# What are S1 S2 and S3 stages in Dissolution?

## What Are S1 S2 And S3 stages In Dissolution in pharmaceutical?

In the pharmaceutical industry, it is a very important test to know the drug dissolution rate in the defined medium. Dissolution is an in-vitro test (Outside body) to predict the invivo (In body) results of the drug.

Let us understand the importance of dissolution testing and its different stages of analysis.

Since binders, graduation, mixing, and coating may impact the release of a drug from a tablet, a dissolution test is carried out to verify if the tablet was released from the liquid solution it was dissolved in.

In the dissolution test, Q refers to the amount of active ingredient that has dissolved.

In order to determine the maximum concentration of an active ingredient, dissolution tests are carried out using 6 units of the dosage form. Of course, this could be different in different monographs according to the nature of the formulation.

## What is S1 (Stage-1) in Dissolution:

The dissolved amount of each unit in S1 stage should not be less than Q+5%. It shows that each product should exceed 5% of the dissolved amount specified in the individual Manograph.

If any of the units falls below the limit, then we have to reanalyse the sample in the next stage. i.e. S2 stage.

## what Is S2 (Stage-2) in Dissolution:

In stage S2, additional 6 units are to be executed, so the average of 12 units (S1+S2) should be equal to or more than Q and no unit should be less than Q-15%. It gives some flexibility to the test results but the average should be equal to or more than Q and one unit below the Q is acceptable.

If any unit falls below Q-15% or the average for 12 units is lower than Q then the sample is analyzed in the S3 stage.

## What is (Stage-3) in Dissolution:

In stage S3, another 12 units are to be analyzed, the average of 24 units (S1+S2+S3) should be equal to or more than Q and no unit is less than Q-25% and not more than 2 units are less than Q-15%. In this S3 dissolution stage, 3 units are acceptable below Q, which gives more flexibility.

These are S1 S2 and S3 stages in dissolution used in pharmaceutical analysis.