Ciprofloxacin Loaded Alginate/Chitosan and Solid Lipid Nanoparticles,Preparation, and Characterization

The aim of the present study was to develop controlled drug delivery systems based on nanotechnology. Two different nanocarriers were selected, chitosan-alginate nanoparticles as hydrophilic and solid lipid nanoparticles as lipophilic carriers. Nanoparticles were prepared and characterized by evaluating particle size, zeta potential, SEM pictures, DSC thermograms, percentage of drug loading efficiency, and drug release profile. The particle size of SLNs and Chi/Alg nanoparticles was 291 ± 5 and 520 ± 16. Drug loading efficiency of Chi/Alg and SLN particles were 68.98 ± 5.5% and 88 ± 4.5%. The drug release was sustained with chitosan-alginate system for about 45 hours whereas for SLNs >98% of the drug was released in 2 hours. Release profile did not change significantly after freeze drying of particles using cryoprotector. Results suggest that under in vitro condition chitosan/alginate systems can act as promising carriers for ciprofloxacin and may be used as an alternative system in sustained delivery of ciprofloxacin.     

Design and In Vitro Evaluation of Solid-Lipid Nanoparticle Drug Delivery for Aceclofenac

Solid-lipid nanoparticles (SLNs) are an interesting nanoparticulate delivery system. The present work was carried out with the aim to develop a prolonged release solid-lipid nanoparticulate system for the drug using aceclofenac. Aceclofenac-loaded solid-lipid nanoparticles (ACSLNs) was prepared by hot high pressure homogenization technique. Tripalmitin was used as the lipid core. Surfactants (Poloxamer 188, Tween 80, and soya lecithin) and co-surfactant (sodium tauro glycholate) were used in the formulations. The prepared ACSLN formulations were characterized for encapsulation efficiency (EE), photon correlation spectroscopy (PCS), scanning electron microscopy (SEM), and x-ray diffraction (XRD). From these studies, mean particle diameter of the formulation prepared with combination of surfactants (Poloxmer 188 and Tween 80) was about 200 nm with spherical morphology and amorphous nature. Higher EE was obtained with SLNs prepared using combination of soya lecithin and poloxmer 188. The organization and distribution of the ingredients in the nanoparticulate system were studied by differential scanning calorimetry (DSC) and the results showed that the drug is incorporated into the solid matrix. The prepared formulations demonstrated favorable in vitro prolonged release characteristics. Experimental in vitro release data were substituted in available mathematical models to establish the release kinetics of ACSLNs and it was found to follow first-order kinetics and Higuchi diffusion mechanism. Our results suggest that these SLN formulations could constitute a promising approach for the drug delivery of aceclofenac.     

Preparation of gamma cyclodextrin stabilized solid lipid nanoparticles (SLNS) using stearic acid–γ-cyclodextrin inclusion complex

The inclusion complexation behaviour of higher chain fatty acid, stearic acid (SA) with gamma cyclodextrin has been investigated. The inclusion complex was characterized by FT-IR, ¹H NMR, 2D NMR, XRD and DSC techniques. The results showed that the SA molecule was entrapped inside the gamma cyclodextrin cavity. Further, inclusion complex was treated with lopinavir at 85 °C and emulsified with hot water at 85 °C. The resulted nanoemulsion was cooled down to form solid lipid nanoparticles (SLNs) stabilized with gamma cyclodextrin. Prepared SLNs were having average particle size of 212.5 ± 4.8 nm, zeta potential of ?19.7 ± 0.66 mV and drug loading of 57.54 ± 0.62 %. The surface characteristics of SLNs were also observed with transmission electron microscopy and atomic force microscopy. Results indicate that inclusion complex of SA and gamma cyclodextrin can be used for SLNs preparation.     

可生物降解固体脂质纳米粒的制备、表征及药物的体外释放

以可生物降解材料硬脂酸为载体, 以葛根总黄酮为模型药物, 采用乳化蒸发-低温固化法制备固体脂质纳米粒. 采用透射电镜研究载药纳米粒形态, 激光粒度分析仪测定其粒径, X射线衍射仪进行物相鉴别, 并对纳米粒的包封率及体外释药特性等进行了研究. 分析结果表明, 所制备硬脂酸固态脂质纳米粒为类球实体, 粒径分布比较均匀, 平均粒径为(263.82±3.6) nm, 包封率为(67.53±0.12)%. X射线衍射分析证明药物以分子或细小粒子分散于脂质骨架中. 体外释药研究结果表明, 纳米粒体外释药先快后慢, 12 h累积释药50%, 包封于降解材料骨架内的药物通过骨架溶蚀缓慢释放. 药物的体外释放符合Higuchi方程.     

Formulation design, preparation and physicochemical characterizations of solid lipid nanoparticles containing a hydrophobic drug: effects of process variables

This study aimed to prepare solid lipid nanoparticles (SLNs) of a hydrophobic drug, tretinoin, by emulsification-ultrasonication method. Solubility of tretinoin in the solid lipids was examined. Effects of process variables were investigated on particle size, polydispersity index (PI), zeta potential (ZP), drug encapsulation efficiency (EE), and drug loading (L) of the SLNs. Shape and surface morphology of the SLNs were investigated by cryogenic field emission scanning electron microscopy (cryo-FESEM). Complete encapsulation of drug in the nanoparticles was checked by cross-polarized light microscopy and differential scanning calorimetry (DSC). Crystallinity of the formulation was analyzed by DSC and powder X-ray diffraction (PXRD). In addition, drug release and stability studies were also performed. The results indicated that 10mg tretinoin was soluble in 0.45±0.07 g Precirol? ATO5 and 0.36±0.06 g Compritol? 888ATO, respectively. Process variables exhibited significant influence in producing SLNs. SLNs with <120 nm size, <0.2 PI, >I30I mV ZP, >75% EE, and ～0.8% L can be produced following the appropriate formulation conditions. Cryo-FESEM study showed spherical particles with smooth surface. Cross-polarized light microscopy study revealed that drug crystals in the external aqueous phase were absent when the SLNs were prepared at ≤0.05% drug concentration. DSC and PXRD studies indicated complete drug encapsulation within the nanoparticle matrix as amorphous form. The drug release study demonstrated sustained/prolonged drug release from the SLNs. Furthermore, tretinoin-loaded SLNs were stable for 3 months at 4°C. Hence, the developed SLNs can be used as drug carrier for sustained/prolonged drug release and/or to improve oral absorption/bioavailability.     

Studies on crystallinity state of puerarin loaded solid lipid nanoparticles prepared by double emulsion method

In this work, solid lipid nanoparticles (SLN) have been prepared from water-in-oil-in-water double emulsion, using monocaprate as solid lipid, sorbitan monooleate (Span 80) and polyoxyethylene sorbitan monolaurate (Tween 20) as emulsifier, and puerarin as target drug. The morphology of SLN with drug loaded or not was investigated by the transmission electron microscope (TEM). The crystal order and structure of particles were studied by differential scanning calorimetry (DSC) and wide angle X-ray diffraction (WAXD), respectively. The results indicate that the diameters of SLN with puerarin inside are larger than those without drugs. The analysis of WAXD and DSC shows that the state of crystallinity SLN prepared by double emulsion method was worse than that of SLN prepared by microemulsion. And also the drug-loaded SLN presents a less ordered crystallinity than the drug-free SLN. But both the drug-free and drug-loaded SLN exist in an amorphous state. The reasons of the phenomenon have been discussed.     

Modification and stabilizing effects of PEG on resveratrol-loaded solid lipid nanoparticles

Resveratrol-loaded solid lipid nanoparticles (SLNs) modified by polyethylene glycol (PEG2000) (RES–PEG–SLNs) were prepared to study the stabilizing influences of PEG2000 on SLNs properties including loading capacity, particle size, photostability, and release. The micromorphology, particle size distribution, drug–lipid–modifier interaction and crystalline structure were characterized to elucidate stabilizing effects of PEG2000 on SLNs. Compared with ordinary SLNs, SLNs modified by PEG2000 at relatively low amounts of [m(PEG2000):m(lipids) = 1:10] exhibit high drug loading, steady nanoparticle size distributions, photostability and sustained release. According to characterizations, RES–PEG–SLNs formation is dependent on the physical interactions of drug–lipid–modifier. Since PEG2000 is doped into lipid matrix in a non-crystalline state, the lipids crystalline arrangement is disrupted. Additionally, RES–PEG–SLNs are crystallized in a PEG2000/lipid eutectic mixture rather than a simple mixture, inhibiting the lipid polymorphism transformation from α- to β-form, and therefore preventing drug exclusion from the lipid matrix. The PEG2000/lipid matrix contains lattice defects, which allow for the incorporation of more resveratrol and preventing it from photodegradation effectively. In contrast to the burst release of SLNs modified without PEG2000, resveratrol is released more slowly from the lattice defects in lipid matrix of RES–PEG–SLNs, resulting in a sustained release fitted by a two-stage exponential kinetic equation. PEG2000 is distributed on the RES–PEG–SLNs surface, increasing repulsion between nanoparticles and avoiding particles aggregation. These results confirm that both matrix doping effects and surface steric hindrance produced by the presence of PEG2000 play important roles in maintaining high loadings, nanoparticle size, photostability and sustained release.     

Anti-tumor efficacy of polymer-platinum(II) complex micelles fabricated from folate conjugated PEG-graft-α,β-poly [(N-amino acidyl)-aspartamide] and cis-dichlorodiammine platinum(II) in tumor-bearing mice

In the present study eugenol loaded solid lipid nanoparticles (SLN) was prepared and characterized for particle size, polydispersity index, zeta potential, encapsulation efficiency, in vitro release and in vivo antifungal activity. Effect of addition of liquid lipid (caprylic triglyceride) to solid lipid (stearic acid) on crystallinity of lipid matrix of SLN was determined by using Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) techniques. Transmission electron microscopy (TEM) was carried out to determine the morphology of SLN. In vivo antifungal activity of eugenol loaded lipid nanoparticles was evaluated by using a model of oral candidiasis in immunosuppressed rats. Particle size results showed that d(90) of SLN(1) (single lipid matrix) and SLN(2) (binary lipid matrix) was 332±14.2 nm and 87.8±3.8 nm, respectively. Polydispersity index was found to be in the range of 0.27-0.4 which indicate moderate size distribution. Encapsulation efficiency of SLN(2) (98.52%) was found to be more than that of SLN(1) (91.80%) at same lipid concentration (2%, w/v). Increasing of the solid lipid concentration from 2% (w/v) to 4% (w/v) resulted in increase in encapsulation efficiency and the particle size. SLN(2) shows faster release of eugenol than that of SLN(1) due to smaller size and presence of liquid lipid which provide less barriers to the diffusion of drug from matrix. TEM study reveals the spherical shape of SLN. FT-IR, DSC and XRD results indicate less crystallinity of SLN(2) than that of SLN(1). In vivo studies show no significant difference in log cfu value of all the groups at 0 day. At 8th day, log cfu value of group treated with saline (control), standard antifungal agent, eugenol solution, SLN(1) and SLN(2) was found to be 3.89±.032, 2.69, 3.39±.088, 3.19±.028 and 3.08±0.124, respectively. The in vivo study results indicate improvement in the antifungal activity of eugenol when administrated in the form of SLN.     

Formulation,Characterization, and Evaluation of Eudragit-Coated Saxagliptin Nanoparticles Using 3 Factorial Design Modules

Background and Introduction: Saxagliptin is a hypoglycemic drug that acts as a dipeptidyl peptidase-4 (DPP-4) inhibitor and is preferably used in the treatment of Type 2 Diabetes Mellitus (T2DM). It is safe and tolerable; however, the major disadvantage associated with it is its low bioavailability. Aim: The present research aimed to enhance the bioavailability of the drug by enteric coating with a polymer that controls the rate of drug delivery, and it was prepared as Solid Lipid Nanoparticles (SLNs). Methodology: In the current study, various SLN formulations were developed using a central composite design (CCD) module using Design Expert-11 software. A modified solvent injection technique was used to prepare Saxagliptin nanoparticles coated with Eudragit RS100. The CCD was used to determine the independent variables and their effect on dependent variables at varied levels. Evaluation studies such as particle size analysis, Zeta potential, polydispersity index (PDI), drug loading, entrapment efficiency, in-vitro drug release studies, and in vivo pharmacokinetic studies were performed for the optimized SLN formulation. The reversed-phase HPLC method was developed and validated for the estimation of the pharmacokinetic parameters of the pure drug and prepared SLNs. Results: The effect of independent variables (A1: amount of lipid, A2: amount of polymer, A3: surfactant concentration, and A4: homogenization speed) on dependent variables (R1: particle size, and R2: entrapment efficiency) was established in great detail. Observed responses of the prepared and optimized Saxagliptin SLN were close to the predicted values by the CCD. The prepared SLNs depicted particle sizes in the range of 212–442 nm. The particle size analysis results showed that an increase in the lipid concentration led to an increase in particle size. The developed bioanalytical method was noted to be very specific and robust. The method accuracy varied from 99.16% to 101.95% for intraday, and 96.08% to 103.12% for inter day operation at low (5 mcg/mL), moderate (10 mcg/mL), and higher (15 mcg/mL) drug concentrations. The observed Zeta potential values for the prepared SLNs were in the range of −41.09 ± 0.11 to 30.86 ± 0.63 mV suggesting quite good stability of the SLNs without any aggregation. Moreover, the polydispersity indices were in the range of 0.26 ± 0.051 to 0.45 ± 0.017, indicative of uniformity of sizes among the prepared SLNs. In vivo study outcomes proved that Saxagliptin oral bioavailability significantly enhanced in male Albino Wistar Rats via SLN formulation and Eudragit RS100 coating approach. Conclusions: The developed and optimized Saxagliptin SLNs revealed enhanced Saxagliptin bioavailability in comparison to the native drug. Thus, this formulation strategy can be of great importance and can be implied as a promising approach to enhance the Saxagliptin bioavailability for facilitated T2DM therapy.     

Physicochemical characterization of nanotemplate engineered solid lipid nanoparticles

As the physicochemical characteristics of solid lipid nanoparticles (SLNs) play a critical role in their success, it is important to understand how the materials and process used in their preparation affect these properties. In this study, two stearyl alcohol-based formulations were prepared using nanotemplate engineering technology and characterized. Both formulations were of a small particle size (<100 nm), ellipsoidal shape, and low polydispersity. (1)H NMR spectroscopy confirmed that the SLNs have the expected solid core structure and PEGylated surface. Analysis of the bulk materials indicated that a number of complex interactions are present among the SLN components, including a eutectic between stearyl alcohol and Brij 78. The decreased crystallinity resulting from these interactions may allow for enhanced drug loading. Physiological stability was identified and confirmed as a potential problem due to the low melting point of the eutectic. However, it is expected that with appropriate formulation modifications nanotemplate engineered SLNs will possess the properties necessary for a successful drug delivery system.     

An easy and effective method for radiolabelling of solid lipid nanoparticles

Nanoparticle biodistribution study is of great importance in bringing nanomedicine to patients. In this article, solid lipid nanoparticle (SLN) with dimension less than 100 nm was successfully radiolabelled with ^99mTc by using sodium borohydride as a reducing agent (instead of stannous salts). Paclitaxel (PTX) was used as a model anticancer drug for the preparation of drug loaded SLN (PSLN). PSLN was characterized by standard methods. Encapsulation efficiency for PTX in PSLN was estimated by HPLC. PTX (Taxol formulation) and PSLN were radiolabelled separately and subsequent characterizations of these complexes were performed. Greater than 95 % radiolabelling efficiency was achieved and the labelling efficiency was calculated to be more than 90 % upto 24 h. Both the above-mentioned complexes passed the in vitro stability tests. PSLN achieved more brain concentration than Taxol as determined by biodistribution studies. This type of radiolabelling technique can be useful in preclinical evaluation of drug loaded SLN.     

Characterization of silver sulfadiazine-loaded solid lipid nanoparticles by thermal analysis

The aim of this study is the solid-state characterization of solid lipid nanoparticles (SLN) based on Compritol^® 888 (C888) and Lutrol^® F68 (F68), loaded with silver sulfadiazine (AgSD), used to develop sponge-like dressings to treat chronic skin ulcers such as decubitis and leg ulcers. Silver compounds like AgSD, in fact, are used to prevent and/or to treat wound colonization that could impair healing, also in the case of antibiotic-resistant bacteria. Thermal analysis, with support from powder X-ray diffractometry and Fourier transform infrared spectroscopy, is used to characterize lipid and drug bulk, unloaded and drug-loaded SLN. In particular, differential scanning calorimetry is used to investigate the degree of crystallinity and the solid-state modification of lipid, two parameters correlated to drug incorporation and drug release rates. The solid-state characterization demonstrates AgSD entrapment in C888 as a core enclosed into F68 shell. AgSD SLN are also stored at different temperatures 25 and 37 °C, respectively, to study the effect of storage conditions, that induce an increase of the lipid crystallinity index correlated to drug release from the lipid matrix.     

Solid lipid nanoparticles prepared by solvent diffusion method in a nanoreactor system

In this study, water-in-oil (W/O) miniemulsion was used as nanoreactor to prepare solid lipid nanoparticles (SLN) by solvent diffusion method. n-Hexane, Tween 80 and Span 80 were used as the oil phase and surfactant combination for preparation of W/O miniemulsion, respectively. The stable miniemulsion with the particle size of 27.1 ± 7.6 nm was obtained when the composition of water/Tween 80/Span 80/n-hexane was 1 ml/18 mg/200 mg/10 ml. Clobetasol propionate (CP) was used as a model drug. The physicochemical properties of the SLN, such as particle size, zeta potential, surface morphology, drug entrapment efficiency, drug loading capacity and in vitro drug release behaviors were investigated, comparing with those of SLN prepared by conventional aqueoethod. The SLN prepared by the novel method displayed smaller particles size and higher dus solvent diffusion mrug entrapment efficiency than those of SLN prepared by the conventional method. The drug entrapment efficiency decreased with increasing of charged amount of drug, and 15.9% of drug loading was achieved as the charged amount of drug was 20%. The in vitro drug release tests indicated that the drug release rate was faster than that of SLN prepared by the conventional method, and the drug content in SLN did not affect the in vitro drug release profile.     

Preparation and characterization of chloroaluminum phthalocyanine-loaded solid lipid nanoparticles by thermal analysis and powder X-ray diffraction techniques

Solid lipid nanoparticles (SLN) without drug and SLN loaded with chloroaluminum phthalocyanine (AlClPc) were prepared by solvent diffusion method in aqueous system and characterized by thermal analyses and X-ray diffraction (XRD) in this study. Determination of particle size, zeta potential (ZP), and encapsulation efficiency were also evaluated. SLN containing AlClPc of nanometer size with high encapsulation efficiency and ZP were obtained. The results indicated that the size of SLN loaded with AlClPc is larger than that of the inert particle, but ZP is not changed significantly with incorporation of the drug. In differential scanning calorimetry (DSC) curves, it was observed that the melting point of stearic acid (SA) isolated and in SLN occurred at 55 and 64 °C, respectively, suggesting the presence of different polymorphs. DSC also shows that the crystallinity state of SLN was much less than that of SA isolated. The incorporation of drug in SLN may have been favored by this lower crystallinity degree of the samples. XRD techniques corroborated with the thermal analytic techniques, suggesting the polymorphic modifications of stearic acid.     

Biocompatible APTES–PEG Modified Magnetite Nanoparticles: Effective Carriers of Antineoplastic Agents to Ovarian Cancer

Magnetite nanoparticles are particularly attractive for drug delivery applications because of their size-dependent superparamagnetism, low toxicity, and biocompatibility with cells and tissues. Surface modification of iron oxide nanoparticles with biocompatible polymers is potentially beneficial to prepare biodegradable nanocomposite-based drug delivery agents for in vivo and in vitro applications. In the present study, the bare (10 nm) and polyethylene glycol (PEG)–(3-aminopropyl)triethoxysilane (APTES) (PA) modified (17 nm) superparamagnetic iron oxide nanoparticles (SPIO NPs) were synthesized by coprecipitation method. The anticancer drugs, doxorubicin (DOX) and paclitaxel (PTX), were separately encapsulated into the synthesized polymeric nanocomposites for localized targeting of human ovarian cancer in vitro. Surface morphology analysis by scanning electron microscopy showed a slight increase in particle size (27?±?0.7 and 30?±?0.45 nm) with drug loading capacities of 70 and 61.5 % and release capabilities of 90 and 93 % for the DOX- and PTX-AP-SPIO NPs, respectively (p?<?0.001). Ten milligrams/milliliter DOX- and PTX-loaded AP-SPIO NPs caused a significant amount of cytotoxicity and downregulation of antiapoptotic proteins, as compared with same amounts of free drugs (p?<?0.001). In vivo antiproliferative effect of present formulation on immunodeficient female Balb/c mice showed ovarian tumor shrinkage from 2,920 to 143 mm³ after 40 days. The present formulation of APTES–PEG-SPIO-based nanocomposite system of targeted drug delivery proved to be effective enough in order to treat deadly solid tumor of ovarian cancer in vitro and in vivo.     

Crystallinity of Dynasan<Superscript>®</Superscript>114 and Dynasan<Superscript>®</Superscript>118 matrices for the production of stable Miglyol<Superscript>®</Superscript>-loaded nanoparticles

This study focuses on the physicochemical characterization of lipid materials useful for the production of the so-called solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC). The chosen lipids were Dynasan^®114 (glyceril trimyristate) and Dynasan^®118 (glyceril tristearate) as solid lipids (SL), melting temperature above 80 °C, and Miglyol^®812 (caprylic/capric triglyceride) and Miglyol^®840 (propylene glycol dicaprylate/dicaprate) as liquid lipids (LL), crystallizing below ?15 °C. Raw lipids (pure or SL:LL mixtures) were analyzed by differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD), and Polarized Light Microscopy (PLM), before and after tempering at 80 °C for 1 h. The selected SL:LL combination was 70% (Dynasan^®114 and 118) and 30% (Miglyol^®812 and 840) for the production of SLN and NLC by high-pressure homogenization (HPH), respectively. Particles with a mean size of 200 nm (polydispersity index <0.329) and zeta potential of ?15 mV were obtained, and their long-term stability was confirmed for 3 months of storage at 7 °C.     

Self-assembled liposomes from electrosprayed polymer-based microparticles

Composite poly(N-isopropylacrylamide) (PNIPAAm)/phosphatidylcholine (PC) microparticles were prepared by electrospraying. PC-based liposomes were subsequently generated upon the addition of water. The microparticles have an average diameter of ca. 1 μm, while the liposomes produced were found to have much smaller diameters of ca. 225–280 nm. The liposomes had zeta potentials of ?44 to ?50 mV, consistent with the formation of a stable suspension. Upon heat treatment, the liposomes exhibit phase transitions due to the influence of PNIPAAm. The liposomes containing 33 % PC have a phase transition temperature of approximately 36 °C, close to physiological conditions. The model drug ketoprofen could be loaded into electrosprayed microparticles and subsequently incorporated into self-assembled liposomes, with an entrapment efficiency for the latter process of ca. 75 %. Sustained drug release regulated by temperature was observed from these drug-loaded materials. At 25 °C, only 45 % of the total drug loading was released after 110 hours, while at 37 °C drug release approached 90 % over the same time period. The self-assembled liposomes reported here, therefore, have great potential as drug delivery devices.     

Synthesis,Bifunctionalization, and Remarkable Adsorption Performance of Benzene‐Bridged Periodic Mesoporous Organosilicas Functionalized with High Loadings of Carboxylic Acids

Highly ordered benzene‐bridged periodic mesoporous organosilicas (PMOs) that were functionalized with exceptionally high loadings of carboxylic acid groups (COOH), up to 80 mol % based on silica, have been synthesized and their use as adsorbents for the adsorption of methylene blue (MB), a basic dye pollutant, and for the loading and release of doxorubicin (DOX), an anticancer drug, is demonstrated. These COOH‐functionalized benzene? silicas were synthesized by the co‐condensation of 1,4‐bis(triethoxysilyl) benzene (BTEB) and carboxyethylsilanetriol sodium salt (CES), an organosilane that contained a carboxylic acid group, in the presence of non‐ionic oligomeric surfactant Brij 76 in acidic medium. The materials thus obtained were characterized by a variety of techniques, including powder X‐ray diffraction (XRD), nitrogen‐adsorption/desorption isotherms, TEM, and ¹³C and ²⁹Si solid‐state NMR spectroscopy. Owing to the exceptionally high loadings of COOH groups, their high surface areas, and possible π? π‐stacking interactions, these adsorbents have very high adsorption capacities and extremely rapid adsorption rates for MB removal and for the controlled loading/release of DOX, thus manifesting their great potential for environmental and biomedical applications.     

Superparamagnetic Fe<Subscript>3</Subscript>O<Subscript>4</Subscript> Nanoparticles Decorated Multiwalled Carbon Nanotubes: Preparation via Cyclic Microwave Approach and Their Drug Release Behavior

Superparamagnetic Fe₃O₄ nanoparticles decorated multiwalled carbon nanotubes were synthesized by cyclic microwave method and the effect of different reaction parameters on the products were also investigated. The as synthesized products were characterized by XRD, TEM, SEM, EDS, FT-IR, VSM, and Uv–Vis spectroscopy. It was observed that precursors’ concentration ratio had great effect on the particle size and decorating quality. Also the effect of the other parameters including irradiation power and time on product size and uniformity of the product were also investigated. The best products with desired particle size distribution obtained when irradiation power and reaction time were 900 W and 6 min, respectively. Aspirin and acetaminophen were applied as a model drug and the drug release behavior of the composite was investigated. It was observed that the drug discharge was highly dependent to the pH and can be tuned by applying magnetic field.     

Influence of α- and γ- cyclodextrin lipophilic derivatives on curcumin-loaded SLN

Solid lipid nanoparticles (SLN) made of different triglycerides (TG) in the presence and in the absence of various modified α- and γ-cyclodextrins (CD) were prepared by the solvent injection technique. A new synthesis of lipophilic derivatives of γ- CD was developed in this work. Curcumin (CU), a natural polyphenol with antitumor, antioxidant and anti-inflammatory properties, was used as model drug. SLNs mean sizes were in the 250–800 nm range and afforded CU entrapment efficiency in the 12–85% range. The presence of CD derivatives with almost the same chain length of TG induced an improvement of nanoparticle characteristics decreasing mean size values and increasing CU entrapment efficiency. A significant reduction in CU photodegradation was noted only when the drug was vehicled in tristearin-SLN, which became less pronounced in the presence of CD-derivatives, determining a loss in photoprotection. The hydrolytic stability of curcumin was highly improved by drug loading in tristearin-SLN, and only slightly by loading it in tricaprin-SLN, and this seemed not to be influenced by the presence of CD derivatives. Skin uptake studies revealed an increase in CU skin accumulation when CU was loaded in SLN obtained with all CD derivatives, particularly with most lipophilic one.