RESUMEN
Super-hydrophobic porous absorbents are convenient, low-cost, efficient and environment-friendly materials in the treatment of oil spills. In this work, a simple Pickering emulsion template method was employed to fabricate an interconnected porous poly(DVB-LMA) sponge. A new co-Pickering stabilization system of Span 80 and NiFe2O4 nanoparticles was used to prepare ultra-concentrated internal phase water-in-oil (W/O) emulsions. After further polymerization, the resulting sponges were generated, which exhibited excellent adsorption selectivity due to the super-hydrophobicity and super-lipophilicity. Furthermore, the characterization results indicated that the composites had superior thermal stability, low density, high porosity and a flexible three-dimensional porous structure. Besides, the addition of nickel ferrite nanoparticles provided the materials with extra magnetic operability. High oil adsorption capacity (up to 36.9-84.2 g g-1), high oil retention, fast adsorption rate and superior reusability allowed the materials to be applied in the treatment of oily water.
RESUMEN
Vaccine drug product thermal stability often depends on formulation input factors and how they interact. Scientific understanding and professional experience typically allows vaccine formulators to accurately predict the thermal stability output based on formulation input factors such as pH, ionic strength, and excipients. Thermal stability predictions, however, are not enough for regulators. Stability claims must be supported by experimental data. The Quality by Design approach of Design of Experiment (DoE) is well suited to describe formulation outputs such as thermal stability in terms of formulation input factors. A DoE approach particularly at elevated temperatures that induce accelerated degradation can provide empirical understanding of how vaccine formulation input factors and interactions affect vaccine stability output performance. This is possible even when clear scientific understanding of particular formulation stability mechanisms are lacking. A DoE approach was used in an accelerated 37(°)C stability study of an aluminum adjuvant Neisseria meningitidis serogroup B vaccine. Formulation stability differences were identified after only 15 days into the study. We believe this study demonstrates the power of combining DoE methodology with accelerated stress stability studies to accelerate and improve vaccine formulation development programs particularly during the preformulation stage.
Asunto(s)
Adyuvantes Inmunológicos/química , Composición de Medicamentos/métodos , Diseño de Fármacos , Vacunas/química , Adyuvantes Inmunológicos/administración & dosificación , Animales , Química Farmacéutica , Composición de Medicamentos/tendencias , Estabilidad de Medicamentos , Femenino , Meningitis Meningocócica/inmunología , Meningitis Meningocócica/prevención & control , Ratones , Neisseria meningitidis/efectos de los fármacos , Neisseria meningitidis/inmunología , Vacunas/administración & dosificación , Vacunas/inmunologíaRESUMEN
The following review provides a comprehensive summary of antimicrobial preservatives that are commonly used in licensed parenteral products to date. The information reviewed includes the general properties of the preservatives, the doses and frequency of their use, the classes of the preserved products (peptide, protein, vaccine, and small molecule products), the interactions with other formulation components, and the criteria commonly used for their selection in parental product formulations. It was revealed that phenol and benzyl alcohol are the two most common antimicrobial preservatives used in peptide and protein products, while phenoxyethanol is the most frequently used preservative in vaccines. Benzyl alcohol or a combination of methylparaben and propylparaben are generally found in small molecule parenteral formulations. The key criteria for antimicrobial preservative selection are the preservative's dose, antimicrobial functionality, and effect on the active ingredient. Additionally, the use of spectroscopic techniques (circular dicroism (CD) and fluorescence) and differential scanning calorimetry (DSC) were identified as common techniques used in evaluating an antimicrobial preservative for its impact on the conformational stability of peptide, protein, and vaccine antigens. The future use of preservatives is also discussed, including antimicrobial agents such as peptides, and regulatory requirements for antimicrobial effectiveness testing.
Asunto(s)
Antiinfecciosos/química , Contaminación de Medicamentos/prevención & control , Preparaciones Farmacéuticas/química , Conservadores Farmacéuticos/química , Tecnología Farmacéutica , Antiinfecciosos/administración & dosificación , Composición de Medicamentos , Estabilidad de Medicamentos , Historia del Siglo XX , Historia del Siglo XXI , Infusiones Parenterales , Inyecciones , Preparaciones Farmacéuticas/administración & dosificación , Conservadores Farmacéuticos/administración & dosificación , Proteínas/química , Tecnología Farmacéutica/historia , Tecnología Farmacéutica/tendencias , Vacunas/químicaRESUMEN
Abnormal production and accumulation of amyloid-beta peptide (Abeta) plays a major role in the pathogenesis of Alzheimer's disease (AD). beta-secretase (BACE1) is responsible for the cleavage at thebeta-site in amyloid beta protein precursor (AbetaPP/APP) to generate the N-terminus of Abeta. Here we report the stepwise identification and characterization of a novel APP-beta-site mutant, "NFEV" (APP_NFEV) in vitro and in cells. In vitro, the APP_NFEV exhibits 100-fold enhanced cleavage rate relative to the "wild-type" substrate (APPwt) and 10-fold increase relative to the Swedish-type mutation variant (APPsw). In cells, it was preferably cleaved among 24 APP beta-site mutations tested. More importantly, the APP_NFEV mutant failed to generate any detectable Abeta peptides in BACE1-KO mouse fibroblast cells. The production of Abeta peptides was restored by co-transfecting human BACE1, demonstrating that BACE1 is the only enzyme responsible for the processing of APP_NFEV in these cells. Analysis of APP_NFEV cleavage products secreted in the media revealed that in cells BACE1 cleaves APP_NFEV at the position between NF and EV, identical to that observed in vitro. A BACE inhibitor blocked the processing of the APP_NFEV beta-site in vitro and in cells. Our data indicates that the "NFEV" mutant is not only an enhanced substrate for BACE1 in vitro, but also a specific substrate for BACE1 in cells.
Asunto(s)
Péptidos beta-Amiloides , Precursor de Proteína beta-Amiloide/genética , Ácido Aspártico Endopeptidasas/genética , Fragmentos de Péptidos , Mutación Puntual/genética , Enfermedad de Alzheimer/enzimología , Enfermedad de Alzheimer/genética , Enfermedad de Alzheimer/inmunología , Secretasas de la Proteína Precursora del Amiloide , Péptidos beta-Amiloides/antagonistas & inhibidores , Péptidos beta-Amiloides/biosíntesis , Péptidos beta-Amiloides/genética , Animales , Anticuerpos Monoclonales/inmunología , Ácido Aspártico Endopeptidasas/metabolismo , Modelos Animales de Enfermedad , Endopeptidasas , Activación Enzimática/fisiología , Fibroblastos/metabolismo , Regulación Enzimológica de la Expresión Génica , Técnicas In Vitro , Ratones , Datos de Secuencia Molecular , Fragmentos de Péptidos/antagonistas & inhibidores , Fragmentos de Péptidos/biosíntesis , Fragmentos de Péptidos/genética , Especificidad por Sustrato , TransfecciónRESUMEN
The process of integrating the reverse-transcribed HIV-1 DNA into the host chromosomal DNA is catalyzed by the virally encoded enzyme integrase (IN). Integration requires two metal-dependent reactions, 3' end processing and strand transfer. Compounds that contain a diketo acid moiety have been shown to selectively inhibit the strand transfer reaction of IN in vitro and in infected cells and are effective as inhibitors of HIV-1 replication. To characterize the molecular basis of inhibition, we used functional assays and binding assays to evaluate a series of structurally related analogs. These studies focused on investigating the role of the conserved carboxylate and metal binding. We demonstrate that an acidic moiety such as a carboxylate or isosteric heterocycle is not required for binding to the enzyme complex but is essential for inhibition and confers distinct metal-dependent properties on the inhibitor. Binding requires divalent metal and resistance is metal dependent with active site mutants displaying resistance only when the enzymes are evaluated in the context of Mg(2+). The mechanism of action of these inhibitors is therefore likely a consequence of the interaction between the acid moiety and metal ion(s) in the IN active site, resulting in a functional sequestration of the critical metal cofactor(s). These studies thus have implications for modeling active site inhibitors of IN, designing and evaluating analogs with improved efficacy, and identifying inhibitors of other metal-dependent phosphotransferases.