Intranasal delivery of nanostructured lipid carriers, solid lipid nanoparticles and nanoemulsions: A current overview of in vivo studies

The management of the central nervous system (CNS) disorders is challenging, due to the need of drugs to cross the blood‒brain barrier (BBB) and reach the brain. Among the various strategies that have been studied to circumvent this challenge, the use of the intranasal route to transport drugs from the nose directly to the brain has been showing promising results. In addition, the encapsulation of the drugs in lipid-based nanocarriers, such as solid lipid nanoparticles (SLNs), nanostructured lipid carriers (NLCs) or nanoemulsions (NEs), can improve nose-to-brain transport by increasing the bioavailability and site-specific delivery. This review provides the state-of-the-art of in vivo studies with lipid-based nanocarriers (SLNs, NLCs and NEs) for nose-to-brain delivery. Based on the literature available from the past two years, we present an insight into the different mechanisms that drugs can follow to reach the brain after intranasal administration. The results of pharmacokinetic and pharmacodynamics studies are reported and a critical analysis of the differences between the anatomy of the nasal cavity of the different animal species used in in vivo studies is carried out. Although the exact mechanism of drug transport from the nose to the brain is not fully understood and its effectiveness in humans is unclear, it appears that the intranasal route together with the use of NLCs, SLNs or NEs is advantageous for targeting drugs to the brain. These systems have been shown to be more effective for nose-to-brain delivery than other routes or formulations with non-encapsulated drugs, so they are expected to be approved by regulatory authorities in the coming years.

Biological evaluation and structure-activity relationships of imidazole-based compounds as antiprotozoal agents

We discovered a series of azole antifungal compounds as effective antiprotozoal agents. They displayed promising inhibitory activities within the micromolar-submicromolar range against P. falciparum, L. donovani, and T. b. rhodesiense. Moreover, most of such compounds showed excellent nanomolar IC₅₀ against T. cruzi, showing also very low cytotoxicity. Discussion of structure-activity relationships and biological data for these compounds are provided against the different parasites. To assess the mechanism of action against T. cruzi we proved that the most potent compounds (3b, 3j-l) inhibited the T. cruzi CYP51. Moreover, the most active derivative 3j dramatically reduced parasitemia in T. cruzi mouse model without acute toxicity.

Reduction-sensitive fluorescence enhanced polymeric prodrug nanoparticles for combinational photothermal-chemotherapy

In this study, a reduction-sensitive supramolecular polymeric drug delivery system was developed for combinational photothermal-chemotherapy of cancer. The multifunctional system was self-assembled by specific host-guest interactions between hydrophilic β-cyclodextrin functionalized hyaluronic acid and adamantane linked camptothecin/dye conjugate, where a near-infrared (NIR) absorbing dye IR825 was loaded. The hydrophilic hyaluronic acid shell endows the assembly with excellent colloidal stability and biocompatibility. The embedded disulfide bond in the camptothecin/dye conjugate was cleaved under reducing environment, leading to the release of the conjugated drug and the recovery of fluorescence emission. Meanwhile, the dye IR825 could efficiently transfer the absorbed light into local heat, making the nanoplatform an effective system for photothermal therapy. As evident by confocal microscopy images, the nanoplatform was quickly internalized by HeLa, MCF-7, and U14 cancer cells and released drug molecules inside the cells. In vitro cell viability assays confirmed that the cancer cells were efficiently killed by the treatment of the nanoplatform under NIR light irradiation. Significant tumor regression was also observed in the tumor-bearing mice upon the administration of the nanoplatform through combinational photothermal-chemotherapy therapy. Hence, this nanoplatform presented a great potential in site-specific combined photothermal-chemotherapy of tumor.

Synthesis and biological properties of new N-Mannich bases derived from 3-methyl-3-phenyl- and 3,3-dimethyl-succinimides. Part V

Twenty four new 1-[(4-phenylpiperazin-1-yl)-methyl]- derivatives of 3-phenyl-3-methyl- (6-17) and 3,3-dimethyl-pyrrolidine-2,5-diones (18-29) have been synthesized and evaluated for their anticonvulsant activity in the maximum electroshock (MES) and subcutaneous pentylenetetrazole (scPTZ) seizure tests after intraperitoneal injection in mice. The acute neurological toxicity was determined using the rotorod screen. Although no anti-seizure properties were found in the scPTZ screen, fourteen compounds revealed protection in electrically induced seizures. From these molecules seven compounds were tested in rats after oral administration (MES test). In the whole series the most effective in rats were 1-[{4-(4-fluorophenyl)-piperazin-1-yl}-methyl]-3-methyl-3-phenyl-pyrrolidine-2,5-dione (8) with ED₅₀ value of 7.78 mg/kg, it's 3-chlorophenyl- (10) and 3,4-dichlorophenyl- (12) analogs with ED₅₀ values of 27.93 mg/kg and 15.11 mg/kg, respectively. To explain the possible mechanism of action for the most active derivatives 8, 10 and 12 the influence on NaV1.2 sodium channel currents were evaluated in vitro. The results of electrophysiological studies showed higher inhibition of NaV1.2 currents in comparison with phenytoin used as a model antiepileptic drug active in electrically induces seizures. Additionally, eleven 3-phenyl-3-methyl-pyrrolidine-2,5-diones as more promising in the anticonvulsant screening were evaluated in the Vibrio harveyi test to estimate their anti/mutagenic activity.