What are the phases of pharmacodynamics?
Drug action usually occurs in three phases: Pharmaceutical phase. Pharmacokinetic phase. Pharmacodynamic phase.
What is the Pharmaceutic phase?
The pharmaceutic phase (dissolution) is the first phase of drug action. In the gastrointestinal (GI) tract, drugs need to be in solution so they can be absorbed. A drug in solid form (tablet or capsule) must disintegrate into small particles to dissolve into a liquid, a process known as dissolution.
What are the four main drug actions?
It is how the body handles a drug. It is the extent to which a drug completes the process of absorption, distribution, metabolism, and excretion.
What is the pharmacokinetic process?
The pharmacokinetic process is concerned with the absorption, distribution, and elimination (by metabolism and excretion) of drugs. It is evident that drug molecules have to pass many structural and metabolic barriers.
What is a half life and how do you calculate a drug’s half life?
In brief :
- Half-life (t½) is the time required to reduce the concentration of a drug by half.
- The formula for half-life is (t½ = 0.693 × Vd /CL)
- Volume of distribution (Vd) and clearance (CL) are required to calculate this variable.
What are 5 pharmacokinetic principles?
They are absorption, distribution, metabolism, and excretion. Each of these processes is influenced by the route of administration and the functioning of body organs.
What are the 8 routes of drug administration?
- Oral route. Many drugs can be administered orally as liquids, capsules, tablets, or chewable tablets.
- Injection routes. Administration by injection (parenteral administration) includes the following routes:
- Sublingual and buccal routes.
- Rectal route.
- Vaginal route.
- Ocular route.
- Otic route.
- Nasal route.
What are the four principles of pharmacokinetics?
There are four main components of pharmacokinetics: liberation, absorption, distribution, metabolism and excretion (LADME). These are used to explain the various characteristics of different drugs in the body.
What are the 4 steps of pharmacokinetics?
Four phases of pharmacokinetics The main processes involved in pharmacokinetics are absorption, distribution, and the two routes of drug elimination, metabolism and excretion. Together they are sometimes known by the acronym ‘ADME’.
What is pharmacodynamics with example?
Pharmacodynamics (sometimes described as what a drug does to the body) is the study of the biochemical, physiologic, and molecular effects of drugs on the body and involves receptor binding (including receptor sensitivity), postreceptor effects, and chemical interactions.
How can you increase the bioavailability of a drug?
Disadvantages are particle growth and possible burst release. A third way to improve bioavailability of oral drugs is to use self-emulsifying drying systems. Oil, surfactant, cosurfactant and the API are combined into an isotropic mixture to form self-emulsifying drug delivery systems.
What is half life of a drug?
What is a drug’s half-life? The half-life of a drug is the time it takes for the amount of a drug’s active substance in your body to reduce by half. This depends on how the body processes and gets rid of the drug.
Which drug has the longest half life?
However, there are numerous other drugs with very long half-life, examples are mefloquine 14–41 days (25), amiodarone 21–78 days (26), and oritavancin 393 h (27). Furthermore, what can be called “long half-life” is always relative to the length of the sampling period.
What does it mean if a drug has a half life of 4 hours?
1 This means if you take a dose of 400 milligrams (mg) of ibuprofen at noon, half of the dose (200 mg) will have been eliminated from your bloodstream by 2 p.m. By 4 p.m., another 100 mg will have been eliminated, and so forth.
Does a shorter half life mean more radioactive?
In general there is an inverse relation between the half-life and the intensity of radioactivity of an isotope. Isotopes with a long half-life decay very slowly, and so produce fewer radioactive decays per second; their intensity is less. Istopes with shorter half-lives are more intense.
Which half-life is more dangerous?
…of which the longest-lived is strontium-90 (28.9-year half-life). This isotope, formed by nuclear explosions, is considered the most dangerous constituent of fallout.
Why is a short half-life dangerous?
Radioisotopes with short half-lives are dangerous for the straightforward reason that they can dose you very heavily (and fatally) in a short time. Such isotopes have been the main causes of radiation poisoning and death after above-ground explosions of nuclear weapons. Long-term isotopes are more complicated.
Which type of radiation has the longest range in air?
Gamma radiation
What is the most dangerous type of radiation and why?
alpha radiation is the most dangerous because it is easily absorbed by cells. beta and gamma radiation are not as dangerous because they are less likely to be absorbed by a cell and will usually just pass right through it.
Which radiation does not give way to a different nucleus?
During gamma decay the nucleus emits radiation without actually changing its composition: We start with a nucleus with 12 protons and 12 neutrons, and we end up with a nucleus with 12 protons and 12 neutrons… but somehow radiation gets released along the way!
What is the most dangerous source of radiation in your house?
radon
Which fruit is most radioactive?
Bananas