Carolina Alves dos Santos

Silver Nanoparticles: Therapeutical Uses, Toxicity, and Safety Issues

The promises of nanotechnology have been realized to deliver the greatest scientific and technological advances in several areas. The biocidal activity of Metal nanoparticles in general and silver nanoparticles (AgNPs) depends on several morphological and physicochemical characteristics of the particles. Many of the interactions of the AgNPs with the human body are still poorly understood; consequently, the most desirable characteristics for the AgNPs are not yet well established. Therefore, the development of nanoparticles with well-controlled morphological and physicochemical features for application in human body is still an active area of interdisciplinary research. Effects of the development of technology of nanostructured compounds seem to be so large and comprehensive that probably it will impact on all fields of science and technology. However, mechanisms of safety control in application, utilization, responsiveness, and disposal accumulation still need to be further studied in-depth to ensure that the advances provided by nanotechnology are real and liable to provide solid and consistent progress. This review aims to discuss AgNPs applied in biomedicine and as promising field for insertion and development of new compounds related to medical and pharmacy technology. The review also addresses drug delivery, toxicity issues, and the safety rules concerning biomedical applications of silver nanoparticles.

Strategic role of selected noble metal nanoparticles in medicine

Abstract Noble metals and their compounds have been used as therapeutic agents from the ancient time in medicine for the treatment of various infections. Recently, much progress has been made in the field of nanobiotechnology towards the development of different kinds of nanomaterials with a wide range of applications. Among the metal nanoparticles, noble metal nanoparticles have demonstrated potential biomedical applications. Due to the small size, nanoparticles can easily interact with biomolecules both at surface and inside cells, yielding better signals and target specificity for diagnostics and therapeutics. Noble metal nanoparticles inspired the researchers due to their remarkable role in detection and treatment of dreadful diseases. In this review, we have attempted to focus on the biomedical applications of noble metal nanoparticles particularly, silver, gold, and platinum in diagnosis and treatment of dreaded diseases such as cancer, human immunodeficiency virus (HIV), tuberculosis (TB), and Parkinson disease. In addition, the role of silver nanoparticles (AgNPs) such as novel antimicrobials, gold nanoparticles (AuNPs) such as efficient drug carrier, uses of platinum nanoparticles (PtNPs) in bone allograft, dentistry, etc. have been critically reviewed. Moreover, the toxicity due to the use of metal nanoparticles and some unsolved challenges in the field have been discussed with their possible solutions.

Antimicrobial effectiveness of silver nanoparticles co-stabilized by the bioactive copolymer pluronic F68

BackgroundSilver nanoparticles (AgNps) have attracted much interest in biomedical engineering, since they have excellent antimicrobial properties. Therefore, AgNps have often been considered for incorporation into medical products for skin pathologies to reduce the risk of contamination. This study aims at evaluating the antimicrobial effectiveness of AgNps stabilized by pluronic™ F68 associated with other polymers such as polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP).MethodsAgNps antimicrobial activity was evaluated using the minimum inhibitory concentration (MIC) method. The action spectrum was evaluated for different polymers associated with pluronic™ F68 against the gram negative bacteria P. aeuroginosa and E. coli and the gram positive bacteria S. Aureus.ResultsAgNps stabilized with PVP or PVA and co-stabilized with pluronic™ F68 are effective against E. coli and P. aeruginosa microorganisms, with MIC values as low as 0.78% of the concentration of the original AgNps dispersion. The antimicrobial action against S. aureus is poor, with MIC values not lower than 25%.ConclusionsAgNps stabilized by different polymeric systems have shown improved antimicrobial activity against gram-negative microorganisms in comparison to unstabilized AgNps. Co-stabilization with the bioactive copolymer pluronic™ F68 has further enhanced the antimicrobial effectiveness against both microorganisms. A poor effectiveness has been found against the gram-positive S. aureus microorganism. Future assays are being delineated targeting possible therapeutic applications.

Anticancer activities of Withania somnifera: Current research, formulations, and future perspectives

Abstract Context: Cancer, being a cause of death for major fraction of population worldwide, is one of the most studied diseases and is being investigated for the development of new technologies and more accurate therapies. Still the currently available therapies for cancer have many lacunae which affect the patient’s health severely in the form of side effects. The natural drugs obtained from the medicinal plants provide a better alternative to fight against this devastating disease. Withania somnifera L. Dunal (Solanaceae), a well-known Ayurvedic medicinal plant, has been traditionally used to cure various ailments for centuries. Objectives: Considering the immense potential of W. somnifera, this review provides a detail account of its vital phytoconstituents and summarizes the present status of the research carried out on its anticancerous activities, giving future directions. Methods: The sources of scientific literature were accessed from various electronic databases such as PubMed, Google Scholar, Science Direct, and library search. Results: Various parts of W. somnifera especially the roots with its unique contents have been proved effective against different kinds of cancers. The most active components withanolides and withaferins along with a few other metabolites including withanone (WN) and withanosides have been reported effective against different types of cancer cell lines. Conclusion: This herb holds an important place among various anticancer medicinal plants. It is very essential to further screen and to investigate different formulations for anticancer therapy in vitro as well as in vivo in combination with established chemotherapy.

Recent advances in use of silver nanoparticles as antimalarial agents

Malaria is one of the most common infectious diseases, which has become a great public health problem all over the world. Ineffectiveness of available antimalarial treatment is the main reason behind its menace. The failure of current treatment strategies is due to emergence of drug resistance in Plasmodium falciparum and drug toxicity in human beings. Therefore, the development of novel and effective antimalarial drugs is the need of the hour. Considering the huge biomedical applications of nanotechnology, it can be potentially used for the malarial treatment. Silver nanoparticles (AgNPs) have demonstrated significant activity against malarial parasite (P. falciparum) and vector (female Anopheles mosquito). It is believed that AgNPs will be a solution for the control of malaria. This review emphasizes the pros- and cons of existing antimalarial treatments and in depth discussion on application of AgNPs for treatment of malaria. The role of nanoparticles for site specific drug delivery and toxicological issues have also been discussed.

Natural colorants from filamentous fungi

In the last years, there is a trend towards the replacement of synthetic colorants by natural ones, mainly due to the increase of consumer demand for natural products. The natural colorants are used to enhance the appearance of pharmaceutical products, food, and different materials, making them preferable or attractive. This review intends to provide and describe a comprehensive overview of the history of colorants, from prehistory to modern time, of their market and their applications, as well as of the most important aspects of the fermentation process to obtain natural colorants. Focus is given to colorants produced by filamentous fungal species, aiming to demonstrate the importance of these microorganisms and biocompounds, highlighting the production performance to get high yields and the aspects of conclusion that should be taken into consideration in future studies about natural colorants.

Stability of furosemide and aminophylline in parenteral solutions

Parenteral solutions (PS) are one of the most commonly used drug delivery vehicles. Interactions among the drug, components in the drugs formulation, and the PS can result in the formation of inactive complexes that limit efficacy or increase side effects. The aim of this work was to evaluate possible interactions between the drugs and PS, assess drug stability and to identify degradation products after 20 h at room temperature. Furosemide (FSM) and Aminophylline (APN) were added to PS containing either 20% mannitol or 0.9% NaCl at pH 6.5-7.5 and 10-11. Their behavior was studied individually and as an admixture, after 1 h oxidation with H2O2, using a spectrophotometer and HPLC. Individually, FSM and APN added to 20% mannitol and 0.9% NaCl solutions had the highest stability at pH 10-11. When FSM and APN were combined, the behavior of FSM was similar to the behavior observed for the drug individually in the same solutions. With the drugs combined in 20% mannitol pH 10-11, HPLC showed that both drugs were stable after a 20 h period yielding two distinct peaks; in oxidized samples, the elution profile showed four peaks with retention times unrelated to the untreated samples.

Influence of Pluronic® F68 on Ceftazidime Biological Activity in Parenteral Solutions

β-Lactam antimicrobials are known to have a low concentration/therapeutic response. However, extending the period in which β-lactam are free in the plasma does directly influence therapeutic outcomes. The objective of this study was to evaluate the influence of Pluronic® F68 on the antimicrobial activity of ceftazidime when admixed with aminophylline in parenteral solutions by the evaluation of its minimal inhibitory concentration (MIC) within 24 h. Ceftazidime, aminophylline, and Pluronics® F68 were evaluated using the MIC method against Escherichia coli and Pseudomonas aeruginosa, with these compounds individually and associated in the same parenteral solutions. When Pluronics® F68 was admixtured with ceftazidime alone or with ceftazidime and aminophylline, it was possible to observe lower MIC values not only at 24 h but also at 0 h for both microorganisms. This indicates that Pluronics® F68 may be able to enhance ceftazidime antimicrobial activity in the presence or absence of aminophylline. This fact suggests that Pluronics® F68 can be applied to allow the administration of ceftazidime under continuous infusion in parenteral solutions, beneficiating hospital pharmacotherapy. It may also be possible to reduce ceftazidime doses in formulations achieving the same therapeutic results.

Association of Silver Nanoparticles and Curcumin Solid Dispersion: Antimicrobial and Antioxidant Properties

The last century, more precisely after 1945, was marked by major advances in the treatment of infectious diseases which promoted a decrease in mortality and morbidity. Despite these advances, currently the development of antimicrobial resistance has been growing drastically and therefore there is a pressing need to search for new compounds. Silver nanoparticles (AgNps) have been demonstrating good antimicrobial activity against different bacteria, viruses, and fungi. Curcumin (CUR) extracted from rhizomes of Curcuma longa has a variety of applications including antiinflammatory, antioxidant, and antibacterial agent. The association between silver nanoparticles and curcumin in a formulation can be a good alternative to control infectious diseases due the antimicrobial properties of both compounds. The objective of this work was to develop a formulation composed of a thermoresponsive gel—with antimicrobial and antioxidant properties due to the association of AgNps with PVP and PVA polymers. After AgNp synthesis, these were incorporated together with the previously prepared CUR/P407 (1:2) solid dispersion (SD) into a polymer dispersion of 20% P407 (thermosensitive gel). Our results showed that the association between the AgNps with CUR SD demonstrated good antioxidant activity as compared to the standard compound. Measures of MIC showed more efficacy against Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) than for Gram-positive bacteria (Staphylococcus aureus). This association enhances antimicrobial activity against E. coli and P aeruginosa and added antioxidant value in formulations.

Broadening the spectrum of small-molecule antibacterials by metallic nanoparticles to overcome microbial resistance

Now-a-days development of microbial resistancce have become one of the most important global public health concerns. It is estimated that about 2 million people are infected in USA with multidrug resistant bacteria and out of these, about 23,000 die per year. In Europe, the number of deaths associated with infection caused by MDR bacteria is about 25,000 per year, However, the situation in Asia and other devloping countries is more critical. Considering the increasing rate of antibiotic resistance in various pathogens, it is estimated that MDR organisms can kill about 10 million people every year by 2050. The use of antibiotics in excessive and irresponsible manner is the main reason towards its ineffectiveness. However, in this context, promising application of nanotechnology in our everyday life has generated a new avenue for the development of potent antimicrobial materials and compounds (nanoantimicrobials) capable of dealing with microbial resistance. The devlopement and safe incorporation of nanoantimicrobials will bring a new revolution in health sector. In this review, we have critically focused on current worldwide situation of antibiotic resistance. In addition, the role of various nanomaterials in the management of microbial resistance and the possible mechanisms for antibacterial action of nanoparticles alone and nanoparticle-antibiotics conjuagte are also discussed.