Polyhexamethylene Biguanide and Nadifloxacin Self-Assembled Nanoparticles: Antimicrobial Effects against Intracellular Methicillin-Resistant Staphylococcus aureus

The treatment of skin and soft tissue infections caused by methicillin-resistant Staphylococcus aureus (MRSA) remains a challenge, partly due to localization of the bacteria inside the host’s cells, where antimicrobial penetration and efficacy is limited. We formulated the cationic polymer polyhexamethylene biguanide (PHMB) with the topical antibiotic nadifloxacin and tested the activities against intracellular MRSA in infected keratinocytes. The PHMB/nadifloxacin nanoparticles displayed a size of 291.3 ± 89.6 nm, polydispersity index of 0.35 ± 0.04, zeta potential of +20.2 ± 4.8 mV, and drug encapsulation efficiency of 58.25 ± 3.4%. The nanoparticles killed intracellular MRSA, and relative to free polymer or drugs used separately or together, the nanoparticles displayed reduced toxicity and improved host cell recovery. Together, these findings show that PHMB/nadifloxacin nanoparticles are effective against intracellular bacteria and could be further developed for the treatment of skin and soft tissue infections

Nanotechnology approaches in the current therapy of skin cancer

Skin cancer is a high burden disease with a high impact on global health. Conventional therapies have several drawbacks; thus, the development of effective therapies is required. In this context, nanotechnology approaches are an attractive strategy for cancer therapy because they enable the efficient delivery of drugs and other bioactive molecules to target tissues with low toxic effects. In this review, nanotechnological tools for skin cancer will be summarized and discussed. First, pathology and conventional therapies will be presented, followed by the challenges of skin cancer therapy. Then, the main features of developing efficient nanosystems will be discussed, and next, the most commonly used nanoparticles (NPs) described in the literature for skin cancer therapy will be presented. Subsequently, the use of NPs to deliver chemotherapeutics, immune and vaccine molecules and nucleic acids will be reviewed and discussed as will the combination of physical methods and NPs. Finally, multifunctional delivery systems to codeliver anticancer therapeutic agents containing or not surface functionalization will be summarized

Nanotechnology and the diagnosis/treatment of leishmaniasis

Aim: The review article updates the current state of the art in the engineering of nanoplatforms against leishmaniasis. Special attention is devoted to the development of drug nanocarriers to be given to patients through the parenteral, topical, and oral routes of administration. Challenges and opportunities coming from advanced formulation methods/strategies introduced in the design of these nanosystems are emphasized. Finally, particular attention is also given to the use of nanoparticulate systems for vaccine delivery and for the diagnosis of the disease. Materials and Methods: To that aim, the Web sites of PubMed, HCAplus, Thomson, and Registry were used as the main sources to perform the search for the most significant research articles published on the subject. The information was then carefully analyzed, highlighting the most important preclinical results in the development of nanomedicines against leishmaniasis, as well considering vaccine delivery systems and nanoparticulate-based diagnosis. Results and Conclusion: The introduction of nanotechnology into the leishmaniasis arena is intended to optimize both the diagnosis and treatment (drug/vaccine therapy) of the disease. The objective is always to improve the selectivity of the imaging molecules or drugs/vaccines toward the parasite, especially when it is located inside phagocytic cells and neutrophils, while keeping to a very minimum the toxic side effects. Of course, only the wise engineering of the nanoparticulate delivery system will assure the best diagnostic/therapeutic outcomes.Objetivos: Este trabajo pretende actualizar la situación actual en el diseño de nanoplataformas contra la leishmaniasis. En este sentido, especial atención merecen los nanotransportadores de fármacos diseñados para ser administrados al paciente a través de las vías de administración parenteral, tópica y oral. Asimismo, se discuten las posibilidades que ofrecen las técnicas o estrategias de formulación más avanzadas en el diseño de estas nanoplataformas biomédicas. Finalmente, también se dedica especial atención a la utilización de estos nanosistemas en la administración de vacunas y en el diagnóstico de la leishmaniasis. Material y Métodos: Con este fin, se utilizaron las páginas Web PubMed, HCAplus, Thomson y Registry como principales fuentes para la búsqueda de los trabajos de investigación más interesantes publicados sobre la materia. La información así obtenida fue cuidadosamente analizada, resaltando aquellos resultados preclínicos más relevantes en cuanto al desarrollo de nanomedicamentos contra la leishmaniasis, y considerando también los nanosistemas transportadores de vacunas y las nanoplataformas de utilidad en el diagnóstico de esta enfermedad. Resultados y conclusiones: La nanotecnología es utilizada para mejorar el diagnóstico y tratamiento de la leishmaniasis. El objetivo es, en todos los casos, la mejora de la selectividad por el parásito de los fármacos, vacunas y moléculas utilizadas como agentes de contraste en técnicas de imagen, especialmente cuando este microorganismo se encuentra localizado en el interior de macrófagos y neutrófilos. Con esta interesante nanoherramienta, se puede también obtener una significativa reducción en la aparición y severidad de la toxicidad asociada a las técnicas de diagnóstico y tratamiento de la leishmaniasis. Es evidente que sólo con un inteligente diseño de estos nanosistemas se logran los mejores resultados de diagnóstico y terapia de la enfermedad

Gemini cationic surfactant-based delivery systems for non-invasive cutaneous gene therapy

Gene transfer represents an important advance in the treatment of both genetic and acquired diseases. Topical gene therapy involves administration of the genetic material onto the surface of skin and mucosal membranes. Cationic gemini surfactants (m-s-m, where m represents the carbon atoms in the alkyl tail and s represents the carbon atoms in the spacer) are a novel category of delivery agents with especially high potential for polynucleotides. This is due to their structural versatility, ability to bind and condense DNA, and relatively low toxicity. The objectives were to design, construct and characterize a cationic, non-viral gemini surfactant-based delivery system for an IFN-ã coding plasmid suitable for cutaneous gene therapy and to evaluate this novel therapeutic approach in a Tsk (tight-skin scleroderma) mouse model to determine its clinical feasibility. The delivery systems were characterized by microscopy, dynamic light scattering (DLS), circular dichroism (CD) and small angle X-ray scattering (SAXS). In vitro gene expression was evaluated in PAM 212 keratinocyte culture. The extent of topical delivery of the plasmid using nanoparticle and nanoemulsion formulations was evaluated by measuring IFN-ã levels in CD1, IFN-ã-deficient and Tsk mice. The effect of transgene expression on collagen synthesis was evaluated in Tsk animals by real-time PCR.The in vitro plasmid–gemini–lipid (PGL) system showed heterogeneous particle size (100-200 nm small particles and 300-600 nm aggregates). Electrostatic interactions between the DNA and PGL systems shifted the negative æ-potential of the DNA (-47 mV) to positive values (30-50 mV). At the same time, condensation of the DNA, and formation of Ø– DNA was indicated by the increase of the overall negative signal in the CD spectra, due to the flattening of the 290 nm peak and shift of the 260 nm peak into the negative region in a structure-dependent manner. Lipid organization of the DNA–DOPE system, in the absence of gemini surfactants, shows hexagonal structure, while addition of gemini surfactant at +/- charge ratio of 10 caused lamellar phase organization. For short spacers (n=3-6), additional Pn3m cubic phase also appear to be present. In vitro transfection efficiency in the 12-n-12 series was found to be dependent on the length of the spacer between the two positively charged head groups, with the n=3 spacer showing the highest activity. The PGL systems with 12-3-12 and 12-4-12 led to significantly higher transgene expression compared to the other surfactants of the series. The transfection efficiency significantly correlated with the surface area occupied by one molecule (a). The effect of the tail length influenced the transfection efficiency, with longer tails being associated with higher protein expression. The highest in vitro transfection efficiency was recorded with the 18:1-3-18:1 surfactant (1.4±0.3 ng/5x10E4 cells). In vivo, high levels of IFN-ã expression were detected in the skin of animals treated with both nanoparticle (359±239 pg/cm2) and nanoemulsion (607±411 pg/cm2) formulations compared to topical naked DNA (136±125 pg/cm2). IFN-ã levels in the skin of animals injected with 5 ìg DNA were 256±130 pg/cm2. IFN-ã levels in the lymph nodes were higher for the nanoparticle formulation (433±456 pg/animal) compared to nanoemulsion (131±136 pg/animal) suggesting different delivery pathway of the two formulations.IFN-ã expression was at high levels in the skin of Tsk mice after 4-day and 20-day treatments (472±171 and 345±276 pg/cm2). Both 4-day and 20-day treatments reduced the procollagen type I á1 mRNA levels for the topical treatment (64 and 70% reduction) and intradermal injection (58 and 72% reduction). Intercellular adhesion molecule-1 (ICAM-1) was upregulated by 50% in both topically treated and injected animals after 20-day treatment. Here, it has been demonstrated that cationic gemini surfactant-based delivery systems are able to transfect epidermal cells in vivo, and the transgene IFN-ã expression is sufficient to cause significant reduction of collagen in an animal model of scleroderma. It has been shown for the first time that topical gene therapy is a feasible approach for the modulation of excessive collagen synthesis in scleroderma-affected skin

Investigation of functionalized carbon nanotubes as a delivery system for enhanced gene expression with implications in developing DNA vaccines for hepatitis C virus

Hepatitis C virus (HCV) causes a significant health problem worldwide due to the lack of effective vaccines. It has been recognized that a rapid, vigorous, and broadly targeted cell-mediated immune response (Th1-like) is often associated with the clearance of HCV infections. DNA vaccines represent a promising means for HCV vaccination because they tend to induce a Th1-biased cell-mediated response in the host cell. Currently, the delivery of DNA vaccine for HCV in large animals as well as in humans is not as effective as in small animals. Nano delivery systems would be a promising approach to overcome this problem. Carbon nanotubes (CNTs) have been extensively studied for delivering drugs, proteins, peptides, and nucleic acids including plasmid DNA to cells and organs with varying degrees of success, but few of them have been applied to DNA vaccine for HCV. This thesis presents a study of using functionalized CNTs (f-CNTs) to improve the efficacy of plasmid DNA vaccine delivery for HCV. First, CNTs were functionalized via 1,3-dipolar cycloaddition reaction with the appropriate amino acids and aldehydes. NMR and TEM results suggested that the CNTs were successfully functionalized and became soluble in water. Then plasmid DNAs which encode green fluorescence protein reporter gene, luciferase reporter gene, and HCV core protein, respectively, were delivered into human hepatoma cells via calcium phosphate precipitation method, f-CNT delivery system, and a combination of f-CNT and calcium phosphate method, respectively. The result showed that f-CNTs, in combination with the calcium phosphate method, significantly enhanced the gene expression in human hepatoma cells. Consequently, this study concludes that the f-CNT can significantly enhance gene expression in liver cells conferred by a plasmid DNA when combined with calcium phosphate precipitation method. Even though the mechanisms of this enhancement await further investigation, the results of this thesis may have important implications in developing DNA vaccines for infectious diseases in general and for hepatitis C in particular

MICROEMULSIONS: PLATFORM FOR IMPROVEMENT OF SOLUBILITY AND DISSOLUTION OF POORLY SOLUBLE DRUGS

ABSTRACTThis study reviews that solubilization of lipophilic drugs with low aqueous solubility has been a major trust area in recent years. It can be seen thatthere is a real and continuing need for the development of effective drug delivery systems for poorly water-soluble drugs to enhance their absorptionand bioavailability. One such approach might be pharmaceutical microemulsions as they have emerged as potential solubility enhancing technologies.Microemulsion system has considerable potential to act as a drug delivery vehicle by incorporating a wide range of drug molecules. Microemulsionhas got advantage like excellent thermodynamic stability, high drug solubilization capacity, improved oral bioavailability and protection againstenzymatic hydrolysis. This review focuses on the basic concept, formulation, characterization, and recent advances in microemulsions as novel drugdelivery system.Keywords: Microemulsion, Lipophilicity, Solubilization, Bioavailability, Phase behavior