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Determination of Shelf Life of Solutions in Laboratory

Determination of the shelf life of solutions including volumetric solutions, reagents and buffer solutions in laboratory.
Incorrect strength or concentration of volumetric solutions, reagents and buffer solutions can alter the results of analyzed products. Solutions prepared for chemical analysis are not stable for a longer period.

The molarities of these solutions may change after a period of time. Shelf life of solutions depends upon the nature of the compound and the solvent also. Therefore, it is necessary to validate the stability period of these solutions individually in which these have to consume. Validation of shelf life is a mandatory GLP and regulatory requirement. There are different ways to assign the shelf life of solutions; following are the simplest methods for the same.

Volumetric Solutions

Volumetric Solutions:
Prepare the volumetric solution and allow standing. After 24 hours determine the molarity of solution in triplicate calculating the mean of the results and continue the determination at an interval of 3 days for 15 days. Determine the RSD of all 5 values. If RSD of all 5 values remains less than 1.0, shelf life of solutions should be assigned 15 days otherwise RSD shall be calculated with first 4 values and shelf life should be assigned 12 days. It the RSD of first 4 values remains more than 1.0, RSD shell be calculated with first three values and shelf life of solutions should be assigned accordingly.

Related: SOP for Preparation and Standardisation of Volumetric Solutions

Reagent Solutions:
Reagents solutions, those are used in analysis as reactants and molarity is not calculated. These are validated on their performance. The Performance of these solutions is checked at an interval of 7 day for 1 month. Evaluate the performance of all 4 tests and assign the life accordingly.

Buffer Solutions:
Buffers are generally used for calibration of pH meters. pH of buffer solutions may change due to chemical degradation. The shelf life of buffer solutions must not be assigned more than 7 days.

Note: Solution should be stored under proper storage conditions otherwise results may alter giving improper shelf life. Validation data should be recorded and maintained for regulatory audits.

Ankur Choudhary is India's first professional pharmaceutical blogger, author and founder of Pharmaceutical Guidelines, a widely-read pharmaceutical blog since 2008. Sign-up for the free email updates for your daily dose of pharmaceutical tips.
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hunazire said... on 6/1/15 22:54

Could you tell me a reference to the guideline which describes the self life of volumetric solution? I am looking for a formal guideline.

Ankur Choudhary said... on 7/1/15 19:53

@hunazire You can find it in FDA -

hunazire said... on 7/1/15 22:39

Ok, but there I could not find volumetric solutions method. Where can I read RSD less than 1.0? Ph.Eur. gives RSD less than 0.2.

Thank you.

Sunil Mayekar said... on 20/1/16 12:09

Could pl provide the Indian Cosmetics manufactures Guidelines.

Sreenivas said... on 22/1/16 12:42

How do you determine shelf life of buffer solutions prepared for HPLC analysis?

Ankur Choudhary said... on 22/1/16 12:47

Check buffers for any haziness, precipitation and their pH.

shishram saini said... on 12/5/17 14:25

our chemical reagent passess the hold time study up to 3 month . can we give a expiary 3 month as per guide line

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