Avermectin Research Articles

Empowering alkali lignin with high performance in pickering emulsion by selective phenolation for the protection and controlled-release of agrochemical

Lignin is a versatile bioaromatic polymer, with great potentials in the preparation of advanced materials due to its anti-UV and anti-oxidant properties. However, the high heterogeneity of lignin seriously hinders its practical applications. In this study, alkali lignin with limited content of hydroxyl groups and a wide distribution of molecular weight was modified by selective phenolation, which not only resulted in a dramatical increase in the content of phenolic hydroxyl groups but also led to a more uniform structure of lignin. Catechol, as compared with phenol and pyrogallol, was the most suitable phenolation reagent to reacted with lignin, and the phenolic hydroxyl content of the catechol modified lignin increased by 318.89%. Besides, the molecular weight and polydispersity index of lignin after the modification decreased, which led to a small and regular size of lignin particles prepared by acid precipitation. Subseqently, lignin particles were used to prepare Pickering emulsions for avermectin (AVM) encapsulation, and the stability as well as the anti-UV and anti-oxidant capacities of Pickering emulsions prepared by using phenolated lignins as solid surfactants were obviously enhanced. The encapsulation efficiency of AVM in Pickering emulsions was also improved, which could reach high above 90%. Moreover, AVM protected by lignin-based Pickering emulsion could be controllably released in line with actual application demands, and the relatively high viscosity of emulsion could effectively avoid the loss of pesticide during spraying to the target.

PH/redox dual responsive from natural polymer-based nanoparticles for on-demand delivery of pesticides

With the increase in global food demand and the destruction of environment, the development of sustainable agriculture has become increasingly more important. Stimuli-responsive controlled-release agrochemicals enhance the bioavailability of active ingredients and reduce the frequency of use and environmental pollution. Herein, 3,3′-dithiodipropionic acid was used as a functional bridge to covalently link the degradable natural polymer zein and chitosan oligosaccharides (CS) to prepare a water-dispersed environmentally friendly pesticide carrier. Subsequently, via hydrophobic and hydrogen bonding interactions photo-decomposable avermectin (AVM) was encapsulated forming a stimuli-responsive intelligent nanopesticide delivery system (AVM@CS-SS-Zein) was developed by encapsulating in the carrier. AVM was released slowly from AVM@CS-SS-Zein particles in a neutral condition and was released rapidly under stimulation of glutathione and alkalinity in simulated insects. The photostability of AVM@CS-SS-Zein was improved by 6-fold compared with that of AVM and the nanoparticles had good adherence to the leaves, slowly releasing AVM and avoiding the light decomposition of active ingredients. When the pests ingest the leaves containing AVM@CS-SS-Zein, the rapid disintegration of the nanoparticles in vivo leads to a good insecticidal effect and the control rate of AVM@CS-SS-Zein on Plutella xylostella was higher than that of AVM. After 120 h of UV irradiation, the pest mortality rate of AVM@CS-SS-Zein was 46.7% while that of AVM and AVM emulsifiable concentrate was only 13.3% and 20.0%, respectively. Therefore, this pH/redox dual stimuli-responsive nanopesticide formulation achieves target control of pests and provides an efficient nanoplatform for green agriculture.

Development and validation of analytical methods by HPLC for quality control of avermectins and milbemycins in bulk samples

This work aims to develop analytical methods using high-performance liquid chromatography with a diode array detector (HPLC-DAD) for analysis and quantification of avermectins (AVMs) and milbemycins (MBMs) in bulk samples. First, the methods were optimized and some parameters such as temperature, flow rate, injection volume and mobile phase with different proportions of solvents were evaluated. The best chromatographic conditions were obtained using the Phenomenex® C18 (150 × 4.60 mm, 5 μm) column at a temperature of 20 °C, flow rate of 1.2 mL min-1, injection volume of 20 μL, and detection at 250 nm. Acetonitrile: ultrapure water (87: 13, v/v) was used as mobile phase for moxidectin and eprinomectin, and acetonitrile: methanol: ultrapure water (53: 35: 12, v/v/v) for abamectin and ivermectin. Under these conditions satisfactory results were obtained, with appropriate limits of detection and quantification, acceptable linearity, precision, accuracy, and robustness. These methods satisfy the need for analytical methods for the multi-determination of MBMs and the B1a and B1b forms of AVMs by HPLC-DAD, which can be considered simple, effective, innovative and should aid in the development of the field.

Basic Amino Acid-Modified Lignin-Based Biomass Adjuvants: Synthesis, Emulsifying Activity, Ultraviolet Protection, and Controlled Release of Avermectin.

Avermectin (AVM) is a highly effective and safe biopesticide but is very sensitive to ultraviolet (UV) light and exhibits poor water solubility. Developing green and multifunctional adjuvants is important for the protection and controlled release of AVM. In this work, a number of water-soluble enzymatic hydrolysis lignins (W-EHLs) were prepared via grafting basic amino acids and used as emulsifiers with co-surfactants to prepare high-internal phase emulsions (HIPEs). The results showed that W-EHLs with co-surfactants could be prepared with HIPEs that contained 90 vol % green oil phases such as turpentine, and the stability of the HIPEs first increased and then decreased when the rate of grafting of basic amino acids on lignin increased from 0.26 to 1.46 mmol/g. The more polar oil droplets were less deformable due to their higher viscosity, thereby affording a stability advantage to HIPEs. Subsequently, the relations between the stability and interfacial viscoelasticity of the emulsion were effectively correlated by interfacial rheology, droplet size, and physical stability tests. The results showed that HIPEs with smaller droplets had poor fluidity and strong interfacial viscoelasticity due to their higher droplet packing density, which resulted in good macroscopic stability. Like the AVM carrier, the retention rate of AVM in HIPEs was 80.1% after UV radiation for 72 h, which represented the highest UV protection efficiency in AVM delivery systems. The release curves showed that the rate of release of AVM from HIPEs was adjusted by controlling the pH value of the medium. In addition, the release of HIPEs is completely in accord with both diffusion and the matrix erosion mechanism. The strategy could be extended to other sensitive pesticides and used to promote the development of sustainable agriculture.

MXene (Ti3C2) Based Pesticide Delivery System for Sustained Release and Enhanced Pest Control.

A multifunctional nanomaterials based pesticide delivery system provides a powerful strategy for the efficient utilization of pesticides. We present here the application of a 2D MXene (Ti3C2) nanomaterial for pesticide delivery and plant protection. Avermectin (AV), a hydrophobic and unstable insecticide, was chosen as the model pesticide. In our study, AV@Ti3C2 was formed by fast adsorption of AV on Ti3C2, with a maximum loading capacity of 81.44%. Compared with hydrophobic AV, AV@Ti3C2 exhibited significantly improved water solubility, which is beneficial for ensuring the bioactivity of pesticide. The AV@Ti3C2 nanoformulation showed pH responsive slow-release behavior, overcoming the burst-release of conventional AV formulations. Besides, AV@Ti3C2 possessed excellent photostability under UV irradiation, which prolonged the persistent period of AV. Therefore, AV@Ti3C2 performed sustaining and enhanced antipest activity, according to the bioactivity assay. Furthermore, AV@Ti3C2 showed satisfactory biosafety, with no negative effect to the germination and growth of maize. Our current research provides a potential candidate, AV@Ti3C2, for pest control, and also broadens the application of 2D MXene materials in plant protection and sustainable agriculture.

Preparation of p-amino salicylic acid-modified polysuccinimide as water-based nanocarriers for enhancing pesticide stability and insecticidal activity

Avermectin (AVM) is a biopesticide with low toxicity and high activity, but has limited use due to its poor water solubility and easy decomposition. A delivery system that can stabilize this biopesticide can play a significant role for improving its biological activity. Herein, water-dispersible functionalized polysuccinimide nanoparticles (PAD) were prepared by a ring-opening reaction and subsequently used to encapsulate AVM via self-assembly to form AVM@PAD nanoparticles with a loading ratio of 10.04 %. The half-life under UV radiation (300 W) of AVM@PAD was three times higher than that of free AVM, demonstrating the excellent protective ability of PAD. In addition, AVM@PAD nanoparticles could sustain the release of AVM for 70 h with a cumulative release rate of 70 %. AVM@PAD nanoparticles also showed a pH-responsive release, and their maximum cumulative release rate was at neutral pH. Moreover, the median lethal concentration (LC50) value of AVM@PAD with respect to Plutella xylostella was 34.50 mg/L, while that of free AVM was 56.05 mg/L. These results showed that the AVM@PAD nanoparticles can potentially and effectively promote drug stability and biological activity in agriculture.

Avermectin induces toxic effects in insect nontarget cells involves DNA damage and its associated programmed cell death

Avermectin (AVM), is widely applied in the fields of agriculture, possess activities against mites and insects. AVM is generally thought to keep the GABA-related chloride channels open in insect cells. However, AVM induces cytotoxicity in non-neural cells still ambiguous. Here we evaluate the cytotoxicity and other mode of action of AVM in Spodoptera frugiperda (Sf9) cells. Our results showed that AVM suppressed the activity of Sf9 cells and induced programmed cell death. DNA damage of Sf9 cells was detected by alkaline comet assay and PARP. The cleavage of poly ADP-ribose polymerase (PARP) and DNA double-strand breaks demonstrated AVM induced DNA damage in Sf9 cells. In addition, a series of established cytotoxicity tests were conducted to explore the mechanism of AVM toxicity in Sf9 cells. Typical apoptosis changes were occurred including increasing the expression of Bax/Bcl-2 and the activation of caspase-9/-3. Subsequently, Western blotting was used to detected autophagy related proteins including LC3, Beclin1 and p62. We found that AVM upregulated LC3, Beclin1 expression and downregulated p62 expressions. Moreover, we found that AVM induced autophagy may through AMPK/mTOR-mediated autophagy pathway. These results showed that AVM-induced DNA damage and programmed cell death in Sf9 cells.

Investigation of non-thermal atmospheric plasma for the degradation of avermectin solution

Increasing concern with regard to food safety in the presence of pesticide residues (PRs) on the surface of agricultural products has resulted in the rapid development of practical degrading technologies for corresponding PRs. In this paper, an unconventional method of degrading pesticides, non-thermal atmospheric plasma (NTAP), was proposed to degrade the avermectin (AVM) in aqueous solution. Optical emission spectroscopy shows that NTAP, consisting of filamentary streamers, contains a variety of reactive oxygen species (ROS) that may interact with AVM. The high-performance liquid chromatography (HPLC)-MS/MS results indicate that the efficiency of AVM degradation seriously depends on multiple operation parameters of the NTAP, including the applied voltage, treatment time and gas flow rate. The maximum degradation rate of AVM was observed to be 97.47% after 240 s exposure under NTAP with an applied voltage of 18 kV and gas flow rate of 1 l min−1. Molecular dynamics simulation based on a reactive force field for the interaction between O (ground state atomic oxygen) and AVM was performed to analyze the underpinning mechanisms. The simulation result shows the possible pathways of the NTAP-generated O degrading AVM by destroying the glycosyl group or fracturing the ester group.

Preparation of novel all-lignin microcapsules via interfacial cross-linking of pickering emulsion

Lignin based microcapsules are highly attractive for protect easy photolysis substances. However, so far, all-lignin microcapsules prepared with water-soluble lignin are not satisfactory in terms of wall thickness and mechanical properties. Herein, we fabricated a novel all-lignin microcapsules (ALMC) by using 1,6-dibromohexane or epichlorohydrin to crosslink lignin particles adsorbed at the Pickering emulsion droplets interface. 1, 6-Dibromohexane demonstrated a stronger cross-linking activity than epichlorohydrin, and could be used in less dosage and at lower temperatures. The shell thickness of ALMC was about 300 nm. Further analysis confirmed that the shell had a double-layer structure, the outer layer was rough and shrinking and the inner layer was smooth and dense. ALMC can be used to encapsulate hydrophobic substances, and a photosensitive pesticide avermectin (AVM) was chosen to be sealed as model object. The AVM-encapsulated ALMC showed ideal sustained-release performance, namely releasing slowly in the early stage without affecting the overall release. After 70 h of UV irradiation, 93.7 % of AVM was retained, while the original AVM without encapsulation almost all of them was photodegraded, which means that the ultraviolet absorption property of lignin provides excellent protection for the core materials.

A stable polyamine-modified zein-based nanoformulation with high foliar affinity and lowered toxicity for sustained avermectin release.

A large amount of pesticides that are not deposited on desired locations due to drift and rolling, endangering the ecological environment and human health. Therefore, it is urgent to develop environmentally friendly and foliar affinity formulations. The design and construction of pesticide nano-delivery system is considered to be an effective way to solve this problem. In this research, polyamine-modified zein (AM-zein) was synthesized by incorporating ethylenediamine-terminated polyethyleneimine into zein to improve its stability as a nanocarrier, enhance electrostatic force between the carrier and pesticides and plant foliage. Avermectin (AVM)-loaded nanoparticles, containing a high positive charge, were prepared by the anti-solvent method using AM-zein as carrier. The nanoparticles can be stored for 30 days without any significant change in the particle size and stably dispersed at pH5-9. Compared to the commercial emulsifiable concentrate (EC), nanoparticles dispersions exhibited better leaf affinity, and the retention of dispersion increased from 7.82 to 13.86 mg/cm2 . Interestingly, we have discovered for the first time that the ultraviolet (UV) barrier effect of zein increases while prolonging the UV exposure time; 30.47% of the encapsulated AVM remained intact after exposure to UV for 60 min, compared to only 17.13% for the EC. Insecticidal activity of AVM nanoparticles did not improve compared to EC, but they demonstrated significantly lower toxicity against zebrafish. This research opens up a new idea for improving the stability of zein nanoparticles, providing a novel path to deliver pesticides efficiently and eco-friendly. © 2021 Society of Chemical Industry.

Avermectin induced DNA damage to the apoptosis and autophagy in human lung epithelial A549 cells

Avermectin (AVM), as a biological insecticide, is widely used in agriculture and forestry production globally. However, inhalation of AVM may pose a risk, and the lung is the direct target, but the cytotoxicity of AVM on human lung cells is still unclear. Here, we attempted to elucidate the cytotoxic effect and molecular mechanism of AVM on human lung A549 cells. The results indicated that AVM inhibits cell proliferation, and enhances programmed cell death (apoptosis and autophagy). In addition, we found the AVM-treated cells showed an obvious drop in mitochondrial membrane potential and LC3-I/II, increased ROS production, DNA double-strand breaks, caspase-3/9 activated, PARP cleaved, cytochrome c and Bax/Bcl-2 content rise. The results showed that AVM induced mitochondria-related apoptosis and autophagy in lung A549 cells. These results indicate that AVM can pose a potential threat to human health by inducing DNA damage and programmed cell death.

Natural rosin modified carboxymethyl cellulose delivery system with lowered toxicity for long-term pest control

The increasing world-wide demand for food has prompted the development of efficient and environmentally friendly pesticide formulations. In this article, we have prepared CMC-g-PRSG carrier based on two compounds from natural materials carboxymethyl cellulose (CMC) and rosin (RS). The model pesticide avermectin (AVM) was encapsulated through hydrophobic interaction, and self-assembled to form nanopesticide AVM@CMC-g-PRSG with an average particle size of 167 nm. The prepared nanopesticide displays enhanced dispersibility and stability of AVM in water, and can effectively adhere to the leaves to prevent loss. The release rate of AVM encapsulated in the nanocarrier can be controlled by adjusting pH, and AVM half-life under ultraviolet radiation shows a 3-fold increase allowing control of pests for prolonged periods of time in practical applications. Biological safety tests showed that AVM@CMC-g-PRSG effectively reduces the toxicity of AVM to aquatic animals. Therefore, the cheap and degradable carrier CMC-g-PRSG can improve the effect of hydrophobic pesticides.

Fluorinated sodium carboxymethyl cellulose nanoparticles as carrier for improving adhesion and sustaining release of AVM

The loss and overuse of avermectin (AVM) on protecting plants pose a threat to ecosystems. To increase the efficacy of AVM, fluorinated sodium carboxymethyl cellulose (CMC-g-PHFBA) was synthesized by inducing poly 2, 2, 3, 4, 4, 4-hexafluorobutyl methacrylate (HFBA), and AVM was then enveloped in CMC-g-PHFBA (AVM@CMC-g-PHFBA) via hydrophobic interaction. According to the results, the samples exhibited desirable angle contact (min = 58.18°), retention rate (max = 60%, after water washing) and LHC (15.5 mg/cm2) on cucumber leaves. AVM@CMC-g-PHFBA also showed good storage stability with obvious Tyndall effect (size <240 nm and charge <–21 mV) for 11 days, with higher anti-UV property. The loaded AVM nanoparticles can release drugs for 95 h, which can be fitted to a zero-order model under different pH conditions for achieving a prolonged pharmacological action. Moreover, the samples have retained insecticidal activity. Collectively, CMC-g-PHFBA nanoparticles are promising delivery systems of AVM with the adhesive and sustained-release property.

Toxic Effects of Fine Plant Powder Impregnated With Avermectins on Mosquito Larvae and Nontarget Aquatic Invertebrates.

The toxic effects of an avermectin-impregnated fine plant powder (AIFP) against larval Aedes aegypti L. (Diptera: Culicidae), Culex modestus Ficalbi (Diptera: Culicidae), and Anopheles messeae Falleroni (Diptera: Culicidae), as well as selected nontarget aquatic invertebrates, were studied under laboratory conditions. The possibility of trophic transfer of avermectins (AVMs) through the food chain and their toxic effects on predaceous species fed AIFP-treated mosquito larvae was also evaluated. Among mosquitoes, Anopheles messeae were the most sensitive to AIFP, while Cx. modestus exhibited the least sensitivity to this formulation. Among nontarget aquatic invertebrates, the greatest toxicity of AIFP was observed for benthic species (larval Chironomus sp. Meigen (Diptera: Chironomidae), whereas predators (dragonflies, water beetles, and water bugs) exhibited the lowest AIFP sensitivity. AIFP sensitivity of the clam shrimp Lynceus brachyurus O. F. Muller (Diplostraca: Lynceidae), the phantom midge Chaoborus crystallinus De Geer (Diptera: Chaoboridae), and the mayfly Caenis robusta Eaton (Ephemeroptera: Caenidae) was intermediate and similar to the sensitivity of the mosquito Cx. modestus. However, these nontarget species were more resistant than An. messeae and Ae. aegypti. Solid-phase extraction of mosquito larvae treated with AIFP and subsequent high-performance liquid chromatography (HPLC) analysis of the extracts revealed an AVM concentration of up to 2.1 ± 0.3 μg/g. Feeding the creeping water bug Ilyocoris cimicoides L. (Hemiptera: Naucoridae) on the AIFP-treated mosquito larvae resulted in 51% mortality of the predaceous species. But no toxicity was observed for Aeshna mixta Latreille (Odonata: Aeshnidae) dragonfly larvae fed those mosquito larvae. The results of this work showed that this AVM formulation can be effective against mosquito larvae.

Anthelmintic Efficacy of Strongyle Nematodes to Ivermectin and Fenbendazole on Working Donkeys (Equus asinus) in and around Hosaena Town, Southern Ethiopia.

Background Gastrointestinal helminth parasite infection is a major influencing factor against profitability of working equines all over the world. Objectives A study was conducted from October 2016 to May 2017 in and around Hosaena to determine the efficacy of benzimidazole (BZ) and avermectin (AVM) chemical groups against strongyle nematodes in working donkeys. Methods A total of 230 donkeys from Hosaena, Soro, Anlemo, and Gombora were randomly allocated into 5 groups of 46 donkeys in each group. All groups, except group 1 (control), were treated with ivermectin 1%, ivertong 10%, fenbendazole, and Fenacure 750 mg, respectively. Fecal samples were collected perrectally before treatment (day 0) and after treatment (day 14), and an egg per gram (EPG) value of >200 was used as a cutoff for inclusion to assess the efficacy of anthelmintics. Results Accordingly, the study revealed that AVM was effective against strongyle nematodes of donkeys with the mean fecal egg count reduction (FECR) of 100% in three study areas and 97.2% in one study area, respectively, whereas BZ resistance was suspected in the areas where the drug was tested, with the mean FECR of less than 94% in the three study areas. The study also revealed that 73% of the donkeys were affected with a severe degree of strongyle infection as determined by EPG, while 10.4% of donkeys were affected with a mild degree of Parascaris equorum infection. Conclusions The findings of the present study are expected to serve as baseline data for future investigations and control actions to design realistic control programs to minimize factors that favor emergence of anthelmintic resistance and improve the overall health of the donkeys. Thus, further detailed studies are needed to determine the factors that reduce anthelmintic efficacy and increase anthelmintic resistance in donkeys.

Deciphering the Biosynthesis of TDP-β-l-oleandrose in Avermectin.

Avermectin (AVM) refers to eight macrolides containing a common l-oleandrosyl disaccharide chain indispensable to their antiparasitic bioactivities. We delineated the biosynthetic pathway of TDP-β-l-oleandrose (1), the sugar donor of AVM, by characterizing AveBVIII, AveBV, and AveBVII as TDP-sugar 3-ketoreductase, 5-epimerase, and 3-O-methyltransferase, respectively. On the basis of this pathway, we successfully reconstituted the biosynthesis of 1 in Escherichia coli. Our work completes the biosynthetic pathway of AVM and lays a solid foundation for further studies.

Preparation and Characterization of Zein-Based Nanoparticles via Ring-Opening Reaction and Self-Assembly as Aqueous Nanocarriers for Pesticides.

Herein, we prepared and compared two water-soluble amphiphilic zein-based nanocarrier systems with avermectin (AVM) payload to enhance pesticide's water-dispersity, foliage wettability, adhesion, anti-UV, and pH-responsive controlled release property. Ethylene glycol diglycidyl ether (EGDE) and diethanolamine (DEA) were utilized to conjugate with hydrophobic zein via a ring-opening reaction and then encapsulated with AVM via a hydrophobic interaction to fabricate a nanopesticide marked as AVM@Zein-EGDE/DEA. For the sake of further improving the nanocarrier's performance, sodium carboxymethyl cellulose (CMC) was grafted with methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA) to form a kind of copolymer CMC-g-P(HEMA-MMA), which was applied to conjugate with Zein-EGDE via a ring-opening reaction. Likewise, another nanopesticide system named AVM@Zein-EGDE/CMC-g-P(HEMA-MMA) was obtained through hydrophobic interactions as well as the electrostatic effect. Various techniques were utilized to confirm chemical interaction, thermal behavior, structural characteristics, and stability. The results showed that AVM encapsulated in Zein-EGDE/CMC-g-P(HEMA-MMA) possessed a larger particle size with an average value of 180-254 nm than AVM loaded in Zein-EGDE/DEA with 144-175 nm but had better stability in aqueous solution. Also, AVM loaded in Zein-EGDE/CMC-g-P(HEMA-MMA) enhanced the encapsulation efficiency, and both of them exhibited excellent pH-responsive sustained release behavior. Besides, the former improved wettability on a cucumber leaf surface and enhanced adhesion ability compared to AVM@Zein-EGDE/DEA because of CMC-g-P(HEMA-MMA) with hydrophobic segments. Similarly, anti-UV performance was also enhanced owing to CMC-g-P(HEMA-MMA) as an additional protective layer. More importantly, the encapsulation of Zein-EGDE/DEA and Zein-EGDE/CMC-g-P(HEMA-MMA) as protective barriers for AVM still retained a similar toxicity level. Overall, we demonstrated the proof of concept for the application of amphiphilic zein-based nanomaterials as aqueous nanocarriers for hydrophobic pesticides.

Effects of two kinds of fishery drugs on the expressions of GAD and GABA-T mRNA in crucian carp (Carassius auratus gibelio)

The objective of this study was to investigate the effects of difloxacin (DIF) and avermectin (AVM) on glutamate decarboxylase (GAD) and GABA-transaminase (GABA-T) in different tissues of crucian carp (Carassius auratus gibelio). After the treatments of DIF and AVM, the mRNA expressions of GAD and GABA-T in different tissues were detected by quantitative real-time PCR (qPCR). The results showed that the mRNA expressions of GAD65, GAD67, and GABA-T in the telencephalon (Tel), mesencephalon (Mes), cerebella (Cer), and medulla oblongata (Med) were downregulated significantly with the safe dose (SD, 20 mg/kg) of DIF (P < 0.05 or P < 0.01). While the expressions of GAD65 and GAD67 in the kidney at 12 h had strikingly upregulated to 13.81 ± 1.06** and 150.67 ± 12.85** times. Treated with the lethal dose of 50% (LD50, 2840 mg/kg b. W.) of DIF, the mRNA expressions of GAD65, GAD67, and GABA-T in all tissues were increased significantly (P < 0.01). The results of AVM group showed that the mRNA expressions of GAD65, GAD67, and GABA-T both in the central and peripheral tissues were all remarkably downregulated at the safe concentration (SC, 0.0039 mg/L) and the lethal concentration of 50% (LC50, 0.039 mg/L), except for the mRNA inhibitions of GAD65, GAD67, and GABA-T in the muscle at 2 h which sharply downregulated to 0.20 ± 0.02ΔΔ × 10−2, 0.57 ± 0.06ΔΔ × 10−1 and 0.44 ± 0.02ΔΔ × 10−1, respectively (P < 0.01).

Preparation and characterization of n-octylamine modified alginate/chitosan microspheres for controlled release of avermectin

Microspheres can be designed to increase the utilization of pesticides and reduce environmental pollution. In this study, the sodium alginate (SA) modified with n-octylamine was prepared, and the microspheres loading avermectin (AVM) were fabricated by orifice-coagulation bath using chitosan and modified/nature SA as the carrier materials. The particle size, granulation ratio, drug loading (DL) rate, embedding rate, swelling and sustained-release properties of microspheres were investigated. The Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were used to characterize the structure and morphology of microspheres. The results showed that the swelling and drug release properties of modified and unmodified microspheres showed good pH and thermo responsive. The DL performance of modified microspheres was improved, the embedding efficiency (EE) and DL were up to 60.3% and 75.8%, respectively. Furthermore, the AVM release time of microspheres with modified SA was prolonged and extended up to 48 h. All results indicated AVM of modified microspheres possessed higher utilization efficiency compared to the unmodified microspheres.

Evidence of safety in the use of Ivermectin in pregnant women: Regarding the use of Ivermectin in COVID-19

La Ivermectina, medicamento derivado macrocíclico formado por una mezcla 80:20 de avermectina B1a y B1b, se ha utilizado por más de 30 años para tratar diversas enfermedades parasitarias en mamíferos, fue aprobada por la Food and Drug Administration (FDA) para el tratamiento de la oncocercosis y la estrongiloidiasis, y en otros países se incluyó su empleo en escabiosis y pediculosis; sin embargo, su espectro de acción incluye a múltiples endo y ectoparásitos; así como su eficacia comprobada para la prevención y control de la malaria. En un reciente estudio in vitro en células Vero/hSLAM infectadas con el virus SARS-CoV-2 (COVID-19) expuestas a Ivermectina 5 μM; después de 48 horas, se encontró una reducción del ARN viral en 5000 veces comparado con el grupo control. Desde entonces, más de 30 ensayos clínicos se encuentran en fase de reclutamiento para evaluar la eficacia de Ivermectina en el tratamiento o profilaxis de SARS-CoV-2; por lo que se estima que en los próximos meses se tengan resultados publicados al respecto.