Rapid Microwave-Assisted Synthesis of pH-Sensitive Carbon-Based Nanoparticles for the Controlled Release of Doxorubicin to Cancer Cells.

Carbon-based nanoparticles (CNPs) are a new type of interesting nanomaterials applied in various pharmaceutical fields due to their outstanding biocompatible properties. Novel pH-sensitive CNPs were rapidly synthesized within 1 min by microwave-assisted technique for doxorubicin (DOX) delivery into five cancer cell lines, including breast cancer (BT-474 and MDA-MB-231 cell lines), colon cancer (HCT and HT29 cell lines), and cervical cancer (HeLa cell lines). CNPs and DOX-loaded CNPs (CNPs-DOX) had nano-size of 11.66 ± 2.32 nm and 43.24 ± 13.25 nm, respectively. DOX could be self-assembled with CNPs in phosphate buffer solution at pH 7.4 through electrostatic interaction, exhibiting high loading efficiency at 85.82%. The release of DOX from CNPs-DOX at pH 5.0, often observed in the tumor, was nearly two times greater than the release at physiological condition pH 7.4. Furthermore, the anticancer activity of CNPs-DOX was significantly enhanced compared to free DOX in five cancer cell lines. CNPs-DOX could induce cell death through apoptosis induction in MDA-MB-231 cells. The findings revealed that CNPs-DOX exhibited a promising pH-sensitive nano-system as a drug delivery carrier for cancer treatment.

Sodium Alginate-Quaternary Polymethacrylate Composites: Characterization of Dispersions and Calcium Ion Cross-Linked Gel Beads.

The objective of this work was to examine the effect of quaternary polymethacrylate (QPM), a water-insoluble polymer with a positive charge, on the characteristics of the sodium alginate (SA) dispersions and the calcium alginate (CA) gel beads containing propranolol HCl (PPN). The SA-QPM composite dispersions presented the formation of flocculates with a negative charge due to the electrostatic interaction of both substances. The QPM addition did not affect the SA dispersions' Newtonian flow, but the composite dispersions' viscosity enhancement was found. The PPN-loaded CA-QPM gel beads had more spherical than the PPN-loaded CA gel beads. The incorporation of QPM caused a bigger particle size, higher drug entrapment efficiency, and greater particle strength of the gel beads. Despite the similar water uptake property, the PPN-loaded CA-QPM gel beads displayed lower burst release and slower drug release rate than the PPN-loaded CA gel beads. However, the drug release from the PPN-loaded CA-QPM gel beads involved drug diffusion and matrix swelling mechanisms. This study demonstrated that adding QPM into the SA dispersions leads to a viscosity synergism. The CA-QPM gel beads display a good potential for use as a bioactive compound delivery system.

Thai glutinous rice starch modified by ball milling and its application as a mucoadhesive polymer.

This study aimed to investigate physicochemical properties and potential application as a mucoadhesive polymer of Thai glutinous rice starch modified by planetary ball milling. XRD and ATR-FTIR results indicated a reduction in crystallinity of starch after ball milling. Different ball milling times, ranging from 5 to 45 min, resulted in modified glutinous rice starch (MGRS) with different levels of crystallinity loss, and therefore varying degrees of cold water solubility, swelling capacity, and gelatinized dispersion viscosity. Investigation of mucoadhesive properties using Texture Analyzer with porcine mucosa demonstrated that MGRS tablets exhibited greater mucoadhesive abilities compared to hydroxypropyl methylcellulose tablets, but weaker than those of sodium carboxymethylcellulose tablets. Tablets made of 15-min-milled MGRS had comparable tableting, swelling and mucoadhesiveness, but lower erosion compared to 45-min-milled MGRS. Conclusively, ball milling treatment could successfully induce the mucoadhesive properties of Thai glutinous rice starch and expand its application as mucoadhesive polymer.

The physicochemical properties of a spray dried glutinous rice starch biopolymer.

Glutinous rice starch (GRS) is a biopolymer used widely in the food industry but not at all in the pharmaceutical industry. There are several ways to modify this biopolymer. Physical modification is simple and cheap because it requires no chemicals or biological agents. The aim of this study was to characterize the physicochemical properties of a spray dried glutinous rice starch (SGRS) produced from pregelatinized GRS. The surface morphology changed from an irregular to concave spherical shape as revealed by Scanning Electron Microscopy (SEM). SGRS was almost amorphous as determined by X-ray Diffraction (XRD) spectroscopy. The water molecules became linked through hydrogen bonds to the exposed hydroxyl group of amorphous SGRS as determined by Near Infrared (NIR) spectroscopy. Then, SGRS formed a colloid gel matrix with water and developed a highly viscous gelatinous form as determined using Differential Scanning Calorimetry (DSC) and a stress control type rheometer. In addition, SGRS can swell and produce a gelatinous surface barrier like a hydrophilic matrix biopolymer which controls drug release. Therefore, a novel application of SGRS is as a sustained release modifier for direct compression tablets in the pharmaceutical industry.

Effect of polysulfonate resins and direct compression fillers on multiple-unit sustained-release dextromethorphan resinate tablets.

The purpose of this work was to investigate the effect of different polysulfonate resins and direct compression fillers on physical properties of multiple-unit sustained-release dextromethorphan (DMP) tablets. DMP resinates were formed by a complexation of DMP and strong cation exchange resins, Dowex 50 W and Amberlite IRP69. The tablets consisted of the DMP resinates and direct compression fillers, such as microcrystalline cellulose (MCC), dicalcium phosphate dihydrate (DCP), and spray-dried rice starch (SDRS). Physical properties of tablets, such as hardness, disintegration time, and in vitro release, were investigated. A good performance of the tablets was obtained when MCC or SDRS was used. The use of rod-like and plate-like particles of Amberlite IRP69 caused a statistical decrease in tablet hardness, whereas good tablet hardness was obtained when spherical particle of Dowex 50 W was used. The plastic deformation of the fillers, such as MCC and SDRS, caused a little change in the release of DMP. A higher release rate constant was found in the tablets containing DCP and Dowex 50 W, indicating the fracture of the resinates under compression, which was attributable to the fragmentation of DCP. However, the release of DMP from the tablets using Amberlite IRP69 was not significantly changed because of the higher degree of cross-linking of the resinates, which exhibited more resistance to deformation under compression. In conclusion, the properties of polysulfonate resin, such as particle shape and degree of cross-linking, and the deformation under compaction of fillers affect the physical properties and the drug release of the resinate tablets.

Influences of layering on theophylline pellet characteristics.

This study evaluated and compared theophylline pellets prepared by both suspension and powder layering processes using the bottom spray coater and the tangential rotary granulator, respectively. Hydroxypropyl methylcellulose (HPMC) and hydroxypropyl cellulose (HPC) were employed as binders at various concentrations. The pellets were coated with Eudragit RS and RL to various levels. It was found that pellet sizes, true densities, and drug contents were comparable and independent of processes and binder levels. However, the increase in binder resulted in lower porosity and pore size, as well as smoother pellet surface. The powder layered pellets possessed higher pellet density and smoother surface than did the suspension layered pellets due to the greater consolidation resulted from tumbling and colliding of pellets. Powder x-ray diffraction pattern revealed that theophylline present in the suspension layered pellets was a mixture of anhydrous form II and hydrate, indicating that transformation could occur in aqueous medium. Drug release from uncoated pellets was found to be complete within 20 min. For coated pellets, the release was markedly decreased with the increase in Eudragit level. Both film thickness and anhydrous/hydrate form influenced the release of drug from the pellets. In general, two methods of layering produced the pellets of slightly differences in pellet properties; however, changes of drug characteristics could occur in suspension.