Photodynamic Antibacterial Therapy of Gallic Acid-Derived Carbon-Based Nanoparticles (GACNPs): Synthesis, Characterization, and Hydrogel Formulation.

Carbon-based nanoparticles (CNPs) have gained recognition because of their good biocompatibility, easy preparation, and excellent phototherapy properties. In biomedicine applications, CNPs are widely applied as photodynamic agents for antibacterial purposes. Photodynamic therapy has been considered a candidate for antibacterial agents because of its noninvasiveness and minimal side effects, especially in the improvement in antibacterial activity against multidrug-resistant bacteria, compared with conventional antibiotic medicines. Here, we developed CNPs from an active polyhydroxy phenolic compound, namely, gallic acid, which has abundant hydroxyl groups that can yield photodynamic effects. Gallic acid CNPs (GACNPs) were rapidly fabricated via a microwave-assisted technique at 200 °C for 20 min. GACNPs revealed notable antibacterial properties against Gram-positive and Gram-negative bacteria, including Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The minimum inhibitory concentrations of GACNPs in S. aureus and E. coli were equal at approximately 0.29 mg/mL and considerably lower than those in gallic acid solution. Furthermore, the GACNP-loaded hydrogel patches demonstrated an attractive photodynamic effect against S. aureus, and it was superior to that of Ag hydrofiber®, a commercial material. Therefore, the photodynamic properties of GACNPs can be potentially used in the development of antibacterial hydrogels for wound healing applications.

Design and Optimization of 3D-Printed Gastroretentive Floating Devices by Central Composite Design.

This study aimed to optimize the size of capsule-shaped 3D-printed devices (CPD) using an experimental design by the response surface methodology to provide a gastroretentive drug delivery system (GRDDS) with optimal floating time. The CPD was fabricated using a fused deposition modeling (FDM) 3D printer. The central composite design was employed for the optimization of the devices. The morphology of the CPD was observed using a digital microscope and scanning electron microscope (SEM). The in vitro floating time and drug release were evaluated using a USP dissolution apparatus II. Appropriate total floating time (TFT) of the devices (more than 3 h) was obtained with the device's body, cap, and bottom thickness of 1.2, 1.8, and 2.9 mm, respectively. The release kinetics of the drug from the devices fitted well with zero-order kinetics. In conclusion, the optimization of CPD for GRDDS using the experimental design provided the devices with desirable floating time and ideal drug release characteristics.

Three-dimensional (3D)-printed devices composed of hydrophilic cap and hydrophobic body for improving buoyancy and gastric retention of domperidone tablets.

The aim of this study was to produce capsule-shaped floating devices (CFD) using a fused deposition modeling (FDM) three-dimensional (3D) printer, for controlling the release and gastric retention of domperidone (DOM) tablets (Motilium-MⓇ). In order to enhance the buoyancy of the devices, a hollow cap with different wall thicknesses (1.2-1.5 mm) was printed with a hydrophilic (polyvinyl alcohol, PVA) filament. The body of the device was made from a hydrophobic (polylactic acid, PLA) filament. Bodies with aperture sizes (1-2 mm) were produced to investigate how this would affect drug release. Morphology, weight variation, ex vivo and in vivo floating time and drug release characteristics were examined. The results revealed that increasing the cap thickness of the devices (1.2 to 1.3 mm) increased the total floating time (TFT). The maximum TFT (10 h) with floating lag time (FLT) < 5 s was observed from Motilium-MⓇ incorporated CFD3-5 (cap with 1.3-mm wall thickness). Decreasing the size of the holes on the devices led to the sustained release of DOM. The CFD5 (cap with 1.3-mm cap thickness and 1.5-mm hole width) delivered approximately 98% release in 10 h, and the release kinetics fit well with the zero-order kinetics (R2 > 0.95). In vivo floating studies in rabbits showed that the floating time of CFD5 was more than 10 h. These results demonstrated that the CFD was successfully designed to provide gastro-retentive drug delivery with the capacity to float and provide sustained drug release.