Friday, 16 May 2008

Quality in medicines design and usage

It's 9.15am now.. and it feels like I've been awake for ages. Trying to study for the abovementioned module which will be examined on later on. Just to test my memory, decided to test my memory on how drug development is..

Normal drug development is done in a few stages. First comes drug discovery by various methods, such as natural product sources, targeted drug design, random synthesis and high throughput screening.

Then, the chemical process development. Here, bulk quantities of the drug is produced and the most cost effective synthetic pathway is to be discovered. Then, the absorption, distribution, metabolism and excretion (ADME) or collectively the pharmacodynamics are studied. Toxicology is also being done on that chemical compound. In vitro testing on cell culture or Ames test (which tests for bacterial mutagenicity), acute toxicity, chronic toxicity, carcinogenicity, and reproductive toxicity are being done.

Then comes pharmaceutics. The form of the drug has to be determined, taking into account the physicochemical properties of the drug and aiming for an oral formulation.

Next comes the clinical trials. This is in 3 parts (or 4 including post marketing surveillance).

Phase 1: Clinical pharmacology and toxicology

This is being done in health volunteers (males age 18-45) to find out the smallest effective and highest tolerated dose. The metabolism and pharmacokinetics of the drug is being observed. Any side-effects are also recorded.

Phase 2: Clinical investigation of therapeutic effect

Assesses the bioavailability of the pilot formulations and also the therapeutic effect of the drug.

Phase 3: Full-scale therapeutic evaluation in patients

Determine the dosage form and also the regimen. The efficacy, benefit, long term tolerance, adverse side effects, contraindications and interactions with other medicines are investigated in this phase. If everything is up to par, the documents can then be sent to the appropriate regulatory agency for approval and registration (MHRA in UK).

Phase 4: Post-marketing surveillance

The drug is already sold.... more research will be done to find out - long term side effects, efficacy, toxicity, and maybe find another indication for the drug. The dosage regimen can also be optimised for better effect.

So.. will I get 100 marks for all that? Cross my fingers that this question will come out and that I can actually remember everything that I have read through.

Sorry to bore you all with all this... It just seems more fun to study this way. (I hope all my details are correct though, I kinda took all these from my notes and paraphrased them..)

Update @ 1546: it was a lousy paper... I was just writing anything and everything that came to my head and I realise that my english is getting worse.

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