Evaluación de microcápsulas de ácido acetilsalicílico preparadas con eftalato de acetilcelulosa, etilcelulosa o sus mezclas, mediante una técnica de adición de emulsión no disolvente

El ácido acetilsalicílico (AAS) se encapsuló con eftalato de acetilcelulosa (EAC), etilcelulosa (EC) o sus mezclasmediante un método de adición de emulsión no disolvente. Se evaluaron los perfiles de liberación de AAS enmicrocápsulas preparadas en diversas proporciones de fármaco y polímero (10:1 y 4:1) y microcápsulas en comprimidosen un pH 1,2 ó 6. Los resultados mostraron que al reducir la proporción de fármaco respecto al polímero sereducía la velocidad de liberación. Las microcápsulas preparadas con EC presentaron el índice de liberación másbajo. Los estudios de liberación in vitro indicaron que la velocidad de liberación del fármaco disminuía tras lapreparación del comprimido, debido a la formación de una matriz no desintegrable. La liberación de AAS en un pH6 es significativamente mayor en todas las microcápsulas, incluso si se utiliza EC, que no es hidrosoluble. Esto sedebe probablemente a la mayor solubilidad del AAS en un pH 6, lo que indica la formación incompleta de la películaalrededor de las partículas de AAS. Los datos de liberación se examinaron cinéticamente y se calcularon los modelosideales para la liberación del fármaco. Los resultados mostraron que en las microcápsulas en comprimidos elcoeficiente de correlación más elevado se obtuvo con la liberación de orden cero. En las microcápsulas en comprimidosque contenían EAC o una mezcla de EAC y EC, la contribución de la erosión fue mayor que en las microcápsulasque no estaban en comprimidos

Evaluation of microcapsules of acetyl salicylic acid prepared with cellulose acetate phthalate, ethycellulose or their mixtures by an emulsion non-solvent addition technique

El ácido acetilsalicílico (AAS) se encapsuló con eftalato de acetilcelulosa (EAC), etilcelulosa (EC) o sus mezclas mediante un método de adición de emulsión no disolvente. Se evaluaron los perfiles de liberación de AAS en microcápsulas preparadas en diversas proporciones de fármaco y polímero (10:1 y 4:1) y microcápsulas en comprimidos en un pH 1,2 ó 6. Los resultados mostraron que al reducir la proporción de fármaco respecto al polímero se reducía la velocidad de liberación. Las microcápsulas preparadas con EC presentaron el índice de liberación más bajo. Los estudios de liberación in vitro indicaron que la velocidad de liberación del fármaco disminuía tras la preparación del comprimido, debido a la formación de una matriz no desintegrable. La liberación de AAS en un pH 6 es significativamente mayor en todas las microcápsulas, incluso si se utiliza EC, que no es hidrosoluble. Esto se debe probablemente a la mayor solubilidad del AAS en un pH 6, lo que indica la formación incompleta de la película alrededor de las partículas de AAS. Los datos de liberación se examinaron cinéticamente y se calcularon los modelos ideales para la liberación del fármaco. Los resultados mostraron que en las microcápsulas en comprimidos el coeficiente de correlación más elevado se obtuvo con la liberación de orden cero. En las microcápsulas en comprimidos que contenían EAC o una mezcla de EAC y EC, la contribución de la erosión fue mayor que en las microcápsulas que no estaban en comprimidos.Acetyl salicylic acid (ASA) was encapsulated with cellulose acetate phthalate (CAP), ethylcellulose (EC) or their mixtures by an emulsion non-solvent addition method. The release profiles of ASA from prepared microcapsules with different ratios of drug to polymer (10:1 and 4:1) and tableted microcapsules were evaluated at pH 1.2 or 6. The results showed that a reduction in the ratio of drug to polymer resulted in a reduction in release rate. The microcapsules prepared with EC showed the lowest release rate. The in vitro release studies showed that the drug release rate decreased after tableting, because of the formation of a non-disintegrating matrix. Release of ASA at pH 6 is significantly higher in all microcapsules, even when using EC which is not water soluble. This is probably due to higher solubility of ASA at pH 6 indicating incomplete film formation around the ASA particles. Release data were examined kinetically and the ideal kinetic models were estimated for drug release. The results showed that for tableted microcapsules the highest correlation coefficient was achieved with the zero-order release. For tableted microcapsules containing CAP or the mixture of CAP and EC contribution of erosion was higher than that of untableted microcapsules

Stabilization and Anticancer Enhancing Activity of the Peptide Nisin by Cyclodextrin-Based Nanosponges against Colon and Breast Cancer Cells

The great variability of cancer types demands novel drugs with broad spectrum, this is the case of Nisin, a polycyclic antibacterial peptide that recently has been considered for prevention of cancer cells growth. As an accepted food additive, this drug would be very useful for intestinal cancers, but the peptide nature would make easier its degradation by digestion procedures. For that reason, the aim of present study to investigate the protective effect of two different β-cyclodextrin-based nanosponges (carbonyl diimidazole and pyromellitic dianhydride) and their anti-cancer enhancement effect of Nisin-Z encapsulated with against colon cancer cells (HT-29). To extend its possible use, a comparison with breast (MCF-7) cancer cell was carried out. The physicochemical properties, loading efficiency, and release kinetics of Nisin complex with nanosponges were studied. Then, tricin-SDS-PAGE electrophoresis was used to understand the effect of NSs on stability of Nisin-Z in the presence of gastric peptidase pepsin. In addition, the cytotoxicity and cell membrane damage of Nisin Z were evaluated by using the MTT and LDH assay, which was complemented via Annexin-V/ Propidium Iodide (PI) by using flowcytometry. CD-NS are able to complex Nisin-Z with an encapsulation efficiency around 90%. A protective effect of Nisin-Z complexed with CD-NSs was observed in presence of pepsin. An increase in the percentage of apoptotic cells was observed when the cancer cells were exposed to Nisin Z complexed with nanosponges. Interestingly, Nisin Z free and loaded on PMDA/CDI-NSs is more selectively toxic towards HT-29 cells than MCF-7 cancer cells. These results indicated that nanosponges might be good candidates to protect peptides and deliver drugs against intestinal cancers

Use of quercetin in animal feed : effects on the P-gp expression and pharmacokinetics of orally administrated enrofloxacin in chicken

Modulation of P-glycoprotein (P-gp, encoded by Mdr1) by xenobiotics plays central role in pharmacokinetics of various drugs. Quercetin has a potential to modulate P-gp in rodents, however, its effects on P-gp modulation in chicken are still unclear. Herein, study reports role of quercetin in modulation of P-gp expression and subsequent effects on the pharmacokinetics of enrofloxacin in broilers. Results show that P-gp expression was increased in a dose-dependent manner following exposure to quercetin in Caco-2 cells and tissues of chicken. Absorption rate constant and apparent permeability coefficient of rhodamine 123 were decreased, reflecting efflux function of P-gp in chicken intestine increased by quercetin. Quercetin altered pharmacokinetic of enrofloxacin by decreasing area under curve, peak concentration, and time to reach peak concentration and by increasing clearance rate. Molecular docking shows quercetin can form favorable interactions with binding pocket of chicken xenobiotic receptor (CXR). Results provide convincing evidence that quercetin induced P-gp expression in tissues by possible interaction with CXR, and consequently reducing bioavailability of orally administered enrofloxacin through restricting its intestinal absorption and liver/kidney clearance in broilers. The results can be further extended to guide reasonable use of quercetin to avoid drug-feed interaction occurred with co-administered enrofloxacin or other similar antimicrobials.Peer reviewedFinal Published versio

Real time Raman imaging to understand dissolution performance of amorphous solid dispersions

We have employed for the first time Raman spectroscopic imaging along with multi-variate curve resolution (MCR) analysis to investigate in real time and in-situ the dissolution mechanisms that underpin amorphous solid dispersions, with data being collected directly from the dosage form itself. We have also employed a novel rotating disk dissolution rate (RDDR) methodology to track, through the use of high-performance liquid chromatography (HPLC), the dissolution trends of both drug and polymer simultaneously in multi-component systems. Two formulations of poorly water-soluble felodipine in a polymeric matrix of copovidone VA64 which have different drug loadings of 5% and 50% w/w were used as models with the aim of studying the effects of increasing the amount of active ingredient on the dissolution performance. It was found that felodipine and copovidone in the 5% dispersion dissolve with the same dissolution rate and that no Raman spectral changes accompanied the dissolution, indicating that the two components dissolve as single entity, whose behaviour is dominated by water-soluble copovidone. For the 50% drug-loaded dispersion, partial RDDR values of both felodipine and copovidone were found to be extremely low. MCR Raman maps along with classical Raman/X-ray powder diffraction (XRPD) characterisation revealed that after an initial loss of copovidone from the extrudate the drug re-crystallises, pointing to a release dynamics dependent on the low water solubility and high hydrophobicity of felodipine. Raman imaging revealed different rates of transition from amorphous to crystalline felodipine at different locations within the dosage form

Injectable gellan gum-based nanoparticles-loaded system for the local delivery of vancomycin in osteomyelitis treatment

Infection spreading in the skeletal system leading to osteomyelitis can be prevented by the prolonged administration of antibiotics in high doses. However systemic antibiotherapy, besides its inconvenience and often low efficacy, provokes numerous side effects. Thus, we formulated a new injectable nanoparticle-loaded system for the local delivery of vancomycin (Vanc) applied in a minimally-invasive way. Vanc was encapsulated in poly(Llactide- co-glycolide) nanoparticles (NPs) by double-emulsification. The size (258 ± 11 nm), polydispersity index (0.240 ± 0.003) and surface potential (-25.9 ± 0.2 mV) of NPs were determined by dynamic light scattering and capillary electrophoresis measurements. They have a spherical morphology and a smooth topography as observed using atomic force microscopy. Vanc loading and encapsulation efficiencies were 8.8 ± 0.1 and 55.2 ± 0.5 %, respectively, based on fluorescence spectroscopy assays. In order to ensure injectability, NPs were suspended in gellan gum and cross-linked with $Ca^{2+}$; also a portion of dissolved antibiotic was added to the system. The resulting system was found to be injectable (extrusion force 11.3 ± 1.1 N), reassembled its structure after breaking as shown by rheology tests and ensured required burst release followed by sustained Vanc delivery. The system was cytocompatible with osteoblast-like MG-63 cells (no significant impact on cells’ viability was detected). Growth of Staphylococcus spp. reference strains and also those isolated from osteomyelitic joints was inhibited in contact with the injectable system. As a result we obtained a biocompatible system displaying ease of application (low extrusion force), self-healing ability after disruption, adjustable drug release and antimicrobial properties

Lead optimization of a pyrazole sulfonamide series of trypanosoma brucei N -myristoyltransferase inhibitors:Identification and evaluation of CNS penetrant compounds as potential treatments for stage 2 human african trypanosomiasis

[Image: see text] Trypanosoma bruceiN-myristoyltransferase (TbNMT) is an attractive therapeutic target for the treatment of human African trypanosomiasis (HAT). From previous studies, we identified pyrazole sulfonamide, DDD85646 (1), a potent inhibitor of TbNMT. Although this compound represents an excellent lead, poor central nervous system (CNS) exposure restricts its use to the hemolymphatic form (stage 1) of the disease. With a clear clinical need for new drug treatments for HAT that address both the hemolymphatic and CNS stages of the disease, a chemistry campaign was initiated to address the shortfalls of this series. This paper describes modifications to the pyrazole sulfonamides which markedly improved blood–brain barrier permeability, achieved by reducing polar surface area and capping the sulfonamide. Moreover, replacing the core aromatic with a flexible linker significantly improved selectivity. This led to the discovery of DDD100097 (40) which demonstrated partial efficacy in a stage 2 (CNS) mouse model of HAT

Modular assembly of proteins on nanoparticles

Generally, the high diversity of protein properties necessitates the development of unique nanoparticle bio-conjugation methods, optimized for each different protein. Here we describe a universal bio-conjugation approach which makes use of a new recombinant fusion protein combining two distinct domains. The N-terminal part is Glutathione S-Transferase (GST) from Schistosoma japonicum, for which we identify and characterize the remarkable ability to bind gold nanoparticles (GNPs) by forming gold–sulfur bonds (Au–S). The C-terminal part of this multi-domain construct is the SpyCatcher from Streptococcus pyogenes, which provides the ability to capture recombinant proteins encoding a SpyTag. Here we show that SpyCatcher can be immobilized covalently on GNPs through GST without the loss of its full functionality. We then show that GST-SpyCatcher activated particles are able to covalently bind a SpyTag modified protein by simple mixing, through the spontaneous formation of an unusual isopeptide bond