Long-term stability of quercetin nanocrystals prepared by different methods.

Objectives: This study aimed to examine the long-term physical stability of quercetin nanocrystals produced by three methods.

Methods: Quercetin nanocrystals were prepared by high pressure homogenization, bead milling and cavi-precipitation. The nanocrystals produced by these methods were compared for particle size, saturation solubility and dissolution of the drug particles, and were subjected to stability testing.

Lutein nanocrystals as antioxidant formulation for oral and dermal delivery.

Lutein is a well known antioxidant and anti-free radical used in cosmetic, nutraceutical industry with potential application in pharmaceutics as supportive antioxidant in treatments. As lipophilic molecule it is poorly soluble in water and has a low bioavailability. Lutein nanosuspension was prepared to enhance dissolution velocity, saturation solubility (C(s)), which are major factors determining oral bioavailability and penetration into the skin.

Lipid nanocarriers for dermal delivery of lutein: preparation, characterization, stability and performance.

Topical application of lutein as an innovative antioxidant, anti-stress and blue light filter, which is able to protect skin from photo damage, has got a special cosmetic and pharmaceutical interest in the last decade. Lutein is poorly soluble, and was therefore incorporated into nanocarriers for dermal delivery: solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC) and a nanoemulsion (NE). Nanocarriers were produced by high pressure homogenization.

State of the art of nanocrystals--special features, production, nanotoxicology aspects and intracellular delivery.

Drug nanocrystals are the latest, broadly introduced nanoparticulate carrier to the pharmaceutical market from the year 2000 onwards. The special features of nanocrystals for the delivery of poorly soluble drugs are briefly reviewed (saturation solubility, dissolution velocity, adhesiveness). The industrially relevant bottom up (precipitation) and top down production technologies (pearl milling, high pressure homogenization, combination technologies) are presented.

A novel approach based on lipid nanoparticles (SLN) for topical delivery of alpha-lipoic acid.

This study describes the development, preparation and characterization of solid lipid nanoparticles (SLN) containing the novel anti-ageing substance alpha-lipoic acid. Lipoic acid is chemically labile, i.e.

Rheology of nanostructured lipid carriers (NLC) suspended in a viscoelastic medium.

Colloidal lipid nanoparticle dispersions have been characterized by rheological measurements using two different nanostructured lipid carrier (NLC)-based formulations intended for cosmetic application of substances like sunflower oil and alpha-tocopherol. This study has shown that rheological and viscoelastic properties of aqueous NLC dispersions are quantitatively very different depending on the composition of the oil phase and the temperature of storage despite similar or even identical particle size. NLC were loaded with 30% active ingredient relative to the particle mass.

Production of solid lipid nanoparticles (SLN): scaling up feasibilities.

Solid lipid nanoparticles (SLN/Lipopearls) are widely discussed as a new colloidal drug carrier system. In contrast to polymeric systems, such as Polylactic copolyol microcapsules, these systems show with a good biocompatibility, if applied parenterally. The solid lipid matrices can be comprised of fats or waxes, and allow protection of incorporated active ingredients against chemical and physical degradation.

Medium scale production of solid lipid nanoparticles (SLN) by high pressure homogenization.

Solid lipid nanoparticles (SLN) were produced by high pressure homogenization using piston-gap homogenizers. Batch sizes varied between 40 ml and 50 l. Because of the different batch sizes, different homogenizer types were used, but the same functional principles were maintained, and the change from 40 ml to 50 l was not critical.

Encapsulation of retinoids in solid lipid nanoparticles (SLN).

SLN have been suggested for a broad range of applications, such as intravenous injection, peroral, or dermal administration. The incorporation of the drug in the core of the SLN has to be ensured for these applications, but the inclusion of drugs in SLN is poorly understood. This study is a contribution to further describe the inclusion properties of colloidal lipids and to propose incorporation mechanisms.

Scaling up feasibility of the production of solid lipid nanoparticles (SLN).

Solid lipid nanoparticles (SLN/Lipopearls) are widely discussed as colloidal drug carrier system. In contrast to polymeric systems, such as polylactic copolyol capsules, these systems show up with a good biocompatibility, if applied parenterally. The solid lipid matrices can be comprised of fats or waxes and allow protection of incorporated active ingredients against chemical and physical degradation.

Solid lipid nanoparticles (SLN) based on binary mixtures of liquid and solid lipids: a (1)H-NMR study.

SLN with improved payloads and enhanced storage stability were investigated. Based on the experiences with solid lipid nanoparticles, a new type of solid lipid nanoparticle has been developed by incorporating triglyceride containing oils in the solid shell of the particle. The structure and mixing behaviour of these particles was characterised by DSC and (1)H-NMR.

Solid lipid nanoparticles (SLN) for controlled drug delivery - a review of the state of the art.

Solid lipid nanoparticles (SLN) introduced in 1991 represent an alternative carrier system to traditional colloidal carriers, such as emulsions, liposomes and polymeric micro- and nanoparticles. SLN combine advantages of the traditional systems but avoid some of their major disadvantages. This paper reviews the present state of the art regarding production techniques for SLN, drug incorporation, loading capacity and drug release, especially focusing on drug release mechanisms.

Characterisation of a novel solid lipid nanoparticle carrier system based on binary mixtures of liquid and solid lipids.

A drug carrier of colloidal lipid particles with improved payloads and enhanced storage stability was investigated. Based on the experiences with hard fats nanoparticles, a new type of solid lipid nanoparticles (SLN) has been developed by incorporating triglyceride containing oils in the solid core of said particle. The structure and mixing behaviour of these particles were characterised and practical implications on controlled release properties tested.

Vitamin A loaded solid lipid nanoparticles for topical use: occlusive properties and drug targeting to the upper skin.

To evaluate the potential use of solid lipid nanoparticles (SLN) in dermatology and cosmetics, glyceryl behenate SLN loaded with vitamin A (retinol and retinyl palmitate) and incorporated in a hydrogel and o/w-cream were tested with respect to their influence on drug penetration into porcine skin. Conventional formulations served for comparison. Excised full thickness skin was mounted in Franz diffusion cells and the formulations were applied for 6 and 24 h, respectively.

Vitamin A-loaded solid lipid nanoparticles for topical use: drug release properties.

Burst release as well as sustained release has been reported for SLN suspensions. For dermal application, both features are of interest. Burst release can be useful to improve the penetration of a drug.

Comparison of wax and glyceride solid lipid nanoparticles (SLN).

The present study compares solid lipid nanoparticles (SLN) formulated with either wax or glyceride bulk material. While most published data deal with glyceride SLN, little knowledge is reported on wax carriers. The two types were compared with respect to drug encapsulation efficacy, particle size distribution after production and storage, and crystal packing.

Solid lipid nanoparticles (SLN/Lipopearls)--a pharmaceutical and cosmetic carrier for the application of vitamin E in dermal products.

Solid lipid nanoparticles (SLN, Lipopearls) are nanoparticles made from solid lipids by high pressure homogenization. Incorporation of chemically labile active ingredients into the solid lipid matrix protects against chemical degradation, which is shown for vitamin E. The SLN are physically stable in aqueous dispersions and also after incorporation into a dermal cream as proven by photon correlation spectroscopy and differential scanning calorimetry.

Coenzyme Q10, a cutaneous antioxidant and energizer.

The processes of aging and photoaging are associated with an increase in cellular oxidation. This may be in part due to a decline in the levels of the endogenous cellular antioxidant coenzyme Q10 (ubiquinone, CoQ10). Therefore, we have investigated whether topical application of CoQ10 has the beneficial effect of preventing photoaging.

Mitogenic activity of high molecular polysaccharide fractions isolated from the cuppressaceae Thuja occidentalis L. enhanced cytokine-production by thyapolysaccharide, g-fraction (TPSg).

Thuja polysaccharide g fraction (TPSg) was shown to be an inducer of the CD4+ fraction of the human peripheral blood T-cell subset (1,2). Furthermore, it could be demonstrated that TPSg is a potent inhibitor of the expression of HIV-1-specific antigens and of the HIV-1-specific reverse transcriptase (3). This report deals with the cytokine pattern induced by TPSg in human peripheral blood lymphocyte (PBL) and purified monocyte/macrophage cultures.

Mitogenic activity of high molecular polysaccharide fractions isolated from the Cupressaceae Thuja occidentale L. I. Macrophage-dependent induction of CD-4-positive T-helper (Th+) lymphocytes.

The arborvitae or Thuja occidentale L., one of the Cupressaceae, has rarely been investigated until now. Several authors have demonstrated that allopathic extracts of this plant could be used as strong antiviral agents directed against plant and animal viruses.