Stable Solid Lipid Nanoparticles Research Articles

Synthesis of Lipid Nanoparticles Incorporated with Ferula assa-foetida L. Extract

Solid Lipid Nanoparticles (SLN) have been prepared by high-pressure homogenization and optimized in order to protect ferulic acid from Ferula assa-foetida L. extract. The influence of lipid and surfactant concentration on the mean particle size (Z-Ave), polydispersity index (PDI), and zeta potential (ZP) of SLN was analyzed. In addition, other parameters for the preparation of ferulic acid-loaded nanoparticles, such as extract concentration and variable parameters for the synthesis method used (e.g., pressure), were adjusted to obtain the smallest particle size and polydispersity index, as well as the highest value for zeta potential, which are characteristic of the stable SLN. The established formulation obtained from the optimized synthesis was composed of 6.0 wt.% of the lipid phase and 1.5 wt.% of surfactant, giving stable SLN with Z-Ave, PDI, and ZP values of 163.00 ± 1.06 nm, 0.16 ± 0.01, and −41.97 ± 0.47 mV, respectively. The loading of ferulic acid from Ferula assa-foetida L. extract within the SLN resulted in particles with a mean size of 155.3 ± 1.1 nm, polydispersity index of 0.16 ± 0.01, zeta potential of −38.00 ± 1.12 mV, and encapsulation efficiency of 27%, the latter being quantified on the basis of RP-HPLC analysis. Our findings highlight the added value of SLN as a delivery system for phenolic phytochemical compounds extracted from Ferula assa-foetida L.

Solid Lipid Nanoparticles Based on Monosubstituted Pillar[5]arenes: Chemoselective Synthesis of Macrocycles and Their Supramolecular Self-Assembly

Novel monosubstituted pillar[5]arenes with one or two terminal carboxyl groups were synthesized by the reaction of succinic anhydride with pillar[5]arene derivative containing a diethylenetriamine function. The ability for non-covalent self-assembly in chloroform, dimethyl sulfoxide, as well as in tetrahydrofuran-water system was studied. The ability of the synthesized macrocycles to form different types of associates depending on the substituent nature was established. The formation of stable particles with average diameter of 192 nm in chloroform and of 439 nm in DMSO was shown for pillar[5]arene containing two carboxyl fragments. Solid lipid nanoparticles (SLN) based on monosubstituted pillar[5]arenes were synthesized by nanoprecipitation in THF-water system. Minor changes in the structure of the macrocycle substituent can dramatically influence the stability and shape of SLN (spherical and rod-like structures) accordingly to DLS and TEM. The presence of two carboxyl groups in the macrocycle substituent leads to the formation of stable spherical SLN with an average hydrodynamic diameter of 364-454 nm. Rod-like structures are formed by pillar[5]arene containing one carboxyl fragment, which diameter is about of 50-80 nm and length of 700-1000 nm. The synthesized stable SLN open up great prospects for their use as drug storage systems.

Physicochemical characteristics and in vitro permeation of loratadine solid lipid nanoparticles for transdermal delivery.

Aim: To prepare loratadine-loaded solid lipid nanoparticles (SLNs) using a modified two-step ultrasound-assisted phase inversion temperature (PIT) process. Results/methodology: Loratadine was dissolved in beeswax and Tween 80 wasdissolved in water. The two phases were mixed together to prepare a water-in-oil emulsion preconcentrate (w/o) at a PIT of 85°C, followed by gradual water addition at 25°C to trigger nanoparticles formation (o/w). Kinetic stability was investigated. No change in the size was observed within 6 months. Fourier-transform infrared spectroscopy demonstrated stability of the emulsions via molecular structure of water at the interface of the o/w nanoemulsions. SLNs enhanced the in vitro skin permeation of loratadine. Conclusion: Stable SLNs were successfully prepared by ultrasound-assisted PIT.

Carvacrol Loaded Solid Lipid Nanoparticles of Propylene Glycol Monopalmitate and Glyceryl Monostearate: Preparation, Characterization, and Synergistic Antimicrobial Activity.

To develop solid lipid nanoparticles (SLNs) with stable lipid matrix structures for the delivery of bioactive compounds, a new class of SLNs was studied using propylene glycol monopalmitate (PGMP) and glyceryl monostearate (GMS) mixtures and carvacrol as a model lipophilic antimicrobial. Stable SLNs were fabricated at PGMP:GMS mass ratios of 2:1 and 1:1, and the carvacrol loading was up to 30% of lipids with >98% encapsulation efficiency and absence of visual instability. Fluorescence spectra and release profiles indicated the carvacrol was successfully encapsulated and homogeneously distributed within the SLNs. SLNs fabricated with equal masses of PGMP and GMS had better stability of carvacrol during storage and higher sphericity than those with a ratio of 2:1 and were much more effective than free carvacrol against Escherichia coli O157:H7 and Staphylococcus aureus. These findings demonstrated the potential applications of the studied SLNs in delivering lipophilic bioactive compounds in food and other products.

A Comprehensive Review on Solid Lipid Nanoparticles as Delivery Vehicle for Enhanced Pharmacokinetic and Pharmacodynamic Activity of Poorly Soluble Drugs

This article describes the current state and future perspectives of solid lipid nanoparticles for achieving high delivery of drugs with greater therapeutic outcomes. The oral route is the most preferred route of administration for majority of drugs. Problems such as poor solubility or chemical stability in the environment of the gastrointestinal tract, poor permeability through the biological membranes or sensitivity to metabolism are well known to result in the rejection of potential drug candidates as oral delivery products. Hence, lipid-based drug delivery systems have been proposed as a means of bypassing the resistant chemical or physical barriers associated with poorly absorbed drugs. Solid lipid nanoparticles (SLNs) can be an attractive one option for oral drug delivery vehicles as they hold tremendous potential to improve the oral bioavailability of drugs, concomitant reduction of drug toxicity and stability of drug in both GIT and plasma. SLNs are in submicron size range and are made of biocompatible and biodegradable materials capable of incorporating both lipophilic and hydrophilic drugs. SLNs are considered as substitute to other colloidal drug systems and are being used as controlled and targeted delivery systems. The SNL technology has greatly revolutionized the delivery systems for poorly soluble drugs. This article describes the methodologies used for preparation and characterization of SNLs. It outlined the development of stable solid lipid nanoparticles by different techniques. Further, it describes the current status of pharmacokinetic and pharmaco-dynamic studies reported on SLN systems. Finally, it provides a brief outlook on current marketed preparation and the future scope of SLN technology.

Optimization of nimesulide-loaded solid lipid nanoparticles (SLN) by factorial design, release profile and cytotoxicity in human Colon adenocarcinoma cell line

The aim of this work is development of a nontoxic, long-term stable solid lipid nanoparticles (SLN) formulation for the loading of Nimesulide (NiM) by a 22 factorial design. The optimized formulation was composed of 10 wt% of glyceryl behenate and 2.5 wt% of poloxamer 188. Immediately after production, Z-Ave of NiM-SLN was 166.1 ± 0.114 nm, with a polydispersity index (PI) of 0.171 ± 0051 and zeta potential nearly neutral (−3.10 ± 0.166 mV). A slight increase of Z-Ave was recorded for NiM-SLN stored at 25 °C for a period of 15 days, whereas at 4 °C particles kept size within similar range. Long-term stability was monitored using TurbiscanLab®, showing a high stability of the nanoparticles with variations in the backscattering profiles below 10%. The release profile of NiM-SLN followed a sustained pattern with ca. 30% of drug released up to 24 h. Empty-SLN and NiM-SLN were nontoxic after exposing Caco-2 cells to the highest concentration (100 μg/mL) up to 48 hours (cell viability higher than 80%). NiM-SLN were lyophilized using different cryoprotectants, producing particles of 463.1 ± 36.63 nm (PI 0.491 ± 0.027) with 5% trehalose. Solid character of NiM-SLN was confirmed by DSC, recording a recrystallization index of 83% for NiM-SLN and of 74% for lyophilized SLN.

Biomimetic Solid Lipid Nanoparticles of Sophorolipids Designed for Antileprosy Drugs.

The objective of the present work was to develop solid lipid nanoparticles (SLNs) as drug-encapsulating structures by the solvent injection method. In this report, for the first time the inherent potential of lactonic sophorolipid (glycolipid) was exploited to formulate SLNs. A range of different Pluronic copolymers were screened by dynamic and static light scattering with the aim of obtaining most stable SLNs. To comprehend the structure of the SLNs, techniques such as transmission electron microscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy, and X-ray diffraction were employed. A clear correlation between the type of Pluronic and size and stability of the SLNs could be drawn. The vector properties of the formed SLNs were assessed for both the encapsulated hydrophobic drugs-rifampicin and dapsone. To elucidate the transport mechanism of drug release, kinetic modeling was carried out on the drug release profiles. The promising results of sophorolipid-based SLNs have actually established a new arena beneath the significantly developed field of SLNs.

Development and Evaluation of Lipid Nanoparticles Containing Natural Botanical Oil for Sun Protection: Characterization and in vitro and in vivo Human Skin Permeation and Toxicity

The use of sunscreen products is widely promoted by schools, government agencies, and health-related organizations to minimize sunburn and skin damage. In this study, we developed stable solid lipid nanoparticles (SLNs) containing the chemical UV filter octyl methoxycinnamate (OMC). In parallel, we produced similar stable SLNs in which 20% of the OMC content was replaced by the botanical urucum oil. When these SLNs were applied to the skin of human volunteers, no changes in fluorescence lifetimes or redox ratios of the endogenous skin fluorophores were seen, suggesting that the formulations did not induce toxic responses in the skin. Ex vivo (skin diffusion) tests showed no significant penetration. In vitro studies showed that when 20% of the OMC was replaced by urucum oil, there was no reduction in skin protection factor (SPF), suggesting that a decrease in the amount of chemical filter may be a viable alternative for an effective sunscreen, in combination with an antioxidant-rich vegetable oil, such as urucum. There is a strong trend towards increasing safety of sun protection products through reduction in the use of chemical UV filters. This work supports this approach by producing formulations with lower concentrations of OMC, while maintaining the SPF. Further investigations of SPF in vivo are needed to assess the suitability of these formulations for human use.

A novel and organic solvent-free preparation of solid lipid nanoparticles using natural biopolymers as emulsifier and stabilizer

In this work, a new and novel organic solvent-free and synthetic surfactant-free method was reported to fabricate stable solid lipid nanoparticles (SLNs) from stearic acid, sodium caseinate (NaCas) and pectin, as well as water. Melted stearic acid was directly emulsified into an aqueous phase containing NaCas and pectin, followed by pH adjustment and thermal treatment to induce the formation of a compact and dense polymeric coating which stabilized SLNs. The preparation procedures and formulations were comprehensively optimized. The inter- and intra-molecular interactions among three ingredients were characterized by fluorescence and Fourier transform infrared spectroscopies. The stability of as-prepared SLNs was evaluated under simulated gastrointestinal conditions, and compared with traditional SLNs prepared with organic solvents. Our results revealed that the SLNs prepared from this organic solvent-free method had superior physicochemical properties over the traditional SLNs, including smaller size and better stability. Furthermore, redispersible SLNs powders were obtained by nano spray drying, but only the SLNs prepared by organic solvent-free method had sub-micron scale, uniform and spherical morphology. The organic solvent-free preparation method was proved to be a promising approach to prepare stable and uniform SLNs for potential oral delivery applications.

Development and Optimisation of Spironolactone Nanoparticles for Enhanced Dissolution Rates and Stability

Stable solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs) formulations to enhance the dissolution rates of poorly soluble drug spironolactone (SP) were being developed. Probe ultra-sonication method was used to prepare SLNs and NLCs. All NLCs contained stearic acid (solid lipid carrier) and oleic acid (liquid lipid content), whereas, SLNs were prepared and optimised by using the solid lipid only. The particles were characterised in terms of particle size analysis, thermal behaviour, morphology, stability and in vitro release. The zeta sizer data revealed that the increase in the concentration of oleic acid in the formulations reduced the mean particle size and the zeta potential. The increase in concentration of oleic acid from 0 to 30% (w/w) resulted in a higher entrapment efficiency. All nanoparticles were almost spherically shaped with an average particle size of about ∼170 nm. The DSC traces revealed that the presence of oleic acid in the NLC formulations resulted in a shift in the melting endotherms to a higher temperature. This could be attributed to a good long-term stability of the nanoparticles. The stability results showed that the particle size remained smaller in NLC compared to that of SLN formulations after 6 months at various temperatures. The dissolution study showed about a 5.1- to 7.2-fold increase in the release of the drug in 2 h compared to the raw drug. Comparing all nanoparticle formulations indicated that the NLC composition with a ratio of 70:30 (solid:liquid lipid) is the most suitable formulation with desired drug dissolution rates, entrapment efficiency and physical stability.

Sustained release Curcumin loaded Solid Lipid Nanoparticles.

curcumin is poorly water soluble drug with low bioavailability. Use of lipid systems in lipophilic substances increases solubility and bioavailability of poorly soluble drugs. The aim of this study was to prepare curcumin loaded Solid Lipid Nanoparticles (SLNs) with high loading efficiency, small particle size and prolonged release profile with enhanced antibacterial efficacy. to synthesize stable SLNs, freeze- Drying was done using mannitol as cryoprotectant. Cholesterol was used as carrier because of good tolerability and biocompatibility. SLNs were prepared using high pressure homogenization method. optimized SLNs had 112 and 163 nm particle size before and after freeze drying, respectively. The prepared SLNs had 71% loading efficiency. 90% of loaded curcumin was released after 48 hours. Morphologic study for formulation was done by taking SEM pictures of curcumin SLNs. RESULTS show the spherical shape of curcumin SLNs. DSC studies were performed to determine prolonged release mechanism. Antimicrobial studies were done to compare the antimicrobial efficacy of curcumin SLNs with free curcumin. DSC studies showed probability of formation of hydrogen bonds between cholesterol and curcumin which resulted in prolonged release of curcumin. Lipid structure of cholesterol could cause enhanced permeability in studied bacteria to increase antibacterial characteristics of curcumin. the designed curcumin SLNs could be candidate for formulation of different dosage forms or cosmeceutical products.

Sustained release Curcumin loaded Solid Lipid Nanoparticles.

curcumin is poorly water soluble drug with low bioavailability. Use of lipid systems in lipophilic substances increases solubility and bioavailability of poorly soluble drugs. The aim of this study was to prepare curcumin loaded Solid Lipid Nanoparticles (SLNs) with high loading efficiency, small particle size and prolonged release profile with enhanced antibacterial efficacy. to synthesize stable SLNs, freeze- Drying was done using mannitol as cryoprotectant. Cholesterol was used as carrier because of good tolerability and biocompatibility. SLNs were prepared using high pressure homogenization method. optimized SLNs had 112 and 163 nm particle size before and after freeze drying, respectively. The prepared SLNs had 71% loading efficiency. 90% of loaded curcumin was released after 48 hours. Morphologic study for formulation was done by taking SEM pictures of curcumin SLNs. RESULTS show the spherical shape of curcumin SLNs. DSC studies were performed to determine prolonged release mechanism. Antimicrobial studies were done to compare the antimicrobial efficacy of curcumin SLNs with free curcumin. DSC studies showed probability of formation of hydrogen bonds between cholesterol and curcumin which resulted in prolonged release of curcumin. Lipid structure of cholesterol could cause enhanced permeability in studied bacteria to increase antibacterial characteristics of curcumin. the designed curcumin SLNs could be candidate for formulation of different dosage forms or cosmeceutical products.

Solid Lipid Nanoparticles for Image-Guided Therapy of Atherosclerosis.

Although the application of nanotechnologies to atherosclerosis remains a young field, novel strategies are needed to address this public health issue. In this context, the magnetic resonance imaging (MRI) approach has been gradually investigated in order to enable image-guided treatments. In this contribution, we report a new approach based on nucleoside-lipids allowing the synthesis of solid lipid nanoparticles (SLN) loaded with iron oxide particles and therapeutic agents. The insertion of nucleoside-lipids allows the formation of stable SLNs loaded with prostacycline (PGI2) able to inhibit platelet aggregation. The new SLNs feature better relaxivity properties in comparison to the clinically used contrast agent Feridex, indicating that SLNs are suitable for image-guided therapy.

Investigation of DNA binding abilities of solid lipid nanoparticles based on p-tert-butylthiacalix[4]arene platform

Amphiphilic thiacalix[4]arene functionalized with guanidinium groups forms stable solid lipid nanoparticles (SLNs) with high binding affinity to double-stranded DNA.

Skin delivery aspects of benzoyl peroxide-loaded solid lipid nanoparticles for acne treatment.

Benzoyl peroxide (BPO) has been a mainstay of topical acne treatment for years. However, is frequently accompanied by cutaneous irritation and erythema. To reduce these side effects many novel drug delivery systems have been developed in the past, of which solid lipid nanoparticles (SLN) demonstrate clear dominance. Hence, we developed a facile method to prepare stable SLN of BPO and evaluated their anti-bacterial activity. BPO-SLN optimized using 2(3) full factorial design provided high occlusion factor, low permeation rate, increased drug deposition, reduced skin irritation and strong anti-bacterial activity in contrast with marketed product. Desired goals were achieved by factorial design approach in shortest possible time with minimum number of experiments. The developed BPO-SLN system provided controlled drug release, thereby reducing the well-known side effects.

Fast disintegrating crystalline solid dispersions of simvastatin for incorporation into orodispersible tablets.

Aim:Spray dried solid dispersion (SDP) of crystalline simvastatin (SIM) in a fast disintegrating matrix of superdisintegrants was studied as a method to enhance SIM dispersibility, rheology, compactibility and compressibility for incorporation into orodispersible tablets (ODTs).Materials and Methods:The superdisintegrants investigated were crospovidone (CP), sodium starch glycollate (SSG) and calcium silicate (CS) were spray dried with simvastatin to form SDPs.Results:The SDPs were characterized and the median particle size of SDPs was similar or greater than the SIM, contributing to good rheology of SDPs, while the low bulk density of SDPs indicated a high compactibility. Interestingly electron micrographs for SDPs showed a CP or CS carrier coating of the SIM crystals, contributing to its rheology. Thermal analysis and X-ray diffraction confirmed that SIM was crystalline in the SDPs and no interaction between SIM and any of the carrier(s) was shown by Fourier transform-infra red. Drug content analysis showed a SIM content of 90-95% in SDPs containing CP or CS, while a higher SIM content of 143% was found in SDP containing SSG. When formulated as ODTs, blend containing SIM SDPs in CP showed ease of tableting, regardless of the turret speed. In comparison, tablet blend consisting of a physical mix (PM) of SIM and CP could only be tableted at the lower turret speed of 7 rpm. ODTs formulated using SIM SDPs in CP showed a higher extent of dissolution, compared to the ODTs containing corresponding PM or the commercially available SIM Zocor® tablets (ANOVA, P < 0.05).Conclusion:SDP using disintegrants as carriers may offer an alternative formulation approach for ODTs of poorly soluble drugs.

Development and evaluation of solid lipid nanoparticles of mometasone furoate for topical delivery.

Introduction:Solid lipid nanoparticles (SLNs) are the new generation of submicron sized lipid emulsions where liquid lipid (oil) has been substituted by solid lipid. Lipids used in the formulation are safe, stable and biodegradable in nature. SLNs offer various advantages for topical drug delivery like ability of deposition into skin with the reduced systemic exposure and reduced local side-effects along with providing sustained release of drug. Mometasone furoate (MF) is a topical glucocorticoid having anti-inflammatory, anti-pruritic, anti-hyper proliferative activity. Owing to these properties it is recommended in chronic inflammation and psoriasis. In market, MF cream and lotion (0.1%) are available, which show slight skin irritation, burning and common side-effects due to steroids.Experimental:To overcome the shortcomings of conventional formulations, there is a need to develop a novel formulation that can reduce these side-effects and show maximum desired effects. Thus, SLN of MF can be prepared, which would help in increasing skin deposition as well as provide sustained release. In this study, SLNs were prepared by solvent - injection method.Results:The F8 batch had shown maximum entrapment up to55.59% and sustained drug release for more than 8 h. The skin permeability of SLN loaded gel was found to be 15.21times more than that of marketed cream. SLN loaded gel showed 83.52% of skin deposition which was 2.67 times more than marketed cream and 20 times more than plain drug loaded gel. The scanning electron microscopy and zeta potential study showed formation of good SLN dispersion. The stability study showed successful formation of stable SLNs. Thus, SLNs proved the potential for topical delivery of corticosteroid drug over the conventional formulations.Experimental:To overcome the shortcomings of conventional formulations, there is a need to develop a novel formulation that can reduce these side-effects and show maximum desired effects. Thus, SLN of MF can be prepared, which would help in increasing skin deposition as well as provide sustained release. In this study, SLNs were prepared by solvent - injection method.

Controlled polymorphic transformation of continuously crystallized solid lipid nanoparticles in a microstructured device: A feasibility study

The contribution describes the transfer from a batch to a micro-continuous process for the production of stable solid lipid nanoparticles as drug carrier systems. Solid lipid nanoparticles are commonly prepared batch-wise often resulting in poorly defined product qualities with regard to the polymorphic state of their lipid matrix. In order to obtain solid lipid nanoparticle dispersions that meet the requirements for an acceptable pharmaceutical product, the manufacture of reproducible product qualities preferably containing the stable crystal form of the respective matrix lipid is necessary. These requests are addressed by the continuous preparation process of solid lipid nanoparticles. A four step feasibility study for the standardized evaluation whether or not a colloidal lipid dispersion is suitable for continuous crystallization of the particles resulting in stable crystal forms is presented. The process is based on the continuous crystallization and subsequent thermal treatment of differently stabilized, tripalmitin-based nanoparticle formulations in microstructured devices. The successful production of the stable crystal form by means of a continuous process chain is shown for a dispersion stabilized with a blend of hydrogenated soybean lecithin and sodium glycocholate.

DNA surface coating of calixarene-based nanoparticles: a sequence-dependent binding mechanism

An amphiphilic calix[4]arene derivative bearing four guanidino moieties at the upper rim and four dodecyl chains at the lower rim was shown to form stable solid lipid nanoparticles (SLNs) in water. The study of the interactions of these cationic SLNs with DNA revealed a sequence-dependent groove binding mechanism.

Cation binding resorcinarene bis-crowns: the effect of lower rim alkyl chain length on crystal packing and solid lipid nanoparticles

A group of seven resorcinarene bis-crown ethers (CNBC5) with two polyether bridges at the upper rim and either propyl, butyl, pentyl, heptyl, nonyl, decyl or undecyl groups at the lower rim were synthesized and their binding properties with Cs+ were investigated by NMR titration. The bis-crowns form 1 : 2 complexes with Cs+ with binding constants of log K 4–5. Crystal structures of bis-crowns and their Cs+ and K+ complexes were studied and different packing motifs were found depending on the alkyl chain length. Short ethyl, propyl and butyl alkyl chains gave a layer or pillar packing where the polar and non-polar regions cannot be distinguished, whereas longer pentyl and decyl chains formed bilayers. Amphiphilic properties and self-assembly in water were studied by preparing solid lipid nanoparticles (SLNs) from the bis-crowns. All investigated compounds formed stable SLNs showing amphiphilic character, which in the case of the short chain bis-crowns probably arises from their locked boat conformation separating the polar face of the molecule from the non-polar face.