The present inventions relates to a solid composition and an aqueous dispersion comprising nanoparticles of the anti-retroviral drugs lopinavir and ritonavir. The solid composition and aqueous dispersion additionally comprise a mixture of a hydrophilic polymer and a surfactant. The surfactant is selected from vitamin-E-polyethylene glycol-succinate (Vit-E-PEG-succinate), a polyoxyethylene sorbitan fatty acid ester, N-alkyldimethylbenzylammonium chloride, sodium deoxycholate, dioctyl sodium sulfosuccinate, polyethyleneglycol-12-hydroxystearate, polyvinyl alcohol (PVA), and a block copolymer of polyoxyethylene and polyoxypropylene, or a combination thereof. The hydrophilic polymer is suitably selected from polyvinyl alcohol (PVA), a polyvinyl alcohol-polyethylene glycol graft copolymer, a block copolymer of polyoxyethylene and polyoxypropylene, polyethylene glycol, hydroxypropyl methyl cellulose (HPMC), and polyvinylpyrrolidone, or a combination thereof. The present invention also relates to processes for preparing both the solid composition and the aqueous dispersion, as well as to their use in therapy for the treatment and/or prevention of retroviral infections such as human immunodeficiency virus (HIV).La présente invention concerne une composition solide et une dispersion aqueuse contenant des nanoparticules des médicaments antirétroviraux que sont le lopinavir et le ritonavir. Ladite composition solide et ladite dispersion aqueuse contiennent, en outre, un mélange associant un polymère hydrophile et un tensioactif. Le tensioactif est choisi parmi les composés suivants : complexe vitamine-E-polyéthylèneglycol-succinate (Vit-E-PEG-succinate), ester d'acide gras de polyoxyéthylènesorbitane, chlorure de N-alkyldiméthylbenzylammonium, désoxycholate de sodium, sulfosuccinate dioctylique de sodium, complexe polyéthylèneglycol-12-hydroxystéarate, alcool polyvinylique (PVA) et copolymère séquencé de polyoxyéthylène et de polyoxypropylène, ou une combinaison de ces composé
