Preparation, characterization and efficacy evaluation of synthetic biocompatible polymers linking natural antioxidants.

The purpose of this work was the synthesis, characterization and efficacy evaluation of new biocompatible antioxidant polymers linking trans-ferulic acid or a-lipoic acid. In particular, ferulic or lipoic acid were introduced in the preformed polymeric backbone. The new antioxidant biopolymers were characterized by Fourier transform infrared spectroscopy and gel permeation chromatography. The degree of functionalization (moles of antioxidant per gram of polymer) was determined by the Gaur-Gupta method for free amino group determination and by the Folin method for the phenolic groups. Their ability to inhibit lipid peroxidation were estimated in rat liver microsomal membranes induced in vitro by tert-BOOH (tert-butyl hydroperoxide), as a source of free radicals. The DPPH (1,1-diphenyl-2-picrylhydrazyl) radical-scavenging effect was also evaluated. The obtained systems, with different solubility, showed strong antioxidant and antiradical activities, suggesting potential use as packaging materials for foods, cosmetics, pharmaceuticals and personal care products. Moreover, the cytotoxicity of the synthesized polymers was also evaluated on Caco-2 cell cultures in order to verify their biocompatibility when exposed to an absorptive epithelial cell line.

Synthesis, characterization, and anti-inflammatory activity of diclofenac-bound cotton fibers.

In the present work, we report on the synthesis of cellulose cotton fibers covalently linked to diclofenac moieties and the evaluation of the anti-inflammatory activity of this new biomaterial. In spite of recent progress in experimental and clinical medicine, the problem of chronic wounds treatment is still debated. In fact, conventional methods are based on the use of ointment-soaked bandages, but several physical and biological factors contribute to making the efficacy of this method quite low. For this reason, we developed the idea to using modified cotton gauzes to prevent inflammation during wound healing. In this light, diclofenac, a nonsteroidal anti-inflammatory drug, was covalently linked to the cellulose backbone of hydrophilic cotton fibers by a heterogeneous synthesis to produce a functionalized biopolymer with a satisfactory degree of substitution and anti-inflammatory activity. Diclofenac was directly linked to fiber microfibril hydroxylic groups using THF with thionyl chloride. The obtained biopolymer was characterized by infrared spectroscopy (FT-IR) to confirm ester linkages. Finally, the anti-inflammatory activity was evaluated in a well-established in vivo model. The results suggested that these biomaterials possess an excellent anti-inflammatory activity in vivo, so they can be efficiently employed in biomedical fields for chronic wound management to ensure a valid protection against inflammation.

L-lysine pro-prodrug containing trans-ferulic acid for 5-amino salicylic acid colon delivery: synthesis, characterization and in vitro antioxidant activity evaluation.

In the present work, we report the synthesis of a new 5-amino salicylic acid (5-ASA) pro-prodrug, useful in Crohn disease treatment, and the evaluation of its antioxidant activity. Using as pharmacological carrier L-lysine amino acid and taking advantage of its intrinsic chemical reactivity, due to the presence of two amino groups, placed on the chiral center and in epsilon-position, we inserted trans-ferulic acid in epsilon-position, through amidation reaction, esterified with methanol the carboxylic group and, finally, submitted the free amino group to diazotation with 5-ASA, principal drug for inflammatory bowel diseases (IBD) care. All intermediates of synthesis and the final product (derivative A) were characterized with usual spectroscopic techniques, as FT-IR, GC/MS and (1)H-MNR. Finally, the derivative A antioxidant activity in inhibiting the lipid peroxidation, in rat-liver microsomal membranes, induced in vitro by two different sources of free radicals, 2,2'-azobis (2-amidinopropane) (AAPH) and tert-butyl hydroperoxide (tert-BOOH), was evaluated. Our pro-prodrug could be successfully applied in pharmaceutical field both as prodrug of 5-ASA than as carrier of trans-ferulic acid.

Preparation, characterization and in vitro activities evaluation of solid lipid nanoparticles based on PEG-40 stearate for antifungal drugs vaginal delivery.

The present article reports the preparation, characterization and performance evaluation of solid lipid nanoparticles (SLNs) based on polyoxyethylene-40 stearate (PEG-40 stearate) for the administration of antifungal agents such as ketoconazole and clotrimazole. These nanoparticles could be useful in the treatment of vaginal infections sustained by Candida albicans. In particular, PEG-40 stearate was made to react with acryloyl chloride in order to introduce an easily polymerizable moiety for the creation of a second shell and to ensure a slow drug release. In addition, the differences on the release profiles between PEG-40 stearate-based nanoparticles, PEG-40 stearate acrylate based and polymerized ones, were analyzed under conditions, simulating the typical environment of Candida albicans infection. Then, the antifungal activity of nanoparticles was also evaluated in terms of minimal inhibitory concentration. Moreover, the nanoparticles were submitted to in vitro studies for evaluating the drug permeability at the site of action. Results indicated that the obtained particles are potentially useful for the treatment of vaginal infections sustained by Candida albicans.

A new pro-prodrug aminoacid-based for trans-ferulic Acid and silybin intestinal release.

The aim of this work was the preparation and characterization of a pro-prodrug able to simultaneously transport silybin, a drug possessing various pharmacological effects, and trans-ferulic acid, a known antioxidant. More specifically, l-phenylalanine-N-(4-hydroxy-3-methoxy-phenyl) prop-2-en-O-(2R,3R)-3,5,7-trihydroxy-2-((2R,3R)-3-(4-hydroxy-3-methoxyphenyl)-2-(hydroxymethyl)-2,3-dihydro-benzo-(1,4)-dioxin-6-yl)croman-4-one was synthesized by using the aminoacid l-phenylalanine (l-Phe) as carrier. Indeed, l-Phe is characterized by an intrinsic chemical reactivity due to the presence of an amino group, placed on the chiral center, and of a carboxylic group. The synthesis has been characterized first by adding silybin by means of carboxylic group and then, with the aim to confer antioxidant properties to this new carrier, by linking trans-ferulic acid to l-Phe via amino group. The so obtained derivative was then characterized by FT-IR, and 1H-NMR spectroscopies. Furthermore, its ability to inhibit lipid peroxidation induced by tert-butyl hydroperoxide in rat liver microsomes, was evaluated. The 1,1-diphenyl-2-picrylhydrazyl radical-scavenging effect, was also assessed. The release of silybin and trans-ferulic acid was determined in simulated gastric and intestinal fluids over the time. The results showed that the covalent bond between both (i) silybin; or (ii) trans-ferulic acid and the amino acid was degraded by enzymatic reactions. In addition, the pro-prodrug, showed strong antioxidant and scavenger activities. Due to these properties, this new pro-prodrug could be applied for the treatment of intestinal pathologies and it might improve the therapeutic potential of silybin which is strongly limited by its low solubility.

Trans-ferulic acid-based solid lipid nanoparticles and their antioxidant effect in rat brain microsomes.

In this study, stearic acid- and stearyl ferulate-based solid lipid nanoparticles containing trans-ferulic acid (SLN-FA and SLN-SF-FA, respectively), were prepared and characterized for loading efficiency, size and shape. In addition, by using rat brain microsomes, we evaluated in vitro the antioxidant activity of these formulations against three well known initiators of lipid peroxidation, such as AAPH, NADPH/ADP-Fe(3+) and SIN-1 which in turn generate the peroxyl and perferryl radicals as well as peroxynitrite, respectively. Commercially available FA and its ethyl ester (FAEE) were used as comparators. Both SLN-FA and SLN-SF-FA dose-dependently reduced lipid peroxidation induced by the three oxidants. Interestingly, SLN-SF-FA displayed greater efficacy (EC50) and potency (maximal activity) against AAPH- and NADPH/ADP-Fe(3+)-induced lipid peroxidation. Our results support the idea that this new formulations could facilitate the uptake of FA by the cells because of their lipophilic structure, thus increasing FA bioavailability. Furthermore, stearyl ferulate-based nanoparticles could prevent the degradation of FA entrapped on their structure, making FA almost entirely available to explicate its antioxidant power once released.

Dextran-pegylated microparticles for enhanced cellular uptake of hydrophobic drugs.

Polyethylene glycol monosubstituted with a polymerizable acrylic moiety was linked to 6-carboxy free position on dextran side chains and then subjected to radical polymerization with a comonomer in order to obtain microspheres for the oral controlled release of ketoconazole, a hydrophobic model drug. Microparticles were submitted to studies on their ability to absorb and retain water. Cell uptake studies, in the presence and absence of mucus, across two different monolayers, respectively, HT29-MTX-E12 and Caco-2, were done. Cytotoxicity studies were carried out to calculate the IC50 value. The ability of microspheres to open monolayers tight junctions was tested by measuring their TEER values. Images of cell uptake were visualized by CLSM. In HT29-MTX-E12 cells, more mucoadhesion and drug internalization is seen thanks to the presence of PEG and dextran chains.

Anticancer activity of a hydrogel containing folic acid towards MCF-7 and MDA-MB-231 cells.

AIM: The aim of the present study was to prepare a hydrogel, based on ellagic acid and glycine, embedded with folic acid, as a subcutaneous implant for the treatment of breast cancer. The function of folic acid is to selectively and actively target tumor cells which are well-known to overexpress folic acid receptors on their surface. MATERIALS AND METHODS: A pro-drug based on L-glycine and ellagic acid, was functionalized with a polymerizable group and loaded with folic acid to make it more natural, non-toxic, compatible and specific for the site of action. Cytotoxicity against MCF-7 cells was also evaluated. Release studies of folic acid were conducted on aliquots of hydrogel at different pH (6.2 and 7.4) and time-points (1, 6, 12 and 24 h) using a shaking water bath at 37°C (body temperature). RESULTS: Our results show that folic acid release by the hydrogel is characterized by a slow kinetic release, especially at pH 6.2. Moreover, it was evidenced that the exposure of human breast cancer cells to ellagic acid-based hydrogel containing folic acid significantly reduced cell viability.

Isoniazid-gelatin conjugate microparticles containing rifampicin for the treatment of tuberculosis.

OBJECTIVES: In this work, a new polymeric microparticle system based on gelatin covalently bound to isoniazid (ISN) and containing rifampicin (RFP) was prepared by spray-drying technique. Microparticle aptitude to nebulisation and their capability of interacting with A549, alveolar basal epithelial cells, were evaluated in vitro. METHODS: Microparticles were obtained by spray drying, and their morphology, size, zeta potential, thermotropic behaviour and nebulisation ability were evaluated. KEY FINDINGS: Microparticles were positively charged with a mean size of 4.88 ± 0.3 µm. Microspheres were able to incorporate both RFP and ISN: encapsulation efficiency was 51 ± 6% and 22 ± 1%, respectively. X-ray diffraction study showed a new extensive and flattened diffraction peak providing evidence that the drugs were dispersed into the microparticles. Differential scanning calorimetry analysis confirmed effective interactions between gelatin and drug molecules by the presence of new transition peaks. Fifty-nine per cent of used microparticles were aerosolised. In-vitro toxicity studies on A549 alveolar basal epithelial cells showed that microparticles decreased cytotoxicity in comparison with the RFP solution. Laser scanning confocal microscopy observation confirmed that fluorescent probes delivered by microparticles are efficiently internalised in A549 cells. CONCLUSIONS: Overall, microparticles based on gelatin covalently bound to ISN and containing RFP showed a promising behaviour for pulmonary drug delivery.

Synthesis, characterization and in-vitro antitubercular activity of isoniazid-gelatin conjugate.

OBJECTIVES: A novel and simple method to synthesize antitubercular-protein conjugate by solid phase synthesis was developed employing a carboxypolystyrene resin. The aim was to covalently bind a drug with antitubercular activity, isoniazid, to a biomacromolecule, gelatin, widely used in the pharmaceutical, cosmetic and food industry. METHODS: Calorimetric and (1) H NMR analyses were performed to verify the bond formation between the antitubercular drug and gelatin. After absorption isoniazid delivers toxic metabolites and so an oxidation test with tert-butyl hydroperoxide was performed to assess the amount of toxic metabolites released from the prodrug (gelatin linked to isoniazid), compared with isoniazid itself. KEY FINDINGS: Spectrophotometric analysis revealed that the protein derivative was an excellent isoniazid prodrug since there was a 40% reduction in release of toxic metabolites (isonicotinic acid) by the prodrug. The results clearly showed that antitubercular moieties, covalently linked to a natural polymer, allowed the introduction of peculiar features for specific pharmaceutical applications into the macromolecule. In addition, antitubercular activity of the new polymer was determined by Middlebrook 7H11 medium against Mycobacterium tuberculosis complex. CONCLUSIONS: The new isoniazid-gelatin conjugate showed significant antitubercular activity and for this reason should be useful as an efficacious tool in the treatment of tuberculosis.

Respirable rifampicin-based microspheres containing isoniazid for tuberculosis treatment.

The purpose of this investigation was to develop small microspheres for delivering antimycobacterial drugs to infected host macrophages. Rifampicin-based microparticles were prepared. The drug was covalently linked to acrylic moieties to obtain a polymerizable derivative for the preparation of materials useful as drug delivery systems that then were loaded with isoniazid acting in synergy with rifampicin. Their antitubercular activity was determined in vitro. Fourier transform infrared spectroscopy confirmed hydrogel structure. Morphological analysis showed microparticles with spherical shape and homogeneous surface. In vitro release studies were performed in media simulating physiologic pH (7.4) and endosomal of alveolar macrophages pH (5.2). A similar amount of isoniazid was delivered within the first 6 h at both pHs, while a smaller amount of the drug was delivered at pH 7.4 in the last phase of the study. In vitro antitubercular activity showed a behavior comparable to that of rifampicin and isoniazid free. Bioactive swelling matrices, showing a high swelling degree into a medium miming intra alveolar environment, were obtained. They could be applied for their antitubercular activity.

Synthesis of pro-prodrugs L-lysine based for 5-aminosalicylic acid and 6-mercaptopurine colon specific release.

The aim of this work is to design, prepare and characterize L-lysine based prodrugs capable of targeting 6-mercaptopurine to the colon, an anti-tumor and immunosuppressant drug, and 5-aminosalicylic acid (5-ASA), drug of choice for inflammatory bowel disease (IBD). More specifically, Nɛ-feruloyl-S-(6-purinyl)-L-lysine and Nɛ-acryloyl-S-(6-purinyl)-L-lysine were synthesized and then characterized by FT-IR, (1)H-NMR and GC/MS spectroscopies. The ability of feruloyl derivative in inhibiting lipid peroxidation in rat liver microsomal membranes, induced in vitro by tert-butyl hydroperoxide as source of free radicals, was evaluated. Moreover, Nɛ-acryloyl-S-(6-purinyl)-L-lysine, polymerizable prodrug, was used to microspheres realization for 5-ASA release. These lasts, obtained by emulsion inverse technique, were characterized by light scattering and scanning electron microscopy (SEM) analysis. The microspheres equilibrium swelling degree was evaluated and showed good swelling behaviour in simulating colonic fluids. Results confirm the possibility that the application range of L-lysine prodrug can be extended to the treatment of intestinal diseases whose conventional therapy envisages medications with serious side effects that, thanks to this new strategy, can be minimized in an optimal way.

A new approach for the evaluation of niosomes as effective transdermal drug delivery systems.

The central motivation for this study was to evaluate if the increased hydrophilic drug permeation across the skin, which is always observed in presence of vesicular systems, is dependent on the structural organization of niosomes, that are used to transport the active molecules, or if it is only dependent on the surfactant dual nature. To answer this question, non-ionic surfactants belonging to the class of Pluronic and sucrose esters were used both as components of niosomal systems or in the form of sub-micellar solutions. The obtained niosomes were characterized by their entrapment efficiency, size and morphology. The enhancing effect of niosomes on the ex vivo percutaneous penetration of a model drug was investigated using a Franz-type diffusion chamber and compared to that obtained by using sub-micellar solution of surfactant or achieving pretreatment of the skin with surfactants' sub-micellar solution or empty niosomes. The results suggest that the surfactants used in this study could be considered as percutaneous permeation enhancers only when they are in the form of drug-loaded vesicular systems: no percutaneous promotion was achieved by using sub-micellar solution containing free Sulfadiazine sodium salt or performing pretreatment with empty niosomes or sub-micellar solutions of the surfactant. In our experiments, only niosomes act as effective transdermal drug delivery systems.

New sucrose cocoate based vesicles: Preparation, characterization and skin permeation studies.

A commercial sucrose cocoate surfactant was used to obtain a new vesicular system for transdermal drug delivery. The preparation, the dimensional and morphological characterizations and the skin permeation profile of these new niosomes were evaluated. Moreover we studied the possible employment of mixture of sucrose cocoate and cholesterol at different weigh ratios for the vesicles preparation and we analyzed the influence of cholesterol on niosomes properties. Diclofenac and Sulfadiazine were used as model drugs. Results suggest that sucrose cocoate was able to form vesicles in the presence or not of cholesterol and the addition of cholesterol leads to a variation of size: larger vesicles were obtained in the absence of cholesterol both in empty and drug-loaded niosomes. All vesicles were spherical and regular in shape. In vitro skin permeation profiles were significantly higher than the free drug solution, indicating the favourable relations between skin and niosomes. The faster release of the drug was found for niosomes with no cholesterol or with a reduced amount of this membrane additive, in particular the optimal formulation was that in which the cholesterol content was about 27 wt% of total lipid amount: probably this value is a good compromise between the membrane stability and its deformation capacity, allowing a higher drug permeation across the skin.