Supercritical antisolvent precipitation of PHBV microparticles

The micronization of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) from organic solutions using supercritical antisolvent (SAS) technique has been successfully achieved. SASexperiments were carried out at different operational conditions and microspheres with mean diameters ranging from 3 to 9 mwere obtained. The effect of CO2 and liquid flow, temperature and pressure on particle size and particle size distribution was evaluated. The microspheres were precipitated from a dichloromethane (DCM) solution. The best process conditions for this mixture were, according to our study, 40 ◦C, 100 bar, 1mLmin−1 liquid flow and 10 L min−1 carbon dioxide flow. Experiments with polymers containing different HV percentages were carried out. The powders obtained became more spherical as the HV content decreased

A comparison between gravimetric and in-situ spectroscopic methods to measure the sorption of CO₂in a biocompatible polymer

In situ ATR-IR spectroscopy was used to simultaneously measure the sorption and swelling of carbon dioxide at high pressures in a biocompatible acrylate copolymer poly(methylmethacrylate-co-ethylhexylacrylate-co-ethyleneglycoldimethacrylate), P(MMA–EHA–EGDMA). The ν3 band of CO2 dissolved in the polymer (at 2335 cm−1) was used to calculate the sorption data and the polymer swelling was determined by analyzing the changes in the absorbance of the ν(C O) band (at 1730 cm−1) of the polymer. Transmission spectroscopy in the near-IR region was also used to study the sorption of CO2 in the polymer using combinational and overtone bands. The experiments were carried out in a pressure range of 2.0–12.0MPa and in a temperature range of 27–40 ◦C. The data for CO2 sorption in this polymer obtained by in situ spectroscopic methods have been compared to the data obtained by the gravimetric technique

Preparation of controlled release microspheres using supercritical fluid technology for delivery of anti-inflammatory drugs

Ethylcellulose/methylcellulose blends were produced using different precipitation techniques and impregnated with naproxen, a non-steroidal anti-inflammatory drug (NSAID). Solvent-evaporation technique was used not only for the preparation of ethylcellulose/methylcellulose microspheres but also to encapsulate naproxen. Supercritical fluid (SCF) impregnation was also performed to prepare naproxen loaded microspheres. The microspheres, impregnated by the SCF technique, were prepared both by solvent-evaporation and by a supercritical antisolvent (SAS) process. In vitro release profiles at pH 7.4 and 1.2, of naproxen-loaded microspheres were evaluated and the results were modelled Fick’s law of diffusion and Power law. Miscrospheres prepared by supercritical antisolvent have a higher loading capacity and present a slower release profile. The systems studied present a release mechanism controlled by drug diffusion which complies Fick’s law of diffusion

Preparation of ethylcellulose/methylcellulose blends by supercritical antisolvent precipitation

The supercritical antisolvent (SAS) techniquewas used to prepare ethyl cellulose/methyl cellulose blends, two biocompatible polymers commonly used as drug carriers in controlled delivery systems. Ethyl cellulose is widely used as a drug carrier. The drug release of the delivery devices can be controlled to some extent by addition of a water-soluble or water swellable polymer, such as methyl cellulose. This leads to the solubility enhancement of poorly water-soluble molecules. SAS experiments were carried out at different operational conditions and microspheres with mean diameters ranging from 5 to 30 m were obtained. The effect of CO2 and liquid flow, temperature and pressure on particle size and particle size distribution was evaluated. The microspheres were precipitated from a mixture of dichloromethane (DCM) and dimethylsulfoxide (DMSO) (4:1 ratio). The best process conditions for this mixture were according to our study 40 ◦C and 80 bar

Preparation of acetazolamide composite microparticles by supercritical antisolvent techniques

The possibility of preparation of ophthalmic drug delivery systems using compressed anti-solvent technology was evaluated. and RL 100 were used as drug carriers, acetazolamide was the model drug processed. Compressed anti-solvent experiments were carried out as a semi-continuous or a batch operation from a liquid solution of polymer(s) + solute dissolved in acetone. Both techniques allowed the recovery of composite particles, but the semi-continuous operation yielded smaller and less aggregated populations than the batch operation. The release behaviour of acetazolamide from the prepared microparticles was studied and most products exhibited a slower release than the single drug. Moreover, the release could be controlled to some extent by varying the ratio of the two Eudragit used in the formulation and by selecting one or the other anti-solvent technique. Simple diffusion models satisfactorily described the release profiles. Composites specifically produced by semi-continuous technique have a drug release rate controlled by a diffusion mechanism, whereas for composites produced by the batch operation, the polymer swelling also contributes to the overall transport mechanism

Enhancing curcumin bioaccessibility through different nanoformulations

5th International Conference on Food Digestion[Excerpt] Introduction: Curcumin, a natural polyphenolic phytochemical, is known for its wide range of biological activities, however it has an extremely low water solubility as well as a low bioavailability, which limit its application as a bioactive ingredient in food. The use of delivery systems at nanoscale such as nanoemulsions (NE) and solid lipid nanoparticles (SLN) has been reported as a promising mean of improving the lipophilic bioactive compounds’ bioavailability and their physical and chemical stability. However, the knowledge of the behaviour of different nanoformulations as well as the fate of bioactive compounds encapsulated within them in the gastrointestinal (GI) tract is of utmost importance to either assess their safety for human consumption and to produce tailored delivery systems (i.e. with optimized bioactivity). The aim of this work was the evaluation of the behaviour of two different bio-based nanoformulations (NE and SLN) incorporating curcumin when submitted to an in vitro digestion and the assessment of their cytotoxicity. [...]Ana C. Pinheiro and Joana T. Martins acknowledge the Foundation for Science and Technology (FCT) for their fellowships (SFRH/BPD/101181/2014 and SFRH/BPD/89992/2012). This work was supported by Portuguese Foundation for Science and Technology (FCT) under the scope of the Project PTDC/AGR-TEC/5215/2014, of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684) and BioTecNorte operation (NORTE-01-0145- FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Novel insights for permeant lead structures through in vitro skin diffusion assays of Prunus lusitanica L., the Portugal Laurel

As a contribution for the generation of libraries in which a natural product (NP) is used as the guiding structure, this work sought to investigate molecular features of triterpenes as deliver leads to cross the stratum corneum at a significant rate. Seeking a bioguided investigation of the dermocosmetic lead-like potential of triterpenes in Prunus lusitanica L., various extracts were obtained by two different methods (Soxhlet extractor and Accelerated Solvent Extraction-ASE) and analyzed by GC–MS and NMR. In vitro assays were conducted to quantify the friedelin 1 and crude plant extract permeation through a membrane of polydimethylsiloxane (PDMS), as well as their skin penetration enhancement capacity using two model molecules, caffeine 19 and ibuprofen 20. Friedelin 1 was identified as the major component (16–77%, GC) with isolated yield of 51% w/w (94%, GC) from Soxhlet residue (1.7% p/p) of the dried aerial parts of the plant harvested when in early flowering stage. Friedelin 1 promoted the penetration of the lipophilic molecule 20, however, it did not influence the permeation of the hydrophilic permeant 20. On the other hand, the crude extract acted as a retardant of the penetration of both substances. Molecular characteristics for the applicability of P. lusitanica L. in the development of dermocosmetics, as well as a new potential use for friedelin 1 in particular, are demonstrated. Probable mechanisms for chemical penetration enhancement using triterpenes as models for transdermal administration are herein discussed

Bio-based nanocarriers incorporating curcumin bioaccessibility and cell viability evaluation

Book of Abstracts of CEB Annual Meeting 2017[Excerpt] For decades, curcumin (Cur), a natural polyphenol product derived from turmeric (Curcuma longa) has been considered one of the most promising bioactive compounds due to its health benefits such as anti-inflammatory, antioxidant and anticarcinogenic properties. However, Cur application as functional compound in food products has been limited due to light, heat, and oxidation sensitive and mainly, to poor aqueous solubility which limit its bioavailability [1]. To increase Cur bioaccessibility and consequently, increase bioavailability, several carriers have been investigated, particularly nanocarriers. Among the various nanocarriers described in the literature, lipid-based nanocarriers may offer a promising tool to increase the stability, efficacy and safety of lipophilic compounds, namely Cur [2]. Moreover, the understanding of Cur-loaded nanocarriers’ behaviour under gastrointestinal (GI) conditions is fundamental to produce safe and customized nanocarriers with optimized bioactivity for oral consumption. The aim of this study was to comparatively analyze the impact of two different lipid nanocarriers incorporating Cur - solid lipid nanoparticles (SLN) and nanoemulsions (NE) – on bioaccessibility and Caco-2 cells viability. [...]info:eu-repo/semantics/publishedVersio

ADENOPATIA CERVICAL COMO MANIFESTAÇÃO DE CANCRO DO CÓLON

Introduction: Colorectal cancer is one of the most frequent cancers worldwide, being the third most common cancer diagnosed and corresponding to the second cause of death by cancer. Approximately 25% of patients have already disseminated disease at the time of diagnosis. Case Report: We present the case of a 68-year-old female patient presented with complaints of cervical mass. She was then submitted to a biopsy of the cervical adenopathy that revealed metastatic adenocarcinoma tissue with probable gastrointestinal origin. A work-up was performed and revealed a sigmoid colon adenocarcinoma. Due to associated morbidities she was submitted to supportive treatment. Discussion: This case demonstrates the singularity of metastatic pattern in colon carcinoma. The mechanism of distant lymph node metastases in colorectal cancer still remains uncertain, nevertheless this represents an advanced stage of the disease that bears a poor prognosis. Conclusion: Few reports in the literature showed a good outcome with primary tumor excision and adjuvant chemotherapy but this decision should be discussed in a multidisciplinary team in order to decide the best treatment option for each patient.Introdução: O cancro colorectal é um dos cancros mais frequentes a nível mundial, sendo o terceiro cancro mais frequentemente diagnosticado e corresponde à segunda causa de morte por cancro. Cerca de 25% dos doentes apresentam doença disseminada à data de diagnóstico. Caso Clínico: Os autores apresentam o caso de uma doente de 68 anos, do sexo feminino, que se apresentou com queixas de uma tumefacção cervical. Foi posteriormente submetida a biópsia excisional que revelou a presença de metástase de adenocarcinoma provavelmente intestinal. Foi realizado o estudo complementar com identificação de um adenocarcinoma do cólon sigmoide. Devido às morbilidades associadas foi oferecido tratamento de suporte. Discussão: Este caso representa a singularidade do padrão de metastização do cancro do cólon. O mecanismo de metastização ganglionar à distância não se encontra totalmente esclarecido, no entanto, representa um estadio de doença avançado com um mau prognóstico associado. Conclusão: Alguns casos na literatura demonstraram bons resultados com a excisão do tumor primário seguida de quimioterapia adjuvante, esta decisão deve ser realizada por uma equipa multidisciplinar de forma a avaliar a melhor opção terapêutica para cada doente