Formulation and in vitro characterization of rifampicin-loaded porous poly (ε-caprolactone) microspheres for sustained skeletal delivery

Photothermal therapy of tuberculosis using targeting pre-activated macrophage membrane-coated nanoparticles

Conventional antibiotics used for treating tuberculosis (TB) suffer from drug resistance and multiple complications. Here we propose a lesion-pathogen dual-targeting strategy for the management of TB by coating Mycobacterium-stimulated macrophage membranes onto polymeric cores encapsulated with an aggregation-induced emission photothermal agent that is excitable with a 1,064 nm laser. The coated nanoparticles carry specific receptors for Mycobacterium tuberculosis, which enables them to target tuberculous granulomas and internal M. tuberculosis simultaneously. In a mouse model of TB, intravenously injected nanoparticles image individual granulomas in situ in the lungs via signal emission in the near-infrared region IIb, with an imaging resolution much higher than that of clinical computed tomography. With 1,064 nm laser irradiation from outside the thoracic cavity, the photothermal effect generated by these nanoparticles eradicates the targeted M. tuberculosis and alleviates pathological damage and excessive inflammation in the lungs, resulting in a better therapeutic efficacy compared with a combination of first-line antibiotics. This precise photothermal modality that uses dual-targeted imaging in the near-infrared region IIb demonstrates a theranostic strategy for TB management.

A Bacterial Responsive Microneedle Dressing with Hydrogel Backing Layer for Chronic Wound Treatment

The treatment of chronic wounds still presents great challenges due to being infected by biofilms and the damaged healing process. The current treatments do not address the needs of chronic wounds. In this study, a highly effective dressing (Dox-DFO@MN Hy) for the treatment of chronic wounds is described. This dressing combines the advantages of microneedles (MNs) and hydrogels in the treatment of chronic wounds. MNs is employed to debride the biofilms and break down the wound barrier, providing rapid access to therapeutic drugs from hydrogel backing layer. Importantly, to kill the pathogenic bacteria in the biofilms specifically, Doxycycline hydrochloride (Dox) is wrapped into the polycaprolactone (PCL) microspheres that have lipase-responsive properties and loaded into the tips of MNs. At the same time, hydrogel backing layer is used to seal the wound and accelerate wound healing. Benefiting from the combination of two advantages of MNs and hydrogel, the dressing significantly reduces the bacteria in the biofilms and effectively promotes angiogenesis and cell migration in vitro. Overall, Dox-DFO@MN Hy can effectively treat chronic wounds infected with biofilms, providing a new idea for the treatment of chronic wounds.

Development and Optimization of Irinotecan-Loaded PCL Nanoparticles and Their Cytotoxicity against Primary High-Grade Glioma Cells

BACKGROUND

High-grade gliomas (HGGs) are highly malignant tumors with a poor survival rate. The inability of free drugs to cross the blood-brain barrier and their off-target accumulation result in dose-limiting side effects. This study aimed at enhancing the encapsulation efficiency (EE) of irinotecan hydrochloride trihydrate (IRH) within polycaprolactone (PCL) nanoparticles with optimized size and charge.

MATERIALS AND METHODS

IRH-loaded PCL nanoparticles were formulated using either the single emulsion (O/W, W/O and O/O) or double emulsion (W/O/O and W/O/W) solvent evaporation techniques. The nanoparticles were characterized for their size, zeta potential and EE, with the optimized nanoparticles being characterized for their drug release and cytotoxicity.

RESULTS

The amorphization of PCL and the addition of electrolytes to the aqueous phases of the W/O/W emulsion produced spherical nanoparticles with a mean diameter of 202.1 ± 2.0 nm and an EE of 65.0%. The IRH-loaded nanoparticles exhibited zero-order release and were cytotoxic against primary HGG cells.

CONCLUSION

The amorphization of PCL improves its EE of hydrophilic drugs, while the addition of electrolytes to the aqueous phases of the W/O/W emulsion enhances their EE further. IRH-loaded PCL nanoparticles have the potential to deliver cytotoxic levels of IRH over a sustained period of time, enhancing the cell death of HGGs.

Preparation and evaluation of ion-exchange porous polyvinyl alcohol microspheres as a potential drug delivery embolization system

The present study aimed to develop a new drug delivery system with efficient drug loading and sustained drug release for potential application in transarterial chemoembolization (TACE). The porous polyvinyl alcohol microspheres (PPVA MS) were prepared by a combination of inverse emulsification and thermal-induced phase separation (TIPS) method, this was followed by the grafting polymerization of sodium 4-styrene sulfonate (SSS) onto the PPVA MS to obtain the grafted PPVA-g-PSSS MS. The prepared PPVA MS showed a well-defined spherical shape with 'honeycomb-like' porous structure, which could be readily tailored by adjusting the quenching temperature. In vitro biocompatibility analysis indicated the non-cytotoxic and hemocompatible nature of PPVA MS. The porous structure and presence of ionically charged groups in the PPVA-g-PSSS MS favoured the loading of cationic doxorubicin (DOX) onto the MS through ionic-interactions and demonstrated a sustained drug release pattern. Moreover, the cytotoxicity of DOX-loaded PPVA-g-PSSS (DOX@PPVA-g-PSSS) MS against HepG2 cells and the intracellular uptake of DOX demonstrated the potent in vitro antitumor activity. Furthermore, the central auricular artery embolization in rabbits showed that both the PPVA-g-PSSS and DOX@PPVA-g-PSSS MS could occlude the auricular arteries and induced superior embolization effects, such as progressive ear appearance changes, irreversible parenchymal damage and fibrosis, and ultrastructural alternations in endothelial cells. Besides, the DOX fluorescence was distributed around the embolized arteries, without decreasing its intensity when prolonged embolization up to 15 days. These findings suggest that the newly developed DOX@PPVA-g-PSSS MS could be employed as a promising drug-loaded embolic agent for the treatment of hepatocellular carcinoma.

Preparation and characterization of novel anti-inflammatory biological agents based on piroxicam-loaded poly-ε-caprolactone nano-particles for sustained NSAID delivery

Piroxicam (PX), a main member of non-steroidal anti-inflammatory drugs (NSAIDs), is mainly used orally, which causes side effects of the gastrointestinal tract. It also has systemic effects when administered intramuscularly. Intra-articular (IA) delivery and encapsulation of PX in biodegradable poly-ε-caprolactone (PCL) nanoparticles (NPs) offer potential advantages over conventional oral delivery. The purpose of this study is the development of a new type of anti-inflammatory bio-agents containing collagen and PX-loaded NPs, as an example for an oral formulation replacement, for the prolonged release of PX. In this study, the PX was encapsulated in PCL NPs (size 102.7 ± 19.37 nm, encapsulation efficiency 92.83 ± 0.4410) by oil-in-water (o/w) emulsion solvent evaporation method. Nanoparticles were then characterized for entrapment efficiency, percent yield, particle size analysis, morphological characteristics, and in vitro drug release profiles. Eventually, the NPs synthesized with collagen were conjugated so that the NPs were trapped in the collagen sponges using a cross-linker. Finally, biocompatibility tests showed that the anti-inflammatory agents made in this study had no toxic effect on the cells. Based on the results, it appears that PX-loaded PCL NPs along with collagen (PPCLnp-Coll) can be promising for IA administration based on particulate drug delivery for the treatment of arthritis.

PCL–DOX microdroplets: an evaluation of the enhanced intracellular delivery of doxorubicin in metastatic cancer cells via in silico and in vitro approaches

A schematic diagram of HCC & TACE; injections of HepaSphere with DOX are made into the femoral artery, abdominal aorta, and hepatic artery to make the tumor shrink to a resectable size due to a shortage of nutrients and drug treatment.