**18. Conclusion**

*M. tuberculosis* is a difficult pathogen to combat and the frontline drugs currently in use are between 40 and 60 years of age. There is an urgent need of novel tuberculosis drugs, but the time to identify, develop and ultimately advance new drug regimens on the market has been extremely slow in the past decade. Organic biochemistry remains to be performed to know the mechanism of activity, to empower lead advancement, and to ensure in vivo effectiveness [20]. Current efforts to develop drugs against tuberculosis are not enough to end the global tuberculosis epidemic. Due to the diversification and complexity of the infection for *M tuberculosis*, no model can completely define the in-vivo conditions in which mycobacteria are found in Tuberculosis patients and there is no sole standard detection condition for generating successful compounds for tuberculosis drug development*.* Recent efforts have focused on the development of whole-cell screening trials because objectivebased biochemical screens of inhibitors over the past two decades have not provided new tuberculosis drugs [68]. There are significant challenges in the discovery of antituberculosis drugs due to the nature of the causative bacteria. The lack of predictive models for the entry of compounds into mycobacteria is also a limiting factor. Several additional barriers in the development of tuberculosis drugs include: there are no well-established (PK)– (PD) paradigms, lack of validation and human-like pathology of animal models currently available for drug discovery, lack of clinical laboratories suitable for clinical trials, and the lack of adequate research funds. The biggest challenge in the development of anti-tuberculosis drugs is to reduce the duration of treatment for patients with drug-sensitive tuberculosis [18]. Noval drugs are needed to achieve this and overcome drug resistance. In addition, it should be possible to use new drugs for patients with HIV/AIDS co-infection. The present condition of tuberculosis drug development is far better than what was seen past 10–15 years ago. Howsoever, the development is still lacking behind because of the significant challenges in the drug discovery against drug-resistant tuberculosis and the shorter duration of the treatment required for tuberculosis prevention [12, 13].

We need to identify essential Tuberculosis targets based on better knowledge of the disease pathogen and physiology, develop sharp screening trials, and prepare compounds specifically designed to provide better clues for antibacterial activities [11]. Recent granuloma models are based on a single cell type to imitate the aggregate complex that is formed. Biomedical engineering methods can produce further diversified but still organized multicellular structures that clearly defines the organization of human granulomas. The challenge is that the need is urgent, but the process of discovery and development requires an excessive number of resources and time. The search for more effective vaccines should continue to provide longterm solutions to tuberculosis. At the same time, the development of drugs and regimes must be accelerated with a clearer approach [1, 9].
