𝗩𝗮𝗹𝗶𝗱𝗮𝘁𝗶𝗼𝗻 𝗼𝗳 𝗱𝗶𝘀𝘀𝗶𝗻𝗳𝗲𝗰𝘁𝗮𝗻𝘁, 𝗘𝗳𝗳𝗶𝗰𝗮𝗰𝘆 𝘁𝗲𝘀𝘁 𝗼𝗳 𝗱𝗶𝘀𝘀𝗶𝗻𝗳𝗲𝗰𝘁𝗮𝗻𝘁

  𝗩𝗮𝗹𝗶𝗱𝗮𝘁𝗶𝗼𝗻 𝗼𝗳 𝗗𝗶𝘀𝗶𝗻𝗻𝗶𝗳𝗲𝗰𝘁𝗮𝗻𝘁

𝟭. 𝗩𝗮𝗹𝗶𝗱𝗮𝘁𝗶𝗼𝗻 𝗼𝗳 𝟳𝟬%𝗶𝗽𝗮, 𝗱𝗲𝘁𝘁𝗼𝗹 𝗮𝗻𝗱 𝘀𝗮𝘃𝗹𝗼𝗻

Disinfectant efficacy testing is concern with demonstrating that a product possesses antimicrobial activity under defined laboratory test conditions. It is the process that is used to compare the antimicrobial activity of a product against other products or known standard. 

The residual population of viable organisms on the  surface in the production / microbiology

laboratory after decontamination is a measure of the effectiveness of the disinfection procedure.

This determination is made by validating the decontaminating procedure through the qualification of the disinfectants used.

  The following Disinfectants used for cleaning the   Production Area and  Microbiology Laboratory

70%ipa

2.5%dettol

5%savlon

  Reason for Qualification / Validation

1) New Disinfectant introduced

2) Re qualification due to change in concentration of disinfectant

Reference

Pharmaceutical Process Validation

Preparation and use of Disinfectant

  

List of Major Equipment 

Horizontal Steam sterilizer.

Incubators

Filtration Assembly

 

Key elements for qualification / validation:

1.Procurement of the disinfectants to be qualified 

2.Procurement of sterile swabs / Contact Plates

Procedure

Rational for use of disinfectants

1.To prevent entry of microbes into manufacturing environment or product.

2.Destroy or remove organisms that are already present in the product or environment.

3.Prevent growth of microbes that may gain subsequent access or may be present

Surface Sampling

Swab Test

Identify an area (about four square feet) in the Test room of the Microbiology Lab. Prior to swabbing the Unclean floor with the respective diluted disinfectant, swab an area on the floor of 25cm² using a sterile swab Swab Method

Transfer the contents of the swab to a tube containing 1ml of sterile phosphate buffer. Agitate the tube such that the contents on the swab are eluted in the buffer. Transfer the elute (1ml) to a sterile Petri dish. Add Trypticase Soya Agar (TSA). Incubate the plate at 30 - 35°C for 5 days.

Evaluate the number of colonies observed on the plate and report

Sample another 25cm² area from the unclean area using a sterile wet swab. Transfer the contents of the swab to a tube containing 1ml of sterile phosphate buffer. Agitate the tube such that the contents on the swab are eluted in the buffer. Transfer the elute (1ml) to a sterile Petri dish. Add Saboraud Dextrose Agar (SDA). Incubate the plate at 20 - 25°C for 5 days.

Evaluate the number of colonies observed on the plate and report.

Swab the identified area with the respective diluted disinfectant and repeat the above exercise at every two hour intervals till end of shift. 

Surface Sampling can also be performed by Contact Plate Method

Contact Plate Method (RODAC) Replicate

Prepare Contact plates using Sterile TSA / SDA having a convex surface area of 25cm². Directly press the surface of the contact plate on the surface to be examined. 

Repeat the exercise for the intervals stated in the Swab Test procedure.

Incubate all TSA plates at 30 - 35°C for 5 days and all SDA plates at 20 - 25°C for 5 days

Processing of Plates

On completion of the Studies the plates are evaluated at the end of 5days.

Contamination using the Swab Method is reported as CFU /  25cm²

Contamination using the Contact Plate Method  is reported as CFU/ plate

Acceptance Criteria

There should be no increase in the counts till end of shift as compared to the initial count

Membrane Filtration Method

This method involves direct mixing of microorganisms with the disinfectant and subsequent filtering of the solution after a certain time interval.

The advantage of this method lies in the capability of completely eliminating bacteriostasis or fungistasis.

Dilute the disinfectants as per the concentrations at which they are used.  Inoculate 10 ml of each diluted disinfectant with 1.0ml of a microorganism suspension of 102  103 CFU/ml.  The microorganism are:

1.Pseudomonas aeruginosa ATCC 9027

2.Escherichia coli ATCC 8739

3.Staphylococcus aureus ATCC 6538

4.Candida albicans ATCC 1023

5.Aspergillus niger ATCC 16404

Shake thoroughly and allow to stand for 15 minutes.  For positive controls inoculate organisms in 10 ml sterile water.  After standing period is over, filter the inoculated disinfectant through 0.45 ( membrane filter, 47 diameter. Wash membrane with 3  100 ml portions of 0.1% peptone buffered saline

For disinfectants inoculated with microorganisms 1, 2 and 3, place membrane on TSA plate.  For disinfectants inoculated with microorganisms 4 and 5 place membrane on SDA plate.  Incubate TSA plates at 30 - 35(C for 4  5 days and SDA plates at 20(C for 4  5 days.

Evaluation

Count number of colonies on each of TSA and SDA plates and record the log

Acceptance CriteriaCriteria

 99.0 % reduction in counts

Conclusion 

Final selection of the disinfectant and its concentration of use is based on the compatibility and microbiological efficacy.

Author BY: Nilam Gawankar ( Microbiologist) 

Nilmaypharmablog

Published on 18/09/2022

1.𝗣𝗲𝗿𝘀𝗼𝗻𝗲𝗹 𝗺𝗼𝗻𝗶𝘁𝗼𝗿𝗶𝗻𝗴 𝗶𝗻 𝗽𝗿𝗼𝗱𝘂𝗰𝘁𝗶𝗼𝗻 𝗮𝗿𝗲𝗮. 𝗣𝗲𝗿𝘀𝗼𝗻𝗻𝗲𝗹 𝗺𝗼𝗻𝗶𝘁𝗼𝗿𝗶𝗻𝗴 𝗶𝗻 𝗽𝗼𝘄𝗱𝗲𝗿 𝗽𝗿𝗼𝗰𝗲𝘀𝘀𝗶𝗻𝗴 𝗮𝗿𝗲𝗮. 𝗣𝗲𝗿𝘀𝗼𝗻𝗻𝗲𝗹 𝗵𝘆𝗴𝗶𝗲𝗻𝗲 𝗽𝗿𝗮𝗰𝘁𝗶𝗰𝗲𝘀 𝗶𝗻 𝗺𝗮𝗻𝘂𝗳𝗮𝗰𝘁𝘂𝗿𝗶𝗻𝗴 𝗮𝗿𝗲𝗮. 

2.𝗪𝗵𝘆 𝟳𝟬%𝗜𝗣𝗔[𝗶𝘀𝗼𝗽𝗿𝗼𝗽𝘆𝗹 𝗮𝗹𝗰𝗼𝗵𝗼𝗹] 𝘂𝘀𝗲 𝗶𝗻 𝗽𝗵𝗮𝗿𝗺𝗮𝗰𝗲𝘂𝘁𝗶𝗰𝗮𝗹 𝗶𝗻𝗱𝘂𝘀𝘁𝗿𝗶𝗲𝘀 𝗮𝘀 𝗱𝗶𝘀𝗶𝗻𝗳𝗲𝗰𝘁𝗮𝗻𝘁  𝗶𝗻𝘀𝘁𝗲𝗮𝗱 𝗼𝗳 𝟭𝟬𝟬% 𝗜𝗣𝗔 𝘂𝘀𝗲𝗱. 𝘄𝗵𝘆 𝟳𝟬% 𝗜𝗣𝗔 𝗶𝘀 𝗺𝗼𝗿𝗲 𝗲𝗳𝗳𝗲𝗰𝘁𝗶𝘃𝗲 𝗱𝗶𝘀𝗶𝗻𝗳𝗲𝗰𝘁𝗮𝗻𝘁? 𝘂𝘀𝗲 𝗼𝗳 𝟳𝟬% 𝗜𝗽𝗮.