The body distribution of i.v. doxorubicin depends mainly on the physicochemical characteristics of the molecule. However, entrapment of that cytostatic drug inside polyalkylcyanoacrylate nanoparticles has been shown to modify its distribution profoundly in the mouse. Polysiohexylcyanoacrylate nanoparticles loaded with [14C]-doxorubicin were studied in comparison with free drug, with emphasis on their distribution pattern in mouse tissue after i.v. administration. An autoradiographic study showed that most of the radioactivity was found in the reticuloendothelial system as soon as a few minutes after i.v. administration of the doxorubicin-loaded nanoparticles. Quantitative determinations by liquid scintillation counting in fresh tissue (spleen, heart, kidneys, liver, lungs, bone marrow) and blood samples confirmed these observations. When the drug was linked to nanoparticles, doxorubicin blood clearance was reduced during the first few minutes after administration, whereas heart and kidney concentrations were substantially decreased. Assays of doxorubicin and doxorubicinol by a specific HPLC analytical method gave results very similar to those obtained by scintillation counting.

Background Subgroups of precarious populations such as homeless people are more exposed to infection and at higher risk of developing severe forms of COVID-19 compared to the general population. Many of the recommended prevention measures, such as social distancing and self-isolation, are not feasible for a population living in shelters characterised by physical proximity and a high population density. The objective of the study was to describe SARS-CoV-2 infection prevalence in homeless shelters in Brussels (Belgium), and to identify risk factors and infection control practices associated with SARS-CoV-2 positivity rates. Methods A total of 1994 adults were tested by quantitative PCR tests in 52 shelters in Brussels (Belgium) between April and June, 2020, in collaboration with Doctors of the World. SARS-CoV-2 prevalence is here described site by site, and we identify risk factors associated with SARS-CoV-2 positivity rates. We also investigate associations between seropositivity and reported symptoms. Results We found an overall prevalence of 4.6% for the period, and a cluster of high rates of SARS-CoV-2 positivity (20–30% in two shelters). Among homeless people, being under 40 years of age (OR (CI95%) 2.3 (1.2–4.4), p = 0.02), having access to urgent medical care (AMU) (OR(CI95%): 2.4 (1.4–4.4)], p = 0.02), and sharing a room with someone who tested positive (OR(CI95%): 5.3 (2.9–9.9), p<0.0001) were factors associated with SARS-CoV-2 positivity rates. 93% of those who tested positive were asymptomatic. Conclusion This study shows high rates of SARS-COV-2 infection positive tests in some shelters, with a high proportion of asymptomatic cases. The survey reveals how important testing and isolation measures are, together with actions taken by medical and social workers during the outbreak.

This study demonstrates that the molecular weight of polyalkylcyanoacrylate nanoparticles can be modified by the composition of the polymerization medium, the nature of the monomers and the drug to be linked to the carrier. The influence of a surfactive agent is particularly important because polymers of very high molecular weight have been obtained. Likewise, polyalkylcyanoacrylate molecular weight distribution has been greatly modified after binding doxorubicin to nanoparticles. These long polymers could induce important changes in carrier degradation, in bound drug bioavailability and in polymer excretion rate. Some additional findings have been added concerning the state of polyalkylcyanoacrylate polymer during the degradation process.

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The current study shows that GPs working solo have divergent views of group practice. However, they clearly perceive advantages to this type of association (e.g. better quality of life and continuity of care). This study also confirms the high level of stress and tiredness felt by GPs and especially senior practitioners.