RESUMEN
In this study, a multiparticulate matrix system was produced, containing two different active pharmaceutical ingredients (APIs): enalapril-maleate and hydrochlorothiazide. The critical control points of the process were investigated by means of factorial design. Beside the generally used microcrystalline cellulose, ethylcellulose was used as matrix former to achieve modified drug release ensured by diffusion. The matrix pellets were made by extrusion-spheronization using a twin-screw extruder. Some pellet properties (aspect ratio, 10% interval fraction, hardness, deformation process) were determined. The aim of our study was to investigate how the two different APIs with different solubility and particle size influence the process. The amount of the granulation liquid plays a key role in the pellet shaping. A higher liquid feed rate is preferred in the pelletization process.
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Fenómenos Químicos , Química Farmacéutica/métodos , Implantes de Medicamentos/síntesis química , Implantes de Medicamentos/metabolismo , SolubilidadRESUMEN
Titanate nanotubes can be used as drug delivery systems, but limited information is available on their interactions with intestinal cells. In this study, we investigated the cytotoxicity and cellular uptake of titanate nanotubes on Caco-2 monolayers and found that up to 5 mg/ml concentration, these nanotubes are not cytotoxic and not able to permeate through the intestinal cell layer. Transmission electron microscopic experiments showed that titanate nanotubes are not taken up by cells, only caused a high-density granulation on the surface of the endoplasmic reticulum. According to these results, titanate nanotubes are suitable systems for intestinal drug delivery.
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Intestinos/efectos de los fármacos , Nanotubos/efectos adversos , Nanotubos/química , Titanio/efectos adversos , Titanio/química , Células CACO-2 , Línea Celular Tumoral , Sistemas de Liberación de Medicamentos , Humanos , Permeabilidad , Titanio/farmacologíaRESUMEN
Introduction: Clostridioides difficile infections (CDI) continue to pose a challenge for clinicians. Fecal microbiota transplantation (FMT) is an effective treatment option in CDI. Furthermore, recent and ongoing studies suggest potential benefits of FMT in other diseases as well. Methods: We would like to present a novel protocol for encapsulation of lyophilized fecal material. Our method provides with better compliance as well as improved flexibility, storage and safety. Results: FMT was conducted in 28 patients with an overall success rate of 82,14% using apsules containing lyophilized stool. 16 of patients were given capsules with lessened bacteria counts. The success rate in this group was 93,75%. Discussion: The results highlight the still unanswered questions about the mechanism of action and contribute to a wider use of FMT in the clinical praxis and in research.
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Infecciones por Clostridium , Trasplante de Microbiota Fecal , Heces , Trasplante de Microbiota Fecal/métodos , Humanos , Infecciones por Clostridium/terapia , Infecciones por Clostridium/microbiología , Heces/microbiología , Resultado del Tratamiento , Femenino , Clostridioides difficile , Liofilización , Masculino , Persona de Mediana Edad , Anciano , AdultoRESUMEN
The importance of in silico modeling in the pharmaceutical industry is continuously increasing. The aim of the present study was the development of a neural network model for prediction of the postcompressional properties of scored tablets based on the application of existing data sets from our previous studies. Some important process parameters and physicochemical characteristics of the powder mixtures were used as training factors to achieve the best applicability in a wide range of possible compositions. The results demonstrated that, after some pre-processing of the factors, an appropriate prediction performance could be achieved. However, because of the poor extrapolation capacity, broadening of the training data range appears necessary.
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Simulación por Computador , Modelos Químicos , Redes Neurales de la Computación , Preparaciones Farmacéuticas/química , Tecnología Farmacéutica/métodos , Algoritmos , Celulosa/química , Química Farmacéutica , Fuerza Compresiva , Lactosa/química , Manitol/química , Papaverina/análogos & derivados , Papaverina/química , Polvos , Ácidos Esteáricos/química , Propiedades de Superficie , Comprimidos , Resistencia a la TracciónRESUMEN
Background and aims: Faecal microbiota transfer (FMT) has managed to earn its place in the Clostridioides difficile infection (CDI) guidelines by having comparable efficacy and recurrence rate of fidaxomicin. After more than 100 successful FMT administration through nasogastric tube, we started using hard gelatine capsules filled with lyophilised faecal sediment and supernatant. Our main question was whether uncoated capsules (containing faecal sediment or supernatant) are comparable to the widely used nasogastric tubes in CDI. We also investigated the effect of storage and time on the survival rate of bacteria in the samples. Methods: We compared the efficacy of our capsules to other treatment options of CDI at the Department of Infectology at the University of Pécs (Hungary). For our study, stool was collected from a single donor. We treated 10 patients with relapsing CDI, 5 of them received supernatant, 5 received sediment. Donor samples were stored on 4 different temperatures and tested to determine the survival rates of bacteria. As pilot projects, we also assessed the changes of bacterial taxa, protein- and lipid compositions. Moreover, we selected 4 patients to compare their samples prior and after FMT by using microbiome (16S amplicon sequencing), protein, and lipid analyses. Results: 4 out of the 5 patients who received supernatant became symptomless within 2 days after FMT. In the sediment group 3 out of 5 patients were cured from CDI. Comparing the supernatant to the sediment, we found significantly lower number of colony-forming units in the supernatant. We found that -80°C is the most suitable temperature to store the samples. The stool lipid profiles of recipients showed a more diverse composition after FMT, and changes in the stool protein profiles were observed as well. In the microbiome analysis, we observed an increase in the alpha diversity after FMT. Conclusions: Our study of 10 patients showed good efficacy of lyophilised faecal supernatant using capsules. The single donor approach proved to be effective in our investigation. A significantly lower CFU number was sufficient for the effect, the separation can be achieved by widely available instruments. For storage temperature, -20°C was sufficient in our clinical practice.
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Clostridioides difficile , Infecciones por Clostridium , Humanos , Trasplante de Microbiota Fecal , Carga Bacteriana , Cápsulas , Heces/microbiología , Infecciones por Clostridium/terapia , Infecciones por Clostridium/microbiología , Bacterias , Lípidos , Resultado del Tratamiento , RecurrenciaRESUMEN
The aim of this study was to investigate the effects of alkalizing components and the nature of the wetting liquid on the properties of matrix pellets prepared by extrusion and spheronization. Atenolol was used as an active pharmaceutical ingredient, ethylcellulose as a matrix former, microcrystalline cellulose as a filler and disodium phosphate anhydrous and trisodium phosphate dodecahydrate as alkalizing materials. Water and a water-ethanol mixture served as granulation liquids. Pellet formation was evaluated via mechanical, dissolution and morphological studies. In order to enhance the dissolution of Atenolol from the pellets, alkalizing components were used and the influence of these components on the pH was tested. Investigations of the breaking hardness, the morphology and the dissolution revealed that the pellets containing trisodium phosphate dodecahydrate and prepared with a higher amount of water as binding liquid displayed the best physico-chemical parameters and uniform dissolution. In in vitro experiments, the dissolution release complied with the texture of the pellets and the effect of pH. The pellets have suitable shape and very good hardness for the coating process and are appropriate for subsequent in vivo experiments.
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Antagonistas de Receptores Adrenérgicos beta 1/química , Álcalis/química , Atenolol/química , Fosfatos/química , Celulosa/análogos & derivados , Celulosa/química , Excipientes/química , Dureza , Concentración de Iones de Hidrógeno , SolubilidadRESUMEN
The aim of this study was to investigate the influence of different processing methods on the profiles of 5-aminosalicylic acid dissolution from controlled-release matrix systems based on Eudragit® RL and Eudragit® RS water-insoluble polymers. The pure polymers and their mixtures were studied as matrix formers using different processing methods, i.e., direct compression, wet granulation of the active ingredient with the addition of polymer(s) to the external phase, wet granulation with water, and wet granulation with aqueous dispersions. In comparison with the directly compressed tablets, tablets made by wet granulation with water demonstrated a 6-19% increase in final drug dissolution, whereas when polymers were applied in the external phase during compression, a 0-13% decrease was observed in the amount of drug released. Wet granulation with aqueous polymer dispersions delayed the release of the drug; this was especially marked (a 54-56% decrease in drug release) in compositions, which contained a high amount of Eudragit RL 30D. The release profiles were mostly described by the Korsmeyer-Peppas model or the Hopfenberg model.
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Composición de Medicamentos/métodos , Mesalamina/administración & dosificación , Mesalamina/química , Resinas Acrílicas/química , Antiinflamatorios no Esteroideos/administración & dosificación , Antiinflamatorios no Esteroideos/química , Preparaciones de Acción Retardada , Polímeros/química , Solubilidad , Comprimidos/química , Agua/químicaRESUMEN
Purpose: Metronidazol and vancomycin were long the two best options against Clostridioides (formerly Clostridium) difficile infections (CDI). Now, the cost of new drugs such as fidaxomicin directs us towards alternative treatment options, such as faecal microbiota transplant (FMT). Its effectiveness is similar to fidaxomicin. There are questions regarding its safety, but the biggest challenges are prejudice and inconvenience. Most protocols refer to FMT applied in the form of a solution. We investigated different modalities of FMT. Methods: Instead of using nasoenteric tubes or colonoscopy, we place frozen or lyophilised stool in non-coated, size "00", hard gelatine capsules or enterosolvent, size "0" capsules. Results: We found that non-coated, size "00", hard gelatine capsules are appropriate for conducting FMT. Capsules containing lyophilised supernatant with a low number of bacteria have been proven to be non-inferior to other FMT modalities. The primary cure rate in the supernatant group was 93.75%, and 66.67% in the sediment group. The overall cure rate was 82.14%. Depending on the protocol, 4-7 capsules are sufficient per patient. Capsules can be stored for up to one year at -20°C. Conclusions: FMT is a feasible alternative to antibiotic treatments in CDI. Our method makes the process flexible and less inconvenient to patients. Long storage time allows a consistent supply of capsules, while small volume and formulation make the procedure tolerable.
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Clostridioides difficile , Infecciones por Clostridium , Microbiota , Trasplante de Microbiota Fecal , Humanos , Recurrencia , Resultado del TratamientoRESUMEN
The binding of two radiolabelled analogues (N-(5-[125I]Iodo-2-phenoxyphenyl)-N-(2,5-dimethoxybenzyl)acetamide ([125I]desfluoro-DAA1106) and N-(5-[125I]Fluoro-2-phenoxyphenyl)-N-(2-[125I]Iodo-5-methoxybenzyl)acetamide ([125I]desmethoxy-DAA1106) of the peripheral benzodiazepine receptor (PBR) (or TSPO, 18kDa translocator protein) ligand DAA1106 was examined by in vitro autoradiography on human post mortem whole hemisphere brain slices obtained from Alzheimer's disease (AD) patients and age-matched controls. Both [(125)I]desfluoro-IDAA1106 and [(125)I]desmethoxy-IDAA1106 were effectively binding to various brain structures. The binding could be blocked by the unlabelled ligand as well as by other PBR specific ligands. With both radiolabelled compounds, the binding showed regional inhomogeneity and the specific binding values proved to be the highest in the hippocampus, temporal and parietal cortex, the basal ganglia and thalamus in the AD brains. Compared with age-matched control brains, specific binding in several brain structures (temporal and parietal lobes, thalamus and white matter) in Alzheimer brains was significantly higher, indicating that the radioligands can effectively label-activated microglia and the up-regulated PBR/TSPO system in AD. Complementary immunohistochemical studies demonstrated reactive microglia activation in the AD brain tissue and indicated that increased ligand binding coincides with increased regional microglia activation due to neuroinflammation. These investigations yield further support to the PBR/TSPO binding capacity of DAA1106 in human brain tissue, demonstrate the effective usefulness of its radio-iodinated analogues as imaging biomarkers in post mortem human studies, and indicate that its radiolabelled analogues, labelled with short half-time bioisotopes, can serve as prospective in vivo imaging biomarkers of activated microglia and the up-regulated PBR/TSPO system in the human brain.
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Enfermedad de Alzheimer/metabolismo , Encéfalo/metabolismo , Receptores de GABA-A/metabolismo , Acetamidas/metabolismo , Anciano de 80 o más Años , Autorradiografía , Femenino , Humanos , Inmunohistoquímica , Radioisótopos de Yodo , Cinética , Masculino , Persona de Mediana Edad , Éteres Fenílicos/metabolismo , Cambios Post Mortem , Valores de ReferenciaRESUMEN
OBJECTIVE: The purpose of this study was to investigate and quantify flow properties, compressibility, and compactibility of various pharmaceutical lactose powders found on the market today (DCL-11, DCL-21, M-200, Flowlac-100, and Tablettose 70, 80, and 100). METHODS: Flow properties were estimated by measuring flow time, angle of repose, and the Hausner ratio. Particle rearrangement was studied using Kawakita's linear model. Compressibility was studied using two 'out-of-die' methods: (i) the Heckel model and (ii) a modified Walker model. Compactibility was quantified using two methods: (i) the tensile strength profile (Cp) and (ii) the compactibility factor (Pr). Statistical approach was used to analyze the results. RESULTS: Flow properties of all materials were passable or better, except for M-200, which has very poor flowability. Compressibility results demonstrated that the most compressible lactose is spray-dried grade of lactose (Flowlac-100) and the least compressible is milled lactose (M-200). Compactibility studies showed that beta-lactose (DCL-21) forms tablets with superior tensile strength in comparison with alpha-lactose. CONCLUSION: Results of the compressibility study showed that the discriminative power of modified Walker model is greater in comparison with Heckel model. Compactibility methods yield similar and comparable results.
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Excipientes/química , Lactosa/química , Modelos Teóricos , Química Farmacéutica/métodos , Polvos , Comprimidos , Resistencia a la TracciónRESUMEN
We demonstrate the feasibility and usefulness of the histoblot immunostaining of cryosections of whole hemispheres of healthy and Alzheimer diseased (AD) human brains by localizing a neuron-specific marker, the anti-neuronal nuclei (NeuN) antigen. As expected, cortical NeuN-immunopositive regions were generally thinner and lighter in the AD brains than in the controls. The advantages of using whole hemisphere histoblots: (1) they provide a low-resolution overview/outline of the antigen distribution in a large surface area, (2) large, thick, and/or unfixed tissue sections from post-mortem samples (perhaps of inferior tissue quality) can be compared, and (3) subsequent immunohistochemistry can be performed on the tissue sections used for the histoblots.
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Enfermedad de Alzheimer/metabolismo , Corteza Cerebral/química , Immunoblotting/métodos , Inmunohistoquímica/métodos , Coloración y Etiquetado/métodos , Anciano , Enfermedad de Alzheimer/patología , Antígenos Nucleares/análisis , Biomarcadores/análisis , Corteza Cerebral/metabolismo , Corteza Cerebral/patología , Colodión , Femenino , Humanos , Procesamiento de Imagen Asistido por Computador , Masculino , Membranas Artificiales , Microtomía , Persona de Mediana Edad , Degeneración Nerviosa/metabolismo , Degeneración Nerviosa/patología , Proteínas del Tejido Nervioso/análisis , Neuronas/metabolismo , Neuronas/patologíaRESUMEN
The authors demonstrate the essence and the application possibility of artificial neural networks in the formulation of pharmaceutical preparations. They draw attention to that the use of ANN the data processing will speed up and more accurate which will cause the decrease of the preliminary investigations and the amounts of the materials.
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Diltiazem/química , Diseño de Fármacos , Implantes de Medicamentos , Red NerviosaRESUMEN
Comorbid depression of Alzheimer's disease (AD) is a common mood disorder in the elderly and a broad spectrum of antidepressants have been used for its treatment. Abeta peptides and other derivatives of the amyloid precursor protein (APP) have been implicated as central to the pathogenesis of AD. However, the functional relationship of APP and its proteolytic derivatives to antidepressant therapy is not known. In this study, Western blotting was used to test the ability of the tricyclic antidepressant (TCA) imipramine or the selective serotonin reuptake inhibitor (SSRI) citalopram to change the release of APP and the protein kinase C (PKC) content. Both antidepressants increased APP secretion in primary rat neuronal cultures. Imipramine or citalopram enhanced the level of secreted APP by 3.2- or 3.4-fold, respectively. Increases in PKC level were observed only after imipramine treatment. These in vitro data suggest that both TCA and SSRI are able to interfere with the APP metabolism. Imipramine promotes the non-amyloidogenic route of APP processing via stimulatory effects on PKC. We propose that PKC is not involved in the mechanism underlying the effects of citalopram on the APP metabolism. Since the secreted APP is not further available for the pathological cleavage of beta- and gamma-secretases, antidepressant medication might be beneficial in AD therapy.
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Precursor de Proteína beta-Amiloide/metabolismo , Citalopram/farmacología , Imipramina/farmacología , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Enfermedad de Alzheimer/complicaciones , Enfermedad de Alzheimer/metabolismo , Péptidos beta-Amiloides/antagonistas & inhibidores , Péptidos beta-Amiloides/metabolismo , Animales , Antidepresivos Tricíclicos/farmacología , Núcleo Basal de Meynert/efectos de los fármacos , Núcleo Basal de Meynert/metabolismo , Células Cultivadas , Medios de Cultivo Condicionados/química , Trastorno Depresivo/complicaciones , Trastorno Depresivo/metabolismo , Relación Dosis-Respuesta a Droga , Proteína Quinasa C/efectos de los fármacos , Proteína Quinasa C/metabolismo , Ratas , Inhibidores Selectivos de la Recaptación de Serotonina/farmacología , Regulación hacia Arriba/efectos de los fármacos , Regulación hacia Arriba/fisiologíaRESUMEN
Gemfibrozil is a lipid-regulating active substance. Dimethyl-beta-cyclodextrin products were prepared from this sparingly soluble pharmacon by means of methods such as physical mixing, kneading, spray drying and ultrasonication. Solid dosage forms (hydroxypropylmethyl cellulose /HPMC/ capsules and tablets) were prepared from the selected products on the basis of their dissolution profile and the in vitro membrane diffusion results. This publication details the results of electronmicroscopic morphological studies, particle size analysis and wetting contact angle determinations, and also the preparation and examination of the resulting solid dosage forms.
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Gemfibrozilo/química , beta-Ciclodextrinas/química , Difusión , Formas de Dosificación , Gemfibrozilo/administración & dosificación , Microscopía Electrónica , Solubilidad , ComprimidosRESUMEN
Dosage forms with fixed dose combinations of drugs is a frequent and advantageous mode of administration, but their production involves a number of technological problems. Numerous interactions in a homogeneous vehicle may be avoided through the use of layered tablets. The mechanical properties of these dosage forms depend on numerous process parameters and material characteristics. The aim of the present study was a detailed investigation of the relationships between the surface characteristics and deformation properties of tableting materials and the tendency of bilayer tablets to undergo lamination. Bilayer tablets were compressed from unlubricated materials with different plastic-elastic properties and surface free energies according to a mixed 2 and 3-level half-replicated factorial design. The results revealed that the surface characteristics play the main role in the lamination of layered tablets and the effect of the plastic-elastic behavior cannot be interpreted without a knowledge of these properties.
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Elasticidad , Comprimidos/síntesis química , Tecnología Farmacéutica/métodos , Propiedades de Superficie , Resistencia a la TracciónRESUMEN
Amyloid-beta (A(beta)) deposits and neurofibrillary pathology are characteristic features of Alzheimer's disease (AD). The association of A(beta) with cerebral vessels is an intriguing feature of AD. While there is considerable evidence of altered activities of the major isoforms of protein kinase C (PKC) in the vasculature and neurons of AD brains, little is known about the relationship between the Abeta toxicity and the altered PKC levels in cerebral endothelial cells. In this study, cultured brain endothelial cells exposed to A(beta)1-40 revealed a translocation of PKC from the membrane fraction to the cytosol. The content of the isoform PKC(alpha), involved in the regulation of amyloid precursor protein (APP) secretion, was decreased in the membrane-bound fraction of rat endothelial cells and increased in the cytosol after A(beta)1-40 treatment. These data suggest that the accumulation of A(beta) peptide in the cerebral vasculature may play a significant role in the down-regulation of PKC seen in the AD cerebral vasculature.
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Péptidos beta-Amiloides/farmacología , Circulación Cerebrovascular/efectos de los fármacos , Endotelio Vascular/efectos de los fármacos , Endotelio Vascular/enzimología , Isoenzimas/metabolismo , Proteína Quinasa C/metabolismo , Péptidos beta-Amiloides/metabolismo , Animales , Western Blotting , Células Cultivadas , Humanos , Inmunohistoquímica , Fragmentos de Péptidos/metabolismo , Proteína Quinasa C-alfa , RatasRESUMEN
The neurotoxic effects of amyloid-beta(1-42) and amyloid-beta(25-35) (A beta) on cholinergic and acetylcholinesterase-positive neurons were investigated in primary cultures derived from embryonic 18-day-old rat basal forebrain. After various time intervals, the cultures were treated with 1, 5, 10 or 20 microM A beta for different time periods. The cholinergic neurons and their axon terminals were revealed by vesicular acetylcholine transporter immunohistochemistry and the cholinoceptive cells by acetylcholinesterase histochemical staining. To assess the toxic effects of these A beta peptides on the cholinergic neurons, image analysis was applied for quantitative determination of the numbers of axon varicosities/terminals and cells. The results demonstrate that, following treatment with 1 or 5 microM A beta for 5, 10, 30, 60 or 120 min, no changes in vesicular acetylcholine transporter immunohistochemical staining were observed. However, after treatment for 30 min with 10 or 20 microM A beta, the number of stained axon varicosities was reduced, and treatment for 2 h they had disappeared. In contrast, vesicular acetylcholine transporter-positivity could be seen in some of the neuronal perikarya even after 3 days after treatment. The acetylcholinesterase staining was homogeneously distributed in the control neurons. After A beta treatment, the histochemical reaction end-product was detected in some of the neuronal perikarya or in the dendritic processes near to the soma. It is concluded that the neurotoxic effects of A beta appear more rapidly in the cholinergic axon terminals than in the cholinergic and acetylcholinesterase-positive neuronal perikarya.
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Acetilcolina/metabolismo , Acetilcolinesterasa/metabolismo , Péptidos beta-Amiloides/toxicidad , Proteínas de Transporte de Membrana , Neuronas/metabolismo , Prosencéfalo/citología , Proteínas de Transporte Vesicular , Animales , Proteínas Portadoras/metabolismo , Recuento de Células , Supervivencia Celular/efectos de los fármacos , Células Cultivadas , Relación Dosis-Respuesta a Droga , Embrión de Mamíferos , Inmunohistoquímica , Fragmentos de Péptidos/toxicidad , Prosencéfalo/embriología , Prosencéfalo/metabolismo , Ratas , Ratas Sprague-Dawley , Factores de Tiempo , Proteínas de Transporte Vesicular de AcetilcolinaRESUMEN
Alzheimer's disease is associated with a significant decrease in the cholinergic input to the neocortex. In a rat model of this depletion, we analyzed the subsequent long-term changes in cholinergic fiber density in two well-defined areas of the frontal and parietal cortices: Fr1, the primary motor cortex, and HL, the hindlimb area of the somatosensory (parietal) cortex, two cortical cholinergic fields that receive inputs from the nucleus basalis magnocellularis (nBM). A specific cholinergic lesion was induced by the intraparenchymal injection of 192 IgG-saporin into the nBM. Choline acetyltransferase (ChAT) immunohistochemistry was applied to identify the loss of cholinergic neurons in the nBM, while acetylcholinesterase (AChE) enzyme histochemistry was used to analyze the decreases in the number of cholinoceptive neurons in the nBM and the cholinergic fiber density in the Fr1 and HL cortical areas in response to the nBM lesion. The immunotoxin differentially affected the number of ChAT- and AChE-positive neurons in the nBM. 192 IgG-saporin induced a massive, irreversible depletion of the ChAT-positive (cholinergic) neurons (to 11.7% of the control level), accompanied by a less dramatic, but similarly persistent loss of the AChE-positive (cholinoceptive) neurons (to 59.2% of the control value) in the nBM within 2 weeks after the lesion. The difference seen in the depletion of ChAT- and AChE-positive neurons is due to the specificity of the immunotoxin to cholinergic neurons. The cholinergic fiber densities in cortical areas Fr1 and HL remained similarly decreased (to 62% and 68% of the control values, respectively) up to 20 weeks. No significant rebound in AChE activity occurred either in the nBM or in the cortices during the period investigated. This study therefore demonstrated that, similarly to the very extensive reduction in the number of ChAT-positive neurons in the nBM, cortical areas Fr1 and HL underwent long-lasting reductions in the number of AChE-positive fibers in response to specific cholinergic lesioning of the nBM.
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Enfermedad de Alzheimer/patología , Núcleo Basal de Meynert/patología , Neuronas Colinérgicas/patología , Modelos Animales de Enfermedad , Vías Nerviosas/patología , Acetilcolinesterasa/metabolismo , Enfermedad de Alzheimer/metabolismo , Animales , Anticuerpos Monoclonales/toxicidad , Núcleo Basal de Meynert/metabolismo , Colina O-Acetiltransferasa/metabolismo , Neuronas Colinérgicas/metabolismo , Inmunohistoquímica , Inmunotoxinas/toxicidad , Masculino , Vías Nerviosas/metabolismo , Ratas , Ratas Sprague-Dawley , Proteínas Inactivadoras de Ribosomas Tipo 1/toxicidad , Saporinas , TiempoRESUMEN
One of the major pathological landmarks of Alzheimer's disease and other neurodegenerative diseases is the presence of amyloid deposits in the brain. The early non-invasive visualization of amyloid is a major objective of recent diagnostic neuroimaging approaches, including positron emission tomography (PET), with an eye on follow-up of disease progression and/or therapy efficacy. The development of molecular imaging biomarkers with binding affinity to amyloid in the brain is therefore in the forefront of imaging biomarker and radiochemistry research. Recently, a dodecamer peptide (amino acid sequence=QSHYRHISPAQV; denominated D1 or ACI-80) was identified as a prospective ligand candidate, binding with high ex vivo affinity to L-Aß-amyloid (K(d): 0.4 µM). In order to assess the ligand's capacity to visualize amyloid in Alzheimer's disease (AD), two (125)I labeled and three (18)F labeled analogues of the peptide were synthesized and tested in post mortem human autoradiography experiments using whole hemisphere brain slices obtained from deceased AD patients and age matched control subjects. The (18)F-labeled radioligands showed more promising visualization capacity of amyloid that the (125)I-labeled radioligands. In the case of each (18)F radioligands the grey matter uptake in the AD brains was significantly higher than that in control brains. Furthermore, the grey matter: white matter uptake ratio was over ~2, the difference being significant for each (18)F-radioligands. The regional distribution of the uptake of the various radioligands systematically shows a congruent pattern between the high uptake regions and spots in the autoradiographic images and the disease specific signals obtained in adjacent or identical brain slices labeled with histological, immunohistochemical or autoradiographic stains for amyloid deposits or activated astrocytes. The present data, using post mortem human brain autoradiography in whole hemisphere human brains obtained from deceased AD patients and age matched control subjects, support the visualization capacity of the radiolabeled ACI-80 analogues of amyloid deposits in the human brain. Further studies are warranted to explore the usefulness of the (18)F-labeled analogues as in vivo molecular imaging biomarkers in diagnostic PET studies.
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Enfermedad de Alzheimer/diagnóstico , Enfermedad de Alzheimer/metabolismo , Cerebro/metabolismo , Radioisótopos de Yodo , Oligopéptidos/metabolismo , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/patología , Autorradiografía , Biomarcadores/metabolismo , Cerebro/patología , Femenino , Radioisótopos de Flúor , Humanos , Persona de Mediana Edad , Neuroimagen/métodos , Estudios Prospectivos , Unión ProteicaRESUMEN
BACKGROUND: Active coating is an important unit operation in the pharmaceutical industry. The quality, stability, safety and performance of the final product largely depend on the amount and uniformity of coating applied. Active coating is challenging regarding the total amount of coating and its uniformity. Consequently, there is a strong demand for tools, which are able to monitor and determine the endpoint of a coating operation. In previous work, it was shown that Raman spectroscopy is an appropriate process analytical tool (PAT) to monitor an active spray coating process in a pan coater [1]. Using a multivariate model (Partial Least Squares-PLS) the Raman spectral data could be correlated with the coated amount of the API diprophylline. While the multivariate model was shown to be valid for the process in a mini scale pan coater (batch size: 3.5 kg cores), the aim of the present work was to prove the robustness of the model by transferring the results to tablets coated in a micro scale pan coater (0.5 kg). METHOD: Coating experiments were performed in both, a mini scale and a micro scale pan coater. The model drug diprophylline was coated on placebo tablets. The multivariate model, established for the process in the mini scale pan coater, was applied to the Raman measurements of tablets coated in the micro scale coater for six different coating levels. Then, the amount of coating, which was predicted by the model, was compared with reference measurements using UV spectroscopy. RESULTS: For all six coating levels the predicted coating amount was equal to the amounts obtained by UV spectroscopy within the statistical error. Thus, it was possible to predict the total coating amount with an error smaller than 3.6%. The root mean squares of errors for calibration and prediction (root mean square of errors for calibration and prediction-RMSEC and RMSEP) were 0.335 mg and 0.392 mg, respectively, which means that the predictive power of the model is not dependent on the scale or the equipment. CONCLUSION: The scale-down experiment showed that it was possible to transfer the PLS model developed on a mini scale coater to a micro scale coater.