Stability study of volumetric solution

Stability study of volumetric solution

Volumetric solutions, called titrants, are meticulously formulated solutions whose concentrations are precisely determined. These are extremely important in quantitative analysis where measurement accuracy is of paramount importance. Prominent examples include standard solutions of acids, bases, and salts used in titrations. These solutions are meticulously prepared according to established protocols and are expected to maintain a specified concentration over a specific period.

Importance of Stability study of volumetric solution

Quality assurance:

Stability studies play an important role in quality assurance in analytical laboratories. This is important to maintain the desired concentration of bulk solutions used in the analysis, thereby preventing inaccuracies that could compromise the reliability of experiments and studies.

Regulatory Compliance:

Various industries, including pharmaceuticals and environmental testing, are subject to strict regulations that require high-quality and accurate analytical data. Stability studies are a prerequisite for compliance with these regulations because they provide documented evidence of the reliability of bulk solutions.

Economic considerations:

Stability studies may require an investment of time and resources but ultimately prove to be cost-effective in the long term. By identifying potential changes in concentration or degradation early, laboratories can avoid using problematic solutions, thereby eliminating the need for re-analysis and wasting valuable resources.

Increasing the accuracy of the method:

Stability studies contribute significantly to the improvement of analytical methods by providing insight into the behavior of bulk solutions over time. This valuable information allows analysts to make necessary adjustments to experimental protocols, ensuring continued measurement accuracy.

Key Parameters of a Stability Study

Storage conditions:

Bulk solutions are often sensitive to factors such as temperature, light, and exposure to air. Stability studies involve storing solutions under different conditions to evaluate their susceptibility to environmental influences.

Analysis method:

Various analytical methods such as spectroscopy, chromatography and titration are used to monitor changes in the chemical composition of bulk solutions. These methods are useful for identifying degradation products and concentration changes.

Sampling interval:

Stability studies are conducted over a predetermined period, including periodic sampling at specified intervals. This allows analysts to monitor changes in the volumetric properties of the solution and establish a reliable shelf life.

SOP on stability study of volumetric solution

Objective :

To lay down a procedure for Carrying out stability studies of volumetric solutions


This Standard Operating Procedure applies to the Quality Control Department followed by the pharmaceutical company name with the location

Responsibility: QC personnel shall be responsible for following the procedure as per SOP.

Abbreviations and Definitions:

SOP: Standard Operating Procedure; a document where step-by-step instructions are cited to serve as support for methods or manners of fulfilling a function or functions reliably and consistently.

RSD: Relative Standard Deviation


Preparation, Standardization, and storage of volumetric solution shall be as per SOP.

Initial standardization of volumetric solution shall be done on the same day or next day as per General Test Procedure or Pharmacopoeia and maintain a record of preparation and standardization.

A set of three volumetric solutions of unique ID.No.shall be prepared for stability study and labeled as per annexure -I. Differentiate these three volumetric solutions by assigning volumetric solution No.VS-1/3,VS-2/3,VS-3/3.

All three volumetric solutions of a set shall be standardized at intervals given below and maintain their record.

Standardization shall be done in 1st week on alternate days i.e.3rd.5th,and 7th day of 1st day standardization.

Standardization shall be done after three days in 2nd and 3rd week i.e.10th, 13th and 16th day of 1st

After that standardization shall be done once in a week for three weeks i.e. 23rd,30th, and 37th day of 1st

Record all observations in a summary sheet.

At each interval, volumetric solutions shall not differ from the prescribed strength by more than 10% the Normality/Molarity shall be determined in triplicate and RSD shall not be more than 0.2%.

Normality / Molarity at each interval should not differ more than 0.2 % of the initial Normality /Molarity i.e. 1st-day Normality /Molarity.

If the solution does not meet the criteria on the 3rd, 5th, 7th, or 10th day then shelf life shall be considered one day.

If the solution does not meet the criteria of up to 10 days and does not meet on the 13th or 16th day then the shelf life shall be considered 7 days.

If the solution does not meet criteria up to 16 days and does not meet on 23rd or 30th day then shelf life shall be considered 15 days.

If the solution does not meet the criteria of up to 30 days and does not meet on the 37th day then the shelf life shall be considered 25 days.

If the solution meets the criteria of up to 37 days then self life shall be assigned one month.

If the same shelf life has been obtained from all three volumetric solutions of a set then that shelf life shall be assigned to that volumetric solution. If the same shelf life has not been obtained then minimum shelf life shall be given to that volumetric solution.

The interval at which more than one solution does not meet the criteria then that solution shall be a standardization for that interval by two different analyses in triplicate and the average result shall be reported, If all six values meet the criteria then the shelf life study shall be continued.

Discontinue the shelf life study if any value does not meet the criteria. Observation shall be recorded.

Prepare a list of the shelf of volumetric solutions which shall be displayed in the Quality Control laboratory.

Forms and Records (Annexures)

Label OF Volumetric Solution for Stability Study

Summary Sheet of Stability Study of Volumetric Solution

List of Shelf Life of Volumetric Solution

Preparation And Standardization of Volumetric Solution

Verification of abnormal result

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About Pharmaceutical Guidanace

Ms. Abha Maurya is the Author and founder of pharmaceutical guidance, he is a pharmaceutical Professional from India having more than 18 years of rich experience in pharmaceutical field. During his career, he work in quality assurance department with multinational company’s i.e Zydus Cadila Ltd, Unichem Laboratories Ltd, Indoco remedies Ltd, Panacea Biotec Ltd, Nectar life Science Ltd. During his experience, he face may regulatory Audit i.e. USFDA, MHRA, ANVISA, MCC, TGA, EU –GMP, WHO –Geneva, ISO 9001-2008 and many ROW Regularities Audit i.e.Uganda,Kenya, Tanzania, Zimbabwe. He is currently leading a regulatory pharmaceutical company as a head Quality. You can join him by Email, Facebook, Google+, Twitter and YouTube

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