Box-Behnken Factorial Design Research Articles

DOPE/CHEMS-Based EGFR-Targeted Immunoliposomes for Docetaxel Delivery: Formulation Development, Physicochemical Characterization and Biological Evaluation on Prostate Cancer Cells

Docetaxel (DTX) is a non-selective antineoplastic agent with low solubility and a series of side effects. The technology of pH-sensitive and anti-epidermal growth factor receptor (anti-EGFR) immunoliposomes aims to increase the selective delivery of the drug in the acidic tumor environment to cells with EFGR overexpression. Thus, the study aimed to develop pH-sensitive liposomes based on DOPE (dioleoylphosphatidylethanolamine) and CHEMS (cholesteryl hemisuccinate), using a Box-Behnken factorial design. Furthermore, we aimed to conjugate the monoclonal antibody cetuximab onto liposomal surface, as well as to thoroughly characterize the nanosystems and evaluate them on prostate cancer cells. The liposomes prepared by hydration of the lipid film and optimized by the Box-Behnken factorial design showed a particle size of 107.2 ± 2.9 nm, a PDI of 0.213 ± 0.005, zeta potential of -21.9 ± 1.8 mV and an encapsulation efficiency of 88.65 ± 20.3%. Together, FTIR, DSC and DRX characterization demonstrated that the drug was properly encapsulated, with reduced drug crystallinity. Drug release was higher in acidic pH. The liposome conjugation with the anti-EGFR antibody cetuximab preserved the physicochemical characteristics and was successful. The liposome containing DTX reached an IC50 at a concentration of 65.74 nM in the PC3 cell line and 28.28 nM in the DU145 cell line. Immunoliposome, in turn, for PC3 cells reached an IC50 of 152.1 nM, and for the DU145 cell line, 12.60 nM, a considerable enhancement of cytotoxicity for the EGFR-positive cell line. Finally, the immunoliposome internalization was faster and greater than that of liposome in the DU145 cell line, with a higher EGFR overexpression. Thus, based on these results, it was possible to obtain a formulation with adequate characteristics of nanometric size, a high encapsulation of DTX and liposomes and particularly immunoliposomes containing DTX, which caused, as expected, a reduction in the viability of prostate cells, with high cellular internalization in EGFR overexpressing cells.

DESIGN AND OPTIMIZATION OF FLUCONAZOLE-LOADED PHARMACOSOME GEL FOR ENHANCING TRANSDERMAL PERMEATION AND TREATING FUNGAL INFECTIONS THROUGH BOX-BEHNKEN DESIGN

Objective: The objective of the selected study was to develop and statistically optimize fluconazole (drug) loaded pharmacosomes (carrier) to enhance transdermal permeation by incorporating into gel base and to treat fungal infections by selecting the Box-Behnken model. Methods: Fluconazole is an antifungal drug which belongs to BCS class-II with high permeability and choice for topical drug delivery. In the study, the levels of the lecithin (lipid), dichloromethane and DMSO are selected as independent variables were varied to study the influence on particle size, % entrapment efficiency and in vitro drug release as dependent variables. Factorial designs through software Design expert version 13 (Box-Behnken design) is applied for this study and the optimization process was carried out using the desirability plots and point prediction techniques. Results: Results of the study with the application of a design expert shows that the optimized drug-loaded pharmacosomes with vesicle size of 158.87±0.56 nm as predicted and zeta potential of-30.6mV indicating good stability of the formulation, entrapment efficiency of 90.6±1.12% and in vitro drug release of 97.59±1.84% respectively. The optimized formulation loaded into gel base and compared with the marketed gel formulation. All the evaluation parameters confirmed that the physical mixture of drug and excipients was compatible without any interactions. Conclusion: Through obtained results, it’s concluded that; the independent variable plays a crucial role in optimizing formulation. Study data provided strong evidence that the optimized vesicular formulation through Box-Behnken factorial design can be potentially useful as a drug carrier for loading drug of selected category for enhancing transdermal delivery.

Factorial design applied to LC-ESI-QTOF mass spectrometer parameters for untargeted metabolomics.

Investigations of untargeted metabolomics are based on high-quality data acquisition usually from multiplatform systems that include high-resolution mass spectrometry equipment. The comprehensive set of results is used as data entry for bioinformatics and machine learning sciences to access reliable metabolic and biochemical information for clinical, forensic, environmental, and endless applications. In this context, design of experiments is a powerful tool for optimizing data acquisition procedures, using a multivariate approach, which enables the maximization of a high-quality amount of information with reduced number of tests. In this study, we applied a 33 Box-Behnken factorial design with central point triplicate for optimizing the ionization of an HPLC-ESI-QTOF method used for screening urine samples. Nozzle voltage (V), fragmentor voltage (V) and nebulizer pressure (psig) were the factors selected for variation. The response surface methodology was applied in the molecular features extracted at each level, resulting in a statistical model that helps evaluating the synergic interaction between these factors. Together with the qualitative analysis of the resulting total ion chromatograms, we came across a reproducible (6.14% RSD) and highly efficient method for untargeted metabolomics of human urine samples. The proposed method can be useful for applications in several urine-based metabolomics-driven studies, as the factorial design can be applied in the development of any analytical protocol considering different LC-MS setups.

Guanidine catalysts for biodiesel production: Activity, process modelling and optimization

Since conventional catalysts for biodiesel production have problems with saponification, ten guanidine derivatives were investigated in this study for their catalytic activity in the production of biodiesel from rapeseed oil and methanol. The most active catalyst was selected for process optimization. The influence of process parameters (reaction time, mass percent of catalyst and alcohol to oil ratio) on the transesterification process was evaluated using a design of experiments following a 33 factorial Box-Behnken design of experiments in conjunction with response surface methodology. An accurate quadratic model was developed (p-value < 0.001, F-value 65.90, R2 0.990) and used for process optimization. The resulting optimal conditions were 1.8 wt% of catalyst, methanol to oil ratio of 6.2:1, and a reaction time of 80 min with a predicted yield of 99.2 mol%. The optimal conditions were verified on a larger scale (1 kg), obtaining a yield of 96.5 mol%, confirming the accuracy of the quadratic model. In addition, the obtained biodiesel was characterized with respect to the main physicochemical and application properties.

Healing Potential of Propolis Extract-Passiflora edulis Seed Oil Emulgel Against Excisional Wound: Biochemical, Histopathological, and Cytokines Level Evidence.

Propolis is rich in natural bioactive compounds, and considering its importance for many skin therapies, emulgel was prepared. This study examines how a propolis extract (PE) and Passiflora edulis seed (PS) oil emulgel affect rat deep skin wound healing. Based on preset criteria of maximum drug content and optimum drug permeation through the stratum corneum along with drug retention in the skin layers, an optimized emulgel formula based on Box-Behnken factorial design was prepared and used for subsequent in vitro and in vivo evaluations. In vivo wound-healing activities of emulgel and control treatments were investigated in a rat model. The optimized emulgel formula exhibited superior healing activity compared with plain PE suspension-treated rats on day 14 of wounding. Histopathological investigations of hematoxylin and eosin and Masson's Trichrome-stained skin sections supported this effect. Emulgel promotes cutaneous wound healing through a variety of mechanisms, including anti-inflammatory through modulation of cytokines tumor necrosis factor-α, interleukin (IL)-1β, and IL-6 production, and promotion of collagen fiber formation, all of which contribute to tissue remodeling. Furthermore, when compared with propolis suspension, emulgel showed significant antioxidant and anti-inflammatory effects. Emulgel significantly increased the skin's hydroxyproline level, antioxidant potential, wound contraction, increased penetration, and localized propolis deposition across the skin. Incorporation of PS oil into the emulgel accelerates the tissue regeneration process. The findings suggest that 5% propolis emulgel could be used as an alternative to treat wounds.

Optimized and Validated Box–Behnken Design Combined Response Surface Methodology to Quantify Acetic Acid Content in Potassium Clavulanate Using High–Performance Liquid Chromatography

A simple and robust high-performance liquid chromatography method with UV detection was developed to quantify acetic acid in potassium clavulanate. The chromatographic separation was performed on the Hypersil BDS C18 column (250×4.6 mm, 5 μm) with optimized response surface methodology combined Box–Behnken experimental design. The mobile phase comprises of a buffer prepared by ammonium dihydrogen orthophosphate (20 mM) containing 0.01% triethylamine, maintained pH between 2.8–3.2 using phosphoric acid and % acetonitrile as per Box–Behnken factorial design. The detection was performed at 235 nm with a mobile phase flow rate of 1 ml/min. The method was validated as per the ICH guidelines. The linearity of the proposed method was rectilinear within the range of 2.5–24.8 μg/ml. The value of the limit of detection (LOD) &amp; limit of quantitation (LOQ) by the validated method was found to be 1.9 and 5.8 μg/ml, respectively. The robustness and ruggedness studies were conducted by small changes with parameters in the proposed method. The % RSD values were within the accepted limit of criteria. This developed method can quantify routine acetic acid content analysis in potassium clavulanate pharmaceutical formulations.

Subcritical water extraction (SWE) modified by deep eutectic solvent (DES) for pectin recovery from a Brazilian berry by-product

This study aims to recover pectin from the jaboticaba by-product using subcritical water extraction modified by deep eutectic solvent (SWE-DES). The extractions followed a Box-Behnken Factorial Design and the operational conditions were optimized through response surface methodology (RSM), being 122 °C, 8% DES, and a flow rate of 2 mL/min. The pectin-rich fractions were evaluated by the degree of esterification (DE), galacturonic acid (GalA) content, total carbohydrate content, in vitro antioxidant activity, and techno-functional characteristics such as water and oil holding capacities (WHC and OHC), emulsifying activity (EA), and emulsion stability (ES). SWE provided yields 1.5–1.8-fold higher than conventional extraction. In general, pectin from jaboticaba presented high methoxylation. The SWE-DES beyond increasing the pectin yield resulted in higher GalA content, antioxidant capacity, and emulsion stability than controls. Therefore, the suggested approach was efficient to recover pectin from jaboticaba by-products with potential application in food formulations.

Topical non-aqueous nanoemulsion of Alpinia galanga extract for effective treatment in psoriasis: In vitro and in vivo evaluation

Non-aqueous nanoemulsion (NANE) of Alpinia galanga extract (AGE) was prepared using Palmester 3595 (MCT oil) as oil phase, Cremophor RH 40-Transcutol P® as surfactant-co-surfactant (Smix), and glycerin as non-aqueous polar continuous phase. The composition was optimized by applying three-level, four factor Box-Behnken design (BBD). The mean droplet size and zeta potential of the optimized AGE NANE was found to be 60.81 ± 18.88 nm and −7.99 ± 4.14 mV, respectively. The ex vivo permeation studies of AGE NANE and AGE per se on porcine skin reported flux of 125.58 ± 8.36 µg/cm2 h−1 and 12.02 ± 1.64 µg/cm2 h−1, respectively. Therefore, the enhancement ratio has shown 10-folds increase in the flux for AGE NANE when compared to extract per se. Later, confocal laser scanning microcopy confirmed that AGE NANE were able to penetrate into skin’s stratum by trans-follicular transport mechanism. The stability studies of AGE NANE confirmed its stability at 30 ± 2 °C/75 ± 5 % RH and 5 ± 3 °C. The efficacy of AGE NANE was evaluated in vivo on imiquimod (IMQ) induced mouse model. The mice treated with low and high doses of AGE NANE (groups VI and VII) showed significant (p < 0.05) amelioration of psoriasis. Results of histopathology indicated reduction in psoriasis area severity index in AGE NANE treated mice (group VI and group VII).

Development, Optimization and Characterization of Ocular Nanoemulsion of an Antifungal Agent using Design of Experiments

Antifungal agents of the echinocandin family act on the fungal cell wall by inhibition of synthesis of β (1, 3)-D-glucan. Currently no market formulation is available for ocular delivery of new antifungal agents from the echinocandin family. Further, currently available eye drops in market have the limitations due to high lacrimal drainage and low corneal permeability. The aim of the present work is to optimize and characterize nanoemulsion of an antifungal agent form echinocandin family for ocular delivery. Nanoemulsion was prepared using high shear homogenization followed by high pressure homogenizer. Solubility studies were carried out to identify suitable oil and surfactant. A three level three factor Box-Behnken design was used to optimize nanoemulsion. Prepared formulation was characterized for globule size, zeta potential, polydispersity index and in vitro drug release study by dialysis method using bottle apparatus. Eye irritation study was carried out by Hen’s egg chorioallantoic Membrane test. Stability study of the prepared formulation was performed as per ICH guidelines. Prepared nanoemulsion is transparent with a blue tinge. Optimized batch of nanoemulsion showed average globule size of 108.5 nm with a polydispersity index of 0.108. The results of in vitro drug release study suggest more than 90% drug release over a period of 24 h. Developed formulation was found to be non-irritant and stable when stored at 40°C and can be used for ophthalmic delivery.

Valorization of Brewer's Spent Grain Using Biological Treatments and its Application in Feeds for European Seabass (Dicentrarchus labrax).

Brewer’s spent grain (BSG) is the main brewery industry by-product, with potential applications in the feed and food industries due to its carbohydrate composition. In addition, the lignocellulosic nature of BSG makes it an adequate substrate for carbohydrases production. In this work, solid-state fermentation (SSF) of BSG was performed with Aspergillus ibericus, a non-mycotoxin producer fungus with a high capacity to hydrolyze the lignocellulosic matrix of the agro-industrial by-products. SSF was performed at different scales to produce a crude extract rich in cellulase and xylanase. The potential of the crude extract was tested in two different applications: -(1) - the enzymatic hydrolysis of the fermented BSG and (2) - as a supplement in aquafeeds. SSF of BSG increased the protein content from 25% to 29% (w/w), while the fiber content was reduced to 43%, and cellulose and hemicellulose contents were markedly reduced to around 15%. The scale-up of SSF from 10 g of dry BSG in flasks to 50 g or 400 g in tray-type bioreactors increased 55% and 25% production of cellulase and xylanase, up to 323 and 1073 U g−1 BSG, respectively. The optimum temperature and pH of maximal activities were found to be 55°C and pH 4.4 for xylanase and 50°C and pH 3.9 for cellulase, cellulase being more thermostable than xylanase when exposed at temperatures from 45°C to 60°C. A Box–Behnken factorial design was applied to optimize the hydrolysis of the fermented BSG by crude extract. The crude extract load was a significant factor in sugars release, highlighting the role of hydrolytic enzymes, while the load of fermented BSG, and addition of a commercial β-glucosidase were responsible for the highest phenolic compounds and antioxidant activity release. The lyophilized crude extract (12,400 and 1050 U g−1 lyophilized extract of xylanase and cellulase, respectively) was also tested as an enzyme supplement in aquafeed for European seabass (Dicentrarchus labrax) juveniles. The dietary supplementation with the crude extract significantly improved feed and protein utilization. The processing of BSG using biological treatments, such as SSF with A. ibericus, led to the production of a nutritionally enriched BSG and a crude extract with highly efficient carbohydrases capable of hydrolyzing lignocellulosic substrates, such as BSG, and with the potential to be used as feed enzymes with remarkable results in improving feed utilization of an important aquaculture fish species.

Supercritical CO2 pretreatment of date fruit biomass for enhanced recovery of fruit sugars

This study explores the use of supercritical CO2 (Sc-CO2) as an innovative and green approach for pretreating date fruits to enhance the total sugar yield by water-based extraction. The pretreatment step was investigated based on Box-Behnken factorial design to evaluate the influence of critical variables on the total sugar yield. Sc-CO2 conditioning of the date pulp was investigated by varying the pressure (10–20 MPa), temperature (25–50 °C), and contact time (30–120 min) in a batch setup. Temperature and pressure variables were identified as the significant parameters for the Sc-CO2 treatment. Optimization analysis showed a maximum total sugar yield of 74.1 g/100 g for Sc-CO2pretreated date pulp at 10 MPa and 46 °C for 59 min. Besides, the pretreatment mechanism involved major effects such as swelling, disruption, and explosion that favored the enhanced recovery of total sugars from the date fruit matrix during the extraction. SEM and XRD studies confirmed changes in the microstructure of the date pulp biomatrix before and after pretreatment. Therefore, the consecutive approach of Sc-CO2 conditioning followed by aqueous extraction appears to be an efficient and promising technique for the enhanced recovery of fruit sugars at relatively low temperatures and without the use of any toxic solvents.

Pyrolytic Oil Yield from Waste Plastic in Quezon City, Philippines: Optimization Using Response Surface Methodology

Plastics play an essential role in packaging materials because of their durability to different environmental conditions. With its importance in the community lies the problem with waste disposal. Plastic is a non-biodegradable material, making it a big problem, especially when thrown in dumpsites. In solving the plastic problem, one efficient way to reduce its volume is through thermal processing such as pyrolysis. This study used the pyrolysis method to recover energy from plastic waste. Liquid oil from plastic was comparable to regular fuel used in powering engines. Before the pyrolysis process, a 3k factorial Box-Behnken Design was used in determining the number of experiments to be used. The output oil yield in each pyrolysis runs was optimized in different parameters, such as temperature, residence time, and particle size using response surface methodology to determine the optimum oil yield. Between polyethylene (PE), mixed plastic, and polystyrene (PS), PS produced its highest oil yield of 90 %. In comparison, mixed plastic produced only its highest oil yield of 45 % in 500 ºC temperature, 120 min residence time, and 3 cm particle size. The produced quadratic mathematical models in PE, mixed, and PS plastic were significant in which the p-values were less than 0.05. Using mathematical models, the optimum oil yield for PE (467.68 ºC, 120 min residence time, 2 cm particle size), mixed (500 ºC, 120 min residence time, 2.75 cm particle size) and PS plastic (500 ºC, 120 min residence time, 2 cm particle size) were 75.39 %, 46.74 %, and 91.38 %, respectively

Optimization and Characterization of Cuscuta reflexa Extract Loaded Phytosomes by the Box-Behnken Design to Improve the Oral Bioavailability.

The purpose of this study is to determine whether the complexing hydroalcoholic extract of Cuscuta reflexa (HECR) with phosphatidyl choline increases its bioavailability. As a result, a novel phytosomal delivery system for the HECR-soya lecithin complex was developed (HECR-phytosome). The HECR-phytosome complex was synthesized and characterized as phytovesicles. The formulation was prepared using a variable concentration of soya lecithin (1:1-1:3 percent w/v), a temperature range of (45-65°C), and sonication time (4-8 min). Optimization of HECR-loaded phytosomal formulations was performed using Design Expert software. A three-factor, three-level Box-Behnken design was used to optimize this HECR delivery system, as dependent variables, vesicular size and entrapment efficiency were evaluated using a Box Behnken factorial design. Further characterization of the optimized formulation included vesicle size, PDI, zeta potential, entrapment efficiency, FTIR, DSC, TEM, and in vitro release. Vesicle sizes ranged from 173.5±6.17 nm to 215.9±6.53 nm, and response rates for entrapment efficiency ranged from 52.9±1.65 to 77.2±1.1%. The uniform structure and spherical shape were demonstrated by transmission electron microscopy. Among the drug release kinetic models, the formulation followed the Higuchi model (R2 = 0.9978), releasing 96.3±3.7% of the polyphenol and flavonoids phytoconstituents from HECR-loaded phytosomes in 12 hours, compared to 49.3±2.5% in the plain extract. In addition, the optimized formulation passes the stability test. Therefore, the results demonstrated that phytosomal nanocarriers have the potential to increase the bioavailability of Cuscuta reflexa extract.

TransfersomILs: From Ionic Liquids to a New Class of Nanovesicular Systems.

Ionic liquids (ILs) have increasingly been studied as key materials to upgrade the performance of many pharmaceutical formulations. In controlled delivery systems, ILs have improved multiple physicochemical properties, showing the relevance of continuing to study their incorporation into these formulations. Transfersomes are biocompatible nanovesicular systems, quite useful in controlled delivery. They have promising characteristics, such as elasticity and deformability, making them suitable for cutaneous delivery. Nonetheless, their overall properties and performance may still be improved. Herein, new TransfersomILs systems to load rutin were developed and the physicochemical properties of the formulations were assessed. These systems were prepared based on an optimized formulation obtained from a Box–Behnken factorial design (BBD). The impact of imidazole-based ILs, cholinium-based ILs, and their combinations on the cell viability of HaCaT cells and on the solubility of rutin was initially assessed. The newly developed TransfersomILs containing rutin presented a smaller size and, in general, a higher association efficiency, loading capacity, and total amount of drug release compared to the formulation without IL. The ILs also promoted the colloidal stability of the vesicles, upgrading storage stability. Thus, ILs were a bridge to develop new TransfersomILs systems with an overall improved performance.

Sustainable and optimized bioethanol production using mix microbial consortium of Saccharomyces cerevisiae and Candida cantarelli

Agro-industrial wastes, the most abundant, readily available, and economical materials are of supreme interest that supports sustainable transformation into high-value fuels. However, the low productivity of ethanol due to the inhibition from the degradation product is a significant concern. In the present study, this limitation has been overcome by fermentation of pre-treated saccharified corn stover (CS) with co-cultures of locally isolated and identified strains, i.e., Saccharomyces cerevisiae (FBL-01) and Candida cantarelli (FBL-01). Three factor Box Behnken Design (BBD) and regression analysis was employed for optimum yield of ethanol. The lignin content in residual solids was decreased to 3.95%, although 91.28% of lignin was decomposed in CS after pre-treatment with 1% (w/v) NaOH. HPLC analysis revealed that concentration of reducing sugars; mannose 21.7 g, fructose 15.08 g, glucose 24.5 g were present in saccharified CS whereas activities of β-glucosidase, endo-glucanase, and exo-glucanase were 46.8 ± 1.43, 53.5 ± 1.24 and 41.3 ± 1.31 U/mL, respectively. SEM analysis confirmed that every step, i.e., pre-treatment, saccharification, fermentation decreased crystallinity, and degree of polymerization of CS. After 6 h fermentation using 3:2 mL (S. cerevisae: C. cantarelli) inoculum size ratio at pH 6 and 35 °C, up to 92.5 g/L ethanol yield was obtained. The present study suggested that bioethanol production could be effectively enhanced by co-cultures of yeast using BBD from corn stover.

Process Optimization of PVDF Piezoelectric Nanofiber Production via Electrospinning

Abstract The aim of this work was to investigate the effect of processing parameters of the electrospinning method on the resulting poly (vinylidene fluoride) (PVDF) fiber diameter. A three factorial Box-Behnken experimental design was employed to study the influence of applied voltage, the capillary-to-collector distance and the applied flow rate on the resulting fiber diameter. We successfully prepared bead-free PVDF nanofibers with fiber diameters ranging from 510-1300 nm. The experimental design analysis did not show significant influence of the studied process parameters under the used boundary conditions on the fiber diameter, thus indicating the robustness of the process.

Statistical optimization of chromium (VI) reduction using response surface methodology (RSM) by newly isolated Stenotrophomonas sp. (a novel strain).

Isolation of Microorganisms capable of reducing toxic chromium (VI) into less toxic one (Cr (III)) has been given attention due to their significance in bioremediation of the contaminated sites. In the present study, Stenotrophomonas sp. Crt94-4A an isolated strain from tannery wastewater and identified genetically by 16s rRNA gene sequencing was able to grow at concentrations up to 354mg/L of Cr (VI). The results revealed 1% (w/v) NaCl, 2% (v/v) (2 × 106CFU) inoculum size, and PH 7 in culture containing glucose and peptone as carbon and nitrogen sources respectively were the best conditions for Cr (VI) reduction. Statistical optimization was performed using Plackett-Burman design where peptone, inoculum size, and NaCl had significant effects on Cr (VI) reduction which were tested by three factors Box-Behnken design (BBD) to determine their correlation. The reduction capacity of Cr (VI) by Stenotrophomonas Sp. Crt94-4A was increased from 82, 55, and 23 to 96, 76, and 45% at 88.5, 177 and 354mg/L of Cr (VI) respectively, which make this strain a good candidate for bioremediation of Cr (VI).

Influence of Process Parameters on the Gas Phase Polymerization of Ethylene: RSM or ANN Statistical Methods?

AbstractThe direct and interactive effects of process variables, including the use of iso‐pentane as an inert condensing agent, on the rate of polymerization and main physical properties of linear low‐density polyethylene are studied using two different statistical methods. Response surface methodology (RSM) based on a three level five factor Box–Behnken design is used to generate the number of experimental runs. The generated dataset is used to develop the RSM and artificial neural network (ANN) models. The effect of the input on the dependent variables is studied using the 3D response surface of the developed RSM model. The developed models are statistically analyzed and compared to determine their performance capability. The ANN model marginally outperforms the RSM model based on the computed statistical parameters but provides less information on the variable interactions.

Lipid extraction from sewage sludge using green biosolvent for sustainable biodiesel production

Sewage sludge is a type of urban waste generated as a byproduct of wastewater treatment in quantities ranging from 9 to 9.5 million tons (dry substance) in Europe. This waste can be considered a source of lipids, which can be converted into biofuels. Recovery of lipids from sludge is a critical step in the overall process, and the choice of the extracting solvent should satisfy efficiency as well as sustainability criteria. This study reports experimental optimisation of lipid extraction from sewage sludge using ethyl butyrate, a green bio-derivable solvent. Extraction conditions were optimised using the desirability function applied to the response surface methodology analysis of a Box–Behnken factorial design of experiments. By carrying out the extraction at 70 °C for 7 h, using an amount of solvent equal to the wet sludge, and without using any acids, 93.7% of the starting lipids were recovered. The extracted lipids were then efficiently converted into biodiesel (fatty acid methyl esters) through direct esterification promoted by AlCl3∙6H2O (catalyst). Furthermore, the residual sludge obtained after the extraction, different to that obtained using hexane, was found to be anaerobically digestible without any inhibition.

Design expert as a statistical tool for optimization of 5-ASA-loaded biopolymer-based nanoparticles using Box Behnken factorial design

BackgroundThe overall objective was to prepare a highly accurate nanocarrier system of mesalamine for the treatment of ulcerative colitis with increased therapeutic efficacy and targeting. In the formulation of nanocarrier systems, optimization is a critical process for understanding nanoformulation variables and quality aspects. The goal of the present work was to determine the effect of independent variables, i.e., the concentrations of chitosan, carboxymethyl inulin (CMI), and the drug on the response variables, i.e., particle size and percent entrapment efficiency of the mesalamine-loaded nanoparticle using the Box Behnken design (BBD). The correlation between the independent and dependent variables was investigated using the Design Expert generated mathematical equations, contour, and response surface designs.ResultAn optimized batch was developed using the ionotropic gel method with selected independent variables (A: + 1 level, B: 0 level, C: − 1 level) and the developed nanoparticles had a particle size of 184.18 nm, zeta potential 26.54 mV, and entrapment efficiency 88.58%. The observed responses were remarkably similar to the predicted values. The morphological studies revealed that the formulated nanoparticles were spherical, and the results of the FTIR and DSC studies indicated the drug-polymer compatibility. The nanoparticle showed less than 5% release in the pH 1.2. In the colonic region (pH 7.4), more than 80 % of the medication was released after 24 h. The kinetics study showed that the Higuchi and Korsemeyer-Peppas models had R2 values of 0.9426 and 0.9784 respectively, for the developed formulation indicating linearity, as revealed by the plots. This result justified the sustained release behavior of the formulation.ConclusionThe mesalamine-loaded chitosan-CMI nanoparticle has been successfully developed using the ionotropic gelation method. The nanoparticles developed in this study were proposed to deliver the drug to its desired site. The developed nanoparticles were likely to have a small particle size with positive zeta potential and high percent drug entrapment. It could be stated from the results that BBD can be an active way for optimizing the formulation and that nanoparticles can be a potential carrier for delivering therapeutics to the colon.