PHASES OF CLINICAL TRIALS

INTRODUCTION

Clinical trials are a process where the medicinal products are tested and are classified in to four phase. In these phases drug development process takes place, each phase has its own methods, where if a drug passes these three phases (I, II, III,) further phase IV process will begin. All these phases are introduced to maintain the safety of the drugs.

Clinical trials play a major role in clinical research to obtain effective medicines in drug development process. 

PRECLINICAL STUDIES

In this phase a drug is taken and testes but does not involve subject, but in vitro and in vivo experiments takes place. Where wide range of doses are given to obtain efficacy, toxicity and pharmacokinetic information. Which helps in choosing the drug for further development.

PHASE 0

In this phase the drug is tested on humans, which is known as micro dosing studies. Where (10- 15) subjects are taken to obtain data on pharmacokinetics. But this phase does not give data on safety or efficacy because the given dose is too low to show up the therapeutic effect. This phase is mainly conducted to obtain pharmacokinetic parameters.

PHASE I

This phase mainly focused on human studies and are designed to test the safety, best dose, side effects and formulation method for a drug. Where in this phase (20-100) subjects are taken and are randomized. The subject is observedfull-time full time and are conducted by CROs contract research organisations. This phase is designed in such a way to obtain information regarding safety, pharmacokinetics & dynamics and tolerability of a drug. Where escalation studies also take place in this phase , so that to find the best and safe dose for further studies.

PHASE II

This phase includes larger group of subjects (50-300), and are performed to know how well the drug is working. If in clinical trails a drug is failed it has had to be failed in phase ii due to side effects. This phase also divided in to PHASE IIA and PHASE IIb. 

Where in phase iia pilot studies and clinical efficacy is known, in phase iib optimisation of drug dose and side effects. Known as randomised and controlled studies. 

PHASE III

This phase consists of large patient groups (300-30000) also expensive, time consuming, difficult trials, where the drug effectiveness is known compared to the standard drug, and are randomized, controlled.  In this phase follow up evaluation takes place also non as pre- marketing phase, regulatory submission also takes place to maintain safety and data. Regulatory agencies FDA (US) OR EMA (European union).

PHASE IV

This phase is known as Post marketing surveillance or drug monitoring trial, to assure long term safety, effectiveness of drug. Which involves safety surveillance nothing but (pharmacovigilance) of a drug by regulatory bodies. This surveillance to identify any adverse effects of drug. If the drug exposes harmful effects, then it is withdrawn from market.

CONCLUSTION 

Clinical trials take a major part in clinical research to ensure the safety and to identify possible adverse effects of a drug, all these phases play a major role in determination of safest drugs with proper studies and surveillance in drug development process.

REFERENCES

1.  "The drug development process". US Food and Drug Administration. 4 January 2018. Retrieved 17 August 2020.

2.  "New Clinical Development Success Rates 2011-2020 Report". BIO, Informa Pharma Intelligence, and QLS Advisors. Feb 2021.

3. The regulatory authority in the US is the Food and Drug Administration; in Canada, Health Canada; in the European Union, the European Medicines Agency; and in Japan, the Ministry of Health, Labour and Welfare

4. Arcangelo VP, Peterson AM (2005). Pharmacotherapeutics for Advanced Practice: A Practical Approach. 

Student Name: Jaya Sheela.

Qualification: B. Pharmacy

e-Mail ID: jayasheela761@gmail.com