*5.1.2 CD-based polycarbonate NSs*

CD-based polycarbonate NSs synthesized using carbonyldiimidazole (CDI) showed antimicrobial activity against various microorganisms such as *E. coli*, *S. aureus*, *P. aeruginosa*, *S. typhi*, *C. albicans*, and Clostridia, when compared with Ciprofloxacin that was used as a standard drug. The formulations were prepared by polymer condensation, and interfacial phenomenon, and were effective for 6 months at a condition of 40°C and 75% of relative humidity [66]. This type of CD NSs was further used to deliver and increase the activity of several anticancer drugs such as paclitaxel [67], bortezomib [68], flutamide [69], tamoxifen [70], etc. Following their high potential to entrap a variety of molecules, the β-CD/CDI NSs were also used to deliver and improve the solubility and dissolution of paliperidone, an antipsychotic drug for the treatment of schizophrenia [71]. Further, rilpivirine is used for the treatment of HIV infection but has low aqueous solubility. Therefore, the β-CD/CDI NSs presented a strategy to improve this drawback and also the bioavailability and dissolution rate [72]. The antioxidant activity of kynurenic acid, an endogenous substance, was improved by loading it in β-CD/CDI NSs. The higher antioxidant activity was observed because of the increment in solubilization of kynurenic acid [60]. CD-based polycarbonate NSs synthesized using diphenyl carbonate (DPC) were used to overcome the poor solubility and stability of Babchi oil that is known for possessing numerous activities such as antifungal, antibacterial, antiviral, antitumor, antioxidant, etc. [73]. Further, the bioactive properties of the piperine, an alkaloid with anti-microbial, anti-inflammatory, anti-cancer properties, etc., were protected by the β-CD/DPC NSs [74]. This type of NSs exhibited complexing ability toward nifedipine, as an oral calcium channel blocking agent that is used to treat angina pectoris and hypertension. It was observed an improvement in the oral solubility of nifedipine after its incorporation into NSs [75].
