Development and Statistical Optimization of Solid Lipid Nanoparticle Formulations of Fluticasone Propionate.

OBJECTIVES: The aim of this study was to develop fluticasone propionate (FP)-loaded solid lipid nanoparticle (SLN) formulations by using factorial design approach. MATERIALS AND METHODS: Tristearin percentages (X1) (1%, 2%, and 4%) and homogenization cycles (X2) (2, 4, and 8 cycles) were selected as independent variables in the factorial design. SLN formulations were optimized by multiple linear regression (MLR) to evaluate the influence of the selected process and formulation independent variables on SLNs' characteristics, namely as encapsulation efficiency (Q1) and particle size (Q2). The polydispersity index and surface charge of the SLNs were also evaluated in this research. Moreover, transmission electron microscopy, differential scanning calorimetry, and in vitro drug release studies were carried out on the optimum SLN formulation. RESULTS: The MLR analysis indicated that as the homogenization cycle (X2) increased in the production process, the mean particle size decreased. CONCLUSION: This research showed that FP-encapsulated SLNs with desired characteristics can be produced by varying the production and content variables of the formulations.

QbD guided early pharmaceutical development study: Production of lipid nanoparticles by high pressure homogenization for skin cancer treatment.

This research attempts to bring together the positive aspects of lipid nanoparticles and Quality by Design (QbD) approach for developing a novel drug delivery system for skin cancers and aktinic keratosis. Lipid nanoparticles which is one of the most efficacious options for topical treatment of skin diseases were prepared due to their ability to overcome the complex structure of skin barrier and to enhance the skin penetration. Since the formulation development contains complex variables of active ingredients, raw materials or production method; all the variables of the product should be elaborated. QbD approach which refers to design and develop formulations and manufacturing processes to maintain the prescribed product quality was also successfully adopted to achieve a time- and cost-saving process ensuring a high-quality product. 5-Fluorouracil (5-FU) loaded lipid nanoparticles, both solid lipid nanoparticles and nanostructured lipid carriers, were developed and characterized by following QbD steps. Optimal lipid nanoparticle formulation with guaranteed quality which was within the design space has been reached through the artificial neural networks. The optimal lipid nanoparticle formulation which is a NLC formulation with a mean particle size of 205,8 ±â€¯9,34 nm, narrow size distribution (0.279 ±â€¯0.01) and negative zeta potantial -30,20 ±â€¯0,92 was produced by high pressure homogenization method. Cytotoxicity profiles of the optimal NLC was determined by cell culture studies on epidermoid carcinoma cells and human keratinocyte cells. Optimal NLC showed significantly higher anticancer effect on epidermoid carcinoma cells than free 5-FU and also less cytotoxicity towards human keratinocyte cells. Optimal NLC was formulated in hydrogel formulation for ease of application which has suitable occlusive and mechanical properties, viscocity and pH for patient complience. The cumulative amount of 5-FU in dermal tissues of rat skin was found 20.11 ±â€¯2.14 µg/cm2 and 9.73 ±â€¯0.87 µg/cm2 after application of NLC enriched hydrogel and 5-FU hydrogel respectively. In conclusion, this study showed that a time and cost saving process ensuring a high-quality product can be obtained by QbD guided formulation development study with the help of artificial neural networks. A novel semisolid dosage form enriched by NLC which is promising for topical treatment of skin cancers was developed.

Development of a HILIC method for the determination of 5-fluorouracil from nano drug delivery systems and rat skin extracts.

This is the first report in literature using hydrophilic interaction liquid chromatography (HILIC) in combination with diode array detector (DAD) for stability indicating determination of 5-Fluorouracil (5-FU) from its bulk form, pharmaceutical preparations, developed solid lipid nanoparticle (SLN) and nano structured lipid carrier (NLC) drug delivery systems as well as the rat skin extracts. The separation was performed at 45 °C, on Sequant Zic HILIC (250 mm × 4.60 mm ID, 5 µm, 200 Ao), peek HPLC column. Mobile phase is consisting of a mixture of acetonitrile: buffer containing 5 mM ammonium acetate (95:5; v/v). The pH of the mobile phase was adjusted to 7.0 using 1 M NaOH. The analysis was carried out at 0.75 mL min-1 flow rate with a detection wavelength of 265 nm and the injection volume was arranged as 10 µL. The developed method was fully validated in accordance with the International Council on Harmonization (ICH) Guidelines. Specificity of this method was demonstrated by forced degradation studies. As a result of calibration studies, the calibration curve was found linear in the concentration range of 1-250 µg mL-1 (R2 = 0.999). The precision of this technique calculated within the frame of intra-day and inter-day based on a percentage of relative standard deviation (RSD%) values (<2%). The limits of detection and quantification were 11 and 37 ng mL-1 respectively. On the other hand, 5-FU loaded SLN and NLC formulations with average particle size of 370 nm were also developed and compared in order to increase the permeation of drug into the rat skin. Ex-vivo Penetration/Permeation Studies indicated that higher dermal accumulation of 5-FU was obtained with NLC formulation. As a conclusion, the present work expressed the optimization and the validation of a selective, simple, precise and accurate fully validated HILIC method with sufficient sensitivity for the estimation of 5-FU in raw materials, marketed formulation and rat skin extract after applying both of the commercial product and newly developed nanoparticulate drug delivery systems on to the rat skins with high percentage recoveries.

Novel Drug Delivery System for Dermal Uptake of Etofenamate: Semisolid SLN Dispersion.

BACKGROUND: Semisolid SLNs are novel strategy for dermal drug administration instead of incorporating the SLN dispersions into conventional semisolids. Etofenamate loaded semisolid SLNs were successfully prepared and in vitro characterization of formulations were performed in our previous study. The present study is an attempt to evaluate the dermal behavior of the semisolid SLNs selected on the basis of previous research and investigate the properties in terms of the convenience for topical applications. OBJECTIVE: The objective of this study is to evaluate the skin penetration characteristics of semisolid SLN formulations. The occlusive and mechanical properties of semisolid SLNs were also evaluated because of their impression on the dermal behavior of the formulations. METHOD: The occlusive properties were investigated by in vitro occlusion test. Texture analysis was performed to define the hardness, compressibility, adhesiveness, cohesiveness and elasticity of the formulations. Rat skin was chosen to evaluate the ex vivo penetration of etofenamate loaded semisolid SLNs and commercial gel product. Coumarin-6 was used to visualize the dermal distribution of the semisolid SLN formulations. For monitorizing the penetration of coumarin-6 into the skin samples Confocal Laser Scanning Microscopy was employed. RESULTS: The occlusive and mechanical properties of C1 coded semisolid SLN formulation were found more favorable in comparison with P1. The cumulative etofenamate amount in skin samples was found to be 39.88 ± 1.50 µg/cm2 for C1 and 30.56 ± 2.10 µg/cm2 for P1 coded formulations. According to CLSM images, greater fluorescence intensities and deeper skin penetrations were obtained with both of the semisolid SLNs in comparison to plain Carbopol gel. CONCLUSION: It can be concluded that the semisolid SLNs are promising alternative dermal drug delivery systems to the conventional dosage forms.

Skin Localization of Lipid Nanoparticles (SLN/NLC): Focusing the Influence of Formulation Parameters.

BACKGROUND: In this study, fluorescein labeled SLN and NLC formulations were prepared for improving the dermal distribution of the hydrophilic active ingredients and for enhancing the skin penetration. METHODS: To determine skin distribution of the lipid nanoparticles ex-vivo penetration/ permeation experiments were performed using full thickness rat skin by means of Franz diffusion cells. Studies on the localization of fluorescence labeled nanoparticles were performed by confocal laser scanning microscopy (CLSM). Cellular uptake studies were performed on human keratinocyte cell line (HaCaT) and visualized by fluorescence microscope. Both tissue and cell uptake were also quantitatively determined by means of fluorimetric method in the skin extract or cell extract. RESULTS: Both imaging and quantification studies suggest that the dermal localization of the lipid nanoparticles depends on their dimensions and particle size distribution. The CLSM images clearly show that the Tripalmitin based lipid nanoparticles have higher accumulation in the skin. It is possible to overcome the stratum corneum barrier function with T-NLC05 coded lipid nanoparticle formulation. Additionally cellular uptake of this NLC formulation is time dependent. Conclusion: It can be concluded that this formulation is promising for treating local skin disorders without systemic side effects. On the other hand obtained results suggest that optimum formulation (T-NLC05) might be an interesting option even for novel cosmetic products.

Quality by design case study 1: Design of 5-fluorouracil loaded lipid nanoparticles by the W/O/W double emulsion - Solvent evaporation method.

With Quality by Design (QbD), a systematic approach involving design and development of all production processes to achieve the final product with a predetermined quality, you work within a design space that determines the critical formulation and process parameters. Verification of the quality of the final product is no longer necessary. In the current study, the QbD approach was used in the preparation of lipid nanoparticle formulations to improve skin penetration of 5-Fluorouracil, a widely-used compound for treating non-melanoma skin cancer. 5-Fluorouracil-loaded lipid nanoparticles were prepared by the W/O/W double emulsion - solvent evaporation method. Artificial neural network software was used to evaluate the data obtained from the lipid nanoparticle formulations, to establish the design space, and to optimize the formulations. Two different artificial neural network models were developed. The limit values of the design space of the inputs and outputs obtained by both models were found to be within the knowledge space. The optimal formulations recommended by the models were prepared and the critical quality attributes belonging to those formulations were assigned. The experimental results remained within the design space limit values. Consequently, optimal formulations with the critical quality attributes determined to achieve the Quality Target Product Profile were successfully obtained within the design space by following the QbD steps.

Development of etofenamate-loaded semisolid sln dispersions and evaluation of anti-inflammatory activity for topical application.

Dermal application of various active substances is widely preferred for topical or systemic delivery. SLNs consist of biocompatible and non-toxic lipids and have a great potential for topical application in drugs. In this study, semisolid SLN formulations were successfully prepared by a novel one-step production method as a topical delivery system of etofenamate, an anti-inflammatory drug. Compritol 888 ATO and Precirol ATO 5 were chosen as lipid materials for the fabrication of the formulations. In-vitro evaluation of the formulations was performed in terms of encapsulation efficiency, particle size, surface charge, thermal behavior, rheological characteristics, in vitro drug release profile, kinetics, mechanisms, stability, and anti-inflammatory activity. The colloidal size and spherical shape of the particles were proved. According to the results of the rheological analysis, it was demonstrated that the semisolid SLN formulations have a gel-like structure. Stability studies showed that semisolid SLNs were stable at 4°C for a six month period. Zero order release was obtained with Precirol ATO 5, while Compritol 888 ATO followed the square root of time (Higuchi's pattern) dependent release. Semisolid SLNs showed higher inhibitory activity of COX in comparison with pure etofenamate. In conclusion, etofenamate-loaded semisolid SLN formulations can be successfully prepared in a novel one-step production method and useful for topical application.

Loading into nanoparticles improves quercetin's efficacy in preventing neuroinflammation induced by oxysterols.

Chronic inflammatory events appear to play a fundamental role in Alzheimer's disease (AD)-related neuropathological changes, and to result in neuronal dysfunction and death. The inflammatory responses observed in the AD brain include activation and proliferation of glial cells, together with up-regulation of inflammatory mediators and of free radicals. Along with glial cells, neurons themselves can also react and contribute to neuroinflammatory changes in the AD brain, by serving as sources of inflammatory mediators. Because excess cholesterol cannot be degraded in the brain, it must be excreted from that organ as cholesterol oxidation products (oxysterols), in order to prevent its accumulation. Among risk factors for this neurodegenerative disease, a mechanistic link between altered cholesterol metabolism and AD has been suggested; oxysterols appear to be the missing linkers between the two, because of their neurotoxic effects. This study shows that 24-hydroxycholesterol, 27-hydroxycholesterol, and 7ß-hydroxycholesterol, the three oxysterols potentially implicated in AD pathogenesis, induce some pro-inflammatory mediator expression in human neuroblastoma SH-SY5Y cells, via Toll-like receptor-4/cyclooxygenase-2/membrane bound prostaglandin E synthase (TLR4/COX-2/mPGES-1); this clearly indicates that oxysterols may promote neuroinflammatory changes in AD. To confirm this evidence, cells were incubated with the anti-inflammatory flavonoid quercetin; remarkably, its anti-inflammatory effects in SH-SY5Y cells were enhanced when it was loaded into ß-cyclodextrin-dodecylcarbonate nanoparticles, versus cells pretreated with free quercetin. The goal of loading quercetin into nanoparticles was to improve its permeation across the blood-brain barrier into the brain, and its bioavailability to reach target cells. The findings show that this drug delivery system might be a new therapeutic strategy for preventing or reducing AD progression.

Microparticulate based topical delivery system of clobetasol propionate.

Psoriasis is a chronic, autoimmune skin disease affecting approximately 2% of the world's population. Clobetasol propionate which is a superpotent topical corticosteroid is widely used for topical treatment of psoriasis. Conventional dosage forms like creams and ointments are commonly prefered for the therapy. The purpose of this study was to develop a new topical delivery system in order to provide the prolonged release of clobetasol propionate and to reduce systemic absorption and side effects of the drug. Clobetasol propionate loaded-poly(D,L-lactic-co-glycolic acid) (PLGA) microspheres were prepared by oil-in-water emulsion-solvent evaporation technique. Particle size analysis, morphological characterization, DSC and XRD analyses and in vitro drug release studies were performed on the microparticle formulations. Emulgel formulations were prepared as an alternative for topical delivery of clobetasol propionate. In vitro drug release studies were carried out from the emulgel formulations containing pure drug and drug-loaded microspheres. In addition, the same studies were performed to determine the drug release from the commercial cream product of clobetasol propionate. The release of clobetasol propionate from the emulgel formulations was significantly higher than the commercial product. In addition, the encapsulation of clobetasol propionate in the PLGA microspheres significantly delayed the drug release from the emulgel formulation. As a result, the decrease in the side effects of clobetasol propionate by the formulation containing PLGA microspheres is expected.