Effect Of Process Variables Research Articles

Exploring microfluidics and membrane extrusion for the formulation of temozolomide-loaded liposomes: investigating the effect of formulation and process variables

Liposomes have gained much attention in drug delivery since the entry of liposomal Doxorubicin (Doxil®) into the market. Liposomes can entrap lipophilic, hydrophilic as well as amphiphilic drug molecules due to their distinctive structural features. Yet the clinical translation of liposomes is limited due to the reproducibility issues owing to a lack of information related to the impact of process parameters and formulation variables on designed liposomes. Recently, preparation techniques like membrane extrusion and microfluidics have been reported to produce liposomes in a reproducible manner. The present research study selected an amphiphilic drug Temozolomide (TMZ). It has a short half-life in the plasma due to its pH-dependent stability. Various critical and non-critical parameters affecting the critical quality attributes were identified and studied using risk-based assessment. The effect of various material attributes and process parameters on the critical quality attributes of the temozolomide-loaded liposomes prepared by microfluidics and membrane extrusion techniques were investigated in detail. Liposomes in the size range of 100–150 nm were targeted. Both techniques were optimized with a minimum number of critical process parameters. The obtained information will be beneficial to formulation scientists for designing liposomes for an amphiphilic drug on a large scale.

Investigation of electrochemical discharge machining process variables during µ - drilling on stir casted novel Zn/ (Ag+ Fe)-MMC for biomedical applications

ABSTRACT Stainless steel, titanium alloy, and cobalt have long-term risks when used as metallic implants. Zinc is essential component of human body and can be used for metallic implants. The research presents the fabrication of novel hybrid Zn/(Ag + Fe)-MMC using stir casting method, analysis of microstructural and mechanical properties of fabricated MMC specimen. Electrochemical Discharge Machining (ECDM) was employed for the µ-drilling on the fabricated MMC. The effect of ECDM process variables like supply voltage, peak current, pulse-on-time, pulse-off-time, feed rate and electrolyte concentration on material removal rate (MRR), overcut (OC) and tool wear (TW) were identified during µ-drilling. Experiments had been performed based on the one factor-at-a-time approach. From the experiments it was found that MRR, OC and TW increase as supply voltage, peak current, pulse-on-time, electrolyte concentration increase and decrease as pulse-off-time increases. An increment in feed rate increases the MRR and TW but overcut decreases. Scanning electron microscopy (SEM) analysis at maximum MRR condition shows rough surface finish and ovality in µ-drilled hole. Whereas high circularity and uniform drilling attributes were obtained along the whole depth at minimum OC condition.

Process Variation Based Electrical Model of STT-Assisted VCMA-MTJ and Its Application in NV-FA

Fast switching speed, low power consumption, and good stability are some of the important properties of spin transfer torque assisted voltage controlled magnetic anisotropy magnetic tunnel junction (STT-assisted VCMA-MTJ) which makes the non-volatile full adder (NV-FA) based on it attractive for Internet of Things. However, the effects of process variations on the performances of STT-assisted VCMA-MTJ and NV-FA will be more and more obvious with the downscaling of STT-assisted VCMA-MTJ and the improvement of chip integration. In this paper, a more accurate electrical model of STT-assisted VCMA-MTJ is established on the basis of the magnetization dynamics and the process variations in film growth process and etching process. In particular, the write voltage is reduced to 0.7 V as the film thickness is reduced to 0.9 nm. The effects of free layer thickness variation (γtf) and oxide layer thickness variation (γtox) on the state switching as well as the effect of tunnel magnetoresistance ratio variation (β) on the sensing margin (SM) are studied in detail. Considering that the above process variations follow Gaussian distribution, Monte Carlo simulation is used to study the effects of the process variations on the writing and output operations of NV-FA. The result shows that the state of STT-assisted VCMA-MTJ can be switched under -0.3%≤γtf≤6% or -23%≤γtox≤0.2%. SM is reduced by 16.0% with β increases from 0 to 30%. The error rates of writing ‘0’ in the NV-FA can be reduced by increasing Vb1 or increasing positive Vb2. The error rates of writing ‘1’ can be reduced by increasing Vb1 or decreasing negative Vb2. The reduction of the output error rates can be realized effectively by increasing the driving voltage (Vdd).

SCREENING OF MOST EFFECTIVE VARIABLES FOR DEVELOPMENT OF TELMISARTAN LIPOSOMES BY TAGUCHI DESIGN

The aim of this study was the selection of the most effective variable for the formulation of telmisartan liposomes. Liposomes were prepared by dry film deposition method using a Rota evaporator. The effects of formulation and processing variables on different response variables were studied using standard Taguchi orthogonal array L8 design. The independent variables selected were the amount of lipid, amount of cholesterol, sonication time, speed of Rota evaporator, hydration time, hydration volume and temperature, and the dependent variable selected were particle size (nm) and entrapment efficiency (%). All the batches of liposomes were prepared as per the Taguchi design. The influence of variables analyzed by Pareto ranking showed that the most effective factors for the selected responses were the amount of cholesterol, amount of lipid and sonication time (P<0.05).

Stereo: Assignment and Scheduling in MPSoC Under Process Variation by Combining Stochastic and Decomposition Approaches

Aggressive scaling in integrated circuits creates new challenges such as an increase in power density, temperature, and especially process variation in designing Multiprocessor Systems-on-Chip (MPSoC). While most of the previous works attempt to mitigate the process variation effects at the system level, the eventual design still suffers from the variability of frequency and leakage power. In this paper, we propose a method called <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Stereo</i> that combines <underline xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">s</u> tochas <underline xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">t</u> ic and d <underline xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">e</u> composition to solve task assignment and scheduling under p <underline xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</u> oc <underline xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">e</u> ss variati <underline xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</u> n in MPSoCs. In our previous work, we formulated a Mixed Integer Linear Programming (MILP) problem for variation-aware task assignment and scheduling to optimize energy consumption while meeting the real-time constraints. To capture the stochastic behavior of process variation, we employed a chance-constrained programming technique to turn the problem into a corresponding stochastic optimization that can be solved by typical ILP solvers. However, it had a scalability problem. To address this issue, in this work, we leverage a Logic-based Benders Decomposition (LBD) approach to improve the running time for finding an optimal solution of assignments and schedulings under process variation phenomenon). We carried out extensive experiments using Embedded System Synthesis Benchmarks Suite (E3S). The experimental results of the Stereo method evince considerable improvements compared to the baseline method in terms of performance-yield and run-time. The Stereo-based MILP method ameliorates performance-yield up to 2× and run-time by 532×. Moreover, for manifold applications, the Stereo-based LBD method archives 3.47×-91.49× run-time improvement compared to the Stereo-based MILP approach and is capable of assigning and scheduling of more than 50 tasks on 9 processors.

Design of VGSOT-MTJ-Based Logic Locking for High-Speed Digital Circuits

Emerging spintronics devices in recent research have received much interest in various fields. Their unique physical aspects are being explored to keep Moore’s law alive. Therefore, the hardware security aspects of system-on-a-chip (SoC) designs using spintronics devices becomes important. Magnetic tunnel junctions (MTJ) are a potential candidate in spintronics-based devices for beyond-CMOS applications. This work uses voltage-gated spin-orbit torque-assisted magnetic tunnel junction (VGSOT-MTJ) based on the Verilog-A behavioral model to design a possible logic-locking system for hardware security. Compared with the SOT MTJ, which uses a heavy metal strip below the MTJ stack, VGSOT-MTJ has an antiferromagnetic (AFM) strip that utilizes the voltage-controlled magnetic anisotropy (VCMA) effect to significantly reduce the JSOT,critical. To design the logic-locking block, we performed a Monte Carlo analysis to account for the effect of process variation (PV) on critical MTJ parameters. Eye diagram tests and mask designing were performed, which included the effect of thermal noise and PV for high-speed digital circuit operations. Finally, transient performance was analyzed to demonstrate the VGSOT-MTJ’s ability to design logic-locking blocks from the circuit operation perspective.

Effects of process variables for NO conversion by double-layered photocatalytic mortar with TiO2 nanoparticles

In this study, we prepared the double-layered photocatalytic mortar, where the top-layer has the minimum thickness of 2 mm. We investigated systematically the effects of various process variables (initial NOX concentration, TiO2 addition amount, UV-A radiation, gas flow rate and relative humidity) on photocatalytic conversion of NOX and also the transient NOX conversions for changing ambient conditions of process variables with time. The higher the nano-TiO2 concentration in the mortar or UV-A radiation intensity is, or the lower the NOX gas flow rate or relative humidity is, the higher the NOX conversion efficiency is. As the initial concentration of NOX increases, NOX conversion efficiency decreases, but the amount of NOX conversion increases. It is confirmed that the prepared photocatalytic mortar could convert NOX in the air efficiently for various conditions of process variables. NOX conversion efficiencies in transient environmental conditions were equivalent to those in fixed conditions for the same process variables. This study provides strong basic data to apply the photocatalytic mortar to convert NOX efficiently using solar energy without the use of extra energy and can be easily extended to future applications to infrastructures such as buildings, tunnels, or roads.

Effect of Near-Dry WEDM Process Variables through Taguchi-Based-GRA Approach on Performance Measures of Nitinol

The machining of Nitinol shape memory alloys (SMA) through conventional machining techniques imposes several challenges due to the alloys’ comprehensive mechanical qualities. Wire electrical discharge machining (WEDM) process is a non-conventional machining technique that is suitable mainly for producing complex shape geometries with excellent surface features for difficult-to-cut materials. The current study attempted the use of a near-dry WEDM process for Nitinol SMA with the consideration of multiple response variables. The studied literature and machine capabilities have identified input factors of pulse-on-time (Ton), pulse-off-time (Toff), and current and output factors of MRR, SR, and RLT. Through the Taguchi approach, a total of nine experimental trials were designed to analyze the performance of the process. The statistical significance of input factors on the performance measures was studied with the help of ANOVA techniques. Statistical analysis for all the output measures has shown that the generated regression terms had a significant influence. For single output measures, the current was found to have a substantial effect on both MRR and SR, while Toff was the most significant contributor in the case of RLT. The obtained results of residual plots for all performance measures implied good ANOVA results. The effect of near-dry WEDM variables was studied on output measures through main effect plots. Grey relational analysis (GRA) has been employed to attain optimal parametric settings of multiple performance measures. GRA technique for the optimal parametric settings of simultaneous performance measures of MRR, SR, and RLT was found to have a Ton of 30 µs, Toff of 24 µs, and current of 4 A. Validation trials were conducted to check the adequacy of the GRA technique. The minor acceptable deviation was recorded among the anticipated and recorded values. This clearly reveals the acceptability of the integrated approach of the Taguchi–Grey method. The surface morphology for the near-dry and wet-WEDM has also been investigated through scanning electron microscopy (SEM). The author considers that the present study will be beneficial for users working in WEDM and near-dry WEDM processes for hard machining materials.

Optimization of preparation of lignite-based activated carbon for high-performance supercapacitors with response surface methodology

Coal-based activated carbon (CBAC) is prepared from lignite as raw material by the potassium-catalyzed steam activation method. The effect of various process variables like activation temperature, activation time, immersion time and the mass ratio of activator to coal on the electrochemical performance are optimized according to the Box–Behnken design and analyzed using response surface methodology (RSM). The optimization synthesis of CBAC is determined by the conditions of the activation temperature of 758.0 °C, the immersion time of 23.9 h, the activation time of 1.9 h, the mass ratio of activator to coal as 5.1:1. The optimal product (CBAC-2) obtain by the above procedure displays a high specific surface area (2380.4 m2 g−1) and a large pore volume (1.1 cm3 g−1). The supercapacitor of CBAC-2 presents a high specific capacitance of 374.1 F g−1 at 1 A g−1 and excellent capacity retention of 93.3 % after 10,000 cycles at 10 A g−1 in 6 M KOH aqueous electrolyte. Therefore, the developed RSM is accurate and precise for regulating the pore size distribution of CBAC. The optimal synthesis of supercapacitor electrodes with the extract from lignite can expand our horizons for utilising low-rank coal.

Lithium promotes Ag-CoOx composite for formaldehyde oxidation at ambient temperature: Chemically adsorbed oxidative oxygen formed by the interaction between AgCoO2 and catalyst parent

Catalytic oxidation at ambient temperature dominates priority in airborne formaldehyde elimination. Herein, the effects of Li+, Na+ and K+ on the catalytic activity of Ag-CoOx composite were comparatively studied. Systematic methods were applied to investigate the factors influencing catalytic activity. Compared with the cases of Na+ and K+, for which the combination with Ag species respectively deteriorated and limitedly increased formaldehyde removal, the incorporation of Li+ greatly boosted formaldehyde degradation. Characterization results certify that the largest amount of chemically adsorbed active oxygen was crucial to the excellent performance of Li-Ag-CoOx, and the advanced oxidizing property can be rationalized by the strong interaction between the exclusively formed AgCoO2 and the catalyst parent. This is the first time to clarify the roles of varied alkaline metals in the complete oxidation of formaldehyde catalyzed by Ag-CoOx materials. Effects of process variables were additionally investigated to uncover the catalyst suitability for in-field application.

Investigation of Amperometric Sensing Mechanism in Gold–C60–Gold Molecular Dot

We investigate through simulations the gold–C60–gold molecular junction as a novel single-molecule amperometric gas sensor. We find it promising for NO and NO2 detection in air and at room temperature, with current variations of the order of the microampere, and presenting the potential capability of achieving the single-molecule sensitivity along with selectivity in the presence of common atmospheric gases. Furthermore, and for the first time, we investigate the current modulation mechanism due to target–sensor intermolecular interactions, providing theoretical insights into the functioning and exclusive properties of this novel device. In particular, we show and motivate the peculiar voltage-dependent response of the sensor that we relate to the distinctive mechanism of transport modulation occurring in the presence of a specific target. Finally, we discuss sensing reliability in air and the effects of probable fabrication process variability on sensing performance. Our results motivate future works on molecular dot-based chemical sensors in terms of the sensor–target exclusive interactions and detection principles, oriented to device-level engineering to find optimal operating conditions.

Optimization and Kinetic Study of the Electrochemical-Assisted Leaching of Valuable Metals in Lithium-Ion Batteries

Efficient recycling of lithium-ion batteries (LIB) is required to meeting future demand of materials and support sustainable decarbonized energy systems. At the center of the recycling process is the recovery of valuable active metals in LIBs. Hydrometallurgical recovery processes are considered cleaner and less expensive than pyrometallurgical processes, and we previously reported a hydrometallurgical process for the leaching of valuable metals in mixed shredded LIBs. [1] In this process the reductant Fe2+, at low concentration, is electrochemically regenerated to complete the leaching of metals of interest Co, Ni, Li, Mn, and removal of Cu from LIB black mass, eliminating the need of H2O2. To accelerate this process and reduce chemical and energy consumption, the effect of process variables needs to be better understood. In this work, we study the effect of added electrochemical mediator concentration (Fe), total current and agitation level on the kinetics and leaching efficiency the EC-leaching process. Moreover, we propose a new multi-stage leaching scheme for the adjustment of final pH and recirculation of iron in the system.

Insights and Applications of Composite Electroplating

Composite electroplating is the process of particle incorporation during the electrolytic deposition of metal. This process produces composite films consisting of a metallic matrix containing a dispersion of small particles. The advantages of composite electrodeposition over other coating methods are the uniformity of deposition even for complex shapes, the strong adhesion to the substrate, reduction of waste compared to dipping or spraying techniques, low levels of contamination, the ability to produce functionally-gradient material and to continuously process parts. In addition, this process avoids the problems associated with high temperature or vacuum processing.There are many contradictory experimental results in literature concerning the effects of the electrocodeposition process variables on particle incorporation. The effects of some of the process variables also vary for different particle-electrolyte combinations and cell configurations. Some of the reported contradictions are a direct consequence of incomparable hydrodynamics. The bulk of experimental electrocodeposition research has been conducted using a vertical parallel plate electrode set-up. In this configuration, the particles are maintained in suspension by either stirring the solution, vibrating a perforated plate at the bottom of the cell, bubbling gas, or pumping the suspension through the cell, all of which result in uncontrollable, and hence incomparable hydrodynamics. Other contradictions are due to the fact that the process parameters were evaluated only for a narrow range of experimental parameters and to differences in particle size and purity.This talk discusses the experimental results and mathematical modeling of electrocodeposition of particles in a metallic matrix. The effects of several key parameters, such as current density, particle loading, electrolyte composition, particle surface charge and polarity, on particle incorporation in electrodeposited composite coatings were studied and modeled. All experiments were done utilizing rotating disk electrodes over a wide range of experimental conditions in which the incorporation behavior changes appreciably, yielding reproducible data for better interpretation of process effects and modeling. These studies were combined with colloidal probe AFM experiments and process archeology using pulse plating which helped to understand the codeposition mechanism.

Correlation analysis between extrusion process variables and quality of purslane leaf powder rice extrudates.

Extrusion has become one of the most popular techniques in food processing, and the process parameters are closely related to product quality. Purslane (Portulaca oleracea L.) can be used in medical and food products as a vegetable and herb. It has limited application in extrusion. The effects of extrusion process variables (screw speed, barrel temperature, and feed moisture) on system variables (specific mechanical energy [SME], die head pressure, and torque) and target variables (water absorption index, water solubility index, iodine blue value, color, pasting properties, and textural properties) of purslane powder compound rice were studied. The results showed that SME was moderately positively correlated with screw speed (r=0.608, p<0.05). However, torque was moderately negatively correlated with feed moisture (r=-0.574, p<0.05), and die head pressure was moderately negatively correlated with barrel temperature (r=-0.635, p<0.01). The target variables of extrudates were also correlated with the system parameters to varying degrees. These results are helpful to control and predict the texture, pasting properties, and other quality characteristics of extruded products containing purslane powder. PRACTICAL APPLICATION: The results showed that torque and die head pressure were moderately negatively related to barrel temperature, specific mechanical energy was moderately positively related to screw speed, peak viscosity and breakdown viscosity were moderately negatively related to specific mechanical energy, and water absorption index was moderately negatively related to torque and die head pressure. It provides a reference for the research of influencing system parameters and changing product quality by controlling extrusion process parameters. In this study, some possibilities for the application of broken rice and purslane in extrusion processing were proposed.

Effect of High Hydrostatic Pressure Processing on Starch Properties of Cassava Flour

The aim of this study was to utilize high-pressure processing (HPP) to modify cassava flour through altering the starch components. Specifically, the effect of HPP processing variables, i.e., pressure (0.10 or untreated, 300, 400, 500, and 600 MPa), flour concentration (FC; 10, 20, and 30%), and holding time (HT; 10 and 30 min) on starch-related properties was studied. Microstructural integrity, thermal properties, and starch susceptibility to digestive enzymes were determined. A three-way ANOVA was performed to identify the interaction effect between these process variables. In general, 600 MPa consistently transformed the crystalline starch into an amorphous one. HPP-induced gelatinization led to enlarged starches with loss of birefringence, reduced relative crystallinity percentage, and changes in short-range order. The three-way interaction between the process variables was evident in the significant progressive rise in onset gelatinization temperature and degree of gelatinization, and the decline in gelatinization enthalpy from 500 to 600 MPa with decreasing FC and increasing HT. These changes caused an increased percentage of rapidly digestible starch and decreased resistant starch fraction. Overall, this study’s results imply the possibility of using HPP to modify the starch component in cassava flour and potentially create flours with varying levels of functionalities.

In-Memory Computation With Improved Linearity Using Adaptive Sparsity-Based Compact Thermometric Code

The article presents an efficient static random access memory (SRAM)-based in-memory computation (IMC) architecture which is capable of performing image classification with improved linearity. In this work, we proposed a thermometric code-based IMC (TC-IMC) to perform multibit multiply-and-accumulate (MAC) operations with improved linearity. An input sparsity-aware compact thermometric code approach is proposed to reduce the number of SRAM bitcells compared to the thermometric code-based encoding without loss of accuracy in the MAC operation. We proposed an optimal sampling time to improve the linearity of the TC-IMC MAC operation with maximum signal margin (SM) based on the detailed nonlinearity analysis of 8T SRAM-based TC-IMC architecture. The test chip measurement results in 180 nm process show that the proposed TC-IMC has 72% better linearity than the traditional IMC. The measured results on 100 Modified National Institute of Standards and Technology (MNIST) and CIFAR-10 test images show an accuracy of 97% and 87%, respectively. In addition, the proposed TC-IMC architecture achieves MAC compute latency of 25 ns, GOPS/kb (normalized to 1 b <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 1 b) of 29.8, and energy efficiency of 2.3 TOPS/W. The simulation result of the entire 10000 MNIST and CIFAR-10 images considering process variation effects shows an accuracy of 98.7% and 90.4%, respectively.

Investigation of the Performance Removal of RB Dye from Aqueous Solution by Using GO-NP/MMMs

The focus of this research is to discover the best possible operating parameters for adding GO element into PES/GO membranes for NF uses. Organic compounds have the potential to contaminate GO-NP/PES membranes. Regarding to address the technical issues that membranes encounter, the new model strives to decrease energy loss while keeping a strong system discharge all across the treatment process. An optimization strategy was employed to establish ideal values for various essential process parameters to achieve a certain quantity of flux above the expected levels. Mathematical and statistical examinations such as response surface technique and statistical analysis of the characteristics (ANOVA) were used to improve the process's performance on a broader level. This research is looked at the effects of process variables, including dye feeding pH (3–11), GO ratio (0–2%), RB dye concentration (10–100 ppm), and the interactions between these factors and PES/GO membrane permeability. With a result of 123.417 ℓ/(m2 h bar), the PES membrane performed the best. The pH had no consequence on the RB dye's reactivity, and the results are verified by a Pareto chart of the normalized effects on dye permeation flow using a significant effect at the 5% significance level.

Effect of Process Variables on Chemical Treatment of Jute Fibers

Effect of Process Variables on Chemical Treatment of Jute Fibers

Ultrasound and Microwave-assisted Extraction of Proteins from Coffee Green Beans: Effects of Process Variables on the Protein Integrity

The demand for proteins is constantly increasing and green extraction methodologies are needed to achieve environmental sustainability goals. The recovery of the by-products of the agri-food chain has also become a priority from a circular economy perspective. Some by-products are still little exploited for the extraction of proteins, such as coffee by-products. In this work, various innovative extraction technologies were applied to recover the protein fraction from the non-compliant coffee green beans (CGB), using a methodological approach that allowed to correlate the process parameters with the final quality of the extracted proteins. The ultrasound-assisted extraction (UAE) technique has been shown to have a minor impact on the quality of the proteins, thanks to the possibility of refrigerating the system, while the microwave-assisted extraction (MAE) shows a certain degree of degradation due to the high temperatures reached. The results indicate that strict temperature control is required during alkaline extraction to preserve the quality of the protein fraction.

Risk-Assessment-Based Optimization Favours the Development of Albumin Nanoparticles with Proper Characteristics Prior to Drug Loading.

Albumin nanocarrier research and development is a challenging area in the field of personalized medicine and in providing advanced therapeutic solutions. Albumin as a biocompatible, nonimmunogenic, and non-toxic protein carrier that can be exploited to conjugate drugs with poor bioavailability to improve on this feature. With many different perspectives and desired target profiles, a systematic structural approach must be used in nanoparticle development. The extended Research and Development (R&D) Quality by Design thinking and methodology proved to be useful in case of specific nanoparticle development processes before. However, the coacervation method is the most frequently applied preparation method for HSA nanoparticles; there is a lack of existing research work which has directly determined the influence of process parameters, control strategy, or design space. With a quality-management-driven strategy, a knowledge space was developed for these versatile nanoparticles and an initial risk assessment was conducted on the quality-affecting factors regarding the coacervation method, followed by an optimization process via Plackett–Burman and Box–Behnken experimental design. As a result of screening the effect of process variables on the fabrication of HSA nanoparticles, an optimized colloidal drug delivery system was engineered with desired nanoparticulate properties.