Nanoparticle-loaded microbubbles for treatment of lung cancer.

Lung cancer is one of the most common cancers and a leading cause of death, with poor prognosis and high unmet clinical need. Chemotherapy is a common part of the treatment, either alone or in combination with other treatment modalities, but with limited efficacy and severe side effects. Encapsulation of drugs into nanoparticles can enable a more targeted delivery with reduced off-target toxicity. Delivery to the lungs is however often insufficient due to various biological barriers in the body and in the tumor microenvironment. Here we demonstrate that by incorporating drug-loaded nanoparticles into air-filled microbubbles, a more effective targeting to the lungs can be achieved. Fluorescence imaging and mass spectrometry revealed that the microbubbles could significantly improve accumulation of drug in the lungs of mice, compared to injecting either the free drug by itself or only the drug-loaded nanoparticles. Therapeutic efficacy was verified in a preclinical mouse model with non-small cell lung cancer, monitoring tumor growth by luminescence.

Polyethylene glycol (PEG) as a broad applicability marker for LC-MS/MS-based biodistribution analysis of nanomedicines.

Polyethylene glycol (PEG) conjugation (PEGylation) is a well-established strategy to improve the pharmacokinetic and biocompatibility properties of a wide variety of nanomedicines and therapeutic peptides and proteins. This broad use makes PEG an attractive 'allround' candidate marker for the biodistribution of such PEGylated compounds. This paper presents the development of a novel strategy for PEG quantification in biological matrices. The methodology is based on sample hydrolysis which both decomposes the sample matrix and degrades PEGylated analytes to specific molecular fragments more suitable for detection by LC-MS/MS. Method versatility was demonstrated by applying it to a wide variety of PEGylated compounds, including polymeric poly(ethylbutyl cyanoacrylate) (PEBCA) nanoparticles, lipidic nanoparticles (Doxil®, LipImage 815™ and lipid nanoparticles for nucleic acid delivery) and the antibody Cimzia®. Method applicability was assessed by analyzing plasma and tissue samples from a comprehensive drug biodistribution study in rats, of both PEBCA and LipImage 815™ nanoparticles. The results demonstrated the method's utility for biodistribution studies on PEG. Importantly, by using the method described herein in tandem with quantification of nanoparticle payloads, we showed that this approach can provide detailed understanding of various critical aspects of the in vivo behavior of PEGylated nanomedicines, such as drug release and particle stability. Together, the presented results demonstrate the novel method as a robust, versatile and generic approach for biodistribution analysis of PEGylated therapeutics.

In depth characterization of physicochemical critical quality attributes of a clinical drug-dendrimer conjugate.

A deep and detailed understanding of drug-dendrimer conjugates key properties is needed to define the critical quality attributes that affect drug product performance. The characterization must be executed both in the formulation media and in biological matrices. This, nevertheless, is challenging on account of a very limited number of suitable, established methods for characterizing the physicochemical properties, stability, and interaction with biological environment of complex drug-dendrimer conjugates. In order to fully characterize AZD0466, a drug-dendrimer conjugate currently under clinical development by AstraZeneca, a collaboration was initiated with the European Nanomedicine Characterisation Laboratory to deploy a state-of-the-art multi-step approach to measure physicochemical properties. An incremental complexity characterization approach was applied to two batches of AZD0466 and the corresponding dendrimer not carrying any drug, SPL-8984. Thus, the aim of this work is to guide in depth characterization efforts in the analysis of drug-dendrimer conjugates. Additionally, it serves to highlight the importance of using the adequate complementary techniques to measure physical and chemical stability in both simple and biological media, to drive a complex drug-dendrimer conjugate product from discovery to clinical development.

Intraperitoneal administration of cabazitaxel-loaded nanoparticles in peritoneal metastasis models.

Colorectal and ovarian cancers frequently develop peritoneal metastases with few treatment options. Intraperitoneal chemotherapy has shown promising therapeutic effects, but is limited by rapid drug clearance and systemic toxicity. We therefore encapsulated the cabazitaxel taxane in poly(alkyl cyanoacrylate) (PACA) nanoparticles (NPs), designed to improve intraperitoneal delivery. Toxicity of free and encapsulated cabazitaxel was investigated in rats by monitoring clinical signs, organ weight and blood hematological and biochemical parameters. Pharmacokinetics, biodistribution and treatment response were evaluated in mice. Biodistribution was investigated by measuring both cabazitaxel and the 2-ethylbutanol NP degradation product. Drug encapsulation was shown to increase intraperitoneal drug retention, leading to prolonged intraperitoneal drug residence time and higher drug concentrations in peritoneal tumors. As a result, encapsulation of cabazitaxel improved the treatment response in two in vivo models bearing intraperitoneal tumors. Together, these observations indicate a strong therapeutic potential of NP-based cabazitaxel encapsulation as a novel treatment for peritoneal metastases.

Alginate Microsphere Encapsulation of Drug-Loaded Nanoparticles: A Novel Strategy for Intraperitoneal Drug Delivery.

Alginate hydrogels have been broadly investigated for use in medical applications due to their biocompatibility and the possibility to encapsulate cells, proteins, and drugs. In the treatment of peritoneal metastasis, rapid drug clearance from the peritoneal cavity is a major challenge. Aiming to delay drug absorption and reduce toxic side effects, cabazitaxel (CAB)-loaded poly(alkyl cyanoacrylate) (PACA) nanoparticles were encapsulated in alginate microspheres. The PACAlg alginate microspheres were synthesized by electrostatic droplet generation and the physicochemical properties, stability, drug release kinetics, and mesothelial cytotoxicity were analyzed before biodistribution and therapeutic efficacy were studied in mice. The 450 µm microspheres were stable at in vivo conditions for at least 21 days after intraperitoneal implantation in mice, and distributed evenly throughout the peritoneal cavity without aggregation or adhesion. The nanoparticles were stably retained in the alginate microspheres, and nanoparticle toxicity to mesothelial cells was reduced, while the therapeutic efficacy of free CAB was maintained or improved in vivo. Altogether, this work presents the alginate encapsulation of drug-loaded nanoparticles as a promising novel strategy for the treatment of peritoneal metastasis that can improve the therapeutic ratio between toxicity and therapeutic efficacy.

Identification of novel cyanoacrylate monomers for use in nanoparticle drug delivery systems prepared by miniemulsion polymerisation - A multistep screening approach.

Poly (alkyl cyanoacrylate) (PACA) polymeric nanoparticles (NPs) are promising drug carriers in drug delivery. However, the selection of commercially available alkyl cyanoacrylate (ACA) monomers is limited, because most monomers were designed for use in medical and industrial glues and later repurposed for drug encapsulation. This study therefore aimed to seek out novel ACA materials for use in NP systems using a toxicity led screening approach. A multistep strategy, including cytotoxicity screening of alcohols as degradation products of PACA (44 alcohols), NPs (14 polymers), and a final in vivo study (2 polymers) gave poly (2-ethylhexyl cyanoacrylate) PEHCA as a promising novel PACA candidate. For the first time, this work presents cytotoxicity data on several novel ACAs, PEHCA in vivo toxicity data, and miniemulsion polymerisation-based encapsulation of the cabazitaxel and NR688 in novel PACA candidates. Furthermore, several of the ACA candidates were compatible with a wider selection of lipophilic active pharmaceutical ingredients (APIs) versus commercially available controls. Combined, this work demonstrates the potential benefits of expanding the array of available ACA materials in drug delivery. Novel ACAs have the potential to encapsulate a wider range of APIs in miniemulsion polymerisation processes and may also broaden PACA applicability in other fields.

A comparative biodistribution study of polymeric and lipid-based nanoparticles.

Biodistribution of nanoencapsulated bioactive compounds is primarily determined by the size, shape, chemical composition and surface properties of the encapsulating nanoparticle, and, thus, less dependent on the physicochemical properties of the active pharmaceutical ingredient encapsulated. In the current work, we aimed to investigate the impact of formulation type on biodistribution profile for two clinically relevant nanoformulations. We performed a comparative study of biodistribution in healthy rats at several dose levels and durations up to 14-day post-injection. The studied nanoformulations were nanostructured lipid carriers incorporating the fluorescent dye IR780-oleyl, and polymeric nanoparticles containing the anticancer agent cabazitaxel. The biodistribution was approximated by quantification of the cargo in blood and relevant organs. Several clear and systematic differences in biodistribution were observed, with the most pronounced being a much higher (more than 50-fold) measured concentration ratio between cabazitaxel in all organs vs. blood, as compared to IR780-oleyl. Normalized dose linearity largely showed opposite trends between the two compounds after injection. Cabazitaxel showed a higher brain accumulation than IR780-oleyl with increasing dose injected. Interestingly, cabazitaxel showed a notable and prolonged accumulation in lung tissue compared to other organs. The latter observations could warrant further studies towards a possible therapeutic indication within lung and conceivably brain cancer for nanoformulations of this highly antineoplastic compound, for which off-target toxicity is currently dose-limiting in the clinic.

In Vivo Antitumor and Antimetastatic Efficacy of a Polyacetal-Based Paclitaxel Conjugate for Prostate Cancer Therapy.

Prostate cancer (PCa), one of the leading causes of cancer-related deaths, currently lacks effective treatment for advanced-stage disease. Paclitaxel (PTX) is a highly active chemotherapeutic drug and the first-line treatment for PCa; however, conventional PTX formulation causes severe hypersensitivity reactions and limits PTX use at high concentrations. In the pursuit of high molecular weight, biodegradable, and pH-responsive polymeric carriers, one conjugates PTX to a polyacetal-based nanocarrier to yield a tert-Ser-PTX polyacetal conjugate. tert-Ser-PTX conjugate provides sustained release of PTX over 2 weeks in a pH-responsive manner while also obtaining a degree of epimerization of PTX to 7-epi-PTX. Serum proteins stabilize tert-Ser-PTX, with enhanced stability in human serum versus PBS (pH 7.4). In vitro efficacy assessments in PCa cells demonstrate IC50 values above those for the free form of PTX due to the differential cell trafficking modes; however, in vivo tolerability assays demonstrate that tert-Ser-PTX significantly reduces the systemic toxicities associated with free PTX treatment. tert-Ser-PTX also effectively inhibits primary tumor growth and hematologic, lymphatic, and coelomic dissemination, as confirmed by in vivo and ex vivo bioluminescence imaging and histopathological evaluations in mice carrying orthotopic LNCaP tumors. Overall, the results suggest the application of tert-Ser-PTX as a robust antitumor/antimetastatic treatment for PCa.

Ultrasound-Mediated Delivery of Chemotherapy into the Transgenic Adenocarcinoma of the Mouse Prostate Model.

Ultrasound (US) in combination with microbubbles (MB) has had promising results in improving delivery of chemotherapeutic agents. However, most studies are done in immunodeficient mice with xenografted tumors. We used two phenotypes of the spontaneous transgenic adenocarcinoma of the mouse prostate (TRAMP) model to evaluate if US + MB could enhance the therapeutic efficacy of cabazitaxel (Cab). Cab was either injected intravenously as free drug or encapsulated into nanoparticles. In both cases, Cab transiently reduced tumor and prostate volume in the TRAMP model. No additional therapeutic efficacy was observed combining Cab with US + MB, except for one tumor. Additionally, histology grading and immunostaining of Ki67 did not reveal differences between treatment groups. Mass spectrometry revealed that nanoparticle encapsulation of Cab increased the circulation time and enhanced the accumulation in liver and spleen compared with free Cab. The therapeutic results in this spontaneous, clinically relevant tumor model differ from the improved therapeutic response observed in xenografts combining US + MB and chemotherapy.