Particle Size Size Distribution Research Articles

Back to Nature: Development and Optimization of Bioinspired Nanocarriers for Potential Breast Cancer Treatment

This study focuses on the preparation and optimization of caffeic acid (CA)-loaded casein nanoparticles (CS NPs) via the Box–Behnken design (BBD) for potential applications in cancer treatment. CS NPs were loaded with CA as a promising anti-cancer molecule. Non-hazardous green materials were exploited for nanoparticle fabrication. The BBD was used, followed by a desirability function to select the optimum formulation. The BBD was adopted as it avoids the runs implemented in extreme conditions, hence making it suitable for proteins. CS NPs were characterized regarding particle size (PS), size distribution (PDI), zeta potential (ZP), drug entrapment, morphology using TEM, differential scanning calorimetry, molecular docking, in vitro release, and cytotoxicity studies. PS, PDI, and ZP had significant responses, while EE% was insignificant. The suggested models were quadratic with high fitting. Optimized NPs showed PS = 110.31 ± 1.02 nm, PDI = 0.331 ± 0.029, ZP = −23.94 ± 1.64 mV, and EE% = 95.4 ± 2.56%. Molecular modeling indicated hydrophobic and electrostatic interactions between CA and CS, accounting for the high EE%. Almost spherical particles were realized with a sustained CA release pattern. Optimized NPs effectively suppressed the growth of MCF-7 cell lines by scoring the lowest IC50 = 78.45 ± 1.7 µg/mL. A novel combination of bioinspired-derived materials was developed for use in breast cancer treatment.

Geographic Variation of Particle Size Distribution in the Kuroshio Region: Possible Causes in the Upper Water Column

Particle size distribution (PSD) in the ocean is a fundamental property that influences carbon export and food webs; however, PSD variation and its causes in oligotrophic oceans are not entirely clear. Here, we used Laser In-Situ Scattering and Transmissometry to investigate PSD (size range 5.2–119 μm) and related variables at 11 stations in the surface layer (0–20 m) of the Kuroshio region of the western North Pacific, where strong current causes dynamic hydrographic and ecological conditions. PSD slopes (range –3.2 to –4.2), derived from the power law model, were steeper at onshore stations and flatter at oligotrophic stations located offshore and at lower latitudes. Notably, slopes tended to become steeper with increasing chlorophyll a concentration, opposing the generally observed relationship between the two variables, whereas they became flatter with increasing transparent exopolymer particle (TEP) concentration. Possible explanations of the above results are localized occurrence of nanophytoplankton and TEP facilitation of particle aggregation. The results support the hypothesis that PSD slopes are controlled by a multitude of factors, including phytoplankton community dynamics and aggregation processes. To determine whether TEP-induced particle aggregation enhances or suppresses carbon export, we need a better understanding of the nature (porosity, density, and sinking velocity) of aggregates in oligotrophic oceans.

Quality by Design Approach for Preparation of Zolmitriptan/Chitosan Nanostructured Lipid Carrier Particles - Formulation and Pharmacodynamic Assessment.

PurposeZolmitriptan (ZT) is a selective serotonin agonist that is used for the treatment of migraine. It belongs to BCS class III with high solubility and low permeability. Besides, the drug is subjected to pre-systemic metabolism. Accordingly, new Zolmitriptan/chitosan nanostructured lipid carriers (ZT/CT NLCs) coated with Tween 80 (stealthy layer) have been developed to overcome such demerits.MethodsThe NLCs were developed by combining ultrasonication and double emulsion (w/o/w) techniques. The lipids were Gelucire and Labrasol. Herein, the quality by design (23 full factorial design) was scrupulously followed, where critical process parameters and critical quality attributes were predefined. The optimized formulation (F8) was fully characterized with respect to entrapment efficiency (%EE), percentage yield (% yield), particle size, size distribution (PDI), zeta potential (ZP), morphological appearance (TEM). In vitro release, stability study and pharmacodynamic evaluations were also assessed. The optimized freeze dried formula was dispensed in in situ gelling hard gelatin capsule encompassing pectin and guar gum for further in vitro and pharmacodynamic evaluations.ResultsThe optimized spherical nanoparticles experienced high percentage EE and yield (78.14% and 60.19%, respectively), low particle size and PDI (343.87 nm and 0.209, respectively), as well as high negative ZP (−25.5 mV). It showed good physical stability at refrigerated conditions. The NLCs dispensed in in situ gelling hard gelatin capsule comprising pectin and guar gum experienced sustained release for 30 h and significantly maintained the pharmacological effect in mice up to 8 h (p < 0.001).ConclusionZT, a BCS class III drug that suffers from poor permeability and pre-systemic metabolism, was successfully maneuvered as nanostructured lipid carrier particles (NLCs). The incorporation of the NLCs in in situ gelling hard gelatin capsules fulfilled a dual function in increasing permeability, as well as sustaining the pharmacodynamic effect. This result would open new vistas in improving the efficacy of other class III drugs.

Nanostructured lipid carriers loaded with simvastatin: effect of PEG/glycerides on characterization, stability, cellular uptake efficiency and in vitro cytotoxicity

Objective: The aim of this study is to evaluate the use of PEG/glycerides of different HLB; oleoyl macrogol-6-glycerides (Labrafil® M 1944 CS) and caprylocaproylmacrogol-8-glycerides (Labrasol®), compared to Labrafac lipophile® as PEG-free glyceride in the preparation of nanostructured lipid carriers (NLCs). PEG/glycerides are suggested to perform a dual function; as the oily component, and as the PEG-containing substrate required for producing the PEGylated carriers without physical or chemical synthesis.Methods: Lipid nanocarriers were loaded with simvastatin (SV) as a promising anticancer drug. An optimization study of NLC fabrication variables was first conducted. The effect of lyophilization was investigated using cryoprotectants of various types and concentrations. The prepared NLCs were characterized in terms of particle size (PS), size distribution (PDI), zeta potential (ZP), drug entrapment, in vitro drug release, morphology and drug–excipient interactions. The influence of glycerides ± PEG on the cytotoxicity of SV was evaluated on MCF-7 breast cancer cells, in addition to the cellular uptake of fluorescent blank NLCs.Results: The alteration between different oil types had a significant impact on PS, ZP and drug release. Both sucrose and trehalose showed the lowest increase in PS and PDI of the reconstituted lyophilized NLCs. The in vitro cytotoxicity and cellular uptake studies indicated that SV showed the highest antitumor effect on MCF-7 cancer cells when loaded into Labrasol® NLCs demonstrating a high cellular uptake as well.Conclusion: The study confirms the applicability of PEG/glycerides in the development of NLCs. Encapsulating SV in Labrasol®-containing NLC could enhance the antitumor effect of the drug.

Self-aggregation of cationically modified poly(ε-caprolactone)2-co-poly(ethylene glycol) copolymers: Effect of cationic grafting ligand and poly(ε-caprolactone) chain length

Cationic copolymers have been attractive to investigate due to their potential to complexation with anionic drugs and expected to use in the pharmaceutical application. In this study, the modified poly(ε-caprolactone)2-co-poly(ethylene glycol) copolymers (P(CL)2-PEG) were successfully synthesized by click reaction. The amount of small molecular cationic ligand, propargyltrimethyl ammonium iodide, was varied and grafted onto various mole ratios of P(CL) to PEG. The effects of P(CL) chain length and amount of the grafting cationic ligand on physicochemical properties of polymers and particles were studied. The number-average molecular weights of the copolymers grafted with cationic ligand were found ranging between 10,000 and 23,000g/mol as investigated by NMR. From DSC study, the results showed that the grafting ligand affected thermal behaviors of the copolymers by increasing the glass transition temperature and decreasing the melting temperature of the copolymers. Furthermore, these cationic copolymers could self-aggregate with their critical aggregation concentration depending on mole ratios of hydrophilic to hydrophobic portions. The particles containing higher amounts of the cationic ligand tended to aggregate in both acidic and basic pH environment and at high salt concentration. Additionally, particle size, size distribution (PdI), and morphology of self-assembling particles varied depending on P(CL) chain length and the amount of the grafting cationic ligand. The synthesized cationic copolymer showed a capability to encapsulate a high negatively charged drug, enoxaparin, with an encapsulation efficiency of 87%. After drug incorporation, the particles substantially changed in size, shape, PdI, and zeta potential to become more suitable for drug delivery. These cationic copolymers with flexible properties will be the candidate for further development as carriers for the delivery of negatively charged drugs.

Rutin nanostructured lipid cosmeceutical preparation with sun protective potential

Skin cancer is related to unprotected exposure to sunlight. Despite the broad expansion of sunscreen market, various researches are focused on the inefficiency and danger of sun products. This study was focused on the development of photoprotective nanoparticulate dermal preparations of the antioxidant flavonoid Rutin (RT). Nanostructured lipid carriers (NLCs) were prepared using different types of lipids. Based on particle size (PS), size distribution (PDI) and Zeta potential (Z) as well as rheological properties, NLC containing Plurol® stearique (NLC-P) and Apifil® (NLC-A) were selected and loaded with different concentrations of RT to form the medicated nanocreams. F4 (NLC-A with 2% RT) attained highest occlusive effect, drug encapsulation and release efficiencies as well as sun protective factor (SPF). Different concentrations of TiO2 were added to F4 aiming to ameliorate the sun protective effect. F7 (containing 5% TiO2) attained the highest SPF and area under the UV absorbance curve and had a critical wavelength above 370nm, which proved its high efficiency as sunscreen. The in-vitro antioxidant effect of F7 was more than two fold that of the standard antioxidant. This study provides a suitable cosmeceutical lipidic colloidal system of Rutin to be employed as a successful photoprotective preparation.

Ice clouds microphysical retrieval using 94‐GHz Doppler radar observations: Basic relations within the retrieval framework

High quality measurements of ice cloud properties from ground‐ and space‐based sensors are key for improving our understanding of processes that affect ice cloud radiative effects and lifetime. Doppler cloud radars provide two independent measurements (reflectivity and Doppler velocity) to constrain the ice clouds microphysical retrievals. However, the retrievals are highly sensitive to the choice of the scattering forward model for non‐spherical particles at millimeter‐wavelengths and the selection of parameters in the mass‐ and velocity‐size relationships, as well as to the representation of the particle size distribution (PSD). In this paper (part 1), the development of the basic relations used in the retrieval is presented. A novel approach for reducing the number of free parameters required to describe the microphysical properties of ice particles is described. The new proposed form of the mass‐size relationship significantly reduces the sensitivity of the quantities of interest to the power law mass exponent, leaving only one parameter controlling mass dimensional relationship. A similar approach is adopted in the velocity calculation. In order to reduce the retrieval's dependence on the size distribution, the PSD defined for liquid‐equivalent diameter is described using the concept of double moment normalization. The two normalizing quantities, mean mass‐weighted diameter (Dm) and ice water content (IWC) are controlled mainly by the PSD size interval that is also an important contributor to the two Doppler observables. Both Dm and IWC are generally not very sensitive to the PSD segments of the smallest and largest particles that are considered as very uncertain.

A systematic investigation of silicalite-1 precursor mixtures with varying degrees of dilution

The effect of the composition on conductivity, pH, and particle size distribution (PSD) in precursor mixtures of silicalite-1 was studied in this work. Mixtures of TPAOH, TEOS, and water spanning a broad composition range were analyzed. Conductivity and pH measurements reported are consistent with previous investigations about the conductivity and pH behavior above and below the critical aggregation concentration (CAC). Dynamic light scattering (DLS) measurements were performed to determine the PSD. ‘Dilute’ mixtures (H2O/TEOS >65) showed trimodal PSDs with nanoparticles of ∼11nm in diameter, small aggregates of ∼340nm in diameter, and aggregates larger than 1μm. The distribution of nanoparticles and aggregates changed with the mixture composition as the intensity-weighted PSDs showed more aggregates in mixtures with higher water content. However, a comparison between intensity-, volume-, and number-weighted PSDs showed that the amount of aggregates present is smaller than the amount of nanoparticles. It was also observed that TPAOH concentration slightly affected the nanoparticle size, which decreased at high TPAOH concentration. On the other hand, concentrated mixtures did not show a clear dependence of PSD or nanoparticle size on the mixture composition. Interestingly, and in contrast with ‘dilute’ mixtures that only showed one population of nanoparticles, two populations of nanoparticles of ∼2nm and ∼30nm were observed in the concentrated mixtures. The information presented in this work attempts to provide a better understanding of silicalite-1 precursors and shows the effect of the composition on the phase behavior of these synthesis mixtures. Thus, this work should help to unify previous findings on nucleation and growth among silicalite-1 mixtures with different compositions.

Resolution of structure characteristics of AE signals in multiphase flow system—From data to information

AbstractThis investigation was performed to study the underlying structure characteristics of acoustic emission (AE) signals, which could be helpful not only to understand a relatively complete picture of hydrodynamics in multiphase flow systems, but also to extract the most useful information from the original signals with respect to a particular measurement requirement. However, due to AE signals are made up of emission from many acoustic sources at different scales, the resolution of AE signals is often very complicated and appears to be relatively poorly researched. In this study, the structure characteristics of AE signals measured both in gas–solid fluidized bed and liquid–solid stirred tank were researched in detail by resorting to wavelet transform and rescaled range analysis. A general criterion was proposed to resolve AE signals into three physical‐related characteristic scales, i.e., microscale, mesoscale, and macroscale. Multiscale resolution of AE signals implied that AE signals in microscale represented totally the dynamics of solid phase and could be applied to measure particle‐related properties. Furthermore, based on the structure characteristics of AE signals, useful features related to particles motion were extracted to establish two new prediction models, one for on‐line measurements of particle size distribution (PSD) and average particle size in gas–solid fluidized bed and the other for on‐line measurement of the suspension height in liquid–solid stirred tank. The prediction results indicated that (1) measurements of PSD and average particle size using AE method showed a fairly good agreement with that using sieve method both for laboratory scale and plant scale fluidized beds, and (2) measurements of the suspension height using AE method showed a fairly good agreement with that using visual method. The results thus validated that the extracted features based on analyses of structure characteristics of AE signals were very useful for establishing effective on‐line measurement models with respect to some particular applications. © 2009 American Institute of Chemical Engineers AIChE J, 2009