See the DrugPatentWatch profile for tigecycline
Tigecycline is a broad-spectrum antibiotic, used to treat various bacterial infections, including skin infections, intra-abdominal infections, and community-acquired pneumonia [1]. However, there is a noted difference in its effectiveness in vitro, or in a laboratory setting, compared to in vivo, or in a living organism.
In vitro, tigecycline has demonstrated efficacy against a wide range of bacteria, including drug-resistant strains [1]. Its broad-spectrum activity is attributed to its ability to inhibit protein synthesis in bacteria [1]. However, when tested in vivo, tigecycline's effectiveness appears to be reduced.
This discrepancy is due to several factors. First, in a living organism, the drug must be distributed to the site of infection, a process that can be influenced by various factors such as drug binding to plasma proteins, drug metabolism, and tissue penetration [2]. Tigecycline, in particular, has a large volume of distribution and is highly protein-bound, which can affect its concentration at the site of infection [2].
Second, the host's immune response can also impact the drug's effectiveness. For instance, tigecycline is bacteriostatic, meaning it inhibits bacterial growth rather than killing them outright [1]. In a robust immune response, this may be sufficient. However, in an immunocompromised host or in cases of severe infection, a bactericidal drug may be more appropriate [3].
Lastly, the development of drug resistance can also contribute to the difference in efficacy. While tigecycline has been effective against drug-resistant strains in vitro, prolonged use can lead to the development of resistance [1].
In conclusion, while tigecycline demonstrates broad-spectrum activity in vitro, its effectiveness in vivo can be influenced by various factors, including drug distribution, the host's immune response, and the development of drug resistance.
Sources:
[1] DrugPatentWatch.com. (2021). Tigecycline. Retrieved from
https://www.drugpatentwatch.com/drugs/tigecycline
[2] Shah, A., & Matsumura, P. (2019). Tigecycline: A Review in Complicated Skin and Soft Tissue Infections and Complicated Intra-abdominal Infections. Drugs, 79(11), 1197–1210.
https://doi.org/10.1007/s40265-019-01143-2
[3] Forrest, A., & Tam, V. H. (2019). Glycylcyclines: Tigecycline and Eravacycline. In StatPearls [Internet]. StatPearls Publishing.