Process optimization by use of design of experiments: Application for liposomalization of FK506

Application of Response Surface Methodology Using Face-centered Central Composite Design for Studying Long-Term Stability of Gliclazide-Loaded Multiparticulate Systems

The appropriate design of experiments (DoE) could support post-approval lean-stability approaches. A three-factor three-level face-centered design was constructed to evaluate the long-term stability of gliclazide (GLZ) alginate-gelatin beads. The formulation variables were GLZ%(X1), alginate:gelatin ratio(X2), and glutaraldehyde%(X3). The studied responses included GLZ release at predefined intervals in 0.1 N HCl (2 h) followed by phosphate buffer (pH 7.4). Model-dependent and independent approaches were utilized for comparison. DoE-model validation and reduction were implemented. All the studied formulations showed non-significant changes in the particle size (p > 0.05) and most of them showed similar release profiles before and after storage. The directions of the relationships between the factors' main effects and the responses (Y1:Q0.5h, Y2:Q2h, and Y3:Q4h) remained unchanged after storage. The optimal factor settings based on the proposed optimization criteria were defined. The optimized formulations (OP-1 and OP-2) showed non-significant changes in the particle size after storage. The release profiles and kinetics of OP-1 and OP-2 remained unchanged after storage. No chemical change was indicated (FT-IR). DSC-thermograms of OP-1 indicated GLZ conversion to a more stable polymorph after storage. While OP-2 showed a change in GLZ crystallinity. The stored and fresh beads' surfaces after GLZ release were almost similar. DoE could be utilized to evaluate, optimize, and predict the effects of different formulation variables on the long-term stability of GLZ alginate-gelatin beads.

Development of an Effective Psoriasis Treatment by Combining Tacrolimus-Encapsulated Liposomes and Iontophoresis

Psoriasis is a chronic T-cell-mediated autoimmune skin disease. Tacrolimus (FK506) is commonly used treatment for psoriasis. However, since the molecular weight of FK506 is more than 500 Da, its skin penetration is limited, so that there is a need to improve the penetrability of FK506 to allow for more effective treatment. To this end, we employed iontophoresis (ItP), which is a physical, intradermal drug delivery technology that relies on the use of weak electric current. Previous findings suggest that activation of cell signaling by the weak electric current applied during ItP may affect the expression of inflammatory cytokines, leading to aggravation of psoriasis. In this study, we analyzed the effect of ItP on the expression of various inflammatory cytokines in the skin, and subsequently examined the therapeutic effect of ItP using negatively-charged liposomes encapsulating FK506 (FK-Lipo) in a rat psoriasis model induced by imiquimod. We found that ItP (0.34 mA/cm2, 1 h) did not affect mRNA levels of inflammatory cytokines or epidermis thickness, indicating that ItP is a safe technology for psoriasis treatment. ItP of FK-Lipo suppressed the expression of inflammatory cytokines induced by imiquimod treatment to a greater extent than skin treated with FK506 ointment for 1 h. Furthermore, epidermis thickening was significantly suppressed only by ItP of FK-Lipo. Taken together, results of this study demonstrate the successful development of an efficient treatment for psoriasis by combining FK-Lipo and ItP, without disease aggravation associated with the weak electric current.

Optimization of the Poly(glycerol citraconate) Synthesis Using the Box-Behnken Design

This work aimed to obtain poly(glycerol citraconate) (PGCitrn) for biomedical applications, analyze the obtained polyester by spectroscopic methods, and optimize its preparation. Polycondensation reactions of glycerol and citraconic anhydride were carried out. It was provided that the results in the reaction are oligomers of poly(glycerol citraconate). Optimization studies were carried out based on the Box-Behnken design. The input variables in this plan were the ratio of functional groups, temperature, and time and occurrence in coded form: -1, 0, or 1. Three output variables were optimized: the degree of esterification, the percentage of Z-mers, and the degree of carboxyl group conversion; they were determined by titration and spectroscopic methods. The optimization criterion was to maximize the values of output variables. A mathematical model and an equation describing it were determined for each output variable. The models predicted the experimental results well. An experiment was conducted under determined optimal conditions. The experimental results were very close to the calculated values. Poly(glycerol citraconate) oligomers with an esterification degree of 55.2%, a Z-mer content of 79.0%, and a degree of rearrangement of carboxyl groups of 88.6% were obtained. The obtained PGCitrn can serve as a component of an injectable implant. The obtained material can be used to produce nonwoven fabrics (with the addition of PLLA, for example), which can be subjected to a cytotoxicity test which can then serve as a dressing material.

Application of Box-Behnken design for optimization of phenolics extraction from Leontodon hispidulus in relation to its antioxidant, anti-inflammatory and cytotoxic activities

To the best of our knowledge, there have been no phytochemical studies concerning the wild plant Leontodon hispidulus Boiss. (Asteraceae). Optimization of the green extraction process of the plant aerial parts, identification of main phenolic compounds, evaluation of antioxidant, anti-inflammatory and anticancer activities of the optimized extract have been carried out. HPLC-analysis was performed using 95% ethanolic extract. 3-Level Box-Behnken Design was applied for optimization of extraction yield and total phenolic content using 3-factors (ethanol/water ratio, material/solvent ratio and extraction time). Antioxidant, anticancer and anti-inflammatory activities were evaluated by ABTS-assay, prostate and cervical carcinoma human cell lines and carrageenan-induced rat paw edema model, respectively. HPLC-analysis showed the presence of quercetin, rutin, kaempferol, chlorogenic and ρ-coumaric acids. Increasing both ethanol/water ratio and material/solvent ratio decreased the yield, while, it increased by prolongation of the extraction time. High material/solvent ratio increased the phenolic content. The optimized extract showed high total phenolic content (104.18 µg/mg) using 201 ml of 74.5% ethanol/water at 72 h and good biological activities. Antioxidant activity was found to be 41.89 mg Trolox-equivalent/gm, with 80% free radicals inhibition. For anti-inflammatory activity, 100 mg/kg of the extract inhibited the edema in rats by 83.5% after 4 h of carrageenan injection as compared to 81.7% inhibition by indomethacin. Prostate carcinoma cell line was more sensitive to the anticancer activity of the extract than cervical carcinoma cell line (IC50 = 16.5 and 23 μg/ml, respectively). The developed extraction procedure proved to be efficient in enriching the extract with phenolic compounds with promising anticancer, anti-inflammatory and antioxidant activities.

Enhancement of cerebroprotective effects of lipid nanoparticles encapsulating FK506 on cerebral ischemia/reperfusion injury by particle size regulation

Delivery of cerebroprotective agents using liposomes has been demonstrated to be useful for treating cerebral ischemia/reperfusion (I/R) injury. We previously reported that intravenous administration of liposomes with diameters of 100 nm showed higher accumulation in the I/R region compared with larger liposomes (>200 nm) by passage through the disintegrated blood-brain barrier, suggesting a size-dependence for liposome-mediated drug delivery. Based on these findings, we hypothesized that regulation of liposomal particle size (<100 nm) may enhance the therapeutic efficacy of encapsulated drugs on cerebral I/R injury. Herein, we prepared lipid nanoparticles (LNP) with particle sizes <100 nm by the microfluidics method and compared their therapeutic potential with LNP exhibiting sizes >100 nm in cerebral I/R model rats. Intravenously administered smaller LNP (ca. 60 nm) exhibited wider accumulation and diffusivity in the brain parenchyma of the I/R region compared with larger LNP (>100 nm). Importantly, treatment with LNP encapsulating the cerebroprotective agent FK506 (FK-LNP) with particle sizes <100 nm showed greater cerebroprotective effects than FK-LNP with sizes >100 nm, and also significantly ameliorated brain injury. These results suggest that particle size regulation of LNP to sizes <100 nm can enhance the therapeutic effect of encapsulated drugs for treatment of cerebral I/R injury, and that FK-LNP could be a promising cerebroprotective agent.

Resveratrol-loaded folate targeted lipoprotein-mimetic nanoparticles with improved cytotoxicity, antioxidant activity and pharmacokinetic profile

The aim of present study was to develop folate receptor targeted lipoprotein-mimetic nanoparticles of resveratrol (RSV). Lipoprotein-mimicking nanocarrier (RSV-FA-LNPs) comprising of phosphatidyl choline, cholesterol, stearyl amine and folic acid-tagged bovine serum albumin (FA-BSA) were prepared. Folic acid was conjugated to bovine serum albumin by amide bond at a binding rate of 9.46 ± 0.49 folate molecules per bovine serum albumin. The particle size and entrapment efficiency of the developed nanoparticles was found to be 291.37 ± 3.81 nm and 91.96 ± 1.83%, respectively. The in vitro release study depicted that developed nanocarrier prolonged the drug release till 72 h in phosphate buffer saline (pH 7.4). The anticancer potential of RSV in case of RSV-FA-LNPs was found to be substantially improved against MCF-7 cells overexpressing folate receptors compared to non-targeted nanoparticles. The pharmacokinetics studies after intravenous administration in healthy Wistar rats depicted that lipoprotein mimicking nanoparticles presented the longer circulation time (>48 h) compared to free drug which disappeared in few hours (6 h). The in vitro and preclinical findings of the present study demonstrated the applicability of lipoprotein mimicking nanocarriers for the safer and effective delivery of bioactives.

A Pellet 3D Printer: Device Design and Process Parameters Optimization

A novel pellet 3D printer was first developed, and its structure was constructed out of three main parts. The material used in this device was polycaprolactone (PCL), which was praised for its good characteristics in the biomanufacturing and chemical industries. Three essential parameters that had important effects on the diameter of the printed fibers were systematically studied using a L9(34) orthogonal design table. Using the fused deposition modelling (FDM) method, some products were printed with this machine. Results showed that the stepper motor’s speed had the most significant effect on the diameter of the printed fibers. The optimal parameters were, a stepper motor speed of 1.256 mm3 s−1, a nozzle moving speed of 9.6 mm s−1, and 1.1 mm of height between the nozzle and the platform. Defects like gaps, warping, and poor surface quality were found to be related to different combinations of process parameters. By using the developed pellet 3D printer, the pre-step of making filaments can be avoided, which will bring convenience to FDM 3D printing.

Selective Liposomal Transport through Blood Brain Barrier Disruption in Ischemic Stroke Reveals Two Distinct Therapeutic Opportunities

The development of effective therapies for stroke continues to face repeated translational failures. Brain endothelial cells form paracellular and transcellular barriers to many blood-borne therapies, and the development of efficient delivery strategies is highly warranted. Here, in a mouse model of stroke, we show selective recruitment of clinically used liposomes into the ischemic brain that correlates with biphasic blood brain barrier (BBB) breakdown. Intravenous administration of liposomes into mice exposed to transient middle cerebral artery occlusion took place at early (0.5 and 4 h) and delayed (24 and 48 h) time points, covering different phases of BBB disruption after stroke. Using a combination of in vivo real-time imaging and histological analysis we show that selective liposomal brain accumulation coincides with biphasic enhancement in transcellular transport followed by a delayed impairment to the paracellular barrier. This process precedes neurological damage in the acute phase and maintains long-term liposomal colocalization within the neurovascular unit, which could have great potential for neuroprotection. Levels of liposomal uptake by glial cells are similarly selectively enhanced in the ischemic region late after experimental stroke (2-3 days), highlighting their potential for blocking delayed inflammatory responses or shifting the polarization of microglia/macrophages toward brain repair. These findings demonstrate the capability of liposomes to maximize selective translocation into the brain after stroke and identify two windows for therapeutic manipulation. This emphasizes the benefits of selective drug delivery for efficient tailoring of stroke treatments.

Optimization of gliclazide loaded alginate-gelatin beads employing central composite design

Objective: The aim of this study was to optimize the formulation of alginate-gelatin (AL-GL) beads containing gliclazide (GLZ) employing design of experiments (DOE).Significance: DOE enabled identification of the interaction between the studied factors, deep understanding of GLZ release pattern and acceleration of the optimization process.Methods: A three-factor, three-level face centered design was employed. The effects of GLZ content (GLZ%, X₁), polymer ratio (AL:GL ratio, X₂), crosslinker concentration (glutaraldehyde, GA%, X₃), and their interaction on incorporation efficiency (IE) and release rate were studied. The optimized formulation was prepared using numerical optimization and evaluated by DSC, FT-IR, SEM and release rate studies.Results: Increasing GA% (X₃) decreased IE (Y₁) with the highest magnitude of effect among the studied factors. On the other hand, increasing alginate content in AL:GL ratio (X₂) increased IE (Y₁). The amount of GLZ released Q_0.5h, Q_2h(pH 1.2) and Q_4h(pH 7.4) decreased by increasing GLZ% (X₁) and AL:GL ratio (X₂). Both drug content and AL:GL ratio appeared to affect water penetration into the gel matrix and drug release. Generally, there was a direct relationship between GA% (X₃) and GLZ release in pH 1.2 (Q_0.5h and Q_2h). However, in pH 7.4 (Q_4h), increasing GA% decreased GLZ release. In addition, increasing GA% caused deviation from zero-order release model. The actual responses of the optimized formulation were in close agreement with the predicted ones.Conclusion: The selected factors and their levels studied in the optimization design were useful for tailoring the anticipated formulation characteristics and GLZ release pattern.