Preparation and Storage of Second-line Anti-TB Drugs used for DST

Preparation and Storage of Second-line Anti-TB Drugs used for DST

1. Freeze the stock solutions preferably at -20ºC or lower in appropriate tubes and use for up to 6 months or up to the date of original expiry, whichever comes sooner.

2.  At the time of testing, make 100 folds dilution (1:100) to achieve the desired concentration and store at -20ºC or lower in appropriate tubes and use for up to 6 months or up to the date of original expiry, whichever comes sooner.

3. Once the working solution drug is thawed, use it immediately and do not re-freeze. Discard unused portions.

4. Always pipette accurately 100uL of the drug to the designated drug labelled MGIT tube.

 Important notes for preparation of drug solutions

1. All the drugs, except Ethionamide, should be filter sterilized. Use a 0.2-micron syringe filter for sterilization of the drugs. Discard the first 20% filtered solutions, and collect the remaining solution for use.

2 In the case of self-sterilizing solutions as well as other aqueous stock solutions, all further dilutions should be made in water, using sterile distilled water and aseptic techniques.

3 If a solvent other than water is recommended, only use sufficient solvent to solubilize the antimicrobial powder and then dilute to the final stock concentration with sterile distilled water.

4 Record batch no., date of preparation and expiry date for all drugs. Store the stock solutions in small aliquots at –20° C / 70° C. Once thawed and used, discard the remainder. Refreezing may affect the potency of the drugs.

Resource

Mycobacteriology Laboratory Manual       

Assessment