SBIR Topic 134: Alternatives to Benzathine Penicillin for Treatment of Syphilis

Syphilis is a sexually transmitted disease caused by T. pallidum. The WHO estimates that 7.1 million persons aged 15-49 acquired syphilis in 2020. Benzathine penicillin (BPG) is the only CDC recommended treatment for syphilis. However, recently shortages of this medicine have been reported worldwide. In addition, BPG is given intramuscularly by injection, which makes it difficult to be administered in countries or regions where proper medical facilities or qualified personnel are not available. To address this, ChromoLogic LCC will develop the Lipophilic Conjugates of Tetracycline as Alternatives to Penicillin G for Syphilis Treatment (LC-TAPS). The LC-TAPS are designed to exhibit improved pharmacokinetics and biodistribution compared to tetracyclines drugs. The minimal inhibitory concentration (MIC) for T. pallidum treated with these three LC-TAPS compounds developed will be determined. It is expected that LC-TAPS will have lower MIC values for T. pallidum compared to tetracyclines. The toxicity of the three LC-TAPS toward the host rabbit cells will be also evaluated. The fluorescent properties of LC-TAPS will be utilized to determine their localization, their cellular uptake and biodistribution in human and rabbit cells. These studies will determine the affinity of LC-TAPS antibiotics for these cells.