Slow Release Behavior Research Articles

Development of Phosphatidylcholine/Tween 80 based biocompatible clove oil-in-water nanoemulsion as a green nanocarrier for controlled herbicide delivery

Recently, the development of ecofriendly and biocompatible agrochemical delivery systems has garnered widespread attention because of their great potential in sustainable agri-food applications. Atrazine (ATZ) is a globally used herbicide used to control weeds, but it suffers from poor aqueous solubility, poor efficacy, and environmental loss. Herein, we report a novel, eco-friendly and biocompatible clove oil-based nanoemulsion as a green nanocarrier to enhance the solubility, bioavailability, and control release of ATZ. Food grade surfactants, Tween 80 and Phosphatidylcholine (PC) were used to formulate clove oil nanoemulsion with size <200 nm using ultrasonic emulsification technique, without any use of organic solvent. The ATZ encapsulation efficiency in NEm was greater than 95%. DLS confirms the nanosize (106 nm) and monodispersity of NEm. HRTEM reveals the spherical morphology of the nanodroplets. FTIR and DSC confirm the successful incorporation of ATZ inside the NEm oil droplet core. ATZ loaded NEm showed excellent thermal and storage stability, low Ostwald ripening rate, slow and sustained herbicide release behavior, which is of vital importance for an herbicide formulation. The release rate was better than commercial ATZ and free ATZ formulations. Results from herbicidal activity assays demonstrate that ATZ NEm exhibited excellent herbicidal activity even at low concentrations as compared to commercial ATZ analogs. In consideration of biocompatible excipients, free of organic solvent, and a simple fabrication process, ATZ loaded clove oil NEm can hold great potential in weed control and sustainable agri-food applications.

Research on preparation and properties of a multifunctional superabsorbent based on semicoke and humic acid

. • A novel superabsorbent composite was prepared by introduction of SC and HA. • Superabsorbent composite showed water retention and slow-release fertilizer functions. • Composite containing 15 wt% of HA and 6 wt% of SC could remarkably improve water retention. • The growth promoting effect of plants was clearly found by adding of PAA/SC/HA in soil. Superabsorbent integrated multiple functions, including absorbing water, preserving water and controlled releasing for fertilizer, which has attracted extensive attention in modern agriculture. In this study, a novel multifunctional superabsorbent of polyacrylic acid/humic acid/semicoke (PAA/HA/SC) with high water retention and favorable slow release performance was developed by incorporation of humic acid (HA) and oil shale semicoke (SC) via a simple free radical polymerization. The water retention, swelling kinetics, pH-dependent and swelling reversibility were investigated systematically. The water retention results showed that the prepared superabsorbent exhibited outstanding water-retention capacities of 824 g/g and 80 g/g in distilled water and 0.9 wt% NaCl solution respectively, as 15 wt% of HA and 6 wt% of SC were introduced into the three dimensional polymeric network of PAA. The slow release behaviors in distilled water and various salt solutions indicated that the release amount of HA was relatively fast in the initial stage, and then became flat after 16 days. Besides, the soil column leaching experiment revealed that the release amount of the HA reached the maximum value of 222.14 mg/L after 9 days, and potted experiment confirmed the growth-promoting effect for plant of PAA/HA/SC. This work explored the practical application of SC in green and sustainable chemical engineering area, also provided an important reference for application of multifunctional superabsorbent in modern agriculture.

Agronomic potential of two different glass-based materials as novel inorganic slow-release iron fertilizers.

Large amounts of chemical fertilizers are still currently used to compensate the soil nutrients scarcity in order to increase and sustain crop yield with consequent rising of environmental pollution and health problems. To mitigate these environmental risks, fertilizers with slow-release behaviours have been developed. The aim of this study was to assess the agronomic potential of two different glass-based materials (by-products from the ceramic sector) as inorganic slow-release iron (Fe) fertilizers. The X-ray powder diffraction confirmed the presence of amorphous structure and the richness in Fe of the investigated materials. The solubility analysis highlighted the slow Fe release from the glassy network and that the maximum of the Fe release was at alkaline pH suggesting their potential use as slow-release Fe fertilizers, especially in calcareous soils. The pot and leaching experiments demonstrated that although the glass-based materials increased the amount of soil available Fe, we did not observe Fe leaching and plant toxicity. This fact would suggest their reliability to increase soil fertility without negative effects on the environment. The use of glass-based materials, specifically by-products from the ceramic sectors, as inorganic slow-release Fe fertilizers can be sustained. The tests performed at three different pH conditions testified the slow-release behaviour of the tested materials and underlined that the Fe release increases at alkaline environment. Therefore, the present study pointed out the glass-based materials by products from the ceramic sector as novel slow-release and environmental-friendly fertilizers in agriculture. © 2021 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

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.

Copper metal-organic framework embedded carboxymethyl chitosan-g-glutathione/polyacrylamide hydrogels for killing bacteria and promoting wound healing

Bacterial infection and its induced oxidative stress as major clinical challenge during wound healing call for an urgent response for the development of medical dressings with multi-functions, such as antioxidant and antibacterial. To meet this demand, copper metal organic framework nanoparticles (HKUST NPs) and carboxymethyl chitosan-g-glutathione (CMCs-GSH) were synthesized and characterized. By embedding HKUST NPs into PAM/CMCs-GSH hydrogel (AOH), we developed a novel hydrogel dressing (HKUST-Hs) with dual effects of antibacterial and antioxidant. The morphology, swelling behavior, oxidation resistance and antibacterial properties of HKUST-Hs were investigated as well as the slow-release behavior of copper ions. Full-thickness cutaneous wound model of rats was created to assess the promoting effect of HKUST-Hs on wound healing. We found that HKUST NPs could be well dispersed in HKUST-Hs by shielding the positive charge of copper ions, and thus copper ions released were uniformly distributed and chelated with CMCs-GSH to promote the swelling stability of HKUST-Hs. Also, HKUST-Hs exhibited good free radical scavenging ability in vitro antioxidant assay. Meanwhile, a gradient sustained-release system of copper ions was formed in HKUST-Hs owing to the inhibition of HKUST NPs to copper release and the chelation of CMCs-GSH, which effectively inhibited the explosive release of copper ions and prolonged the release period, thereby reducing cytotoxicity. In vitro antibacterial test demonstrated there was synergistic antibacterial effect between the slow-released copper ions and CMCs-GSH, which improved the antibacterial activity and antibacterial persistence of HKUST-Hs. Finally, HKUST-Hs accelerated wound healing in vivo by continuously killing bacteria and inhibiting oxidative stress.

Preparation, Characterization, and Anti-Cancer Activity of Nanostructured Lipid Carriers Containing Imatinib.

Breast cancer is the most widespread malignancy in women worldwide. Nanostructured lipid carriers (NLCs) have proven effective in the treatment of cancer. NLCs loaded with imatinib (IMA) (NANIMA) were prepared and evaluated for their in vitro efficacy in MCF-7 breast cancer cells. The hot homogenization method was used for the preparation of NANIMAs. An aqueous solution of surfactants (hot) was mixed with a molten mixture of stearic acid and sesame oil (hot) under homogenization. The prepared NANIMAs were characterized and evaluated for size, polydispersity index, zeta potential, encapsulation efficiency, release studies, stability studies, and MTT assay (cytotoxicity studies). The optimized NANIMAs revealed a particle size of 104.63 ± 9.55 d.nm, PdI of 0.227 ± 0.06, and EE of 99.79 ± 0.03. All of the NANIMAs revealed slow and sustained release behavior. The surfactants used in the preparation of the NANIMAs exhibited their effects on particle size, zeta potential, encapsulation efficiency, stability studies, and release studies. The cytotoxicity studies unveiled an 8.75 times increase in cytotoxicity for the optimized NANIMAs (IC50 = 6 µM) when compared to IMA alone (IC50 = 52.5 µM) on MCF-7 breast cancer cells. In the future, NLCs containing IMA will possibly be employed to cure breast cancer. A small amount of IMA loaded into the NLCs will be better than IMA alone for the treatment of breast cancer. Moreover, patients will likely exhibit less adverse effects than in the case of IMA alone. Consequently, NANIMAs could prove to be useful for effective breast cancer treatment.

A new class of biochar-based slow-release phosphorus fertilizers with high water retention based on integrated co-pyrolysis and co-polymerization

The development of slow-release phosphorus fertilizers (SRFs) with high water retention is of significance for modern agriculture. Herein, a new class of biochar-based SRFs are developed by an integrated co-pyrolysis and co-polymerization process (PSRFs). The water-retention performance and P slow-release behavior of PSRFs are evaluated, which are compared with other types of biochar-based SRFs derived from biochar-based phosphorus adsorption (MSRFs), co-pyrolysis of biomass-bentonite-nutrients (BSRFs), and the application of coating on BSRFs (CSRFs). The results show that the obtained PSRFs exhibits high water retention with the maximum swelling capacity of 94.2 g/g, far outstripping other tested SRFs. The water-retention performance of PSRFs is found to be positively correlated with their crosslinking agent contents. In addition, PSRFs has excellent P slow-release performance which is comparable with CSRFs (~51.5% of P release after 30 days), but much better than MSRFs and BSRFs with a complete P release after 30 days. Furthermore, pot experiments reveal that PSRFs has the highest P utilization efficiency (75.83% after 60 days), which can promote the growth of pepper seedlings better than other SRFs. Moreover, the soil burial tests indicate that PSRFs has a good biodegradability with the degradation ratio of 33.46% in 75 days. Finally, biological abundance analysis further reveals that Actinobacteria in soil is mainly responsible for the metabolism of starch and sodium alginate in PSRFs.

Preparation of Polyurea Microcapsules by Interfacial Polymerization of Isocyanate and Chitosan Oligosaccharide.

(2-((1-(4-chlorophenyl)-1H-pyrazol-3-yl)oxy)-N-(3,4-dichlorophenyl)-propanamide) is a new oil-soluble compound with good fungicidal activity against Rhizoctonia solani. Chitosan oligosaccharide (COS) is the depolymerization product of chitosan and can be developed into biological pesticides, growth regulators, and fertilizers due to its various bioactivities. COS is an oligomer of β- (1 → 4)-linked d –glucosamine and can be taken as a polyamine. In this study, microcapsules were prepared by interfacial polymerization of oil-soluble methylene diphenyl diisocyanate and water-soluble COS. The effects of several key preparation parameters, e.g., emulsifier dosage, agitation rate during emulsification, and core/shell ratio, on properties of the microcapsules such as the encapsulation efficiency, particle size, and size distribution were investigated. The microcapsules were characterized by infrared spectroscopy, thermogravimetric analysis, and scanning electron microscopy, etc., and the encapsulation efficiency and release behaviors were investigated. The results show that the microcapsules have a smooth surface and 93.3% of encapsulation efficiency. The microcapsules showed slow-release behavior following a first-order kinetic equation, and the accumulative release rates of the microcapsules with core/shell mass ratios of 8.0/4.0, 8.0/5.0, and 8.0/6.0, were 95.5%, 91.4%, and 90.1%, respectively, on day 30. Due to many high biological activities, biodegradability, and the pure nature of COS, microcapsules formed from COS are promising for applications in controlled release of pesticides, growth regulators, and fertilizer.

Facile Fabrication of N-Slow Release Fertilizer Hydrogel Beads by Alginate-Based Composites

A novel slow-release N-fertilizer hydrogel beads were developed using sodium alginate (SA) and alginate-talcum (ST) composite as N-absorbent. In this work, the hydrogel composite were fabricated by simple method and low cost. N-fertilizer hydrogel beads were prepared two types, for SA types, which were different sodium alginate (1(SA1), 3(SA3), 5(SA5), 7(SA7), and 10(SA10) wt%). And, for ST types, sodium alginate and talcum were vary ratios to 1:0.5(S1T0.5), 1:1(S1T1), and 1:2 (S1T2). The chemical structure of hydrogel composite beads were characterized via Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). The release behavior were investigate by Zero-order kinetic model, First-order kinetic model, Higuchi model and Korsmeyer-Peppas model. We have found that the N-fertilizer release constants in Korsmeyer-Peppas model were decrease with increase SA content for 1-5 wt% in SA hydrogel beads. However, SA contents were more than 5 wt% which rapidly enhanced fertilizer release. In addition, to add talcum in ST hydrogel beads significantly reduced fertilizer release rate. The N-fertilizer hydrogel beads exhibits significantly slow release behavior. These results indicates that the development of slow-release fertilizer hydrogel beads can be improve the effectiveness of N-fertilizer.

An environmental-friendly pesticide-fertilizer combination fabricated by in-situ synthesis of ZIF-8

Stimulus-responsive pesticide or fertilizer systems have been emerged to improve the use efficiency of agrochemicals, reduce over-application and ensuing environmental problems. However, environmental-friendly synthesis of these systems still remain challenging. In this work, an environmental-friendly synthesis strategy has been developed to form a pesticide and fertilizer combination to achieve the integration of plant protection and nutrient supply. This pesticide-fertilizer combination system was fabricated using ammonium zinc phosphate (ZNP) and in-situ synthesized zeolitic imidazolate framework-8 (ZIF-8) as nutrients resources, and dinotefuran (DNF) as a pesticide. DNF was encapsulated in-situ (loading capacity of 12.32 ± 0.46%) during the ZIF-8 crystal synthesis process, rather than loaded by further adsorption, which improved its stability and prevented premature or rapid release. The hydrophobic ZIF-8 provided a pH-responsive slow-release behavior. The cumulative released DNF within seven days at pH 4.0, 7.0 and 10.0 was 66.30%, 40.41%, and 37.44%, respectively. The pesticide-fertilizer combination system showed significant effects on corn seed pre-cultivation, soil cultivation and pest control. This work provides a strategy for the integration of pesticide and fertilizer, which will reduce negative environmental effects caused by their over-applications and have great potential in modern sustainable agriculture.

Preparation of liposomes composed of supercritical carbon dioxide-philic phospholipids using the rapid expansion of supercritical solution process

The synthesis of supercritical carbon dioxide-philic phospholipids allowed the vitamin E acetate (VEA) liposomes composed of them to be successfully prepared using the rapid expansion of supercritical solution (RESS) process without any organic solvent. The single-factor analysis and the response surface methodology combined with Box–Behnken design were used to optimize the operation conditions. The results indicated that pressure was the most important factor to the encapsulation efficiency of the liposomes, which was increased with a higher pressure. Temperature and mass ratio also had some effects, while the interaction of the three factors was not significant. The liposomes prepared under the optimal conditions (i.e., temperature of 55.45 °C, pressure of 25.00 MPa, and mass ratio of 6.35:1) showed good stability as well as the slow and continuous release behavior. The encapsulation efficiency, average particle size, PDI, and zeta-potential of the prepared liposomes were 92.84 ± 0.98%, 247.4 ± 6.5 nm, 0.295 ± 0.012, and −42.55 ± 0.64 mV, respectively.

Intranasal co-delivery of berberine and evodiamine by self-assembled thermosensitive in-situ hydrogels for improving depressive disorder

The orally administrated antidepressants not only caused side effects such as dizziness, diarrhea, and drug resistance, but also worked slowly. Therefore, new antidepressants and preparations derived from natural medicines play an important role in the study of antidepressant drugs. It was reported that the two components of Zuojin pill, berberine (BBR) and evodiamine (EVO), were used in combination to improve depressive disorder. In our study, a self-assembled thermosensitive in-situ hydrogel was prepared to achieve sustained co-delivery of BBR and EVO. The preparation process of hydrogel consists of two steps, namely, the inclusion of the drugs and thermosensitive self-assembly of the hydrogel. In vitro experimental results indicated that the prepared hydrogel showed a good thermosensitive property under physiological temperature. The hydrogel had a slow and controlled release behavior for BBR and EVO, according with first-order equation. In vivo experimental results indicated that compared to intragastric administration of drug solution, the intranasal administration of hydrogel increased bioavailability of BBR and EVO, approximately 135 and 112 folds, respectively. The hydrogel at a low dose significantly reversed behavioral despair of the mice, improved depressive symptom of rats, and treated depressive disorder by regulating the abnormal levels of monoamine neurotransmitters (including 5-hydroxytryptamine, noradrenalin and dopamine) metabolism and related metabolic pathways such as purine, citrate cycle, scorbate and aldarate, butanoate, vitamin B6, and pyrimidine metabolism. Therefore, as a drug co-delivery system, the intranasally administrated hydrogels with a good release and high bioavailability provides a non-invasive therapeutic strategy for the clinical treatment of depression, which attains antidepressant effects by regulation of the monoamine neurotransmitters metabolism and related metabolic pathways.

Diatoms decorated with gold nanoparticles by In-situ and Ex-situ methods for in vitro gentamicin release

The use of natural diatoms is currently a topic of interest for therapeutic applications due to its facilities, low cost, and biocompatibility. Here, we report the chemical modification of diatoms Aulacoseria genus microalgae-derived biosilica from Guayllabamba - Ecuador decorated with gold nanoparticles by In-situ and Ex-situ methods to study the in vitro gentamicin loading and release properties in simulated body fluid (SBF). Successful decoration of the diatoms and loaded with gentamicin was confirmed using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Raman spectroscopy and Fluorescence Microscopy. We follow the In-vitro drug release by using Ultraviolet-Visible Spectroscopy (UV–vis). Our results revealed that diatoms decorated with gold nanoparticles using the Ex-situ method (Au/CTAB-Diatom) showed a faster release reaching a maximum of 93% in 10 days and a lower loading rate, while the samples decorated by the In-situ method presented longer and slower release behavior. Fluorescence properties were enhanced after the gentamicin loaded. The advantage of this work is the control of the structural and optical properties of diatoms decorated with gold nanoparticles for the gentamicin drug delivery.

Controlled release and release kinetics studies of boron through the functional formulation of carboxymethyl tamarind kernel gum-based superabsorbent hydrogel

The novel Boron micronutrient-loaded superabsorbent hydrogel (BSH) was synthesized via in situ mechanism having carboxymethyl tamarind kernel gum (CMTKG) as its principle component. The synthesis was established by thermal gravimetric analysis examination, scanning electron microscopy micrographs studies, and Fourier transform infrared analysis. The influence of various solvents, such as standard saline solution, different pH solutions (4, 9, 12), and distilled water on the swelling degree of BSH, was examined. Out of all the mentioned solvents, the highest swelling degree was noticed by the distilled water (465 g/g). The BSH was also examined for the agricultural application to assess the release of the boron micronutrient. It was established by studying and calculating the release behavior pattern along with the release kinetics of BSH in water, and as well in soil. It is significant to note that in soil, BSH exhibited 20.07% for the 1st day which notably increased to 76.17% on the 80th day. Release kinetic studies suggested that the Korsmeyer–Peppas model fitted the best out of all the models used, in the case of water, which also revealed that the release of boron from BSH was independent of the polymeric network as it followed Fickian diffusion mechanism. However, in the case of soil, the release was observed to follow the Higuchi model. The half-life and time period for the release of 95% and 99% were calculated as per the Olson’s single exponential model, to predict the pattern of boron release from developed BSH formulation. Release time for 99% boron in the soil, 274 days (with a half-life of 38 days), was found higher than in water, 9.33 days (with a half-life of 1.29 days). Thus, moisture-retaining BSH also successfully revealed slow boron release behavior.

Multi-stimuli-responsive magnetic hydrogel based on Tragacanth gum as a de novo nanosystem for targeted chemo/hyperthermia treatment of cancer

A novel magnetic pH- and redox-responsive drug delivery system (DDS) based on natural Tragacanth gum (TG) was developed for targeted chemo/hyperthermia treatment of cancer. Firstly, acrylic acid (AA) monomer was grafted onto a maleic anhydride-functionalized TG macromonomer (MATGM) through a free radical copolymerization. Magnetic nanoparticles (MNPs) were synthesized through chemical co-precipitation, and subsequently were modified using (3-aminopropyl)triethoxysilane coupling agent. The magnetic stimuli-responsive hydrogel for targeted cancer therapy was synthesized by the incorporation of modified-MNPs and folic acid (FA), and simultaneous crosslinking of TG-g-PAA copolymer using cystamine (Cys) moiety. Doxorubicin hydrochloride (Dox) was loaded into the fabricated magnetic hydrogel (MH), and its release was studied under pH- and redox-triggered condition. The anti-cancer activity of the Dox-loaded DDS was examined against MCF7 cells through MTT assay by both chemotherapy and chemo/hyperthermia therapy approaches. It was revealed that the developed DDS has higher anti-cancer activity (~ 24%) owing to its “smart” and slow drug release behavior as well as synergic effect of hyperthermia therapy. A novel magnetite pH- and redox-responsive drug delivery system (DDS) based on natural Tragacanth gum (TG) was design and developed for targeted chemo/hyperthermia therapy of solid tumors.

Optimization of Tilmicosin-Loaded Nanostructured Lipid Carriers Using Orthogonal Design for Overcoming Oral Administration Obstacle.

Tilmicosin (TMS) is widely used to treat bacterial infections in veterinary medicine, but the clinical effect is limited by its poor solubility, bitterness, gastric instability, and intestinal efflux transport. Nanostructured lipid carriers (NLCs) are nowadays considered to be a promising vector of therapeutic drugs for oral administration. In this study, an orthogonal experimental design was applied for optimizing TMS-loaded NLCs (TMS-NLCs). The ratios of emulsifier to mixed lipids, stearic acid to oleic acid, drugs to mixed lipids, and cold water to hot emulsion were selected as the independent variables, while the hydrodynamic diameter (HD), drug loading (DL), and entrapment efficiency (EE) were the chosen responses. The optimized TMS-NLCs had a small HD, high DL, and EE of 276.85 ± 2.62 nm, 9.14 ± 0.04%, and 92.92 ± 0.42%, respectively. In addition, a low polydispersity index (0.231 ± 0.001) and high negative zeta potential (−31.10 ± 0.00 mV) indicated the excellent stability, which was further demonstrated by uniformly dispersed spherical nanoparticles under transmission electron microscopy. TMS-NLCs exhibited a slow and sustained release behavior in both simulated gastric juice and intestinal fluid. Furthermore, MDCK-chAbcg2/Abcb1 cell monolayers were successfully established to evaluate their absorption efficiency and potential mechanism. The results of biodirectional transport showed that TMS-NLCs could enhance the cellular uptake and inhibit the efflux function of drug transporters against TMS in MDCK-chAbcg2/Abcb1 cells. Moreover, the data revealed that TMS-NLCs could enter the cells mainly via the caveolae/lipid raft-mediated endocytosis and partially via macropinocytosis. Furthermore, TMS-NLCs showed the same antibacterial activity as free TMS. Taken together, the optimized NLCs were the promising oral delivery carrier for overcoming oral administration obstacle of TMS.

Preparation, characterization, and in vitro release study of vincristine sulfate-loaded chitosan–polyethylene glycol–oleic acid composites

Vincristine sulfate (VCS) was used in combination with other chemotherapeutic agents for the treatment of a variety of cancers, including acute lymphoblastic leukemia, cervical cancer, and breast cancer. However, rapid release of the drug at the site of specific action was still a challenge for antitumor treatment. Recently, hybrid carriers bearing the versatile properties of each component were promising materials in order to improve the effects of therapeutic drugs. This work aimed to prepare and characterize chitosan (CHS)–polyethylene glycol (PEG)–oleic acid (OA) composites as a carrier for VCS delivery. The structure, thermal stability, and surface morphology of CHS/PEG/OA composites were characterized by using Fourier transform infrared spectroscopy, thermal gravimetric analysis, differential thermal analysis, differential scanning calorimeter, scanning electron microscopy, and atomic force microscopy. Additionally, swelling degree, water uptake capacity, gas permeability, water contact angle, and in vitro hydrolytic degradation properties of the composites were examined in detail. The VCS-loaded CHS/PEG/OA composites were prepared and drug-loading efficiency was evaluated. CPO-2 sample with a loading efficiency of 64.1 ± 0.6% was selected for in vitro release. due to the highest drug loading efficiency. In vitro release behavior was performed in phosphate-buffered saline buffer (pH 7.4). The release of VCS was completed in almost 24 h and the release data were best fitted to Korsmeyer–Peppas model. The release results revealed that CHS/PEG/OA composites with slow-release behavior could be a promising drug carrier for therapeutic drugs such as VCS.

A study on chitosan-coated liposomes as a carrier of bovine serum albumin as oral protein drug

The development of protein drug liposomes was limited due to the instability of the structure of liposomes, such as easy aggregation, easy fusion, and drug leakage. The object of this work was to prepare bovine serum albumin (BSA) loaded liposomes (BSA-Lip) using BSA as a protein model drug and then BSA-Lip was further coated with chitosan (CH-BSA-Lip) in order to improve the stability of phospholipid bilayer membrane. It was found that the particle size of BSA-Lip increased after being coated with chitosan and the surface potential changed from negative charge to positive charge due to the electrostatic interaction between liposomes and chitosan. After chitosan coating, the encapsulation efficiency of liposomes also increased due to the interaction between positively charged chitosan and negatively charged BSA. Fourier transform infrared spectroscopy analysis confirmed that BSA was encapsulated into liposomes and chitosan was successfully coated on the surface of liposomes. Transmission electron microscopy showed that the particles were nanosized and spherical. The physical stability and in vitro digestion stability of liposomes were examined by observing the changes of particle size and potential. It was found that chitosan coating enhanced the stability of liposomes significantly. The in vitro release profile of CH-BSA-Lip possessed a slow release behavior, and BSA release was governed by both diffusion and dissolution from phospholipid bilayer.

Magnetite-Functionalized Plumbagin for Therapeutic Applications

Synthesis of hybrid drug molecules from naturally occurring organic compounds has potential applications in several fields, including theranostics. In this work, we report the extraction of plumbagin from the roots of Plumbago indica L. and used it as a precursor to prepare plumbagin-functionalized magnetite nanoparticles (PFMNPs). The derived PFMNPs were analyzed using analytical techniques to understand their structural characteristics and chemical environment. Transmission electron microscopy and X-ray photoelectron spectroscopy confirmed the possibility of atomic interactions between plumbagin and magnetite nanoparticles. More importantly, we demonstrated the slow-release behavior of plumbagin and antimicrobial activity of the synthesized PFMNPs, which exhibited exciting activity, signifying the potential possibility of these materials in pharmaceutical industries. In general, pristine plumbagin’s practical applicability is very limited due to its high volatility and low photo and thermal stability. However, plumbagin’s magnetite functionalization was found to improve the photo-thermal stability, displaying significant control over release behavior. More importantly, the synthesized PFMNPs exhibited excellent antimicrobial activity and biocompatibility, demonstrating the potential possibility of these materials in pharmaceutical industries.

PCL Based CIP-Loaded Double-Layer Films Deposited by Low-Electron Beam Dispersion Method and its Antibacterial Properties

In this paper, low-electron beam dispersion (EBD) method is used to prepare a kind of double-layer films on different substrates. The bottom layer is a mechanically stirred mixture of the degradable polycaprolactone (PCL) and ciprofloxacin (CIP), and the top layer is polyurethane (PU) film. The molecular structure, chemical composition and morphology of the double-layer films were investigated by FTIR, XPS and SEM. The results showed that the surfaces of the double-layer films are uniform and the thicknesses can reach micron level. In addition, the two layers are well bonded. Then the films were sliced and immersed in PBS solution, and the time-dependent variable was used to analyze the kinetic slow-release behavior of CIP in the double-layer films by agar diffusion antibacterial experiments. It can be seen that sustained release time of CIP in the double-layer films can be up to 7 days, which is due to fact that the upper PU film working as a sealing layer helps to realize the drug slow-release. Based on the above research, the comprehensive performance of the films with the composition of PCL:CIP/PU=1:1/1 is the best.