Applying the Taguchi method for optimized fabrication of bovine serum albumin (BSA) nanoparticles as drug delivery vehicles

The objective of the present study was to optimize the fabrication of bovine serum albumin (BSA) nanoparticle by applying the Taguchi method with characterization of the nanoparticle bioproducts.BSA nanoparticles have been extensively studied in our previous works as suitable carrier for drug delivery, since they are biodegradable, non-toxic and non antigenic. A statistical experimental designmethod (Taguchi method with L16 orthogonal array robust design) was implemented to optimize experimental conditions of the purpose. Agitation speed, initial BSA concentration, pH and temperaturewere considered as process parameters to be optimized. As the result of Taguchi analysis in this study, temperature and agitation speed were the most influencing parameters on the particle size. Theminimum size of nanoparticles (~74 nm) were obtained at 4°C, pH 7.5, 15 mg ml-1 BSA concentration and agitation speed of 500 rpm. As for characterization of the products, Atomic Force microscopy(AFM), Scanning Electron microscopy (SEM) and Sodium Dodecyl Sulphate- Poly Acrylamide Gel Electrophoresis (SDS-PAGE) as well as Fourier Transform Infra-Red (FTIR) techniques were employed

Production of protein nanoparticles for food and drug delivery system

No Abstrac

Production of biological nanoparticles from bovine serum albumin for drug delivery

Bovine serum albumin (BSA) was used for generation of nanoparticles in a drug delivery system. The size of the fabricated nano-particles was measure by laser light scanning. Several process parameterswere examined to achieve a suitable size of nanoparticle such as pH, temperature, BSA concentration, agitation speed, glutaraldehyde concentration, organic solvent adding rate and the ratio of BSA/organic solvent. The smallest size of nanoparticles achieved, was 101 nm and the largest size was 503 nm. The most effective parameters for the fabrication of the nanoparticles were the agitation speed and the media temperature. The minimum size of nanoparticles at the desired incubator of 4°C and constant agitation rate of 300 - 400 rpm was obtained. The impact of protein concentration and additional rate of organic solvent (i.e. ethanol) upon the particle size was investigated. The protein concentration of 5-40 mg.ml-1 was resulted; the main effect on the particle size and minimum mean size diameter gained was 30 mg.ml-1 protein concentration. The nanoparticle sample was purified with 50,000 g centrifuge then followed by dialysis, micro and ultrafiltration and then analyzed by SEM, PCS as well as SDS gel electrophoresis

Investigation on batch biosorption of lead using Lactobacillius bulgaricus in an aqueous phase system

In this research, the biosorption of lead by Lactobacillus bulgaricus was investigated. The mechanism for the biosorption was similar to ionic exchanger. The media pH, weight of dried biomass and initial lead concentration were investigated at ambient temperature. At highacidic solution (p

EvoBot: Towards a Robot-Chemostat for Culturing and Maintaining Microbial Fuel Cells (MFCs)

In this paper we present EvoBot, a RepRap open-source 3D-printer modified to operate like a robot for culturing and maintaining Microbial Fuel Cells (MFCs). EvoBot is a modular liquid handling robot that has been adapted to host MFCs in its experimental layer, gather data from the MFCs and react on the set thresholds based on a feedback loop. This type of robot-MFC interaction, based on the feedback loop mechanism, will enable us to study further the adaptability and stability of these systems. To date, EvoBot has automated the nurturing process of MFCs with the aim of controlling liquid delivery, which is akin to a chemostat. The chemostat is a well-known microbiology method for culturing bacterial cells under controlled conditions with continuous nutrient supply. EvoBot is perhaps the first pioneering attempt at functionalizing the 3D printing technology by combining it with the chemostat methods. In this paper, we will explore the experiments that EvoBot has carried out so far and how the platform has been optimised over the past two years

Raman Spectroscopy as a Predictive Tool for Monitoring Osteoporosis Therapy in a Rat Model of Postmenopausal Osteoporosis

Pharmacological therapy of osteoporosis reduces bone loss and risk of fracture in patients. Modulation of bone mineral density cannot explain all effects. Other aspects of bone quality affecting fragility and ways to monitor them need to be better understood. Keratinous tissue acts as surrogate marker for bone protein deterioration caused by oestrogen deficiency in rats. Ovariectomised rats were treated with alendronate (ALN), parathyroid hormone (PTH) or estrogen (E2). MicroCT assessed macro structural changes. Raman spectroscopy assessed biochemical changes. Micro CT confirmed that all treatments prevented ovariectomy-induced macro structural bone loss in rats. PTH induced macro structural changes unrelated to ovariectomy. Raman analysis revealed ALN and PTH partially protect against molecular level changes to bone collagen (80% protection) and mineral (50% protection) phases. E2 failed to prevent biochemical change. The treatments induced alterations unassociated with the ovariectomy; increased beta sheet with E2, globular alpha helices with PTH and fibrous alpha helices with both ALN and PTH. ALN is closest to maintaining physiological status of the animals, while PTH (comparable protective effect) induces side effects. E2 is unable to prevent molecular level changes associated with ovariectomy. Raman spectroscopy can act as predictive tool for monitoring pharmacological therapy of osteoporosis in rodents. Keratinous tissue is a useful surrogate marker for the protein related impact of these therapies. The results demonstrate utility of surrogates where a clear systemic causation connects the surrogate to the target tissue. It demonstrates the need to assess broader biomolecular impact of interventions to examine side effects. [Figure not available: see full text.]

Biodegradable microparticulate drug delivery system of diltiazem HCl

The efficacy of a drug in a specific application requires the maintenance of appropriate drug blood level concentration during a prolonged period of time. Controlled release delivery is available for many routes of administration and offers many advantages (as microparticles and nanoparticles) over immediate release delivery. These advantages include reduced dosing frequency, better therapeutic control, fewer side effects, and, consequently, these dosage forms are well accepted by patients. Advances in polymer material science, particle engineering design, manufacture, and nanotechnology have led the way to the introduction of several marketed controlled release products and several more are in pre-clinical and clinical development. The objective of this work is to prepare and evaluate diltiazem HCl loaded albumin microparticles using a factorial design. Albumin (natural polymer) microparticles were prepared by emulsion heat-stabilization method. Selected formulations were characterized for their entrapment efficiency, particle size, surface morphology, and release behavior. Analysis of variance for entrapment efficiency indicates that entrapment efficiency is best fitted to a response surface linear model. Surface morphology was studied by scanning electron microscopy. Scanning electron microscopy of the microparticles revealed a spherical, nonporous and uniform appearance, with a smooth surface. The geometric mean diameter of the microparticles was found to be 2-9 µm, which more than 75% were below 3.5 µm and drug incorporation efficiency of 59.74 to 72.48% (w/w). In vitro release profile for formulations containing diltiazem HCl loaded BSA microparticles with heat stabilization technique shows slow controlled the release of the drug up to 24 hours. The release pattern was biphasic, characterized by an initial burst effect followed by a slow release. All selected microparticles exhibited a prolonged release for almost 24 hours. On comparing regression-coefficient (r²) values for Hixson Crowel, Higuchi and Peppas kinetic models, different batches of microparticles showed Fickian, non-Fickian, and diffusion kinetics. The release mechanism was regulated by D:P ratio. From the statistical analysis it was observed that as the drug:polymer (D:P) ratio increased, there was a significant increase in the encapsulation efficiency. Based on the particle size, entrapment efficiency and physical appearance, DTM-3 formulations were selected for in vivo release study and stability study. The in vivo result of drug loaded microparticles showed preferential drug targeting to liver followed by lungs, kidneys and spleen. Stability studies showed that maximum drug content and closest in vitro release to initial data were found in the formulation stored at 4 ºC. In present study, diltiazem HCl loaded BSA microparticles were prepared and targeted to various organs to satisfactory level and were found to be stable at 4 ºC.A eficácia terapêutica de um fármaco depende da manutenção de seu nível plasmático adequado em determinado intervalo de tempo. Nesse sentido, a liberação modificada de fármacos está disponível em muitas vias de administração e oferece muitas vantagens (como micropartículas e nanopartículas) quando comparada às formulações de liberação imediata. Essas vantagens incluem reduzida frequência da dosagem, melhor controle terapêutico e menos efeitos colaterais. Assim sendo, esses produtos apresentam maior aceitação pelos pacientes. Os avanços na ciência dos materiais, na engenharia das partículas, em manufatura e em nanotecnologia permitiram a introdução no mercado de vários produtos de liberação modificada e vários outros se encontram em desenvolvimento pré-clínico e clínico. O objetivo do presente trabalho foi preparar e avaliar o fármaco cloridrato de diltiazem associado a micropartículas de albumina utilizando planejamento fatorial. As micropartículas de albumina, um polímero natural, foram preparadas por método de emulsão empregando estabilização por calor. As formulações selecionadas foram caracterizadas no que se refere à sua eficiência de encapsulamento, tamanho médio de partículas, morfologia de superfície e perfil de liberação do fármaco. A análise de variância relativa à eficiência de encapsulamento indicou superfície de resposta linear. Com referência à morfologia superficial, essa foi avaliada empregando microscopia eletrônica de varredura. Essa análise revelou micropartículas esféricas, não porosas e de aparência uniforme, com superfície lisa. O diâmetro médio das micropartículas foi entre 2 e 9 µm, sendo que mais de 75% das micropartículas se apresentaram abaixo de 3,5 µm. Além disso, a eficiência de encapsulamento foi entre 59,74 e 72,48%. Quanto ao ensaio para avaliação do perfil de liberação in vitro do fármaco associado às micropartículas, as formulações apresentaram liberação lenta até 24 horas. O comportamento foi caracterizado por liberação inicial (efeito burst) seguida por liberação lenta. Todas as fórmulas selecionadas apresentaram liberação prolongada por aproximadamente 24 horas. Na comparação entre os valores de coeficientes de regressão (R²), os modelos propostos por Hixson Crowel, Higuchi e Peppas, para diferentes formulações de micropartículas, demonstraram cinética de liberação de acordo com modelo Fickiano e não-Fickiano. O mecanismo de liberação do fármaco foi regulado pela razão entre o fármaco e o polímero. A análise estatística revelou significativo aumento da eficiência de encapsulamento quando essa razão aumentou. As avaliações relativas à análise dimensional das micropartículas, à eficiência de encapsulamento do fármaco e à morfologia permitiram a seleção da formulação DTM-3 para os ensaios de liberação in vivo e para o estudo da estabilidade. O ensaio de liberação in vivo do fármaco associado às micropartículas demonstrou sítio-alvo preferencial no fígado, seguido pelos pulmões rins e baço. No presente estudo, as micropartículas de albumina contendo cloridrato de diltiazem foram adequadamente preparadas e orientadas satisfatoriamente para vários órgãos. Além disso, a formulação selecionada apresentou estabilidade físico-química a 4 ºC

The effect of bore fluid type on the structure and performance of polyetherimide hollow fiber membrane in gas-liquid contacting processes

The effect of bore fluid type on the structure and performance of polyetherimide hollow fiber membranes in contactor application was investigated. Water was used as phase inversion promoter in spinning dope and water and pure NMP were used as bore fluid. SEM micrographs show that the major parts of both membranes consist of spongelike structure which is related to the high viscosity of spinning dope that reduces the diffusion of coagulant (water) into membrane sublayer and decreases the rate of phase inversion. In the case of water as bore fluid (membrane #M1) there is skin layer on the inner surface of membrane and some drop-shaped voids in the structure of membrane but in the case of pure NMP as bore fluid (membrane #M2), the inner surface of membrane is skinless with big pores and there are fingerlike macrovoids, originating from the inner surface and extending to the vicinity of outer surface which is related to the penetration of bore fluid and dissolving the polymer. Furthermore, membrane #M2 has higher mean pore size and effective surface porosity. The absorption flux of both fabricated membranes was investigated in the case of liquid in lumen side (case #1) and liquid in shell side (case #2) where in case #1, membrane #M1 has higher absorption flux but in case #2, membrane #M2 has higher absorption flux. The different trend in absorption flux confirms that the surface of membrane in contact with the gas phase in a membrane contactor should be skinless with big pores to facilitates the diffusion of solute gas through membrane but the pore size on the surface of membrane in contact with the liquid phase should be adjusted to obtain high absorption flux and low wettabilit

Kinetics study of hydrazodicarbonamide synthesis reaction

In this study, the kinetics of hydrazodicarbonamide (HDCA) synthesis reaction was investigated. Hydrazodicarbonamide is prepared by reaction of urea and hydrazine in acidic medium. Synthesis of HDCA from urea and hydrazine is a two steps reaction. In the first step, semicarbazide is synthesized from the reaction of one mole of urea and one mole of hydrazine and in the second step, semicarbazide reacts with urea to produce hydrazodicarbonamide. By controlling the temperature and pH in the reaction, hydrazine concentration and the amount of produced hydrazodicarbonamide were measured and using these data, reaction rate constants were calculated. Based on this study, it was found that the semicarbazide formation reaction from hydrazine is the rate limiting step. Rate of semicarbazide synthesis is -r1 = 0.1396 [NH2NH2]0.5810 and the rate of hydrazodicarbonamide synthesis is -r2 = 0.7715 [NH2NHCONH2]0.8430