Layer-by-layer vaginal films for acyclovir controlled release to prevent genital herpes.

Genital herpes is one of the most common sexually transmitted infections worldwide. It mainly affects women, as the rate of sexual transmission from male-to-female is higher than from female-to-male. The application of vaginal antivirals drugs could reduce the prevalence of genital herpes and prevent future infections. Layer-by-layer vaginal films were prepared by the solvent evaporation method using iota-carrageenan, hydroxypropyl methylcellulose and the polymethacrylates Eudragit® RS PO and Eudragit® S100, for the controlled release of acyclovir. The films were characterized by texture analysis and Raman spectroscopy. Swelling, mucoadhesion, and drug release studies were conducted in simulated vaginal fluid. The results show that Layer-by-Layer films exhibited adequate mechanical properties. The structuring of the layer-by-layer films allowed the controlled release of acyclovir and produced a prolonged mucoadhesion residence time of up to 192 h. The films formed in layer 2 by the combination of Eudragit® RS PO and S100 showed a controlled release of acyclovir for eight days, and adequate mechanical properties. These promising formulations for the prevention of genital herpes deserve further evaluation.

Smart vaginal bilayer films of Tenofovir based on Eudragit® L100/natural polymer for the prevention of the sexual transmission of HIV.

In the absence of an effective vaccine, vaginal microbicides are essential for preventing the sexual transmission of HIV to women. Antiretroviral vaginal films have emerged as promising choices, especially those offering mucoadhesivity and controlled drug release. Tenofovir-loaded bilayer films based on Eudragit® L100 (EL100) and a biopolymer - gum arabic, karaya gum, pectin or tragacanth gum - were developed in a single-stage process. Cytotoxicity studies in three human cell lines indicated no toxicity of the excipients at the concentrations tested. Raman spectroscopy and SEM confirmed the formation of the two layers and their anchoring. Texture analysis showed no major differences between the batches. The swelling of the film is conditioned by its biopolymer nature and by the amount of EL100, which acts as structuring agent thus enhancing swelling. Tragacanth gum-based batches showed high mucoadhesion regardless the amount of EL100. The controlled release of Tenofovir in simulated vaginal fluid was faster in the presence of simulated seminal fluid due to the dissolution of EL100. Films containing 400 mg of EL100 and tragacanth gum are promising candidates for future studies, as they could sexually safeguard women from HIV for at least one week and ensure greater protection during intercourse.

Amino Functionalized Micro-Mesoporous Hybrid Particles for the Sustained Release of the Antiretroviral Drug Tenofovir.

The sustained release of an antiretroviral agent to women mucosa has been proved as an excellent strategy to reduce the sexual transmission of HIV. Hybrid micro-mesoporous particles have been synthesized and functionalized with a silane coupling agent followed by loading the antiretroviral tenofovir. It has been observed that the disposition of the silane molecule on the surface of the particles determines the interaction mechanism with the antiretroviral molecule loaded independently on the surface area of the particles. In this sense, available and free amino groups are required to achieve a smart pH-responsive material, a condition that is only achieved in those materials containing a silane chemisorbed monolayer. Moreover, the modulation of the release kinetics attributed to the presence of the silane monolayer covering the mesopores has been confirmed by fitting the releasing curves to the first order and Weibull models. The developed micro-mesoporous particles have been demonstrated to be excellent smart-release vehicles for antiviral agents and can be safely used in polymer mucoadhesive vaginal gels.

Development and In Vitro/Ex Vivo Characterization of Vaginal Mucoadhesive Bilayer Films Based on Ethylcellulose and Biopolymers for Vaginal Sustained Release of Tenofovir.

Young women in sub-Saharan Africa have the highest risk of human immunodeficiency virus (HIV) acquisition through sexual contact of all groups. Vaginal controlled release of antiretrovirals is a priority option for the prevention of sexual transmission of the virus in women. In this manuscript, bilayer films were prepared based on ethylcellulose and a natural polymer (xanthan or tragacanth gum) plasticized with glycerol and tributylcitrate for tenofovir-controlled release. The mechanical properties and microstructure of the blank films were characterized by texture analysis, Fourier transform infrared spectroscopy, and scanning electron microscopy. The loaded films were evaluated in simulated vaginal fluid through release and swelling studies and ex vivo mucoadhesion assessments. The results show that the preparation method produced bilayer films with adequate mechanical properties. The contribution of both layers allowed the sustained release of tenofovir and a mucoadhesion time of up to 360 h. The toxicity of the materials was evaluated in three cell lines of vaginal origin. The films constituted by ethylcellulose and xanthan gum in a 2:1 proportion (EX2-D) showed the longest mucoadhesion time, with 15 days of tenofovir-controlled release, zero toxicity, and optimal mechanical properties. These films are therefore a promising option for offering women a means of self-protection against the sexual transmission of HIV.

Vaginal Polyelectrolyte Layer-by-Layer Films Based on Chitosan Derivatives and Eudragit® S100 for pH Responsive Release of Tenofovir.

Women are still at high risk of contracting the human immunodeficiency virus (HIV) virus due to the lack of protection methods under their control, especially in sub-Saharan countries. Polyelectrolyte multilayer smart vaginal films based on chitosan derivatives (chitosan lactate, chitosan tartate, and chitosan citrate) and Eudragit® S100 were developed for the pH-sensitive release of Tenofovir. Films were characterized through texture analysis and scanning electron microscopy (SEM). Swelling and drug release studies were carried out in simulated vaginal fluid and a mixture of simulated vaginal and seminal fluids. Ex vivo mucoadhesion was evaluated in bovine vaginal mucosa. SEM micrographs revealed the formation of multilayer films. According to texture analysis, chitosan citrate was the most flexible compared to chitosan tartrate and lactate. The swelling studies showed a moderate water uptake (<300% in all cases), leading to the sustained release of Tenofovir in simulated vaginal fluid (up to 120 h), which was accelerated in the simulated fluid mixture (4-6 h). The films had high mucoadhesion in bovine vaginal mucosa. The multilayer films formed by a mixture of chitosan citrate and Eudragit® S100 proved to be the most promising, with zero toxicity, excellent mechanical properties, moderate swelling (<100%), high mucoadhesion capacity, and Tenofovir release of 120 h and 4 h in vaginal fluid and the simulated fluid mixture respectively.

Development of mucoadhesive vaginal films based on HPMC and zein as novel formulations to prevent sexual transmission of HIV.

Although vaginal films were initially developed for a fast release of the drug, with the adequate formulation they can also be useful for sustained release. The latest strategies for the prevention of the sexual transmission of HIV have moved towards sustained-release dosage forms, so films may be an effective strategy that could also improve the patient's comfort. A hydrophilic polymer (hydroxypropylmethyl cellulose) and an amphiphilic polymer (zein) have been evaluated for the development of Tenofovir sustained-release vaginal films. The modification of the film's properties by the inclusion of polar (glycerol and polyethylene glycol 400 (PEG)) and amphiphilic (tributyl citrate and oleic acid) plasticisers was also evaluated. The films' physicochemical and mechanical properties were determined. The in vitro release of Tenofovir from the films and their bioadhesive capacity and behaviour in simulated vaginal fluid were also assessed. The combination of hydroxypropylmethyl cellulose and zein in films (ratio 1:5), with the inclusion of PEG (40% w/w) proved not only to have excellent mechanical properties, but was also able to release TFV in a sustained manner for 120 h and remain attached to biological tissues throughout this time. This film could be an interesting option for the prevention of sexual transmission of HIV.

Dapivirine Bioadhesive Vaginal Tablets Based on Natural Polymers for the Prevention of Sexual Transmission of HIV.

Young sub-Saharan women are a group that is vulnerable to the sexual transmission of HIV. Pre-exposure prophylaxis through vaginal microbicides could provide them an option for self-protection. Dapivirine has been demonstrated to have topical inhibitory effects in HIV, and to provide protection against the sexual transmission of this virus. This paper reports on the studies into swelling behaviour, bioadhesion and release carried out on dapivirine tablets based on chitosan, locust bean gum and pectin, to select the most suitable formulation. The modified simulated vaginal fluid led to a high solubility of dapivirine and allowed the dapivirine release profiles to be characterized in sink conditions; this aqueous medium is an alternative to organic solvents, which are not a realistic option when evaluating systems whose behaviour varies in aqueous and organic media. Of the formulations evaluated, dapivirine/pectin tablets containing 290 mg of polymer and 30 mg of dapivirine present the most moderate swelling, making them the most comfortable dosage forms. Their high bioadhesive capacity would also allow the formulation to remain in the action zone and release the drug in a sustained manner, pointing to this formulation as the most promising candidate for future evaluations of vaginal microbicides for the prevention of HIV.

Freeze-dried bioadhesive vaginal bigels for controlled release of Tenofovir.

Nowadays, million women live with the human immunodeficiency virus (HIV) worldwide and many of them are dying per year, particularly in Sub-Saharan Africa. The development of systems that can be accessed by this population group to prevent the sexual transmission of the virus is therefore necessary. The aim of this work was the formulation of freeze-dried bioadhesive vaginal bigels releasing Tenofovir in a controlled manner. Systems containing three different proportions of guar gum hydrogel and sesame oil were prepared, adding Span®60 or Span®60 and Tween®60 as surfactants. Drug and excipients were evaluated by cytotoxicity assays, showing no toxicity at the concentrations tested neither for the drug nor any of the excipients. Fresh formulations were characterised through texture analyses and confocal laser microcopy. The system with the lowest guar gum hydrogel/sesame oil proportion and containing Span®60 and Tween®60 (batch ST1) had the highest consistency and adhesion capacity according to texture analyses. Furthermore, a genuine bigel microstructure was observed. After freeze-drying, swelling, bioadhesion and drug release tests were performed on the resulting systems. ST1 showed the longest bioadhesion time and the most controlled release, as well as a low swelling grade, becoming an interesting option for preventing HIV sexual transmission in women.

Influence of Chitosan Swelling Behaviour on Controlled Release of Tenofovir from Mucoadhesive Vaginal Systems for Prevention of Sexual Transmission of HIV.

The main challenges facing efforts to prevent the transmission of human immunodeficiency virus (HIV) are the lack of access to sexual education services and sexual violence against young women and girls. Vaginal formulations for the prevention of sexually transmitted infections are currently gaining importance in drug development. Vaginal mucoadhesive tablets can be developed by including natural polymers that have good binding capacity with mucosal tissues, such as chitosan or guar gum, semisynthetic polymers such as hydroxypropylmethyl cellulose, or synthetic polymers such as Eudragit® RS. This paper assesses the potential of chitosan for the development of sustained-release vaginal tablets of Tenofovir and compares it with different polymers. The parameters assessed were the permanence time of the bioadhesion-determined ex vivo using bovine vaginal mucosa as substrate-the drug release profiles from the formulation to the medium (simulated vaginal fluid), and swelling profiles in the same medium. Chitosan can be said to allow the manufacture of tablets that remain adhered to the vaginal mucosa and release the drug in a sustained way, with low toxicity and moderate swelling that ensures the comfort of the patient and may be useful for the prevention of sexual transmission of HIV.

Chitosan and Kappa-Carrageenan Vaginal Acyclovir Formulations for Prevention of Genital Herpes. In Vitro and Ex Vivo Evaluation.

Vaginal formulations for the prevention of sexually transmitted infections are currently gaining importance in drug development. Polysaccharides, such as chitosan and carrageenan, which have good binding capacity with mucosal tissues, are now included in vaginal delivery systems. Marine polymer-based vaginal mucoadhesive solid formulations have been developed for the controlled release of acyclovir, which may prevent the sexual transmission of the herpes simplex virus. Drug release studies were carried out in two media: simulated vaginal fluid and simulated vaginal fluid/simulated seminal fluid mixture. The bioadhesive capacity and permanence time of the bioadhesion, the prepared compacts, and compacted granules were determined ex vivo using bovine vaginal mucosa as substrate. Swelling processes were quantified to confirm the release data. Biocompatibility was evaluated through in vitro cellular toxicity assays, and the results showed that acyclovir and the rest of the materials had no cytotoxicity at the maximum concentration tested. The mixture of hydroxyl-propyl-methyl-cellulose with chitosan- or kappa-carrageenan-originated mucoadhesive systems that presented a complete and sustained release of acyclovir for a period of 8-9 days in both media. Swelling data revealed the formation of optimal mixed chitosan/hydroxyl-propyl-methyl-cellulose gels which could be appropriated for the prevention of sexual transmission of HSV.

Negatively charged glyconanoparticles modulate and stabilize the secondary structures of a gp120 V3 loop peptide: toward fully synthetic HIV vaccine candidates.

The third variable region (V3 peptide) of the HIV-1 gp120 is a major immunogenic domain of HIV-1. Controlling the formation of the immunologically active conformation is a crucial step to the rational design of fully synthetic candidate vaccines. Herein, we present the modulation and stabilization of either the α-helix or ß-strand conformation of the V3 peptide by conjugation to negatively charged gold glyconanoparticles (GNPs). The formation of the secondary structure can be triggered by the variation of the buffer concentration and/or pH as indicated by circular dichoism. The peptide on the GNPs shows increased stability toward peptidase degradation as compared to the free peptide. Moreover, only the V3ß-GNPs bind to the anti-V3 human broadly neutralizing mAb 447-52D as demonstrated by surface plasmon resonance (SPR). The strong binding of V3ß-GNPs to the 447-52D mAb was the starting point to address its study as immunogen. V3ß-GNPs elicit antibodies in rabbits that recognize a recombinant gp120 and the serum displayed low but consistent neutralizing activity. These results open up the way for the design of new fully synthetic HIV vaccine candidates.

The artemisia L. Genus: a review of bioactive essential oils.

Numerous members of the Anthemideae tribe are important as cut flowers and ornamental crops, as well as being medicinal and aromatic plants, many of which produce essential oils used in folk and modern medicine and in the cosmetics and pharmaceutical industry. Essential oils generally have a broad spectrum of bioactivity, owing to the presence of several active ingredients that work through various modes of action. Due to their mode of extraction, mostly by distillation from aromatic plants, they contain a variety of volatile molecules such as terpenes, phenol-derived aromatic and aliphatic components. The large genus Artemisia L., from the tribe Anthemideae, comprises important medicinal plants which are currently the subject of phytochemical attention due to their biological and chemical diversity. Artemisia species, widespread throughout the world, are one of the most popular plants in Chinese traditional preparations and are frequently used for the treatment of diseases such as malaria, hepatitis, cancer, inflammation and infections by fungi, bacteria and viruses. Extensive studies of the chemical components of Artemisia have led to the identification of many compounds as well as essentials oils. This review summarizes some of the main reports on the chemistry and anti-infective activities of Artemisia. Li. essential oils from the data in the recent literature (2000-2011).

Quinoline-based compounds as modulators of HIV transcription through NF-kappaB and Sp1 inhibition.

18 quinoline-based compounds were tested for antiviral properties against human immunodeficiency syndrome (HIV). The compounds tested here contain quinoline or tetrahydroquinoline rings and can be divided into two main groups: group 1 includes 4-(2-oxopyrrolidinyl-1)-1,2,3,4-tetrahydroquinolines with 2-(3-nitrophenyl) substituent (N-series) or 2-(3-aminophenyl) moiety (H-series), and group 2 includes 2-(3-nitrophenyl)- or 2-(3-aminophenyl)-substituted quinolines (S-series). Two different antiviral assays were performed in order to test the anti-HIV activity of compounds: 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and recombinant virus assay (RVA). Results showed that the most active compounds were 2-aryl quinolines, particularly those containing methoxy substituents or no substituents in the quinoline skeleton. HIV transcription inhibition appears to be their target in both resting and phorbol myristate acetate (PMA) activated primary lymphocytes, and nuclear factor-kappaB (NF-kappaB) and specificity protein-1 (SP1) seems to be the most important transcription factors involved in their action.

Gold nanoparticles capped with sulfate-ended ligands as anti-HIV agents.

Gold nanoparticles coated with multiple copies of an amphiphilic sulfate-ended ligand are able to bind the HIV envelope glycoprotein gp120 as measured by surface plasmon resonance (SPR) and inhibit in vitro the HIV infection of T-cells at nanomolar concentrations. A 50% density of sulfated ligands on approximately 2 nm nanoparticles (the other ligands being inert glucose derivatives) is enough to achieve high anti-HIV activities. This result opens up the possibility of tailoring both sulfated ligands and other anti-HIV molecules on the same gold cluster, thus contributing to the development of non-cocktail based multifunctional anti-HIV systems.

An update on drug interactions with the herbal medicine Ginkgo biloba.

Medicinal plants are gaining in popularity due to the various advantages they offer, such as fewer side-effects, better patient compliance, relatively low cost and high accessibility as well as their high acceptability due to a long history of use. There is a widespread belief among the general public that herbal preparations are "good for humans" as they are "all natural". However, the increasing use of herbal medicinal products in the community where people are also receiving prescription medicines suggests that adverse herb-drug interactions may be have significant public health consequences. There is little understanding or appreciation of the fact that these "all natural" preparations are actually a combination of potentially biologically active compounds already existing in marketed products in unknown quantities. Among the most popular herbal products used worldwide is Ginkgo biloba, used for the treatment of cerebral insufficiency, peripheral vascular diseases, and frequently taken for the enhancement of memory function. Although the safety of Ginkgo biloba is promising, accumulated data show evidence of significant interactions with medications, which can place individual patients at great risk. In this review, we examined the literature from 2000 to 2008 and focused on the importance of the risk of drug interactions and potential side effects when Ginkgo biloba is involved. The aim of this systematic review is to assess the clinical evidence on interactions between Ginkgo biloba and drugs.

Anti-infectious activity in the Cistaceae family in the Iberian Peninsula.

Infectious diseases caused by bacteria, fungi, viruses and parasites are still a major threat to public health, despite the tremendous progress in human medicine. New antimicrobials are needed in medicine due to the rapid emergence of new resistant and opportunistic microbes and the increasing number of patients suffering from immunosuppressive situations, e.g., acquired immunodeficiency syndrome, transplantation, cancer, etc Research on new antimicrobial substances must therefore be continued and all possible strategies should be explored. Plants have been a source of therapeutic agents from more than 5000 years. Approximately 25% of modern medications are developed from plants. In the area of infectious diseases, 75% of new drugs originated from natural sources between 1981 and 2002. As less than 10% of the world's biodiversity has been tested for biological activity, many more useful natural lead compounds are awaiting discovery. The Cistaceae family comprises a large number of species, growing in the warm temperate regions of the Mediterranean area, that have been and are still used as medicinal plants, particularly in folk medicine. In the present review, we analyse the past, present and future of medicinal plants of the Cistaceae family present in the Iberian Peninsula, both as potential antimicrobial crude drugs as well as a source of natural compounds that act as new anti-infectious agents.

Natural marine anti-inflammatory products.

The marine environment has been shown to be the source of a great diversity of chemical structures with promising biological activities. The isolation, biological evaluation, chemical properties and synthetic elaborations of the products of marine organisms and microorganisms have attracted the attention of organic chemists, medicinal chemists, biologists and pharmacists. Marine organisms and microorganisms have provided a large proportion of the natural anti-inflammatory products over the last years. Marine organisms include green algae, brown algae, red algae, sponges, coelenterates, bryozoans, molluscs, tunicates, echinoderms, miscellaneous marine organisms and marine microorganisms and phytoplankton. This review describes current progress in the development of a selection of new anti-inflammatory agents from marine sources. The chemistry and biological evaluation are discussed.

El estudio de la interacción virus-hospedador como fuente de nuevas dianas en la infección por el VIH / No disponible

En los últimos 10 años se ha producido un progreso en el tratamiento de la infección por VIH que ha mejorado la supervivencia y calidad de vida de los pacientes seropositivos. Sin embargo, la erradicación del VIH sea imposible con las terapias actuales. Este hecho junto a la emergencia continua de resistencias frente a los fármacos disponibles hace que la búsqueda de nuevos antirretrovirales sea un proceso en continuo desarrollo. Hasta el momento los fármacos desarrollados se han dirigido frente a proteínas virales, la transcriptas a inversa, la proteasa y más recientemente la envuelta viral. Pero el hecho de que el VIH se aproveche de la maquinaria celular para su replicación y el descubrimiento y caracterización de factores celulares indispensables para permitir el ciclo del VIH ha permitido definir nuevas dianas celulares. Estas dianas abarcan un amplio espectro de moléculas que van desde proteínas de adhesión, receptores de entrada, factores celulares, y en general cualquier estructura o molécula celular implicadas en la replicación del virus y en los mecanismos de resistencia celular a la infección, como los sistemas APOBEC y Trim 5 alpha recientemente descritos. En el tratamiento de la infección por el VIH se abre por tanto una nueva perspectiva en la que los factores celulares implicados en la replicación viral son una diana preferente y previsiblemente se desarrollarán en los próximos años una serie de “antiretrovirales de base celular” (AU)

In the last ten years a progress in the HIV infection treatment has occurred leading to an improved life quality and survival of seropositive patients. However, HIV eradication is not possible with the actual therapies. This fact together with the continuous emergence of resistances against available drugs made the search of new antiretrovirals a continuous process in development. To date, available drugs have been targeted to viral proteins, reverse transcriptase, protease and, recently, viral envelope. The fact that HIV use the cellular machinery to replicate and the discovery and characterization of cellular factors essential for the HIV cycle has led to define new cellular targets. This targets include a great number of different molecules like adhesion proteins, entry receptors, cellular factors and, in general, any cell structure or molecule involved in virus replication and in cell resistance mechanisms to infection, like APOBEC and Trim 5 alpha systems recently described.HIV infection treatment present now new perspectives in which cellular factors involved in viral replication are a preferred target rather than viral ones, and it seems that, in the next years, “cellular based antiretroviral drugs” will be developed (AU)

Screening of South American plants against human immunodeficiency virus: preliminary fractionation of aqueous extract from Baccharis trinervis.

Ethanolic and aqueous extracts of 14 South American medicinal plants were tested for inhibitory activity on human immunodeficiency virus (HIV). Both extracts were relatively non-toxic to human lymphocytic MT-2 cells, but only the aqueous extract of Baccharis trinervis exhibited potent anti-HIV activity in an in vitro MTT assay. To delineate the extract-sensitive phase, some studies of the antiviral properties of the active extract are described in this paper. Based on the results presented here, a separation scheme was devised, which permitted the preliminary fractionation of the extract, with the aim of finding an inhibitor of this virus.