Test 4: 46 principles part 2 Flashcards
Solubility in the blood depends large on the — partition coefficient
blood/gas
what routes of exposure is the fastest/most effective
IV > inhalation > IP > SQ > IM > ID > oral > dermal
— the ratio of un-ionized:ionized, the greater the potential for absorption across a —
Higher
lipid membrane
simple diffusion/active transport: Un-ionized (uncharged) molecules have greater lipid solubility and thus can traverse phospholipids bilayers with greater ease than charged (ionized) molecules
when water flows in bulk across a porous membrane, any solute small enough to pass through the pores flows with it
filtration
saturable process not driven by concentration gradients, instead moving xenobiotics against concentration gradients
active transport
Quantity or percentage portion of total chemical that was absorbed and available to be processed
Bioavailability (F) = Systemic Availability
F=100 means 100% of drug made it into the blood
While —, toxicants cannot cross capillary walls to be distributed into the extravascular space or filtered by the kidneys
bound (reversibly) to plasma proteins
4 reasons toxin do not enter CNS
- endothelial cells are tightly joined- do not let many things through
- ATP dependent multidrug resistant proteins move chemicals out of brain
- astrocytes block things through capillaries
- lower protein in CNS- prevent protein bound water insoluble compounds
— lipid solubility enhances penetration into the CNS, while — diminishes it
Increased
ionization
ideal metabolic system should produce metabolities that are — soluble and —. Enzymes used should be —
water
nontoxic
broad enough substrate specificity to properly handle any newly encountered substances
types of phase 1 metabolism
Hydrolysis
Oxidation – alcohol dehydrogenase, aldehyde dehydrogenase, monoamine oxidase, cytochrome P-450
Reduction
Phase I metabolism converts apolar, lipophilic chemicals into more polar & more hydrophilic metabolites via introduction or liberation of functional groups
— metabolism converts apolar, lipophilic chemicals into more polar & more hydrophilic metabolites via introduction or liberation of functional groups
Phase I
Hydrolysis
Oxidation- cytochrome P450
reduction
— conjugates either the chemical itself or its metabolite formed during phase I with a functional group that results in a multifold increase in water solubility
Phase II
Glucuronidation
Sulfation
Amino acid conjugation
Acylation
Methylation
phase II metabolism works by
conjugates either the chemical
itself or its metabolite formed during phase I with a functional group that results in a multifold increase in water solubility
Glucuronidation
Sulfation
Amino acid conjugation
Acylation
Methylation
what happens with cats and acetaminophen
cats lack enzyme to metabolize by glucoronidation
cytochrome P-450 metabolizes it into N- acetybenzoquinoneimine, which binds to hepatic proteins & leads to centrilobular necrosis (liver necrosis)
zero order kinetics
Only a finite amount of chemical can be
eliminated per unit of time
pathway becomes saturated and drug starts to accumulate (alcohol)
1st order kinetics
Rate of elimination is proportional to the amount of chemical in the body at that time
Not saturable pathway
1 ppm= — mg/kg
1 part per million (ppm)
= 1 mg/kg
= 0.91 grams/ton
= 1 microgram (µg)/mL
1 ppm= — grams/ton
1 part per million (ppm)
= 1 mg/kg
= 0.91 grams/ton
= 1 microgram (µg)/mL
1 ppm= — (μg)/mL
1 part per million (ppm)
= 1 mg/kg
= 0.91 grams/ton
= 1 microgram (µg)/mL
1 ppm to %
1 ppm = 1 mg/kg = 0.0001%
So moving the decimal point 4 places to the right converts % to ppm
10% = — mg/mL
10% = 100 mg/mL
moving the decimal point 1 place to the right converts % to mg/mL
So 1 ounce, fluid or dry, is
approximately equal to — g or — mL
30
30
1 teaspoon = — mL
5 mL
1 tablespoon = — mL
15 mL
2 tablespoons= — mL
30= 1 fluid oz
The label for a medicated poultry feed states that Drug A is present at 50 parts per million (ppm)
What is the concentration of Drug A in mg/kg and g/ton?
1 ppm = 1 mg/kg = 0.91 g/ton = 0.0001% = 1 μg/mL
So, 50 ppm = 50 mg/kg = 45.5 g/ton
100 mg of Drug B causes hepatic necrosis in dogs and 700 mg causes CNS depression
If a dog eats 12 pounds of food containing 25 mg/kg of Drug B, what effects can be expected?
1 lbs = 0.454 kg
1 kilogram = 2.2 pounds
12 lbs ➗ 2.2 = 5.4 kg
5.45 kg x 25 mg/kg Drug B = 136 mg Drug B
Hepatic necrosis would be expected, but not CNS depression
A full 8 ounce bottle of weed killer containing 15% Chemical C was chewed open by a goat
Now the bottle is completely empty
What is the maximum dose of Chemical C that the goat may have ingested?
1% solution = 10 mg/mL
1 fluid oz = 29.6 mL or ≈ 30 mL
15% = 150 mg/ml
8 ounces × ~30 ml/fluid oz ≈240 ml
240 ml × 150 mg/ml = 36,000 mg
65-pound Labrador retriever has eaten a homemade chocolate cake that contained among other ingredients, 4 oz of unsweetened chocolate (393 mg caffeine per ounce) and 1.5 cups of strong brewed coffee (30 mg caffeine per ounce)
What total dosage of caffeine has this dog ingested?
4 oz choc x (393 mg caff/oz)= 1572 mg
65lbs dog ➗ 2.2= 29.5 kg dog
1.5 cups x 8 oz/cup × 30 mg/oz = 360 mg
Total amount caffeine ingested = 1572 mg + 360 mg = 1932 mg
Total dosage of caffeine = 1932 mg ÷ 29.5 kg = 65.5 mg/kg
A 350-gram female rat needs to receive 50 mg/kg of Drug D twice a day
The drug solution contains 45 mg/mL of Drug D
How much of the drug solution
should the rat receive each day?
How much drug solution should be
dispensed for a 21- day course of
treatment?
350 grams × 1 kg/1000 grams = 0.35 kg rat
0.35 kg × 50 mg/kg = 17.5 mg of Drug D per dose
45 mg/1 mL = 17.5 mg/x
solve for x
x = 0.39 mL
Because there are 2 dose periods, 0.39 × 2 = 0.78 mL/day
So 0.78 mL/day × 21 days = 16.33 mL drug solution needed
Your dog has recently been placed on a sodium- restricted diet but hates her new sodium-free
dog food
You want to try mixing Brand E chicken soup containing 950 mg of sodium per cup into her food to make it more palatable
If she can have no more than 1200 mg of sodium per day and is
fed twice a day, how much broth can you add to each meal in cups?
1200 mg of sodium per day ÷ 2 meals/day = 600 mg sodium per meal
600 mg ÷ 950 mg/cup ≈ 0.63 cups per meal
0.63 cups × 8 oz/cup = 5.04 oz per meal
5 oz ÷ 8 oz/cup = 5/8 cup
Disinfectant F is sold as a 45% solution and has to be diluted to a 5% solution in water before use. To prepare 1 gallon of 5% solution, how much concentrated solution and water should be mixed together?
5% = 50 mg/mL
1 gallon = 3.785 L = 3785 mL
50 mg/mL = x/3785 mL
x= (50 x 3785)
x = 189,250 mg of Disinfectant F needed to make 1 gallon of 5% solution
189,250 mg ÷ 450 mg/mL = 421 mL of concentrated 45% solution
421 mL + x mL water = 3785 mL total
x = 3364 mL water = 3.364 L
