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| Pregunta | Respuesta |
| Vad kan hända när två molekyler sätts samman? | Additive effect 2+2 = 4 Synergistic effect 2+2 = 10 Potentiating effect 0+2 = 7 Antagonistic effect: - Functional ant. 2-2 = 0 - Chemical ant. 2+2 = 1 (chemicals react with each other) - Dispositional ant. 2+2 = 1 (tillgångsant. ?) - Receptor ant. 2+2 = 1 |
| ligand | ett ämne som kan binda in specifikt till en receptor |
| antidoter | motgifter |
| Toxicity of a chemical depends on... | Physical form Purity Route of exposure Exposed organism Sex Age Individual markers |
| Molecular properties | - Size - Form - Electron distr. - how easily the electrons in the molecule can move around - Electron mobility - how easily the electronclouds can move generating polar effects - Dipole moment - a vector. Depends on the bond and the distance. - Polarisability - Charge - Electrophilicity - "likes electrons". Dangerous!! Nucleophilicity - can donate electrons. |
| Chemical prop. | - Volatility - how easily a liquid/solid can vaporize? - Lipophilicity - likes oil? Can the molecule be transported through fatty tissues eyc? - Hydrophilicity - likes water? - Solubility - reactivity - Surface activity - can change the surface proparties of other compondents - Excitability - some can absorb light and become excited - Acidity/basicity Absorption/adsorption - take something inside (like a sponge) / get something onto the surface |
| Volatility | ○ Determines the mobility and risk for exposure of chemicals ○ A chemical in any condensed form will always loose molecules to the gas phase, due to its vapour pressure ○ The boiling point at atmosphere pressure is a convenient measure of volatility, which can be found in the literature or determined Volatility is determined by the size and the intermolecular forces |
| Solubility | ○ Determines how a chemical is taken up by an organism and distributed in it ○ Lipophilic, or hydrophobic, compounds are soluble in fat ○ Hydrophilic, or lipophobic, compounds are soluble in water ○ Hydrophilicity is promoted by charged or strongly polarised groups A practical measure for solubility is P (or logP), which denotes how a chemical is distributed between octanol and water. = How much of the moleucles goes to watar and how much goes to octane (the ratio). Usually a molecule have to have a logP of about 1-5 to be toxic/used as medication? |
| Reactivity | ○ Free radicals ○ Acids and bases ○ Oxidative and reductive agents ○ Explosives ○ Photoexitable agents ○ Ligands (non-covalent binding) ○ Electrophiles (covalent binding) |
| Electrophiles | Can have… ▪ A good leaving group that the nucleophile can replace ▪ A strained ring with a polarised bond that the nucleophile can attack ▪ A polarised unsaturation conjugated with an electron-withdrawing group (Michael acceptors) ▪ A polarised unsaturation with leaving group on the positively charged atom ○ Electro and neuclephiles react with each other. In a biological system (like us) you do not want to have a lot of reactions. "Nature" has therefore "decided" that our body uses nucleophiles. We are a mixture of different nucleophiles (for instance: water, proteins). So (in most cases) we do not want to have electrophiles. |
| Observable effects | - Irritating - Carcinogenic - Accumulating - if it is a stable molecule - Persistent - persist changes. Will stay in the environment. - Allergenic - Intoxicating - Burning - Explosive |
| Intermolecular forces | Ionic forces (strong) Hydrogen bonds (strong) Dipole interactions (with polar groups) van der Waals forces |
| Hur kan de minimis principle mättas? | 1. The specific-number view: a risk is de minimis provided the probability falls below a certain number, e.g., 10-6. 2. The non-detectability view: a risk is de minimis provided it can not be detected. 3. The natural-occurence view: a risk is de minimis provided the probability does not exceed the natural occurence of the risk. |
| Metabolic activation/inactivation | Metabolically turned in to a more/less toxic molecule |
| Reversible/irreversible effects | if the chemical is removed the symptoms will go away/stay |
| Toxilogical concepts | • Acute and chronic effects • Delayed effects • Reversible and irreversible effects • Local and systemic effects • Target organ • Critical concentration • Metabolic activation/inactivation • Tolerance |
| Oral (food, drinks) | or, orl |
| Intravenous (in blood circulation) | iv, ivn |
| Intraperitoneal (in abdominal cavity) | ip, ipr |
| Inhalation (air) | in, ihl |
| Subcutan (under skin) | sc, scu |
| Dermal (on skin) | D, skn |
| Transport through cell membranes | • Diffusion • Facilitated diffusion (Passive transport) • Ion channel (Passive transport) • Active transport • Endo-/ exocytosis • Paracellular transport All depend on chemical properties |
| Diffusion | The efficiency depends on the size of the molecule: • Small (H2O, MeOH) molecules can pass easily • Large (M<1000) lipophilic molecules can pass • Large hydrophilic molecules (e.g. glucose) cannot pass • Ions cannot pass |
| Facilitated diffusion | • Cannot concentrate a compound on one side • Important for hydrophilic molecules that are not sufficiently small |
| Ion channels | Passive transport (in the direction of concentration gradient) Can be open and closed (alltså kan regeleras) |
| Paracellular transport | transport between the cells tänk fågeln |
| Absorption in the gut/intestines | • Not many compounds can escape • Small, hydrophobic molecules can be absorbed by diffusion • Hydrophilic molecules or ions can be absorbed by facilitated diffusion or ion channels • Large molecules (e.g. proteins) can be absorbed by endocytosis • Insoluble molecules are poorly absorbed • Chemicals are mainly absorbed in the small intestines • Chemical reactions may take place in the stomach • Enzymatic conversions may also take place Membrane passage is influenced by pH |
| Absorption through the skin | • Small, nonpolar molecules can pass easily (e.g. MeOH, HgMe2) • DMSO can increase the permeability of skin |
| xenobiotic | A xenobiotic is a chemical substance found within an organism that is not naturally produced or expected to be present within the organism. It can also cover substances that are present in much higher concentrations than are usual. |
| Distribution of xenobiotics depends on... | - Solubility (• Lipophilic compounds distributed to lipophilic tissues • Hydrophilic compounds distributed to blood, eyeballs, muscles • Pb, F can deposite in bones) - Biological barriers (e.g. blood-brain barrier, “BBB”) (• Water, glucose can pass • Small lipophilic molecules can pass • Large, hydrohilic molecules or ions cannot pass) - Transformations/Conversions |
| Kidneys... | ... |
| Excretion via the liver | • Blood from the intestines is extracted by liver cells • Metabolites are either pumped back into the blood or to the bile, which is transported to the intestines • Major routes for larg |
| Enterohepatic circulation | Enterohepatic circulation refers to the circulation of biliary acids, bilirubin, drugs or other substances from the liver to the bile, followed by entry into the small intestine, absorption by the enterocyte and transport back to the liver. Enterohepatic circulation extends the time that an exogenous chemical stays in the body |
| Two molecules that can be excreted in the lungs | • Diethyl ether (major route) • Ethanol (small portion) |
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