Improving stability and oral bioavailability of hydroxycamptothecin via nanocrystals in microparticles (NCs/MPs) technology

Nanocrystals and nanosuspensions: an exploration from classic formulations to advanced drug delivery systems

Nanocrystals and nanosuspensions have become realistic approaches to overcome the formulation challenges of poorly water-soluble drugs. They also represent a less-known but versatile platform for multiple therapeutic applications. They can be integrated into a broad spectrum of drug delivery systems including tablets, hydrogels, microneedles, microparticles, or even functionalized liposomes. The recent progresses, challenges, and opportunities in this field are gathered originally together with an informative case study concerning an itraconazole nanosuspension-in-hydrogel formulation. The translational aspects, historical and current clinical perspectives are also critically reviewed here to shed light on the incoming generation of nanocrystal formulations.

Computer-aided design of molecularly imprinted polymer reinforced by double hybrid monomers for selective purification of hydroxycamptothecin

A kind of hydroxycamptothecin (HCPT) hybrid molecularly imprinted polymer (AT/MA-HMIPs) with high selectivity and hard silicon skeleton was successfully prepared based on double hybrid monomers. The relationship between templates and functional monomers was studied through computer molecular simulation and experiments. Three single-monomer molecularly imprinted polymers were prepared as controls. The Langmuir isotherm and pseudo-second-order kinetic models were found to fit well with the adsorption results. The maximum adsorption capacity was 18.79 mg/g, and equilibrium was reached within 20 min. Moreover, it shows excellent selectivity (imprinting factor is 10.73) and good recoverability (after 10 adsorption-desorption cycles, the adsorption capacity only decreases by 7.75%) for HCPT. The purity of HCPT can reach 80.86% after being put into a solid phase extraction column and used in an actual sample, and the yield was 61.43%. This study lays the fundament for the development of excellent HCPT molecularly imprinted composites.

Design and Characterization of Dexamethasone Loaded Microsponges for the Management of Ulcerative Colitis

Ulcerative colitis is an inflammatory condition with ulcerations throughout the colon. The existing remedies have some limitations such as drug inactivation, poor absorption, and adverse reactions. The present study aimed to design novel microsponge formulations to enhance remission of the dexamethasone (as a model pharmaceutical ingredient) in the colon. Microsponges were prepared by using the quasi-emulsion technique. The optimal formulation was selected by applying the design of experiments approach which used methylcellulose (MC) (0.75-2%, w/w), polyvinylalcohol (PVA)(0.5-1%, w/w), and tween 80 (TW80) (1.5-2.5%, w/w). The critical quality attributes were selected as particle size and entrapment efficiency. The particle size and encapsulation efficiency were found as 140.38 ± 9.2 µm and 77.96 ± 3.4 %. After the optimization; morphological, thermal, and physicochemical characterization studies were performed. Ultimately, the optimal formulation was investigated by using the acetic acid-induced ulcerative colitis model in rats. The physicochemical characterization studies confirmed that the formulation components were compatible with each other. The in vitro release mechanisms were fitted to First order kinetics at pH 1.2 (R²:0.9563), and Korsmeyer-Peppas kinetics at pH 4.5 (R²: 0.9877), and pH 6.8 (R²: 0.9706). The medicated microsponges exhibited remarkable recovery compared to the control group of the in vivo ulcerative colitis model (p<0.05). It could be concluded that microsponges were evaluated as a promising alternative drug delivery system for the management of ulcerative colitis.

Advances in Antitumor Nano-Drug Delivery Systems of 10-Hydroxycamptothecin

10-Hydroxycamptothecin (HCPT) is a natural plant alkaloid from Camptotheca that shows potent antitumor activity by targeting intracellular topoisomerase I. However, factors such as instability of the lactone ring and insolubility in water have limited the clinical application of this drug. In recent years, unprecedented advances in biomedical nanotechnology have facilitated the development of nano drug delivery systems. It has been found that nanomedicine can significantly improve the stability and water solubility of HCPT. NanoMedicines with different diagnostic and therapeutic functions have been developed to significantly improve the anticancer effect of HCPT. In this paper, we collected reports on HCPT nanomedicines against tumors in the past decade. Based on current research advances, we dissected the current status and limitations of HCPT nanomedicines development and looked forward to future research directions.