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Welcome to my home page. Microbiology Solutions blog is created to help pharmaceutical professionals of different background like microbiology, quality control, production and quality assurance. This blog contains pharmaceutical microbiology topics and different concepts which will be very useful for pharmaceutical professionals. In this blog you will find clear, easy to understand and knowledgeable topics which would definitely help pharmaceutical professionals.

71 comments:

  1. In which position does membrane filtered plates should be kept? (Upright or inverted) and why.
    Thank you.

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    1. Charles wesley, In pharmaceuticals different companies have different practices. Some incubate membrane filtered plates in upright position and some incubate in inverted position. Normally plates are incubated in inverted position to prevent the microbial growth from the moisture which collect on the lid of the petriplates in form of condensate and this condensate can disrupt the colonies. But condensate might be a problem at higher temperature not at low temperature. As per FDA protocol (Bacteriological Analytical Manual, Chapter 18, Yeasts, Molds and Mycotoxins) plates should be incubated in upright position for fungal growth. So, for fungal growth incubate the plates in upright position and for bacterial growth incubated in inverted position as per requirement.


      Thanks and have a nice day!

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    2. sir pls provide me complete information about water purification system step by step from source water to wfi.

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  2. sir pls provide me complete information about water purification system step by step from source water to wfi.

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    1. http://www.pharmacopeia.cn/v29240/usp29nf24s0_c1231.html
      This is the link for USP chapter. You'll get the information.

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  3. Why R2A media used for water analysis

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    1. Sir , R2A is a good source for the growth of broken cellwalls and also have the capability for allowing the growth of alagal strains. SCDM doesnt have this nature. I hope so...

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  4. Why R2A media used for water analysis

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    1. R2A media is basically low nutrient media and in water, generally slow growing bacteria are found which have low nutrient requirement for their growth. The growth of these slow growing bacteria can be supressed by faster growing bacteria in high nutrient media.That's why R2A media used for water analysis.

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  5. hi sir ..what is the difference between 95% and 100% while doing manufacturing in sterile products??....

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    1. Please clarify your question so that i can give clear answer.

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  6. This comment has been removed by the author.

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  7. Hello Sir. Ur answers are very helpful to me..Thanks for ur blog..
    1) I have few doubts in MLT of Oral drugs and Water about quantity. We manufacture anti cancer drugs, where raw material is costly so they will provide only 1grm for MLT..Can we justify?
    2) If yes..How should i take sample quantities for MB to get E.Coli, can I use 0.1mL in 10mL of MB before streaking into MA?
    3) Can I take 0.1mL of sample for both MB and XLDA from the same SCDM broth?

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    1. If product is costly then 1st you have to validate the method on reduce qty.
      F.eg. 1gm in 9ml SCDM (1:10) you also take 1.2 gm or 1.4 gm after that directly incubate for 48 hrs & accordingly subculture on selective media.

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  8. Sir, how to do growth promotion test . either we do GP test for every new lot or each and every time whenever we prepared media . pls clarify

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    1. shahul hameed, growth promotion test has to be done for every new received lot as well as every time whenever we prepare media.

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  9. Hi please send me the definition of inhibitory test used in growth promotion test.

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    1. Inhibitory test has been done in case of selective media.In case of inhibitory test not less than 100 cfu culture shall be spreaded on the media and there should not be any growth on the selective media in case of inhibitory test. Specified microorganism shall be used as mentioned in the pharmacopoeia. For example in case of cetrimide agar media, P.aeruginosa shall be used for growth promotion test and E.coli shall be used for growth inhibition test.

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  10. Sir,During monitoring why 1000 liters required for active air sampling

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    1. For Active air sampling one cubic meter area is required for sampling and one cubic meter area exactly contains 1000 liters of air.

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    2. is it possible to reduce the sampling size? Like if a room has 4 locations, then is it possible to take 1000 L sample in total for all of these locations? I mean, 250L for each location?
      Thank you

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    3. Dear Khairuzzaman Zaman, its 1000 liters per location.

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  11. In Microbiology, container closure integrity test is performed with final inoculum concentration of B.diminuta must be 10 6.Why is in 10 6 only y cant we use 10 7 or 10 5 culture.
    Raguvarman M

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  12. Sir why we used to remove air from autoclave chamber with bowiedick kit..What is scientific relation between air and steam...For air removing why we specifically use bowiedick kit sir. Apart from bowiedick any test is recommend for air removing purpose sir.

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    Replies
    1. Dear Ragu Varman, Air is bad conductor of heat. Air pockets prevent steam penetration.If air pockets remain in autoclave chamber then sterilization will not be effective. That's why Bowie and Dick test is performed to check the air removal from the autoclave.

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  13. Dear sandeep sir as you told that we have to use NLT100 CFU for inhibitory test of selective media .I have one Dout in culture suspension we are maintaining count 10-100cfu .so from where we will spread culture of NLT 100 CFU.

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    1. We should maintain the more than 100 cfu for GIT

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    2. Dear Sundaresan Madeswaran, for GIT acceptance criteria no growth should be observed in the media. By using more than 100 cfu you are just challenging your media with higher number of microorganisms. Hope you understand.
      Thanks

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    3. Dear Rupesh chandra Sharma, you can preserve one higher concentration dilution with the dilution selected for GPT.

      Thanks

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  14. Hello sir
    why we are exposing the plates for 4 hrs only in passive why not less than or more than 4hrs

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  15. Dear sir
    In Environmental Monitoring Aactive Air Sampling 1000Lts of air monitor if any reson is there sir please give the answer.

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    1. Dear Sampath,
      Me too finding difficulty about this. i found that it is obvious to collect 1000L sample. if you found anything that can reduce the sample size please let me know. (zaman.zaman37@gmail.com- this is my email address) The good news is if you are working in non sterile facility, then you can even skip the active air sampling altering with the Passive sampling. (See USP 1115)
      Thank you

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  16. Hi sir
    EM-Active air sampling results report MPN method why not report original count sir.

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    1. Dear sampath nallella, it is because there is probability of sampling of microorganism from same air sampler sieve hole. For that feller correction table is used.

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  17. Hi sir how to calculate bacterial endotoxin test maximum valid dilution and how to make
    control standard endotoxin dilution

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    1. Dear Chandra Mohan, for calculation of maximum valid dilution there is a formula given.
      MVD= Endotoxin limit x Concentration of sample/ Lysate sensitivity (^)
      For example if you are having a product with limit of 0.20 EU/mg, concentration of 100 mg/mL and Lysate sensitivity of 0.125 EU/mL then calculated MVD will be= 0.20 EU/mg x 100 mg/mL
      ----------------------
      0.125 EU/mL
      MVD= 160

      Control standard endotoxin dilution preparation.
      For example you have CSE of 40 EU/mL as per CoA and you have to prepare 1 EU/mL concentration of CSE. For that
      Actual concentration/concentration to be prepared equals to the number of times CSE to be diluted. That is 40 is the actual conc. and 1 EU/ mL to be prepared then 40/1=40. You have to dilute the CSE 40 times to get conc. of 1EU/mL. So, 1 mL CSE+39 mL LRW gives you 1EU/mL conc.To reduce consumption of CSE and LRW you can prepare by using 0.1 mL CSE+ 3.9 mL LRW to get 1 EU/mL CSE conc. The dilution ratio will be same in both dilutions.
      Hope its clear. Revert if need more explaination.

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    2. Thank u sir sir one more question please explain inhibition and enhancement in bet when we perform enhancement and inhibition

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    3. In every new product validation you have to perform inhibition and enhancement test.

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    5. Sandeep sir I have one query about Enhancement that what is the maening of Enhancement in bet method validation.

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  18. Dear Sir,
    Are the pass boxes graded area? if yes which grade and which Microbiological test requires to qualify the pass box? i am doing only the surface monitoring test. what about non viable particle, active and passive air sampling? most importantly i need to know that, the dynamic pass boxes are graded or not.
    Thank you

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    1. Dear Khairuzzaman Zaman, dynamic pass boxes are installed between the area of two different grades for transfer of material.You should qualify the pass box one higer grade than your clean room area. For example if pass box is installed between B and C grade area then your high clean area is grade B and you have to qualify the pass box in grade A.If you installed DPB in between grade C and D then C is the higher grade and you have qualify the pass box in grade B.
      Hope its clear for you.
      Thanks

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    2. why to qualify at one higher level, is there any reason please explain.

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  19. On which basis for microbiological analysis size of media plates defined ???

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  20. On which basis for microbiological analysis size of media plates defined ???

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  21. Hi sandeep dhiman my question is how can i make 100 cfu organism from 8 crore organisms

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    1. Dear Faraz FC, you can make serial dilution to get the count in desired range.

      Thanks!

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    2. Hi Sandeep Dhiman How r you i have three question

      1 what is difference between purified water and distilled water we are using distilled water for media preparation kindly clear concept ?
      2 why E.coli bacteria is not used in TSA and TSB media according to USP <61, 62>. ?
      3 For growth promotion test which method should we used either pouring method or spreading method kindly answer me with reference ?
      Thanks

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  22. Can endotoxins or exotoxins be controlled by immunosuppressive drugs?

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  23. If water sample fail in phase I of water system validation then it is acceptable.it is necessary to investigate and take CAPA.

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  24. Why <1 or <10 cfu term used instead of zero?

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  25. Hello sir,
    Which technique is better in water analysis and why? Membrane filtration or pour plate technique

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    1. Hi Sunil, Membrane filtration method is more reliable then pour plate method.

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  26. Hi sir..What is the acceptance criteria in microbial enumeration test method validation of non sterile api

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    1. Dear Sridhar, your non sterile API should meet the specification of total aerobic microbial count and total yeast and mold count as per pharmacopoeia and percent recovery in positive product control should be greater than 70% as compared to positive control.

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  27. Hi Sandeep,

    Why don't you share your knowledge frequently in any topic. As microbiology is so vast subject and at the same time very interesting. Plz keep posting..

    Regards
    Biswajit

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    Replies
    1. Dear Biswajit, asking this question shows your interest in microbiology as well as in this blog. Thanks for your support and soon you will find new topics.

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  28. Is it requires to perform gloved finger dab in non sterile area

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    1. There is not need to perform finger dab in non sterile area as non sterile material handled in non sterile area.

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  29. No. As per USP chapter 1115

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  30. My question is During MLT analysis Why SCDM used for diluent why not purified water ?And finally we pour desired agar medium.

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  31. Sir
    What type of dye used in Bowdick kid and whatdye removal principle

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  32. What the relation between dye reomovl and air removal

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  33. Nice. Thank you for sharing pharma industry updates.

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  34. Sandeep sir.. please explain area qualification

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  35. Sir, we are using Bioballs for GPT. The manufacturer's certificate of analysis (COA) mentions lower and upper limit of the available microbial cells in the each bioball lot. As per our standard criteria, the recovery of cfu should be between 10-100 cfu. Now please give clarity on which criteria shall we follow... lowe & upper limit in COA or 10-100cfu while result reading.

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  36. Kindly explain about Vitek 2 cards

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  37. Hello sir,
    For gowning requalification is there any +/- days,as +/-15days

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  38. Hello Sir,
    Currently we perform total viable count test using pour plate method for raw and potable water .
    If we are proposing to perform TVC by alternate method i.e using membrane filtration method so do I need to perform validation in this case. What does guideline suggest ?

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