Context: The inhibitors of cyclooxygenase (COX)-2 play an important role in cancer chemoprevention. Certain COX-2 inhibitors exert antiproliferative and pro-apoptotic effects on cancer cells. Objective: In this study, meloxicam, which is an enolic acid-type preferential COX-2 inhibitor, was encapsulated in poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles (NPs) to maintain local high concentration, and its efficacy was determined. Methods: NPs were prepared by using salting-out and emulsion-evaporation steps. Meloxicam-loaded NP formulations were evaluated with respect to the drug loading, particle size, polydispersity index, zeta potential, drug release rate, and residual poly(vinyl alcohol) (PVA) percentage. The effects of PLGA and PVA molecular weight variations on the physicochemical properties of NPs were investigated. Stability of meloxicam in NPs was assessed over 3 months. COX-2 expressing human colon adenocarcinoma cell line HT-29 was used in cellular uptake and viability assays. Results: NPs had a spherical shape and a negative zeta potential, and their size ranged between 170–231 nm with a lower polydispersity index. NPs prepared with high molecular weight PLGA were shown to be physically stable over three months at 4°C. The increase in molecular weight of the polymer and emulsifier reduced the in vitro release rate of meloxicam from NPs. Meloxicam-loaded NPs showed cytotoxic effects on HT-29 cells markedly at 800 µM. Cancer cells had high uptake of coumarin-6-loaded NPs. Conclusion: The PLGA NPs developed in this study can be a potentially effective drug delivery system of meloxicam for the treatment of colon cancer.

In this study, development of modified release tablet formulations containing diltiazem hydrochloride-loaded microspheres to be taken once rather than two or three times a day was attempted. For this purpose, ethylcellulose microspheres were prepared by emulsion-solvent evaporation technique. The influence of emulsifier type and drug/polymer ratio on production yield, encapsulation efficiency, particle size, surface morphology and in-vitro release characteristics of the microspheres was evaluated. Suitable microspheres were selected and tabletted using different tabletting agents, Ludipress, Cellactose80, Flow-Lac100 and excipients Compritol888 ATO, KollidonSR. Tablets were evaluated from the perspective of physical and in-vitro drug release characteristics. It was seen that type and ratio of the excipients played an important role in the tabletting of the microspheres. As a result, two tablet formulations containing 180 mg diltiazem hydrochloride and using either Compritol888 ATO or KollidonSR were designed successfully and maintained drug release for 24 h with zero order and Higuchi kinetics, respectively.