Development and optimization of a one step process for the production and sterilization of liposomes using supercritical CO2.

Liposomes are very interesting drug delivery systems for pharmaceutical and therapeutic purposes. However, liposome sterilization as well as their industrial manufacturing remain challenging. Supercritical carbon dioxide is an innovative technology that can potentially overcome these limitations. The aim of this study was to optimize a one-step process for producing and sterilizing liposomes using supercritical CO2. For this purpose, a design of experiment was conducted. The analysis of the experimental design showed that the temperature is the most influential parameter to achieve the sterility assurance level (SAL) required for liposomes (≤10-6). Optimal conditions (80 °C, 240 bar, 30 min) were identified to obtain the fixed critical quality attributes of liposomes. The conditions for preparing and sterilizing empty liposomes of various compositions, as well as liposomes containing the poorly water-soluble drug budesonide, were validated. The results indicate that the liposomes have appropriate physicochemical characteristics for drug delivery, with a size of 200 nm or less and a PdI of 0.35 or less. Additionally, all liposome formulations demonstrated the required SAL and sterility at concentrations of 5 and 45 mM, with high encapsulation efficiency.

Genetic diversity of Echinococcus multilocularis specimens isolated from Belgian patients with alveolar echinococcosis using EmsB microsatellites analysis.

The genetic diversity of Echinococcus multilocularis (E. multilocularis) specimens isolated from patients with alveolar echinococcosis (AE), is a major field of investigation to correlate with sources of infection, clinical manifestations and prognosis of the disease. Molecular markers able to distinguish samples are commonly used worldwide, including the EmsB microsatellite. Here, we report the use of the EmsB microsatellite polymorphism data mining for the retrospective typing of Belgian specimens of E. multilocularis infecting humans. A total of 18 samples from 16 AE patients treated between 2006 and 2021 were analyzed through the EmsB polymorphism. Classification of specimens was performed through a dendrogram construction in order to compare the similarity among Belgian samples, some human referenced specimens on the EWET database (EmsB Website for the Echinococcus Typing) and previously published EmsB profiles from red foxes circulating in/near Belgium. According to a comparison with human European specimens previously genotyped in profiles, the 18 Belgian ones were classified into three EmsB profiles. Four specimens could not be assigned to an already known profile but some are near to EWET referenced samples. This study also highlights that some specimens share the same EmsB profile with profiles characterized in red foxes from north Belgium, the Netherlands, Luxembourg and French department near to the Belgian border. Furthermore, Belgian specimens present a genetic diversity and include one profile that don't share similarities with the ones referenced in the EWET database. However, at this geographical scale, there is no clear correlation between EmsB profiles and geographical location. Further studies including additional clinical samples and isolates from foxes and rodents of south Belgium are necessary to better understand the spatial and temporal circumstances of human infections but also a potential correlation between EmsB profiles and parasite virulence.

[Evaluation of the knowledge on alveolar echinococcosis among general practitioners in the province of Liege : impact of a formative intervention]. / Évaluation des connaissances de l'échinococcose alvéolaire réalisée auprès des médecins généralistes de la Province de Liège : impact d'une intervention formative.

Alveolar echinococcosis is an indigenouszoonosis caused by the growth of the larval stage of a small tapeworm, Echinococcus multilocularis. Despite a low incidence in Belgium, with about 10 cases on average recorded per year, this parasitosis poses a real public health problem because it often remains difficult to diagnose and is potentially fatal in the absence of treatment. General practitioners are on the frontline, but they do not always know enough about the disease, which causes a delay in the diagnosis and impacts the prognosis. The present study aims to assess the level of knowledge of alveolar echinococcosis among general practitioners in the province of Liège via a questionnaire, on the one hand, and to increase their level of knowledge via a formative intervention using a video capsule, on the other hand. We have performed a randomized controlled experimental study, which showed that general practitioners in the province of Liège have limited knowledge on alveolar echinococcosis. This mainly concerns symptomatology, diagnostic tools and treatment. The formative intervention carried out allowed increasing their level of knowledge about this disease.

L'échinococcose alvéolaire est une zoonose autochtone provoquée par le développement tissulaire de la larve d'un petit ténia, Echinoccocus multilocularis. Malgré une faible incidence en Belgique, avec une moyenne de 10 cas recensés par an, cette parasitose pose un réel problème de santé publique car elle reste souvent difficile à diagnostiquer et potentiellement mortelle en l'absence de traitement. Les médecins généralistes sont en première ligne, mais ils ne connaissent pas toujours suffisamment la maladie, ce qui retarde le diagnostic et compromet le pronostic. La présente étude visait à évaluer les connaissances à propos de l'échinococcose alvéolaire des médecins généralistes de la province de Liège via un questionnaire approprié et à accroître leur niveau de connaissance via une intervention formative sous forme de capsule vidéo. Nous avons réalisé une étude à visée expérimentale randomisée contrôlée qui a montré que les médecins généralistes de la province de Liège ont des connaissances partielles sur la symptomatologie, les outils de diagnostic et le traitement. L'intervention formative réalisée a permis d'augmenter leur niveau de connaissances à propos de cette maladie.

Use of supercritical CO2 for the sterilization of liposomes: Study of the influence of sterilization conditions on the chemical and physical stability of phospholipids and liposomes.

The effects of four potential supercritical carbon dioxide (ScCO2) sterilization conditions on the chemical stability of 9 phospholipids and on the physicochemical characteristics of liposomes consisting of stable phospholipids, as well as their sterilization efficiency were evaluated. These conditions were : C1 (ScCO2/70 °C/150 bar/240 min), C2 (ScCO2/0.25 % water/ 0.15% H2O2/ 0.5% acetic anhydride/38° C/85 bar/45 min), C3 (ScCO2/0.08 % peracetic acid/35° C/104 bar/180 min) and C4 (ScCO2/200 ppm H2O2/40 °C/270 bar/90 min). The results showed for phospholipids, a significant increase in hydrolysis products of 3.77 to 14.50 % and an increase in oxidation index of 6.10 to 430.50 % with unsaturated phospholipids for all tested conditions while with saturated phospholipids, no significant degradation was observed. Concerning the liposome formulation, no change in dispersion color and no phospholipid degradation were observed. However, a decrease in liposome size from 126.90 nm to 111.80 nm, 96.27 nm, 99.60 nm and 109.13 nm and an increase in the PdI from 0.208 to 0.271, 0.233, 0.285, and 0.298 were found with conditions C1, C2, C3 and C4 respectively. For the sterilization efficiency, conditions C1, C2 and C3 achieved the required sterility assurance level (SAL) of 10-6 for liposomes.