, 90 bottom Th.
75
Define the beta radiation.
Ejection of electrons from the nucleus formed during the conversion of neutrons to protons.
76
Define a beta particle.
Electrons and thus have negligible mass and negative charge.
77
State the effect of the beta radiation.
mass number stays the same but the atomic number increases by 1 unit.
78
Define the gamma radiation.
Emission of the energy as electromagnetic waves or photons which have short wavelengths in the ranges of 0.0005 to 0.1 nm and frequencies above 10^19 Hz.
79
State the effect of gamma radiation.
As it results from energy changes in the nucleus it doesn't alter the atomic number or mass.
80
State the presence of gamma radiation.
Accompanies alpha and beta radiation as the energy of the radionuclide is lowered during radioactive decay.
81
State the effect of radiation on particles.
Interaction with an atom and cause the removal of electrons also other than those in the outer shell it forms highly unstable radicals which might immediately react with nearby molecules causing chemical changes (oxidation).
82
Define ionizing effect.
Reason for why radiation is dangerous to living cells
exposure to radiations causes ionization of the biological molecules in cells which might form radicals, affect the genetic material or lead to cell death and mutations.
83
Define the ionization density.
Average energy released along a unit length of their track
all radioactive emissions are ionizing but they differ in ionization density.
84
List the events occurring in the nucleus when the radionuclides decay into a more stable form.
- ejection of a neutron
- ejection of a proton
- conversion of a neutron to a proton with the ejection of an electron (beta particle)
- conversion of a proton to a neutron with the ejection of a positron
- release of additional energy by the emission of photons (gamma rays)
85
Define a positron.
Antiparticle of an electron with the same mass but a positive charge.
86
State the intensity of the ionization density in alpha particles and gamma rays.
Alpha particles - high ionization density because of their relatively large mass and 2+ charges.
Gamma rays and x-rays - lower ionization density.
87
State the consequence of the higher ionizing density of the alpha particles.
Release most of their energy into a small region.
Thus more destructive to biological material.
88
Define and state the full name of TAT.
Targeted Alpha Therapy
Radioimmunotherapy, treatment of dispersed cancers (metastasized ones).
89
Describe the technique of TAT.
Using of alpha-emitting radionuclides directed at the biological target by attaching them to carriers such as antibiotics and thus carrying the radionuclide to exactly the right place.
90
Give reason why alpha particles are effective in TAT.
- high ionizing density and thus high probability of killing cells at target.
- short range of alpha particle radiation minimizing unwanted irritation of normal tissue surrounding target cancer cells.
91
State the most common isotope used in TAT and its target treatment.
Lead-212
pancreatic, ovarian and melanoma cancers
92
Define the half-life.
Time taken for the concentration of a reactant to decrease to one half of its original value.
93
State the factors not affecting the rate of radioactive decay.
- temperature
- pressure
- presence of other substances
94
State the kinetics that radioactive decay follows.
first order reaction
r=k[N]
95
State and define the SI unit of isotope activity.
becquerel (Bq)
one unit equals the decay of one nucleus per second.
96
State an alternative name for the rate of radioactive emission.
isotope activity
97
Define nuclear imaging.
A technique providing detailed information about an individuals internal organs in diagnosis of diseases.
98
Define radiotherapy.
disease treatment, especially cancer, destroying targeted cells with the use of beams of radiation.
99
Define a radiopharmaceutical.
A pharmaceutical with a radionuclide (tracer) attached, designed to target a certain part of the body, which allows the progress of the drug to be traced through emitting gamma rays from inside of the body.
100
Give example of a most used radiopharmaceutical.
technetium-99m
101
Distinguish between the development of cold and hot spots in radiotherapy.
cold spots - isotopes partially taken up
hot spots - isotopes taken up in excess
both kinda bad
102
State the full name and function of a PET scan.
positron emission tomography
scan giving 3D images of tracer concentration in the body
103
State the mechanism behind PET scan.
positron-emitting traced is injected into the patients body where it accumulates in the target tissue and the emitted positrons from the tracer combine with electrons releasing energy as gamma rays
104
State with reason the main isotope used in PET scans for cancer detection.
fluorine-18
as it bonds to glucose which uptake is different in cancer and healthy cells
105
Describe the mechanism of action of an MRI.
powerful magnets produce a strong magnetic field which forces protons in the body to align with that field and sends pulses of radio waves from a scanner as the radio waves are turned off the atoms return to their original position and send back radio signals which are received by a computer and converted into an image.
106
State the full name and function of the MRI.
magnetic resonance imaging
production of images of internal body organs and soft tissues.
107
State the advantage of MRI.
Does not use ionizing radiation in contrast to other imaging techniques and thus considered non-invasive.
Because the radio waves are low-energy waves.
108
State the full name and function of BNCT.
Boron Neutron Capture Therapy
Therapy used to treat brain and neck tumors.
109
State the mechanism of action of BNCT.
Patients is given a high dose of non-radioactive boron-10 which concentrates in malignant brain tumors.
Irritation occurs with neutron of sufficient energy to be absorbed by the boron.
The emission of high-energy alpha particles are able to kill the cancer cells in the given tumor.
110
State the characteristics of radionuclides that makes them useful in cancer treatment.
Strong beta-emitters and gamma emitters that enables imaging.
111
State the most used radionuclides in cancer therapy.
lutetium-177
yttrium-90 (also in arthritis)
112
Define teletherapy for cancer treatment and its most used isotope.
Radiation delivered from a distance through linear accelerator.
cobalt-60 (decaying into stable nickel-60)
113
Describe the internal radionuclide therapy.
a radioactive material is taken into the body (solid implant or liquid) in the form of implant near the site of tumor which will emit radiation.
114
State examples of radioactive liquids and their target disease in internal radionuclide therapy.
phosphorus-32 - blood disorders
strontium-89 - bone cancers, pain control
iodine-131 - thyroid cancer
115
List the common side-effects of radiotherapy.
- fatigue
- nausea
- hair loss
- sterility
- skin reaction
116
Distinguish high level waste from low level waste.
High-level waste - gives off large amounts of ionising radiation for a long time and the isotopes have long half-lives.
low-level waste - gives off small amounts of ionizing radiation for a short time and the isotopes have short half-lives.
117
Describe the disposal of the nuclear low-level waste.
Interim storage in sealed containers where the radioactivity decays in hours or days.
Waste disposed in conventional means like compaction, landfill, sewer.
118
Describe the disposal of the nuclear high-level waste.
stored first under water in cooling ponds for 5-10 years because of the significant heat emissions during decay
later transferred to dry storage in heavily shielded structures
119
Define superbugs and list an example.
bacteria that carry several resistant genes and cause infections that are very difficult to treat
methicillin-resistant Staphylococcus aureus MRSA
120
Define green chemistry.
design of chemicals in a way that is less harmful to humans and the environment.
121
State the principles of green chemistry.
1. prevention
2. atom economy
3. less hazardous chemical synthesis
4. designing safer chemicals
5. safer solvents and auxiliaries
6. design for energy efficiency
7. use of renewable feedstocks
8. reduce derivatives
9. catalysis
10. design for degradation
11. real-time analysis of pollution prevention
12. accident prevention
122
State the function of Tamiflu.
antiviral lessening the spread of flu virus within the body through preventing the release of new viral particles from their host cells.
123
State the precursor of Tamiflu.
shikimic acid or its salt shikimate
found in the star anise and extracted through a lengthy process.
124
Give example of a green chemistry success story in the pharmaceutical industry.
production of Viagra by Pfizer through a modified reaction route producing just a quatre of the waste compared to the original process with the reduction of solvent used and avoidance of the use of toxic and hazardous reagents.
125
Define vapor pressure.
pressure exerted by a vapor equilibrium with its liquid at a given temperature in a closed system.
126
Describe and state the function of Raoul's law.
Calculation of vapor pressure of each component.
For an ideal solution the vapor pressure on each component equals the vapor pressure of the pure component multiplied by its mole fraction.
127
Define the mole fraction.
Number of moles of the component divided by the total number of moles present.
128
State what does fractional distillation rely on.
Differences in volatility.
129
State on what does the solubility of a compound depend on.
Ability to interact and form stable bonds with the solvent.
130
State the characteristics of organic molecules dissolving well in organic solvents.
- high hydrocarbon content (long carbon chains)
- aromatic rings
- smaller proportion of polar functional groups
131
State the characteristics of organic molecules dissolving well in water.
- higher proportion of functional groups that are polar and form hydrogen bonds (like hydroxyl, carboxyl, amino).
- additionally enhanced by the presence of ionic groups such as salts.
132
State the principle on which solvent extraction relies on.
Two immiscible solvents in which the required solute has very different solubilities.
133
State the relationship between the molecular size and volatility.
lowers with increasing molecular size due to an increase in LDF.
134
Define androgens, state their alternative name and their effects in humans.
male steroid hormones
anabolic steroids
role in promoting tissue growth, especially muscles,
performance-enhancing drugs because they increase strength and endurance.
135
State the adverse effects of steroids.
- risk of cancer
- heart problems
- hormone balance disturbance
- risks to feritlity
136
State the most common method of steroid detection in blood and urine samples.
gas chromatography-mass spectrometry.
137
State the techniques used in gas chromatography-mass spectrometry and their functions.
- gas chromatography - separation of the chemical mixture into pure chemicals.
- mass spectroscopy - identification and quantification of the components.
138
State and define the two phases of gas chromatography.
- stationary phase - a microscopic layer of non-volatile liquid, usually a polymer, which is coated on the walls of an inert solid support.
- mobile phase - inert carrier gas, e.g. helium.
139
State how exactly are more volatile compounds distinguished in gas chromatography.
eluted more quickly and have thus shorter retention times.
140
State the instrument measuring the ethanol concentration in the sample of breath and their principle of function.
breathalysers
redox reaction of oxidation of ethanol to ethanoic acid by potassium dichromate (VI)
chromate VI is reduced to chromate III causing a change from orange to green.
141
State the modern instrument measuring the ethanol concentration in the sample of breath and their principle of function.
intoximeters/alcosensor
fuel cell redox reactions
which consists of two platinum electrodes with a porous acid electrolyte between
exhaled air passes over the cell and any ethanol present is oxidized to ethanoic acid.
142
Define dyspepsia.
feelings of pain and discomfort in the upper abdomen, include indigestion and heartburn
143
Describe how histamine is related to the secretion of gastric juice.
interacts at receptors known as H2 in the parietal cells in the gastric glands and thus stimulates the secretion of stomach acid.
144
State the mechanism of action of Ranitidine (Zantac) drug.
H2-receptor antagonist
which will compete with histamine for binding at the H2 receptors
145
State the role and the alternative name for a gastric proton pump.
H+/K+ ATPase enzyme
which hydrolysis ATP to actively transport the K+ ions outside of stomach lumen and the H+ ions into the lumen.
146
Define an antacid.
drug helping combat excess stomach acid through neutralizing the hydrochloric acid.
147
State what chemically antacids usually are and give an example.
weakly basic compounds, metal oxides, hydroxides, carbonates or hydrogencarbonates
calcium hydroxide, magnesium hydroxide, aluminum hydroxide.
148
State why several antacid formulations contain both aluminum and magnesium compounds.
they complement each other
magnesium tends to be faster acting but aluminum compounds dissolve more slowly and thus provide longer lasting relief.
149
State what occurs when in a buffer solution the concentrations [acid]=[salt] and conversely when [base]=[salt].
[acid]=[salt] => pH=pKa
[base]=[salt] => pH=pKb
