Fluid Thioglycollate Medium w 0.5% Soya lecithin & 4% Tween 80

LQ270C3 contains Fluid Thioglycollate Medium supplemented with 0.5% soya lecithin and 4% Tween 80 (polysorbate 80). These neutralizing agents inactivate quaternary ammonium compounds (benzalkonium chloride), phenolics, and other antimicrobial preservatives commonly found in pharmaceutical products. Essential for sterility testing of preserved products where standard FTM would give false-positive results due to preservative carryover inhibiting microbial growth.

Products requiring neutralizing FTM include: (1) Multi-dose injectables with preservatives (benzalkonium chloride, phenol, cresol), (2) Ophthalmic solutions with BAK or other preservatives, (3) Nasal sprays and inhalation products, (4) Topical pharmaceuticals with antimicrobial agents, (5) Disinfectants and antiseptics for sterility verification, (6) Any product where standard FTM validation shows preservative interference. USP <71> requires demonstrating preservative neutralization.

Soya lecithin neutralizes quaternary ammonium compounds (QACs) like benzalkonium chloride by binding to their cationic sites, inactivating their antimicrobial activity. Tween 80 (polysorbate 80) is a non-ionic surfactant that neutralizes phenolic compounds and helps disperse lipophilic antimicrobials. Together they provide broad-spectrum neutralization while maintaining FTM's ability to support growth of test organisms. Effectiveness must be validated per USP <71> for each specific product and preservative combination.

Yes, USP <71> Section 4 requires validation that neutralizing agents effectively inactivate preservatives without inhibiting microbial growth. Validation steps: (1) Growth promotion test with <100 CFU of test organisms in presence of product, (2) Comparison with growth in media without product, (3) Recovery ≥70% demonstrates adequate neutralization, (4) Test with all preservative concentrations in your product, (5) Include all required ATCC strains. Document validation in your laboratory protocols.

If standard lecithin/Tween concentrations are insufficient: (1) Increase sample dilution to reduce preservative concentration, (2) Use membrane filtration method and rinse thoroughly to remove preservatives, (3) Add additional specific neutralizers (sodium thiosulfate for halogens, beta-lactamase for antibiotics), (4) Use custom media formulations with higher neutralizer concentrations, (5) Employ alternative methods like direct inoculation. Consult USP <71> Table 1 for additional neutralizing agents. HiMedia can formulate custom media.

The 300mL bottle format allows flexible dispensing volumes for membrane filtration sterility testing. After filtering preserved products through 0.45μm or 0.22μm membranes to remove preservatives, filters are transferred to bottles containing neutralizing FTM. The larger volume ensures adequate medium for submerged incubation of membrane filters. Also used for testing large volume parenterals or multiple units in a single container. More cost-effective than individual tubes for high-volume testing.