Rapid turbidimetric assay to potency evaluation of tigecycline in lyophilized powder

•A simple turbidimetric method to quantify tigecycline in lyophilized powder was developed.•The validation of turbidimetric method was carried out.•The results obtained by HPLC and turbidimetric methods showed no significant difference.•An alternative methodology for the routine quality control of the tigecycline is suggested.

Tigecycline, a first-in-class glycylcycline and an analog of the semisynthetic antibiotic minocycline, is a potent, broad-spectrum antibiotic that acts by the inhibition of protein translation in bacteria. This glycylcycline inhibits Gram-positive, Gram-negative, atypical, anaerobic and antibiotic-resistant organisms. There is no microbiological analytical method for tigecycline in lyophilized powder reported yet. Thus, this paper reports the development and validation of a simple, sensitive, accurate and reproducible turbidimetric method to quantify tigecycline in lyophilized powder, using Staphylococcus aureus as microorganism test and 3 × 3 parallel line assay design, with twenty tubes for each assay. The validated method showed good results of linearity in the concentration range from 3 to 4.32 μg/mL (r2 = 0.9999), selectivity, precision, robustness and accuracy of 99.74%. The results demonstrated the validity of the proposed bioassay, which allows reliable quantitation of tigecycline in pharmaceutical samples and therefore can be used as a useful alternative methodology for the routine quality control of this medicine.