Almost all drugs are marketed as tablets or capsules. Before the development of this kind of dosage forms, it’s important to know certain fundamental, physical and chemical properties of the drug molecule and the other properties of the drug powder which decides many of the subsequent events and approaches in formulation development. This first learning phase is called the pre-formulation.
Definition
The preformulation studies can be defined as the investigation of the physical and chemical properties of a drug when it acts alone or when it combines with the other drug products. The main objective of this kind of study is to generate useful information to the formulator in developing safe and stable dosage forms with good bioavailability.
Preformulation studies
During the early stages of any new drug development, the chemists in cooperation with the pre-formulator, record some of the information that can be used as pre-formulation data. An early information may include the following
- Gross particle size
- Melting point
- Infrared analysis
- Thin layer chromatographic purity
This information is found to help greatly in pre-formulation work.
Objectives of pre-formulation studies
- To establish Physico-chemical parameters of a new drug.
- To determine its kinetics and stability.
- To establish its compatibility with common molecules.
The major areas of pre-formulation studies are:
Organoleptic characters: Under organoleptic characters, the color, odor, taste of the drug must be recorded.
Bulk characters: Crystal habit of the drug can affect the bulk and physic-chemical properties of the molecule. Hence the crystalline characteristics of the molecule are to noted under Bulk characters.
Solubility analysis: The size of the particle can influence a lot of variety of important factors including:
- Dissolution rate
- Dependability
- Uniform distribution
- Penetrability
- Lack of grittiness
They also determine the amount of drug dissolved, the amount of drug available for absorption.
Stability analysis: Stability analysis is carried out in two ways namely
- Solution stability
- Solid-state stability
Thus the pre-formulation studies provide useful information for the subsequent formulation of a physico-chemically stable and biopharmaceutical suitable dosage form.
Preclinical development
In any drug development, preclinical development which is also called as preclinical studies is a stage that begins before the clinical trials (testing the drug in humans). During the process, the feasibility, iterative testing and drug safety data are collected for future references. Generally, a drug from its design stage takes about 2 years to convert into a compound and come into market (in case of high range molecule).
Objectives of preclinical studies
They determine the safe dose for first-in-man study and also assess the safety profile of the product. The product need not be the only drug, they can also be new medical devices, drugs, and diagnostic tools.
Types of Preclinical studies
The preclinical studies are determined under two types:
- In vitro: It is test taking place outside a living organism or a test-tube.
- In vivo: it is a test taking place in a living organism.
Usually, preclinical studies are not a long process. But this study must provide detailed information about the dosage and the toxicity levels. Based on the preclinical test results, the researchers decide whether the drug should be tested in people.
