Protein corona formation on lipidic nanocapsules: Influence of the interfacial PEG repartition

The parameters currently used for characterization of nanoparticles, such as size and zeta potential, were not able to reflect the performance of a nanocarrier in the biological environment. Therefore, more thorough in vitro characterization is required to predict their behavior in vivo, where nanoparticles acquire a new biological identity due to interactions with biomolecules. In this present study, we performed in vitro characterization in biological fluids for lipid nanocapsules (LNCs) with varying means sizes (50 nm and 100 nm), different electrical surface charges and different Poly Ethylene Glycol (PEG) compositions. Then, different methods were applied to show the impact of the protein corona formation on LNCs. Even if all formulations attached to plasmatic proteins, a higher thickness of corona and highest protein binding was observed for certain LNC50 formulations. A better knowledge of the phenomenon of protein adsorption over NPs in the plasmatic media is a cornerstone of clinical translation. In fact, after short blood circulation time, it is not the initially designed nanoparticle but the complex nanoparticle bearing its protein corona which circulates to reach its target.

[Engagement of students enrolled in fifth year of pharmacy studies in their academic or salaried pharmaceutical activities during the first period of lockout due to the COVID-19 pandemic (16th March-11th May 2020)]

OBJECTIVES

To characterize the engagement of students enrolled in the fifth year of pharmaceutical studies in the management of the health crisis due to the COVID-19 pandemic, and to identify some determinants of this engagement during this period.

METHODS

With the health crisis, new missions have been entrusted during hospital internships, whereas certain internship sites were removed in hospitals and as part of the health service organization. In addition, some students who were no longer in internship returned to the hospital setting for helping in critical activities. Student engagement was studied with a questionnaire and focus groups including six or seven students in each group.

RESULTS

Forty-three students participated to the study. The answers to the questionnaire highlighted that they were engaged, that they usually did not wait for compensation, and that most of them were satisfied by their activity during the crisis. The thematic analysis demonstrated that despite a feeling of frustration, which was often associated with the interruption of rewarded activities, and despite a stress due to the particular context, student engagement was supported by a better consideration of the pharmacist's role as a professional in public health and by a better acknowledgement of this role by other health professionals.

CONCLUSION

This level of engagement is particularly encouraging because it is the witness of the ability of pharmacists to mobilize for general interest, even in adverse context.

Successful treatment of a recurrent Aspergillus niger otomycosis with local application of voriconazole

Fungal otitis (otomycosis) is a common infection encountered by otolaryngologists. Nevertheless, its management can be challenging because of its high recurrence rate and of the limited therapeutic options. A 45-year-old woman suffered from recurrent otomycosis. The ineffectiveness of successive antibiotic cures and repeated topical treatments with nystatin and then with econazole cream led to perform microbiological analyses. Culture of ear swab grew Aspergillus niger. The use of a 1% voriconazole sterile solution previously validated for treatment of eye infections was considered after ensuring the absence of known ototoxic effects of the antifungal and of the excipients. The patient was advised to apply locally this voriconazole solution daily for 14 days (3 drops, 3-4 times a day). Full recovery was obtained at the end of the treatment, and no relevant side effects were noticed. More than one year after completion of therapy, there was no recurrence. Our observation shows that voriconazole 1% solution is an interesting option for treating otomycosis which failed to respond to usual therapeutic options. Further prospective studies are now warranted to confirm these findings.

In vivo evaluation of paclitaxel-loaded lipid nanocapsules after intravenous and oral administration on resistant tumor

Aim & methods: The aim of the present work was to encapsulate paclitaxel (Ptx) in various lipid nanocapsules (LNCs) formulations and then to compare their pharmacokinetics and efficacy on a subcutaneous isograft model in rats. Results: Three different Ptx formulations were obtained. Drug payloads ranged from 1.32 to 3.62 mg Ptx/g of formulation. After oral administration the area under concentration–time curve was higher (p < 0.05) if Ptx was encapsulated, (1,2 Distearoyl-sn-glycero-3–phosphoethanolamine-N-[amino(PEG)] (DSPE-PEG-NH2)) LNCs displaying the highest area under concentration–time curve (p < 0.05). Efficacy was better than control for standard LNCs after oral administration (p < 0.05) and for (DSPE-PEG-NH2) LNCs after intravenous administration. Despite good absorption, (DSPE-PEG-NH2) LNCs failed to remain efficient after oral route. Conclusion: This study highlights the importance of efficacy studies paired to pharmacokinetic studies for nanomedicines.

The gastrointestinal stability of lipid nanocapsules

The in vitro gastrointestinal stability of lipid nanocapsules (LNCs) was studied in different media. The size of LNCs was determined in simulated gastric and intestinal media. In updated fasted state simulated intestinal fluid (FaSSIF-V2) and updated fed state simulated intestinal fluid (FeSSIF-V2) media, the encapsulation ratio of paclitaxel-loaded LNCs was also measured. The size of LNCs was not modified after 3h in simulated gastric fluid and simulated intestinal fluid described by the United States Pharmacopeia, in FaSSIF, FaSSIF-V2, and in FeSSIF. Moreover, in the presence of pancreatin in FeSSIF-V2, a decreased above 30% of the loading of paclitaxel was observed. This was attributed to the presence of lipase in pancreatin that could interact with Lipoid (a mixture of phosphatidylcholine and phosphatidylethanolamine), present on the shell of LNC. As a conclusion, LNCs were stable on gastric medium and fasted state intestinal medium.

The adaptation of lipid nanocapsule formulations for blood administration in animals

In many cell-culture and animal models, the therapeutic effects of the entrapped drugs in lipid nanocapsules (LNCs) were preserved with low toxicity. These results allow foreseeing further preclinical efficiency and toxicity studies in animals. In this article, preliminary studies were performed to check the genetically modified organism (GMO) status of the LNCs components and to determine the effects of the acidity of the LNCs dispersions in acid-base balance in rats. Then, several freezing protocols to store paclitaxel-loaded LNCs dispersions for a 6-month period were compared. Results indicate that the Lipoïd S75-3 could not be certified GMO-free. The same soya bean lecithin certified to be GMO-free permitted to produce LNCs with expected characteristics. The blood administration of blank LNCs dispersions in rats induced no modifications of blood acidity, but a significant decrease of the base excess was observed. Injections of LNCs dispersions in animals might induce iatrogenic acidosis. We finally demonstrated that the best protocol to store LNCs dispersion for a 6-month period is by freezing in liquid nitrogen. This protocol minimized the characteristics modifications and interrupted the drug-release phenomenon. These original data are expected to prepare of LNCs dispersions well adapted for i.v. administration in animals.

Development and characterization of interleukin-18-loaded biodegradable microspheres

Immunostimulation represents a promising approach designed to specifically eradicate malignant cells. Since glioma tumour cells hole up in the central nervous system (CNS) in a particularly inauspicious milieu to antitumour immune reactions we here propose a new strategy to revert the properties of this microenvironment by administering an antitumour cytokine into the CNS tumour itself. Thus, biodegradable poly(D,L-lactide-co-glycolide) (PLGA) sustained-release microspheres for stereotaxic implantation loaded with interleukin-18 (IL-18), that is known to exert antitumour activity and trigger immune cell-mediated cytotoxicity, were developed. Different tests for assessing IL-18 bioactivity were set-up and evaluated. A specific bioassay was considered as the most reliable test. The stability and integrity of IL-18 was then verified during the encapsulation process. Consequently, two procedures of IL-18 encapsulation in PLGA microparticles (W/O/W and S/O/W) were investigated. As determined by radiolabelling studies using 125I-IL-18 and a continuous flow system, the in vitro release profile of IL-18 was optimum with S/O/W method with a moderate burst effect and a subsequent progressive discharge of 16.5+/-8.4 ng/day during the next 21 days against 6.1+/-4.2 ng/day with the W/O/W method. Considering analytical testing of IL-18 together with its preserved biological activity after release from microspheres, amounts of the active cytokine obtained with S/O/W method were relevant to plan in vivo evaluation to validate the therapeutic strategy.

Development of new polymer-based particulate systems for anti-glioma vaccination

Biodegradable and biocompatible microspheres represent a promising alternative to conventional adjuvants for anti-tumour vaccination. Focusing on glioma, we developed two poly(D,L-lactide-co-glycolide) (PLGA)-based particulate systems presenting tumour antigens associated with plasma membranes or with cell lysates. Glioma cell fractions were prepared for adsorption onto poly-D-lysine (PDL)-coated PLGA microspheres formulated using a double-emulsion procedure. Adsorption was followed by (125)I-radiolabelling, Western blot and confocal laser scanning microscopy. Only a panel (34%) of the proteins isolated from both cell fractions adsorbed onto PDL-coated PLGA microspheres. The integrity of the epitopes after loading was preserved, as shown by identification of plasma membrane and cytoplasmic markers. Finally, one of the major potential advantages of those particulate systems resides in the fact they not only serve as injectable adjuvant matrices presenting tumour antigens to antigen presenting cells, but also as potential reservoirs for controlled delivery of active immunostimulant molecules.

Oxaliplatin loaded PLAGA microspheres: design of specific release profiles

Oxaliplatin loaded PLAGA microspheres have been prepared by solvent extraction process. Parameters affecting the release kinetics in vitro have been studied in order to design specific release profiles suitable for direct intra-tumoral injection. By varying the nature and the relative proportions of different polymers we managed to prepare microspheres with good encapsulation efficiency (75-90%) and four different release profiles: zero order kinetics (type II) and the classical sigmoïd release profile with three different sizes of plateau and burst. These results, if correlated with in vivo activity, are promising to enhance effectiveness of local tumor treatment.