Structure Of Solid Lipid Nanoparticles Research Articles

Preparation of Thymol Nanoliposome and Solid Lipid Nanoparticle and Evaluation of their Inhibitory Effects on Leishmania Major Promastigotes

Introduction: Thymol has an antiprotozoal effect. Nanoparticulate systems are useful carriers for both small and large drug molecules, which can protect them from some chemical and biological damages as well as target drug delivery to specific organs or receptors. In this work, the nano-liposomal system and solid lipid nanoparticles loaded by thymol were prepared and the effectiveness of them were evaluated on Leishmania major promastigotes.
 Methods: Several formulations of nano-liposomes and solid lipid nanoparticles were prepared, and the amount of thymol loading, in-vitro release profile, particle size, and zeta potential were evaluated. Finally, the best formulations were serially diluted and incubated for 24, 48, and 72 hours on Leishmania major promastigotes, which cultured on Novy–MacNeal–Nicolle medium, and the results were analyzed.
 Results: The highest loading of thymol in nano-liposomes (92%) was seen in the formulations made with phosphatidylcholine (Called L3), and among the solid lipid nanoparticles, the formulation prepared with glycerol monostearate (S1) had the most entrapment efficiency of thymol (87%). These formulations were selected to evaluate the release rate of thymol. The results showed that S1 has a slower release rate than L3; this may be due to the presence of Glycerol monostearate in solid lipid nanoparticles structure. The best formulations, L3 and S1, were chosen for anti-Leishmaniosis assessment; which showed that all three forms of free thymol, nanoliposomes, and solid lipid nanoparticles inhibited Leishmania major. The half maximal inhibitory concentration (IC50) of free thymol, nanoliposome, and solid lipid nanoparticles for a 24-hour incubation are 7.8, 62.5, and 125, respectively, which decrease to 7.8, 7.8, and 15.6 for 48 hours and 7.8, 0.49, and 0 for 72 hours of incubation.
 Conclusion: Thymol has a significant effect on the inhibition of Leishmania major promastigotes and usage of thymol in the form of liposomes or solid lipid nanoparticles can sustain the drug release and have a lower IC50 during the longer incubation time.

In vitro release behavior of SLN, NLC, and NE: An explanation based on the particle structure and carried molecule location

Studying the in vitro release behavior of active pharmaceutical ingredients incorporated into colloidal lipid systems is paramount in predicting their in vivo performance. As a contribution in this regard, this paper reports the relationship between the in vitro release behavior and the structure of solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC), and nanoemulsions (NE) containing methyl and propylparaben. These colloidal systems are prepared from binary mixtures of trimyristin (MMM) and medium-chain triglycerides (MCT), stabilized with poloxamer 188, using the emulsification-diffusion technique. The structure of the colloidal lipid systems is investigated by differential scanning calorimetry, X-ray diffraction, and Raman spectroscopy. The release behavior depends on the type of nanoparticle dispersion, the physical state of the lipid matrix, the location of the paraben molecule into the particle, and the distribution coefficient and solubility of parabens in the matrix components. Binary mixtures of MMM and MCT lead to the formation of biphasic structures wherein a separated liquid phase of MCT + MMM could locate on the surface of the β-trimyristin crystals. The parabens molecules could be in an amorphous or solubilized state in the interface between the β-trimyristin crystals and the stabilizing agent layer or dissolved in the MCT + MMM liquid phase.

Incorporation of ion exchange functionalized-montmorillonite into solid lipid nanoparticles with low irritation enhances drug bioavailability for glaucoma treatment

Montmorillonite-loaded solid lipid nanoparticles with good biocompatibility, using Betaxolol hydrochloride as model drug, were prepared by the melt-emulsion sonication and low temperature-solidification methods and drug bioavailability was significantly improved in this paper for the first time to application to the eye. The appropriate physical characteristics were showed, such as the mean particle size, Zeta potential, osmotic pressure, pH values, entrapping efficiency (EE%) and drug content (DC%), all showed well suited for possible ocular application. In vitro release experiment indicated that this novel system could continuously release 57.83% drugs within 12 h owing to the dual drug controlled-release effect that was achieved by ion-exchange feature of montmorillonite and structure of solid lipid nanoparticles. Low irritability and good compatibility of nanoparticles were proved by both CAM-TBS test and cytotoxicity experiment. We first discovered from the results of Rose Bengal experiment that the hydrophilicity of the drug-loaded nanoparticles surface was increased during the loading and releasing of the hydrophilic drug, which could contribute to prolong the ocular surface retention time of drug in the biological interface membrane of tear-film/cornea. The results of in vivo pharmacokinetic and pharmacodynamics studies further confirmed that increased hydrophilicity of nanoparticles surface help to improve the bioavailability of the drug and reduce intraocular pressure during administration. The results suggested this novel drug delivery system could be potentially used as an in situ drug controlled-release system for ophthalmic delivery to enhance the bioavailability and efficacy.

Morphology and Structure of Solid Lipid Nanoparticles Loaded with High Concentrations of β-Carotene.

Solid lipid nanoparticles (SLNs) containing up to 37.5 wt % all-trans β-carotene in the lipid phase are potential water-dispersible food colorants. SLNs have been made by hot-melt high-pressure homogenization with fully hydrogenated sunflower oil and with polysorbate 80 and sunflower lecithin as stabilizers. Atomic force microscopy revealed the SLNs had thin platelet structures most likely derived from the triglyceride crystal β-form, as detected by X-ray diffraction. No indications of crystalline β-carotene were detected. High-performance liquid chromatography analysis showed the extensive isomerization of β-carotene into more than 10 cis isomers, suggesting that it is present as an amorphous mixture. The high β-carotene loadings did not affect the triglyceride crystal structure and the morphology of the SLNs. It is suggested the SLNs consist of a platelet core of crystalline triglyceride surrounded by an amorphous β-carotene-containing layer. The layered structure is suggested to affect the coloring power of the SLNs at β-carotene loadings above 15 wt % of the lipid phase.

Assessing the performance of copaiba oil and allantoin nanoparticles on multidrug-resistant Candida parapsilosis

This study investigated the chemical and morphological structure of solid lipid nanoparticles made from copaiba oil. Moreover, the influence of allantoin in the formulations was investigated, as was the mechanism of action of the nanoparticles against multidrug-resistant Candida parapsilosis. Formulations were prepared via high-pressure homogenisation. Photon correlation spectroscopy and laser diffraction showed nanoparticles with diameters below 150 nm, narrow size distribution and negative zeta potential values. The nanoparticles' antifungal activity was assessed using a sorbitol protection assay. The ergosterol content and the influence of sorbitol on the minimum inhibitory concentrations were determined. The nanoparticles displayed nonspecific action on fungal cells. The antifungal effect is related to a complex synergism of natural substances with deeper action on cell replication. Thermogravimetric analysis showed that the individual behaviour of each component was modified in the formulation. Transmission electron microscopy showed differences in morphology caused by the presence of allantoin. The smaller particles can penetrate deeply into fungal cells. These findings indicated that even without antifungal effects when used in isolation, the incorporation of allantoin modified the size distribution, zeta potential and morphological structure of copaiba oil nanoparticles, resulting in particles with greater antifungal effects against multidrug-resistant yeasts.

Structure of solid lipid nanoparticles produced by a microwave-assisted microemulsion technique

The current study investigates the structure of solid lipid nanoparticles, prepared using a recently reported microwave-assisted microemulsion technique, by multi-angle static and dynamic light scattering and small angle X-ray scattering techniques.

Investigations on the structure of solid lipid nanoparticles (SLN) and oil-loaded solid lipid nanoparticles by photon correlation spectroscopy, field-flow fractionation and transmission electron microscopy

Recently, colloidal dispersions made from mixtures of solid and liquid lipids were described to combine controlled release characteristics with higher drug loading capacities than solid lipid nanoparticles (SLN). It has been proposed that these nanostructured lipid carriers (NLC) are composed of oily droplets which solubilize the drug and which are embedded in a solid lipid matrix. The structures of SLN and NLC based on glyceryl behenate and medium chain triglycerides were characterized by photon correlation spectroscopy (PCS) and laser diffraction (LD), field-flow fractionation (FFF) with multi-angle light scattering detection (MALS), and cryo transmission electron microscopy (cryo TEM). PCS indicates that SLN and NLC differ from a nanoemulsion with respect to Brownian motion due to asymmetric particle shapes. Non-spherical particles, in case of SLN and NLC, lead to higher polydispersity indices compared to the nanoemulsion. In FFF, the nanodroplets elute much earlier than SLN- and NLC-platelets although their PCS and LD data show similar particle sizes. In TEM platelet (for SLN), oil loaded platelet (“nanospoons”; for NLC) and droplet (for nanoemulsion) structures were observed. In contrast to literature reports, the investigated SLN appear as thin platelets. NLC are found to be lipid platelets with oil spots sticking on the surface. Very short diffusion pathways in platelets, increased water-lipid interfaces and low drug incorporation in crystalline lipids are the drawback of SLN and NLC compared to conventional nanoemulsions.