Ophthalmic administration of a 10-fold-lower dose of conventional nanoliposome formulations caused levels of intraocular pressure similar to those induced by marketed eye drops.

The purpose of this study was to compare the in vivo efficacy of several timolol (TM)-loaded liposomal formulations with current TM antiglaucoma treatment (aqueous 0.5% w/v eye drops). In this study, conventional liposomes (CL) and deformable liposomes, without (DL1) and with ethanol (DL2) were prepared and characterized. In addition, in vitro release and permeation studies, as well as in vivo lowering intraocular pressure (IOP) and biocompatibility studies were performed. It was found that the quali and quantitative lipid bilayer composition played a significant role in modifying the physical properties of vesicles. The deformability study and electronic microscopy images revealed that membrane elasticity of DL1 and DL2 was much higher than CL. However, in vitro permeation results showed that the flux and permeability coefficient were significantly higher in CL compared to DL. The IOP study revealed that TM-loaded CL showed the best pharmacological activity, in comparison to deformable vesicles. Compared to the eye drops, CL formulation could equally reduce the IOP but using a concentration 10-fold lower, whereas the effective time was significantly longer. In addition, the formulations showed no irritant effects after instillation on the ocular surface.

Deformability properties of timolol-loaded transfersomes based on the extrusion mechanism. Statistical optimization of the process.

The purpose of this work was to analyze the deformability properties of different timolol maleate (TM)-loaded transfersomes by extrusion. This was performed because elastic liposomes may contribute to the elevation of amount and rate of drug permeation through the corneal membrane. This paper describes the optimization of a transfersome formulation by use of Taguchi orthogonal experimental design and two different statistical analysis approaches were utilized. The amount of cholesterol (F1), the amount of edge-activator (F2), the distribution of the drug into the vesicle (F3), the addition of stearylamine (F4) and the type of edge-activator (F5) were selected as causal factors. The deformability index, the phosphorous recovery, the vesicle size, the polydispersity index, the zeta potential and percentage of drug entrapped were fixed as the dependent variables and these responses were evaluated for each formulation. Two different statistical analysis approaches were applied. The better statistical approach was determined by comparing their prediction errors, where regression analysis provided better optimized responses than marginal means. From the study, an optimized formulation of TM-loaded transfersomes was prepared and obtained for the proposed ophthalmic delivery for the treatment of open angle glaucoma. It was found that the lipid to surfactant ratio and type of surfactant are the main key factors for determining the flexibility of the bilayer of transfersomes. From in vitro permeation studies, we can conclude that TM-loaded transfersomes may enhance the corneal transmittance and improve the bioavailability of conventional TM delivery.

Effect of processing on polyamine content and bioactive peptides released after in vitro gastrointestinal digestion of infant formulas.

This study examined the influence of processing on polyamines and peptide release after the digestion of a commercial infant formula designed for children during the first months of life. Polyamine oxidase activity was not suppressed during the manufacturing process, which implicates that polyamine concentrations were reduced over time and during infant formula self-life. In gel electrophoresis, in vitro gastrointestinal digestion of samples with reduced amount of enzymes and time of digestion shows an increase in protein digestibility, reflected in the increase in nonprotein nitrogen after digestion and the disappearance of ß-lactoglobulin and α-lactalbumin bands in gel electrophoresis. Depending on the sample, between 22 and 87 peptides were identified after gastrointestinal digestion. A peptide from ß-casein f(98-105) with the sequence VKEAMAPK and antioxidant activity appeared in all of the samples. Other peptides with antioxidant, immunomodulatory, and antimicrobial activities were frequently found, which could have an effect on infant health. The present study confirms that the infant formula manufacturing process determines the polyamine content and peptidic profile after digestion of the infant formula. Because compositional dissimilarity between human milk and infant formula in polyamines and proteins could be responsible for some of the differences in health reported between breast-fed and formula-fed children, these changes must be taken into consideration because they may have a great effect on infant nutrition and development.

Surface functionalizing of a lipid nanosystem to promote brain targeting: step-by-step design and physico-chemical characterization.

The use of lipid nanosystems as drug delivery to the central nervous system may be advantageous over the current strategies. The aim of this study was to develop and characterize functionalized liposomes for treatment of brain diseases. The covalent method of coupling IgG to liposomes via the derivatized lipid 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine-N-[4-(p-maleimidophenyl)butyramide](MPB-PE) was investigated. Optimized coupling conditions are shown to result in the efficient conjugation of IgG to liposomes containing low concentrations of MPB-PE (3/1 SH:IgG). The qualitative analysis has shown that after the extrusion process, more homogeneous populations of vesicles have been obtained with a nanometric size suitable to be effective to further anchor the protein. Negative values of zeta potential demonstrate that they are stable systems. Lyophilization was used to maintain the stability of the formulation. These very interesting results encourage further investigations to formulate peptide- and protein-loaded immunoliposomes, making targeting of liposomes as an attractive approach for brain drug delivery.

Development and validation of a high performance chromatographic method for determining sumatriptan in niosomes.

In this paper, a novel, precise, specific, accurate and rapid reversed-phase high performance liquid chromatographic method was developed, optimized and validated for determining sumatriptan succinate in niosomes with the best chromatographic peak resolution, reduced run time and low cost of analysis. The formulation has been previously optimized in terms of composition and preparation technique to obtain a high drug encapsulation efficiency and adequate vesicle size distribution. This method showed the best resolution by using Spherisorb OSD2 C18 column (250 mm × 4.6 mm, 5 µm) using phosphate buffer (0.05 M):acetonitrile (80:20, v/v; pH adjusted to 6.0) as a mobile phase at a flow rate of 1 mL/min and wavelength of 214 nm. The main objective of this research was to demonstrate the robustness of the reversed-phase HPLC method development by applying the Taguchi robust methodology. The signal-to-noise ratio (S/N) was employed as a quality measurement. This tool permits to establish the influence of some selected factors (acetonitrile:phosphate ratio, pH buffer, oven temperature and flow rate) on two responses (peak areas and retention time). On the basis of the results obtained, we can conclude that this analytical method was robust for all the factors studies, as exception of the flow rate, where the higher quality was obtained for the fewer values (0.8 mL/min). Therefore, this parameter must be carefully controlled when this method was employed, to avoid any modification in the peak areas overall.

Insulin-loaded PLGA microparticles: flow focusing versus double emulsion/solvent evaporation.

CONTEXT: Oral administration of insulin is severely limited by very low bioavailability. Biocompatible polymeric nanocarriers have been investigated to overcome this problem. Flow focusing (FF) has revolutionized current engineering of poly(D,L-lactide-co-glycolide) (PLGA) based micromedicines. This technique has never been used to formulate insulin-loaded PLGA microparticles. OBJECTIVE: Investigation of the benefits rising from the synthesis of insulin-loaded PLGA microplatforms by FF, compared to double emulsion/solvent evaporation method. MATERIALS AND METHODS: Both synthesis methodologies were compared in terms of geometry, surface physicochemical properties and insulin vehiculization capabilities. The stability of the peptide during the formulation procedure was further analysed. RESULTS: FF permitted the preparation of insulin-loaded microcarriers with better geometry and physicochemical properties for the oral route, along with greater insulin loading capabilities and sustained insulin release kinetics. DISCUSSION AND CONCLUSION: Results have lead to the identification of the best formulation conditions for the engineering of insulin-loaded PLGA microparticles against diabetes.

Protein-loaded PLGA microparticles engineered by flow focusing: physicochemical characterization and protein detection by reversed-phase HPLC.

In the present study, a novel synthesis technique based on the flow focusing (FF) technology is investigated for the preparation of green fluorescent protein (GFP)-loaded poly(D,L-lactide-co-glycolide) (PLGA) microparticles. To our knowledge, this novel technique has never been applied to the formulation of proteins in polymeric systems. A simple, specific and rapid reversed-phase HPLC (RP-HPLC) method was validated for the determination of GFP in PLGA microparticles with the best chromatographic peak resolution, reduced run time and low cost of analysis. In order to achieve the finest GFP-loaded polymeric particles, experimental parameters mainly associated to the FF device were studied (liquid flow rate and pressure of the focusing air). Very high GFP encapsulation values (>90%) were obtained by this technique, and the electrokinetic characterization of these systems suggested that this protein was incorporated into the polymeric matrix. This study is intended to offer information on which to base the development of high molecular weight protein-loaded polymeric delivery systems prepared by FF.

[Quality of data on folic acid content in vegetables included in several Spanish Food Composition Tables and new data on their folate content]. / Calidad de los datos del contenido en ácido fólico en vegetales recogidos en varias tablas de composición de alimentos españolas, y nuevos datos sobre su contenido en folatos.

The relationship between adequate folate intake, adequate serum levels, and lowering the risk of suffering from cardiovascular diseases, neural tube defects, neural illness and some kind of cancers have been widely studied. Because of the expected health benefits, the consumption of foods with high folate content or enriched foods is increasing. Therefore, an adequate folate intake is important in order to reach acceptable serum levels. Reliable food composition data are necessary in order to evaluate and estimate the populations folate intake, elaborate diets and formulate recommended dietary intakes. For this reason, we revised folic acid data in Spanish Food Composition Tables (FCT). The quality of the data was evaluated and compared with other well-known international Food Composition Tables as well as with a high-resolution liquid chromatographic method (HPLC) validated in our laboratory. We evaluated all data about folate content, as well as all the information given like data origin, analytical method, sampling or original database. For the HPLC method, the food samples were incubated with hog kidney conjugase. After that, the samples were purified and concentrated by strong anion exchange (SAX), then the folate content was quantified by HPLC with a combination of two ultraviolet and fluorescence detectors. The evaluation and comparison of data was established according to some parameters, which define the quality of data, giving punctuation depending on the compliance with these parameters. The study of different sources showed that nutrients were different in definition, analysis method, units and expression of data, and that this fact could have a potential influence on TCA data values. In addition, it has been possible to show a wide variation in food number, name of these foods as well as the analysis of raw or cooked products with different composition. When the quality conditions were tested, the Spanish FCT had the lowest punctuation in folate content data. That is because the Spanish FCT did not use a validated method to quantify folic acid in foods (Direct method of FCT elaboration), but they used folate content data from others FCT (Indirect method of FCT elaboration). These data manifest the importance of getting a consensus method to determine folate content in foods with the aim to obtain a FCT with reliable folate data.