Month: April 2025

Sr. No. 

Procedure 

Safety Precautions: 

Always wear Personal Protective Equipments such as safety goggles, gloves, masks during washing of glassware’s. 

Do not use brushes that are so worn that the spine hits the glass as a result serious scratches may result and scratched glass is more prone to break during analysis. 

Inspect the glassware before each use and discard if scratched on inner surfaces, chipped, cracked or damaged in any way. 

Do not drop glassware’s from height. 

Do not bang glassware’s to sink or tap. 

Rubber sink and counter mats can help reduce the chance of breakage and resultant injury. 

Visually check glassware’s for any cracks before washing. Broken glassware’s may cause injury. 

Protect cleaned glassware’s from dust by placing them in dust free cabinets and cover the glassware with stopper, foil, paraffin or by keeping in tilt position.  

Do not collect or touch broken glass pieces with bare hands. It can cause injury. Send the broken glassware for destruction. 

Do not shake glassware’s too much vigorously as it may get cracks by pressure. 

Do not keep alkaline liquids in volumetric flasks or burettes for longer time as a result stoppers or stopcocks may get stick. 

Ensure that the soap has been thoroughly removed from the glassware’s. If soap comes in contact with acid, a film of grease may be formed. 

Never use strong alkaline products and hydrofluoric acid as cleaning agents. These materials dissolve glass, leading to damage and eventual breakage. 

5.2 

General Procedure: 

Wear safety goggles, gloves, masks before starting the washing of glassware’s. 

Wash the glassware’s as soon as possible after use, so that residue can be removed easily with general detergent (non ionic) solution. 

Drain off any non hazardous contents present in flasks, beakers, test tubes etc. in the sink and hazardous contents in the waste containers and then rinse the glassware’s with tap water before transferring them into soap solution. 

Drain off hazardous contents from the flask, beakers or any other glassware before giving it for washing. 

Remove the markings of pen marker on glassware’s with the methanol/IPA. 

Remove the silicon grease on glassware’s with Acetone or use fuming sulphuric acid for about 30 minutes and then rinse with purified water. 

Gently scrub inner and outer portions of glassware’s with scrubber or nylon brushes. If thorough cleaning is not possible immediately, soak the glass wares in water and keep. 

If adhesive material is not removed or dissolved in water then soak the glass wares in detergent solution (0.1% SLS) or any other soap solution till adhesive material is removed or dissolved. 

Preparation of 0.1% SLS: – Dissolve 1gm of SLS in 1000ml water. (Quantity can be prepared as per requirement). 

During washing all parts of glassware’s should be gently scrubbed with nylon brush.  

Rinse the glassware’s with running tap water; allow the water to run into and over the glassware’s for short time until no foam of soap is produced on shaking. Shake and empty at least six times with tap water. 

All the glassware’s should be finally rinsed with purified water twice and kept in tilted position to drain off water completely.  

Dry the glass wares in the glassware drying oven at 60 °C ±5°C in tilt Position. Do not dry the glass wares more than the above mentioned temperature limit as it may alter calibration of the glassware’s. 

New glassware’s should be soaked in 1% solution of hydrochloric acid or nitric acid for about 5-6 hours before washing as new glassware’s are slightly alkaline in reaction. 

If glassware becomes unduly cloudy  or dirty or contains coagulated organic matter then glass wares should be given chromic acid treatment as follow:- 

Chromic acid solution: Dissolving 84 gm of chromium trioxide in 700 ml water and add slowly, with stirring 400 ml of sulphuric acid. (While preparing solution use personal protective equipments such as goggles, gloves, a mask as chromic acid is classified as a carcinogen).  OR 

Dissolving 200 gm of Sodium Dichromate in about 100 ml water, cooling in ice-bath and adding slowly to it, with stirring, 1500 ml of sulphuric acid. 

Pour the few ml of chromic acid solution on dirty glassware’s and leave them for minimum 15 minutes.  

Add small amount of potable water with shaking. Rinse several times with water or allow to keep in water for about one hour as the chromic acid is highly acidic in nature and finally rinse with purified water twice. 

Dry the washed glassware’s in the glassware drying oven at 60 °C ±5°C in tilt Position. 

Use the washed glassware within one week of the washing. After one week re-wash the same glassware’s before use even if they are not used. 

Store the washed and dried glassware in a designated and clean cupboard with proper labelling. 

5.3 

For washing burettes, separating funnels:  

Remove the stopcock or rubber tip and wash with water/soap solution. Be careful that the tips of the burettes, funnels should not hit the sink or the water tap.  

Rinse it under running tap water until all the dirt is removed. Allow the water to run into and over the burettes, separating funnels for short time and then rinse them with purified water.  

Shake and empty at least six times with tap Water and two times with purified water. Wash the stopcocks or rubber tips separately. Dry separating funnels and burettes in the glassware drying oven at 60 °C ±5°C. 

5.4 

For washing Pipettes:  

Place the pipettes in the jar containing water or soap solution placing the tips downward immediately after use.  

Rinse them with tap water before placing them in jar. Ensure that the water level in the jar is high enough to immerse the maximum portion of the pipettes.  

Do not drop them into the jar. This may break the tips and render the pipettes useless for accurate measurements.  

At the time of washing, rinse them under running tap water until all the dirt is removed. Allow the water to run into and over the pipettes for short time and then rinse them with purified water.  

Shake and empty at least six times with tap Water and two times with purified water. Dry them in the glassware drying oven at 60 °C ±5°C. 

   5.5 

Glassware Cleaning Validation:- 

Design Glassware Cleaning Validation protocol before starting the study.  

Glassware Cleaning Validation for API/Product Residue:- 

Choose an available “difficult to clean” API 

A standard solution of the API shall be prepared as described in the testing method (Refer STP/GTP). 

Select the glassware’s in the laboratory such a way that it will cover minimum and maximum capacity which is generally used for standard/sample preparation. 

For Example refer below Table:-  

Take each type one glassware as mentioned above. 

(Note: – Actual glassware’s capacity may vary depend upon the availability glassware’s in the laboratory.)  

Each of the selected volumetric flasks/conical flasks/test tubes shall be filled to about 10% of its nominal volume with the Standard solution, close and shake such a way that the inner walls of the flasks will be covered by the liquid. Then Glassware’s shall be emptied and allowed to dry. 

Each of the selected pipettes shall be filled with its nominal volume with the Standard solution such a way that the inner walls of the pipettes will be covered by the liquid. Drain the liquid from pipette and allow to dry. 

Gently scrub all parts of glassware’s with nylon brush under tap water.  

Rinse the glassware’s with running tap water; allow the water to run into and over the glassware’s. Shake and empty the Glassware’s at least six times with tap water. 

All the glassware’s should be finally rinsed with purified water twice and kept in tilted position to drain off water completely.  

All the cleaned Glassware’s shall then filled and shake with the diluent solution used for the preparation of the Standard Solution.  

Take the diluent solution from the Glassware’s and analyse as per testing method of the API/Product used. 

Take the readings of standard solution and residual solution. 

Calculate the residual amount of API for each cleaned Glassware’s by referring STP/GTP. 

Acceptance Criteria:- 

Traces of the API should not be more than 0.1% of standard solution.  

If above criteria is not meeting for any cleaned glassware then increase the rinsing time and perform Glassware cleaning validation again. 

Glassware Cleaning validation For Detergent/Soap Solution Residue:- 

Soak the glass wares in detergent solution (0.1% SLS) or any other soap solution for about 30 minutes. 

Preparation of 0.1% SLS: – Dissolve 1gm of SLS in 1000ml water. (Quantity can be prepared as per requirement). 

Select the glassware’s in the laboratory such a way that it will cover minimum and maximum capacity which is generally used for standard/sample preparation. 

For Example refer below Table:-  

Gently scrub all parts of glassware’s with nylon brush under tap water.  

Rinse the glassware’s with running tap water; allow the water to run into and over the glassware’s for short time until no foam of soap is produced on shaking. Shake and empty at least six times with tap water. 

All the glassware’s should be finally rinsed with purified water twice and kept in tilted position to drain off water completely. 

All the cleaned Glassware’s shall then filled and shake with the water (diluent solution) used for the preparation of the 0.1% SLS.  

Take the water (diluent solution) from the Glassware’s and analyse as per testing method  

Take the readings of 0.1% SLS solution/Soap solution and residual solution. 

Calculate the residual amount of SLS/Soap solution for each cleaned Glassware’s by referring STP/GTP. 

Acceptance Criteria:- 

No traces of the SLS/Soap solution should be detected.  

If above criteria is not meeting for any cleaned glassware then increase the rinsing time or use different detergent and perform Glassware cleaning validation again. 

The Glassware Cleaning Validation protocol shall contain the following information; 

Glassware Cleaning Validation protocol cover page 

Protocol Pre-approval sheet 

Introduction 

Objective 

Scope 

Responsibilities 

Definition and Abbreviation 

Procedure 

Observed Deviation/OOS 

Attachments 

References  

Summary and Conclusion 

Protocol Post-Approval sheet 

Abbreviation 

Expansion 

SOP 

Standard Operating Procedure 

QC 

Quality Control  

QA 

Quality Assurance  

gm 

gram 

ml     

Millilitre 

± 

Plus or minus 

°C     

Degree centigrade 

% 

Percentage   

SLS 

Sodium Lauryl Sulfate