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2.
3 Biotech ; 14(6): 157, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38766324

RESUMEN

Brucine (BRU), an active constituent of Strychnos nux-vomica L., is one of the potential agents to control subside swelling in arthritis. However, its hydrophobic nature, poor permeation, shorter half-life, narrow therapeutic window, and higher toxicity impede its clinical applications. Hence, this investigation was aimed to develop and evaluate novel BRU loaded ß-cyclodextrin (ß-CD) nanosponges (BRUNs) hydrogel consisting rosemary essential oil (RO), which have been tailored for delayed release, enhanced skin permeation, and reduced irritation, while retaining anti-oxidant and anti-inflammatory activities of this bioactive. Firstly, BRUNs were fabricated by melt technique and characterized appropriately. BRUNs6 demonstrated two fold enhancement in BRU solubility (441.692 ± 38.674) with minimum particle size (322.966 ± 54.456) having good PDI (0.571 ± 0.091) and zeta potential (-14.633 ± 6.357). In vitro release results demonstrated delayed release of BRU from BRUNs6 (67 ± 4.25%) over 24 h through molecular diffusion mechanism. Further, preserved anti-inflammatory (53.343 ± 0.191%) and antioxidant potential (60.269 ± 0.073%) of bioactive was observed in BRUNs6. Hence, this Ns batch was engrossed with Carbopol®934 hydrogel with RO and characterized. In vitro (release and anti-inflammatory activity), ex-vivo (skin permeability) and in vivo (carrageenan-induced inflammation) assays along with irritation study were conducted for fabricated hydrogels. Results revealed that in vitro release of BRU was further delayed from Ns hydrogel with RO (56.45 ± 3.01%) following Fickian mechanism. Considerable enhancement in skin permeability (60.221 ± 0.322 µg/cm2/h) and preservation of anti-inflammatory activity (94.736 ± 2.002%) was also observed in BRUNs6 hydrogel containing RO. The irritation of BRU was found reduced (half) after its entrapped in Ns. Further, as a proof of concept, BRUNs6 hydrogel with RO effectively reduced (75.757 ± 0.944%) carrageenan-induced inflammation in rat model in comparison to pure BRU (54.914 ± 1.081%). Hence, BRUNs hydrogel with RO can be considered as a promising alternative for dermal delivery of BRU in arthritis.

3.
Gels ; 9(7)2023 Jul 14.
Artículo en Inglés | MEDLINE | ID: mdl-37504455

RESUMEN

Leflunomide (LEF), a disease-modifying anti-rheumatic drug, has been widely explored for its anti-inflammatory potential in skin disorders such as psoriasis and melanoma. However, its poor stability and skin irritation pose challenges for topical delivery. To surmount these issues, LEF-loaded solid lipid nanoparticles (SLNs) integrated with hydrogels have been developed in the present investigation. SLNs developed by microemulsion techniques were found ellipsoidal with 273.1 nm particle size and -0.15 mV zeta potential. Entrapment and total drug content of LEF-SLNs were obtained as 65.25 ± 0.95% and 93.12 ± 1.72%, respectively. FTIR and XRD validated the successful fabrication of LEF-SLNs. The higher stability of LEF-SLNs (p < 0.001) compared to pure drug solution was observed in photostability studies. Additionally, in vitro anti-inflammatory activity of LEF-SLNs showed good potential in comparison to pure drugs. Further, prepared LEF-SLNs loaded hydrogel showed ideal rheology, texture, occlusion, and spreadability for topical drug delivery. In vitro release from LEF-SLN hydrogel was found to follow the Korsmeyer-Peppas model. To assess the skin safety of fabricated lipidic formulation, irritation potential was performed employing the HET-CAM technique. In conclusion, the findings of this investigation demonstrated that LEF-SLN hydrogel is capable of enhancing the photostability of the entrapped drug while reducing its skin irritation with improved topical delivery characteristics.

5.
Plants (Basel) ; 12(5)2023 Mar 03.
Artículo en Inglés | MEDLINE | ID: mdl-36904028

RESUMEN

Natural plants and their products continue to be the major source of phytoconstituents in food and therapeutics. Scientific studies have evidenced the benefits of sesame oil and its bioactives in various health conditions. Various bioactives present in it include sesamin, sasamolin, sesaminol, and sesamol; among these, sesamol represents a major constituent. This bioactive is responsible for preventing various diseases including cancer, hepatic disorders, cardiac ailments, and neurological diseases. In the last decade, the application of sesamol in the management of various disorders has attracted the increasing interest of the research community. Owing to its prominent pharmacological activities, such as antioxidant, antiinflammatory, antineoplastic, and antimicrobial, sesamol has been explored for the above-mentioned disorders. However, despite the above-mentioned therapeutic potential, its clinical utility is mainly hindered owing to low solubility, stability, bioavailability, and rapid clearance issues. In this regard, numerous strategies have been explored to surpass these restrictions with the formulation of novel carrier platforms. This review aims to describe the various reports and summarize the different pharmacological activities of sesamol. Furthermore, one part of this review is devoted to formulating strategies to improve sesamol's challenges. To resolve the issues such as the stability, low bioavailability, and high systemic clearance of sesamol, novel carrier systems have been developed to open a new avenue to utilize this bioactive as an efficient first-line treatment for various diseases.

6.
Nanomaterials (Basel) ; 12(23)2022 Nov 26.
Artículo en Inglés | MEDLINE | ID: mdl-36500833

RESUMEN

Sesamol (SES) possesses remarkable chemotherapeutic activity, owing to its anti-inflammatory and antioxidant potential. However, the activity of SES is mainly hampered by its poor physicochemical properties and stability issues. Hence, to improve the efficacy of this natural anti-inflammatory and cytotoxic agent, it was loaded into ß-cyclodextrin nanosponges (NS) prepared using different molar ratios of polymer and crosslinker (diphenyl carbonate). The particle size of SES-laden NS (SES-NS) was shown to be in the nano range (200 to 500 nm), with a low polydispersity index, an adequate charge (-17 to -26 mV), and a high payload. Field emission scanning electron microscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy were used to characterize the bioactive-loaded selected batch (SES-NS6). This batch of nanoformulations showed improved solubilization efficacy (701.88 µg/mL) in comparison to bare SES (244.36 µg/mL), polymer (ß-CD) (261.43 µg/mL), and other fabricated batches. The drug release data displayed the controlled release behavior of SES from NS. The findings of the egg albumin denaturation assay revealed the enhanced anti-inflammatory potential of SES-NS as compared to bare SES. Further, the cytotoxicity assay showed that SES-NS was more effective against B16F12 melanoma cell lines than the bioactive alone. The findings of this assay demonstrated a reduction in the IC50 values of SES-NS (67.38 µg/mL) in comparison to SES (106 µg/mL). The present investigation demonstrated the in vitro controlled release pattern and the enhanced anti-inflammatory and cytotoxic activity of SES-NS, suggesting its potential as a promising drug delivery carrier for topical delivery.

7.
J Food Sci Technol ; 59(3): 898-908, 2022 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-35153320

RESUMEN

Ellagic acid (EA) is a polyphenolic bioactive with a wide range of pharmacological activities. Regrettably, it possesses poor solubility, stability and permeability (in the gastrointestinal tract); and first-pass metabolism. Therefore, to address these challenges, the present research was aimed to encapsulate EA in cyclodextrin nanosponges (CDNS). Herein, the melt method and microwave-assisted technique have been employed for crafting CDNS. EA was loaded in CDNS via freeze-drying, followed by appropriate characterization. EA-CDNS were also assessed for encapsulation, particle size, zeta potential, and polydispersity index, which presented satisfactory results. In vitro, antioxidant activity was conducted using the DPPH (2, 2-diphenyl-1-picrylhydrazyl) assay. The solubilization efficacy of EA was analyzed in distilled water and compared with CDNS, which demonstrated ten folds augmentation for the selected batch. A remarkable improvement in the photostability of EA was also observed after its inclusion. In nutshell, the results demonstrated the superiority of the melt method in terms of solubility, entrapment, photostability, and antioxidant potential.

8.
Pharmaceutics ; 14(2)2022 Feb 09.
Artículo en Inglés | MEDLINE | ID: mdl-35214115

RESUMEN

Dermal disorders such as psoriasis and eczema are associated with modifications in the chemical and molecular composition of the skin. Clobetasol propionate (CP), a superpotent topical glucocorticoid, is widely used for the therapeutic management of various skin conditions, owing to its strong anti-inflammatory, antipruritic, vasoconstrictive, and antiproliferative activities. Safety studies demonstrated that CP is safer for a shorter period, however, with prolonged application, it shows secondary side effects such as photosensitivity, Cushing-like syndrome, allergic contact dermatitis, osteonecrosis, hypopigmentation, steroid acne, and skin atrophy. Therefore, the US FDA (United States Food and Drug Administration) has restricted the usage of CP to not more than 15 days. Research scientists addressed its several formulations and drug delivery issues, such as low water solubility, less stability, photodegradation, and poor absorption, by incorporating them into novel nanobased delivery platforms. With the utilization of these technologies, these drawbacks of CP have been resolved to a large extent to reestablish this moiety. This article explores the physicochemical properties and mechanism of action of CP. Additionally, an attempt has been made to discover and highlight the possible features of the novel nanosystems, including nanoemulsions, nanosponges, solid lipid nanoparticles, nanostructured lipid carriers, and nanogels, reported for CP. The stability and safety concerns of CP, along with its commercial status, are also discussed.

9.
ACS Omega ; 7(3): 3099-3108, 2022 Jan 25.
Artículo en Inglés | MEDLINE | ID: mdl-35097305

RESUMEN

The effect of high pressure on the structure of orthorhombic Mn3(VO4)2 is investigated using in situ Raman spectroscopy and X-ray powder diffraction up to high pressures of 26.2 and 23.4 GPa, respectively. The study demonstrates a pressure-induced structural phase transition starting at 10 GPa, with the coexistence of phases in the range of 10-20 GPa. The sluggish first-order phase transition is complete by 20 GPa. Importantly, the new phase could be recovered at ambient conditions. Raman spectra of the recovered new phase indicate increased distortion and as a consequence the lowering of the local symmetry of the VO4 tetrahedra. This behavior is different from that reported for isostructural compounds Zn3(VO4)2 and Ni3(VO4)2 where both show stable structures, although almost similar anisotropic compression of the unit cell is observed. The transition observed in orthorhombic Mn3(VO4)2 could be due to the internal charge transfer between the cations, which favors the structural transition at lower pressures and the eventual recovery of the new phase even upon pressure release in comparison to other isostructural compounds. The experimental equation of state parameters obtained for orthorhombic Mn3(VO4)2 match excellently with empirically calculated values reported earlier.

10.
Biomolecules ; 11(3)2021 02 25.
Artículo en Inglés | MEDLINE | ID: mdl-33669097

RESUMEN

Alzheimer's disease (AD) is a gradually growing irreversible illness of the brain that almost affects every fifth person (aged > 80 years) in the world. World Health Organization (WHO) also revealed that the prevalence of this disease will enhance (upto double) significantly upto 2030. The poor cholinergic transmission at the synapse is considered to be one of the main reasons behind the progression and occurrence of this disorder. Natural inhibitors of acetylcholine (ACh) such as galanthamine and rivastigmine are used commercially in the treatmentof AD. The biomolecules such assesquiterpenes, possess a great structural diversity and are responsible for a plethora of pharmacological properties. The potential of various sesquiterpenes as anticholinesterase has been reviewed in this article. For this purpose, the various databases, mainly PubMed, Scopus, and Web of Science were investigatedwith different keywords such as "sesquiterpenes+acetylcholinesterase" and "sesquiterpenes+cholinesterase+inhibitors" in the surveyed time frame (2010-2020). A vast literature was evident in the last decade, which affirms the potential of various sesquiterpenes in the improvement of cholinergic transmission by inhibiting the AChE. After data analysis, it was found that 12 compounds out of a total of 58 sesquiterpenes were reported to possess IC50 < 9µM and can be considered as potential candidates for the improvement of learning and memory. Sesquiterpene is an important category of terpenoids, found to possess a large spectrum of biological activities. The outcome of the review clearly states that sesquiterpenes (such as amberboin, lipidiol,etc) from herbs could offer fresh, functional compounds for possible prevention and treatment of AD.


Asunto(s)
Acetilcolinesterasa/metabolismo , Enfermedad de Alzheimer/tratamiento farmacológico , Inhibidores de la Colinesterasa/uso terapéutico , Sesquiterpenos/química , Sesquiterpenos/uso terapéutico , Animales , Galantamina/uso terapéutico , Humanos , Rivastigmina/uso terapéutico
11.
Mater Sci Eng C Mater Biol Appl ; 119: 111605, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33321649

RESUMEN

Clobetasol propionate (CP), a superpotent topical corticosteroid, holds great promise for psoriasis treatment. However, common side effects like skin atrophy, steroidal acne, hypopigmentation and allergic contact dermatitis associated with it, hamper its utility for topical application. Taking this into consideration, the current work was aimed to fabricate CP loaded cyclodextrin nanosponge (CDNS) based hydrogel, to alleviate the aforementioned side effects, while controlling drug release. Nanosponges were crafted employing ß-cyclodextrin (polymer) and diphenyl carbonate (cross linker) and evaluated appropriately. The selected formulation augmented 45 folds water solubility, with respect to pure CP. The formulation possessed entrapment efficiency (56.33 ± 0.94%), particle size (194.27 ± 49.24 nm) with polydispersitive index (0.498 ± 0.095), surface charge (-21.83 ± 0.95 mV) and drug release (86.25 ± 0.28%). Selected CP-CDNS were found crystalline and uniform in size. Further, in vitro cell viability analysis has been performed using THP1 cells to evaluate cytocompatibility of CP nanosponges. The chosen CP nanosponges were then embedded into Carbopol hydrogel, and characterized for rheological behaviour, spreadability, and texture profile. The developed nanoformulations were also assessed in vivo using mouse tail model. Histological and biochemical assessments have been conducted to explore their antipsoriatic activity via oxidative stress biomarkers. The degree of orthokeratosis was observed remarkably (p < 0.001) amplified by CP-CDNS14 hydrogel as compared to untreated group (control) and CP hydrogel. In addition, drug activity and change in epidermal thickness were found significant. Our findings altogether advocated the profound potential of prepared CP nanogel in the topical treatment of psoriasis, with improved patient compliance.


Asunto(s)
Clobetasol , Psoriasis , Administración Tópica , Animales , Clobetasol/metabolismo , Clobetasol/uso terapéutico , Liberación de Fármacos , Hidrogeles , Ratones , Psoriasis/tratamiento farmacológico , Psoriasis/metabolismo , Piel/metabolismo
12.
Phys Rev E ; 102(1-1): 013310, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32795082

RESUMEN

Blood flowing through microvascular bifurcations has been an active research topic for many decades, while the partitioning pattern of nanoscale solutes in the blood remains relatively unexplored. Here we demonstrate a multiscale computational framework for direct numerical simulation of the nanoparticle (NP) partitioning through physiologically relevant vascular bifurcations in the presence of red blood cells (RBCs). The computational framework is established by embedding a particulate suspension inflow-outflow boundary condition into a multiscale blood flow solver. The computational framework is verified by recovering a tubular blood flow without a bifurcation and validated against the experimental measurement of an intravital bifurcation flow. The classic Zweifach-Fung (ZF) effect is shown to be well captured by the method. Moreover, we observe that NPs exhibit a ZF-like heterogeneous partition in response to the heterogeneous partition of the RBC phase. The NP partitioning prioritizes the high-flow-rate daughter branch except for extreme (large or small) suspension flow partition ratios under which the complete phase separation tends to occur. By analyzing the flow field and the particle trajectories, we show that the ZF-like heterogeneity in the NP partition can be explained by the RBC-entrainment effect caused by the deviation of the flow separatrix preceded by the tank treading of RBCs near the bifurcation junction. The recovery of homogeneity in the NP partition under extreme flow partition ratios is due to the plasma skimming of NPs in the cell-free layer. These findings, based on the multiscale computational framework, provide biophysical insights to the heterogeneous distribution of NPs in microvascular beds that are observed pathophysiologically.


Asunto(s)
Eritrocitos/metabolismo , Microvasos/metabolismo , Modelos Biológicos , Nanopartículas , Hemodinámica , Cinética
13.
Asian J Pharm Sci ; 15(3): 273-291, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32636947

RESUMEN

Dermatological disorders have a huge psychosocial impact, causing significant impairment of patient's life. Topical therapy plays a pivotal role in management of such disorders. Conventional topical delivery systems result in overmedication/undermedication, leading to adverse effects and reduction in therapeutic efficacy. Consequently, researchers have been striving towards the development of alternative delivery systems for dermatological applications. In the last decade, microsponges emerged as an attractive option for topical delivery. Their characteristic particle size offers enhanced benefits, making them superior to the contemporary microcarriers. The present review furnishes a comprehensive account of state of the art, important factors affecting the performance and mechanism of drug release from topically applied microsponges, along with characterization techniques. Further, a list of marketed products and their applications for common dermatological disorders has been presented. All in all, this paper is an attempt to lay a bibliographic foundation for researchers working in this field and foster further investigations in this arena.

14.
Biomolecules ; 10(7)2020 06 30.
Artículo en Inglés | MEDLINE | ID: mdl-32630018

RESUMEN

Several pharmacological properties are attributed to ergot alkaloids as a result of their antibacterial, antiproliferative, and antioxidant effects. Although known for their biomedical applications (e.g., for the treatment of glaucoma), most ergot alkaloids exhibit high toxicological risk and may even be lethal to humans and animals. Their pharmacological profile results from the structural similarity between lysergic acid-derived compounds and noradrenalin, dopamine, and serotonin neurotransmitters. To reduce their toxicological risk, while increasing their bioavailability, improved delivery systems were proposed. This review discusses the safety aspects of using ergot alkaloids in ocular pharmacology and proposes the development of lipid and polymeric nanoparticles for the topical administration of these drugs to enhance their therapeutic efficacy for the treatment of glaucoma.


Asunto(s)
Alcaloides de Claviceps/farmacocinética , Alcaloides de Claviceps/uso terapéutico , Oftalmopatías/tratamiento farmacológico , Administración Tópica , Animales , Disponibilidad Biológica , Alcaloides de Claviceps/química , Humanos , Lípidos/química , Nanopartículas , Polímeros/química
15.
Curr Drug Res Rev ; 12(2): 82-96, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32484107

RESUMEN

OBJECTIVE: Dithranol (DTH) is a well-known moiety that has long been used promisingly to impede and treat skin disorders, particularly psoriasis. Nowadays, a rekindled interest in the use of DTH for this disorder has been observed. Side effects associated with conventional topical formulations of this moiety have aroused the interest of the scientific community in investigating novel cargos of DTH for psoriasis management. RESULTS: Previous research has evidenced the anti-inflammatory and anti-proliferating potential of DTH. Numerous studies have indicated that DTH inhibits polymorphonuclear (PMN) leucocyte, modulates epidermal cell receptors and promotes anti-psoriatic action. However, some deterrent factors like poor solubility, stability, toxicity, staining and skin irritation hamper its use as a potential therapeutic agent. With the adoption of novel drug delivery technologies, the above mentioned inherent limitations of DTH have been compensated to reestablish this drug moiety. CONCLUSION: This article reviews novel drug delivery aspects, safety concerns, clinical evidence, current status, and future opportunities of DTH in the management of psoriasis. Further, it will update researchers on this promising drug moiety, which is free from systemic adverse responses in comparison to other therapeutic molecules like steroids, for psoriasis treatment.


Asunto(s)
Antralina/administración & dosificación , Fármacos Dermatológicos/administración & dosificación , Psoriasis/tratamiento farmacológico , Administración Cutánea , Animales , Antralina/efectos adversos , Antralina/farmacología , Fármacos Dermatológicos/efectos adversos , Fármacos Dermatológicos/farmacología , Sistemas de Liberación de Medicamentos , Humanos , Solubilidad
16.
Expert Opin Drug Deliv ; 17(7): 963-992, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-32441158

RESUMEN

INTRODUCTION: The inception of nanostructured lipid carriers (NLCs) proved to be a revolutionary step toward the treatment of dermatological disorders. To uncover its true potential, it is imperative that the system be characterized and evaluated comprehensively. AREAS COVERED: The present review has been written to furnish an in-depth account of analytical tools and evaluation procedures under one roof. Besides discussing the challenges of topical delivery and benefits of NLCs, the paper elaborates on their physicochemical characterization. Further, in vitro evaluation of NLCs for dermatological benefits, followed by their evaluation in a hydrogel/cream base is covered. Lastly, disease-specific evaluation of NLC-based formulations is presented. EXPERT OPINION: The research endeavors for NLCs have largely focused on the fabrication of NLCs for different bioactives. However, scientific efforts should be aimed toward the lesser explored realm of NLCs, i.e. exploitation of analytical techniques, such as Parelectric spectroscopy, Electron Spin Resonance, and Nuclear Magnetic Resonance spectroscopy. NLCs have been proven for their potential to foster the therapeutic modalities applicable to cutaneous disorders. More attention needs to be devoted to their evaluation for disease-specific parameters. The futuristic steps must involve clinical studies, to lay the path for their commercialization.


Asunto(s)
Sistemas de Liberación de Medicamentos , Lípidos/química , Nanoestructuras , Administración Tópica , Animales , Portadores de Fármacos/química , Humanos , Hidrogeles , Tamaño de la Partícula , Absorción Cutánea
18.
Expert Opin Drug Deliv ; 17(3): 357-377, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-32064958

RESUMEN

Introduction: From a biopharmaceutical standpoint, the skin is recognized as an interesting route for drug delivery. In general, small molecules are able to penetrate the stratum corneum, the outermost layer of the skin. In contrast, the delivery of larger molecules, such as peptides and proteins, remains a challenge. Nanoparticles have been exploited not only to enhance skin penetration of drugs but also to expand the range of molecules to be clinically used.Areas covered: This review focus on Solid lipid nanoparticles (SLN) and Nanostructured lipid carriers (NLC) for skin administration. We discuss the selection criteria for lipids, surfactants, and surface modifiers commonly in use in SLN/NLC, their production techniques, and the range of drugs loaded in these lipid nanoparticles for the treatment of skin disorders.Expert opinion: Depending on the lipid and surfactant composition, different nanoparticle morphologies can be generated. Both SLN and NLC are composed of lipids that resemble those of the skin and sebum, which contribute to their enhanced biocompatibility, with limited toxicological risk. SLN and NLC can be loaded with very chemically different drugs, may provide a tunable release profile, can be produced in a sterilized environment, and be scaled-up without the need for organic solvents.


Asunto(s)
Sistemas de Liberación de Medicamentos , Lípidos/química , Nanopartículas , Administración Cutánea , Portadores de Fármacos/química , Humanos , Nanoestructuras , Piel/metabolismo , Enfermedades de la Piel/tratamiento farmacológico , Tensoactivos/química
19.
Curr Pharm Biotechnol ; 21(4): 341-351, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31752650

RESUMEN

BACKGROUND: Citronella Oil (CO) was used by the Indian army as mosquito repellant to repel mosquitoes at the beginning of the 20th century and later in 1948, it was registered in the USA for commercial purposes. Due to its ecofriendly nature, CO possesses immense potential as a mosquito repellent. METHODS: Citronella oil is a valuable alternative to synthetic mosquito repellents commonly used nowadays. However, its volatile nature, poor stability in air and high temperature restrict its application. Its direct application on skin may lead to skin irritation. To surmount the above-mentioned issues, the present research aims to develop Microsponge (MS), a novel dosage form for enhancing the utility and safety of CO. Quasi emulsion solvent diffusion method was chosen for crafting MS using ethyl cellulose with various drug-polymer ratios and characterized. In vitro cytotoxicity evaluation was also carried out to check the dermal safety of COMS. RESULTS: The present results revealed that the size of all prepared formulation lies in the micro range (20 ± 3 to 41 ± 4 µm), with good payload (42.09± 3.24 to 67.08± 6.43%). The results of FE-SEM depicted that MS were spherical in shape with porous nature. Cytotoxicity results indicated that COMS were safe on skin cells, when compared to pure CO. The optimized MS were also assessed for larvicidal assay against larvae of Anopheles culicifacies. CONCLUSION: The CO micro-formulations were found to possess enhanced stability of this oil. Entrapment of CO in MS resulted in a better vehicle system in terms of safety, stability and handling benefits of this oil.


Asunto(s)
Celulosa/análogos & derivados , Portadores de Fármacos/química , Repelentes de Insectos/farmacología , Aceites de Plantas/farmacología , Animales , Anopheles/efectos de los fármacos , Línea Celular , Supervivencia Celular/efectos de los fármacos , Celulosa/química , Composición de Medicamentos , Emulsiones , Humanos , Repelentes de Insectos/química , Repelentes de Insectos/toxicidad , Queratinocitos/efectos de los fármacos , Larva/efectos de los fármacos , Aceites de Plantas/química , Aceites de Plantas/toxicidad
20.
J Phys Chem A ; 123(45): 9770-9780, 2019 Nov 14.
Artículo en Inglés | MEDLINE | ID: mdl-31633920

RESUMEN

Surface-enhanced Raman scattering (SERS) study carried on thiazolidine-2,4-dione (TZD), a pharmacologically active heterocyclic compound, points to the presence of TZD dimer formed by plasmon-induced dimerization reaction of TZD on the surface of silver nanoparticles (Ag NP) at TZD concentrations of 10-3 M and above. The evidence for the presence of dimer was obtained from the appearance of a prominent band at 1566 cm-1 corresponding to the ν(C═C) band (a characteristic vibrational band observed for the Knoevenagel condensation reaction products) which is absent in the normal Raman scattering (NRS) spectra of TZD solid/solution. The observed spectrum compares well with the calculated spectrum of dimer obtained using density functional theory (DFT) calculations. The dimerization reaction is plausibly induced by the transfer of hot electrons generated by the nonradiative plasmon decay of Ag NP, and the proposed reaction mechanism is discussed. However, at lower concentrations (10-4-10-6 M), the characteristic dimer peak (1566 cm-1) is absent and the SERS spectra resemble more the NRS spectrum of TZD with a few changes. The spectral analysis supported by DFT calculations showed that TZD molecules undergo deprotonation and get adsorbed on the Ag NP surface as enolate forms. The proximity of TZD molecules on the surface of Ag NP is a necessary factor for the dimerization to occur. At lower concentrations, most molecules lie apart and reactions between molecules become less feasible, and they remain as monomers on the surface, while at higher concentrations the molecules are closer to each other on the Ag NP surface favoring the dimerization reaction to take place, leading to the formation of the dimer.

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