Development and validation of a bioanalytical method for the simultaneous determination of heroin, its main metabolites, naloxone and naltrexone by LC-MS/MS in human plasma samples: Application to a clinical trial of oral administration of a heroin/naloxone formulation.

A bioanalytical method using high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and validated for simultaneous quantification of heroin, its main metabolites and naloxone. In addition, naltrexone was detected qualitatively. This method was used to analyse human plasma samples from a clinical trial after oral administration of a heroin/naloxone formulation in healthy volunteers. O-methylcodeine was used as an internal standard. Samples were kept in an ice-bath during their processing to minimize the degradation of heroin. A short methodology based on protein precipitation with methanol was used for sample preparation. After protein precipitation, only the addition of a formic acid solution was needed to elute heroin, 6-monoacetylmorphine, morphine, naloxone and naltrexone. Morphine metabolites were evaporated to dryness and reconstituted in a formic acid solution. Chromatographic separation was achieved at 35 °C on an X-Bridge Phenyl column (150 × 4.6 mm, 5 µm) using a gradient elution with a mobile phase of ammonium formate buffer at pH 3.0 and formic acid in acetonitrile. The run time was 8 min. The analytes were monitored using a triple quadrupole mass spectrometer with positive electrospray ionization (ESI+) in multiple reaction monitoring (MRM) mode. The method was found to be linear in a concentration range of 10-2000 ng/mL for M3G and 10-1000 ng/mL for the rest of compounds. Quality controls showed accurate values between -3.6% and 4.0% and intra- and inter-day precisions were below 11.5% for all analytes. The overall recoveries were approximately 100% for all analytes including the internal standard. A rapid, specific, precise and simple method was developed for the determination of heroin, its metabolites, naloxone and naltrexone in human plasma. This method was successfully applied to a clinical trial in 12 healthy volunteers.

Optoacoustic imaging enabled biodistribution study of cationic polymeric biodegradable nanoparticles.

Nanosized contrast agents for molecular imaging have attracted widespread interest for diagnostic applications with high resolution in medicine. However, many solid nanoparticles exhibit a great potential to induce toxicity, hindering their use for clinical applications. On the other hand, near-infrared (NIR) dyes have also been used for extensive biological applications, but show some limitations due to their poor aqueous stability, tendency to aggregation and rapid elimination from the body. An alternative proposed in this work to overcome these limitations is the use of NIR dye-loaded nanoparticles. Here we introduce nanoparticles constructed with poly(D,L-lactide-co-glycolic acid) (PLGA), a biodegradable and biocompatible polymer widely used for biomedical applications, attached to the polycation polyethyleneimine (PEI) to obtain positively charged nanoparticles. The in vivo biodistribution of the cationic PEI-PLGA nanoparticles was investigated after administration through three different routes (intravenous, intraperitoneal and subcutaneous) using multispectral optoacoustic tomography (MSOT). The prepared nanoparticles exhibited good colloidal stability and adequate optical properties for optoacoustic imaging. The in vivo biodistribution assays indicated a strong accumulation of the particles in the liver and spleen, and retention in these organs for at least 24 h. Therefore, these nanoparticles could find promising applications in MSOT due to a sharp and characteristic optoacoustic spectrum and high optoacoustic signal generation, and become a promising building block for theranostic strategies.

Development of surface modified biodegradable polymeric nanoparticles to deliver GSE24.2 peptide to cells: a promising approach for the treatment of defective telomerase disorders.

The aim of the present study was to develop a novel strategy to deliver intracellularly the peptide GSE24.2 for the treatment of Dyskeratosis congenita (DC) and other defective telomerase disorders. For this purpose, biodegradable polymeric nanoparticles using poly(lactic-co-glycolic acid) (PLGA NPs) or poly(lactic-co-glycolic acid)-poly ethylene glycol (PLGA-PEG NPs) attached to either polycations or cell-penetrating peptides (CPPs) were prepared in order to increase their cellular uptake. The particles exhibited an adequate size and zeta potential, with good peptide loading and a biphasic pattern obtained in the in vitro release assay, showing an initial burst release and a later sustained release. GSE24.2 structural integrity after encapsulation was assessed using SDS-PAGE, revealing an unaltered peptide after the NPs elaboration. According to the cytotoxicity results, cell viability was not affected by uncoated polymeric NPs, but the incorporation of surface modifiers slightly decreased the viability of cells. The intracellular uptake exhibited a remarkable improvement of the internalization, when the NPs were conjugated to the CPPs. Finally, the bioactivity, addressed by measuring DNA damage rescue and telomerase reactivation, showed that some formulations had the lowest cytotoxicity and highest biological activity. These results proved that GSE24.2-loaded NPs could be delivered to cells, and therefore, become an effective approach for the treatment of DC and other defective telomerase syndromes.

Emerging therapeutic approaches based on nanotechnology for the treatment of diseases associated with telomere dysfunction.

Telomeric diseases are a group of rare progeroid genetic syndromes, presenting premature aging phenotypes, characterized for defects on telomere maintenance. In humans, telomeres are heterochromatic structures consisting of long TTAGGG repeats located at the chromosomal ends, which shorten progressively after each DNA replication because of the 'end replication problem'. Critically short telomeres activate a DNA damage response that leads to the arrest of the cell cycle and resulting in cellular senescence or apoptosis. Furthermore, excessively short telomeres are prone to create telomeric fusions, causing genomic instability and malignant transformation. In order to counteract this process, there are two enzymatic complexes, the telomerase complex, with the capacity to elongate telomeres; and the shelterin complex, which protects them from being recognized as DNA breaks. Over the last few decades, several studies have confirmed that critically short telomeres and defects in telomere-associated enzymatic complexes are involved in the development of a group of rare human genetic diseases, with the accumulation of excessive telomere attrition as the underlying cause of these pathologies. Despite the severity of these disorders, there is no curative treatment for any of them. In light of this, this review summarizes the most important defective telomere diseases, their current management, and it presents possible therapeutic strategies based on nanotechnology which may open up new possibilities for their treatment.

Development and validation of a rapid HPLC method for the quantification of GSE4 peptide in biodegradable PEI-PLGA nanoparticles.

In this work a high performance liquid chromatographic (HPLC) method has been developed and validated for the content determination of GSE4 peptide in PEI-PLGA nanoparticles. Chromatographic separation was performed on a C18 column, and a gradient elution with a mobile phase composed of methanol and 0.1% aqueous trifluoroacetic acid (TFA) solution, at a flow rate of 1ml/min, was used. GSE4 peptide identification was made by fluorescence detection at 290nm. The elution of methanol:TFA was initially maintained at (20:80, v/v) for one min and the gradient changed to (80:20, v/v) in 6min. This ratio was then followed by isocratic elution at (80:20, v/v) during another min and for further 3min it was linearly modified to (20:80, v/v). The developed method was validated according to the ICH guidelines, being specific, linear in the range 10-100µg/ml (R(2)=0.9996), precise, exhibiting good inter-day and intra-day precision reflected by the relative standard deviation values (less than 3.88%), accurate, with a recovery rate of 100.18±0.95%, and stable for 48h at 5°C or at RT when encapsulated in nanoparticles. The method was simple, fast, and successfully used to determine the peptide content in GSE4-loaded PEI-PLGA nanoparticles.

Nanoparticle delivery systems for cancer therapy: advances in clinical and preclinical research.

Conventional anticancer drugs display significant shortcomings which limit their use in cancer therapy. For this reason, important progress has been achieved in the field of nanotechnology to solve these problems and offer a promising and effective alternative for cancer treatment. Nanoparticle drug delivery systems exploit the abnormal characteristics of tumour tissues to selectively target their payloads to cancer cells, either by passive, active or triggered targeting. Additionally, nanoparticles can be easily tuned to improve their properties, thereby increasing the therapeutic index of the drug. Liposomes, polymeric nanoparticles, polymeric micelles and polymer- or lipid-drug conjugate nanoparticles incorporating cytotoxic therapeutics have been developed; some of them are already on the market and others are under clinical and preclinical research. However, there is still much research to be done to be able to defeat the limitations of traditional anticancer therapy. This review focuses on the potential of nanoparticle delivery systems in cancer treatment and the current advances achieved.

Granulación por fusión en mezcladores granuladores de alta velocidad / Melt granulation in high shear mixer

La granulación por fusión en un solo paso es una técnica alternativa basada en la utilización de un agente aglutinante sólido que funde a temperaturas entre 50-80 ºC, en lugar de solventes acuosos u orgánicos. Esta propiedad permite emplear esta técnica para la formulación de fármacos sensibles a la humedad, evitar el controvertido uso de solventes orgánicos y acortar el proceso de granulación en términos de tiempo y energía al eliminar la fase de secado. Asimismo, una adecuada selección del agente aglutinante y del resto de excipientes permitirá el desarrollo y elaboración de formas farmacéuticas tanto de liberación inmediata como de liberación controlada. Uno de los equipos más empleados en la granulación por fusión es el mezclador granulador de alta velocidad, que permite realizar esta técnica en un solo paso. Además, una vez optimizado el proceso, permite su aplicación a escala industrial. En este artículo se realiza una descripción de la técnica de granulación por fusión y las variables que influyen en dicho proceso en un mezclador granulador de alta velocidad

Preparation of sustained release hydrophilic matrices by melt granulation in a high-shear mixer.

PURPOSE: The objective of this work was to prepare theophylline sustained release matrix tablets based on the combination of hydroxypropyl methylcellulose (HPMC K4M and K100M) and different meltable binders by melt granulation in a high-shear mixer. METHODS: Dissolution profiles of each formulation were compared to those of TheoDur 200 mg tablets and the mean dissolution time (MDT) and similarity factor (f2 factor) were calculated. The matrices swelling behavior was investigated by texture analysis. RESULTS: The results obtained show that the type of excipient influenced the drug release rate. In particular, the dissolution rate was delayed when lipophilic binders were used and only formulations containing Gelucire 50/13 or PEG 6000 with HPMC K4M had a profile similar to the commercial formulation. The release mechanism of theophylline from the formulations was described by Peppas's equation showing a non-Fickian release mechanism. The investigation of matrices swelling behavior showed that the gel layer thickness increased continuously over the time period studied. Moreover, a correlation between gel layer thickness and strength with the percentage released was found. CONCLUSIONS: These results suggest that melt granulation could be an easy and fast method to formulate sustained release tablets.

Enhancing immunogenicity and reducing dose of microparticulated synthetic vaccines: single intradermal administration.

PURPOSE: Our purpose was to evaluate the ability of a polymeric vehicle to release a model synthetic vaccine to the skin in order to reach a potent activation of the specific immune response. METHODS: The peptide-loaded poly-D,L-lactide-co-glycolide acid (PLGA) microparticles were prepared by a double emulsion technique and administered to Balb/c mice. The immune response (antibody and T cell activation) obtained by the intradermal (i.d.) and the subcutaneous (s.c.) routes was tested. RESULTS: When similar doses of peptide-loaded microparticles were injected s.c. or i.d. in mice, the antipeptide IgG antibody immune response was found to be significantly higher after i.d. injection into the skin. We could also reduce the dose of antigen 10 times by the i.d. route and find a similar antibody response to that obtained by the s.c. immunization. At the lowest i.d. dose level, the IgG2a/IgG1 ratio was also incremented and the IgE production decreased. The i.d. microparticles induced, at both dose levels, a marked IFN-gamma secretion by peptide-stimulated splenocytes and lymph node cells and a significant T cell proliferation in spleen cell cultures. CONCLUSIONS: The results demonstrate that peptide-loaded microparticles were efficiently administered by the i.d. route because lower doses were required and powerful antibody and T cell responses were obtained compared to the conventional s.c. administration.

Cell microencapsulation technology for biomedical purposes: novel insights and challenges.

The aim of cell microencapsulation technology is to treat multiple diseases in the absence of immunosuppression. Using this technique, cells are immobilized within carefully designed capsules that allow the long-term function of the graft. Although the potential impact of this field is likely to be wide-ranging, the past few years have seen several 'firsts' that have brought the whole technology much closer to a realistic clinical application.