Activate the endogenous Cu2+ switch for Zn(DDC)2 liposomes conversion: Providing a safer and less toxic alternative in cancer therapy.

The ancient anti-alcohol drug disulfiram (DSF) has gained widespread attention for its highly effective anti-tumor effects in cancer treatment. Our previous studies have developed liposome of Cu (DDC)2 to overcome the limitations, like the poor water solubility. However, Cu (DDC)2 liposomes still have shown difficulties in severe hemolytic reactions at high doses and systemic toxicity, which have limited their clinical use. Therefore, this study aims to exploratively investigate the feasibility of using DSF or DDC in combination also can chelate Zn2+ to form zinc diethyldithiocarbamate (Zn (DDC)2). Furthermore, this study prepared stable and homogeneous Zn (DDC)2 liposomes, which were able to be released in the tumor microenvironment (TME). The released Zn (DDC)2 was converted to Cu (DDC)2 with the help of endogenous Cu2+-switch enriched in the TME, which has a higher stability constant compared with Zn (DDC)2. In other words, the Cu2+-switch is activated at the tumor site, completing the conversion of the less cytotoxic Zn (DDC)2 to the more cytotoxic Cu (DDC)2 for effective tumor therapy so that the Zn (DDC)2 liposomes in vivo achieved the comparable therapeutic efficacy and provided a safer alternative to Cu (DDC)2 liposomes in cancer therapy.

Stable Atropine Loaded Film As a Potential Ocular Delivery System For Treatment Of Myopia.

PURPOSE: The objective of the present study was to prepare stable and high bioavailability ocular atropine loaded films (ATR-films) as potential ocular drug delivery systems for the treatment of myopia. METHODS: ATR-films were prepared by the solvent casting method and the physical properties of films were evaluated including thickness, water content, light transparency, disintegration time, and mechanical properties. FT-IR, DSC, XRD, TGA, AFM, and Raman spectroscopy were performed to characterize the film. The stability test was conducted under different conditions, such as high humidity, high temperature, and strong light. The pharmacokinetic study and irritation assessment were conducted in rabbits. The efficacy of ATR-films was evaluated by refraction and ocular biometry in myopia guinea pigs. RESULT: After optimizing the formulation, the resulting ATR-film was flexible and transparent with lower water content (8.43% ± 1.25). As expected, the ATR-film was stable and hydrolysate was not detected, while the content of hydrolysate in ATR eye drops can reach up to 8.1867% (limit: < 0.2%) in the stability study. The safety assessment both in vitro and in vivo confirmed that the ATR-film was biocompatible. Moreover, the bioavailability (conjunctiva 3.21-fold, cornea 2.87-fold, retina 1.35-fold, sclera 2.05-fold) was greatly improved compared with the ATR eye drops in vivo pharmacokinetic study. The pharmacodynamic study results showed that the ATR-film can slow the progress of form-deprivation myopia (~ 100 ± 0.81D), indicating that it has a certain therapeutic effect on form-deprivation myopia. CONCLUSION: The ATR-film with good stability and high bioavailability will have great potential for the treatment of myopia.

Toxicity Reduction and Efficacy Promotion of Doxorubicin in the Treatment of Breast Tumors Assisted by Enhanced Oral Absorption of Curcumin-Loaded Lipid-Polyester Mixed Nanoparticles.

Curcumin (CUR), a polyphenol derived from turmeric, exhibits anticancer and anti-inflammatory properties. However, it has poor water solubility, stability, and oral bioavailability. To overcome these limitations, lipid-polyester mixed nanoparticles (NPs) embedded in enteric polymer-EudragitL100-55(Eu) were formulated (CUR-NPs-Eu). NPs composed of mPEG-b-PCL have a hybrid core made up of middle chain triglyceride (MCT) and poly(ε-caprolactone) (PCL) for enhancing drug loading. The CUR-NPs with MCT content of 10% had a particle size of 121.2 ± 16.8 nm, ζ potential of -16.25 ± 1.38 mV, drug loading of 9.8%, and encapsulation efficiency of 87.4%. The transport of the CUR-NPs-Eu across Caco-2 monolayers is enhanced compared with CUR alone (1.98 ± 0.94 × 10-6 of curcumin versus 55.43 ± 6.06 × 10-6 cm/s of curcumin-loaded NPs) because of the non-disassociated nanostructure during absorption. The absolute bioavailability of CUR-NPs-Eu was 7.14%, which was drastically improved from 1.08% of the CUR suspension (CUR-Sus). Therefore, in the xenograft 4T1 tumor-bearing mice, increased drug accumulation in heart and tumor was noticed because of enhanced oral bioavailability of CUR. The chemosensitizing effect of CUR was attributed to its NF-κB reduction effect (148 ± 11.83 of DOX alone versus 104 ± 8.71 of combined therapy, ng/g tissue). The cardioprotective effect of CUR was associated with maintenance of cardiac antioxidant enzyme activity and down-regulation of NF-κB. This study provided a partial illustration of the mechanisms of chemosensitizing and cardioprotective effects of CUR utilizing the oral availability promotion effect brought by the NPs-Eu formulation. And these results further demonstrated that the capability of this NPs-Eu system in oral delivery of poorly soluble and poorly permeable drugs.

A Comprehensive Preclinical Evaluation of Intravenous Etoposide Lipid Emulsion.

PURPOSE: Etoposide is one of the principal chemotherapeutic agents used for the treatment of small cell lung cancer (SCLC). There are some disadvantages of currently available etoposide injections (EI) such as low LD50, necessary dilution before clinical application, thus, etoposide lipid emulsion (ELE) was developed and expected to have a comparable or better effect on SCLC. METHODS: ELE was prepared through high-pressure homogenization method, and a series of evaluations such as encapsulation efficiency (EE%), in vitro release, stability studies, pharmacokinetics study, safety assessment and pharmacodynamic study were systematically performed. RESULTS: ELE had high EE% and good stability. Pharmacokinetics study revealed ELE had a longer T1/2 F compared with EI, which is in agreement with in vitro release in which ELE released slower than EI (EI released over 80% within 12 h, while ELE released 50%). Safety tests showed there was no hematology or significant tendency of accumulated toxicity, and LD50 of ELE was higher than EI. Furthermore, percentage of tumor inhibition (TI%) of ELE was comparable with EI in the same dose. CONCLUSIONS: Unlike EI, ELE could further increase the dose, which endowed etoposide with a greater potential for cytotoxic agent. LE is a promising delivery system for etoposide.