Showing papers on "Solid lipid nanoparticle published in 2007"

Importance of solid lipid nanoparticles (SLN) in various administration routes and future perspectives.

Abstract: Solid lipid nanoparticles (SLN) have been reported to be an alternative system to emulsions, liposomes, microparticles and their polymeric counterparts for various application routes since the early 1990s due to their advantages Various research groups have also increasingly focused on improving their stability in body fluids after administration by coating of particles with hydrophilic molecules such as poly(ethylene)glycol (PEG) derivatives Altering surface characteristics by coating SLN with hydrophilic molecules improves plasma stability and biodistribution, and subsequent bioavailability of drugs entrapped Their storage stability is also increased This paper basicly reviews types of SLN, principles of drug loading and models of drug incorporation The influence of PEG coating on particle size and surface characteristics is discussed followed by alteration in pharmacokinetics and bioavailability of drugs in order to target the site of action via SLN The future direction of research and clinical implications of SLN is also considered

Lipid-based colloidal carriers for peptide and protein delivery – liposomes versus lipid nanoparticles

Abstract: This paper highlights the importance of lipid-based colloidal carriers and their pharmaceutical implications in the delivery of peptides and proteins for oral and parenteral administration. There are several examples of biomacromolecules used nowadays in the therapeutics, which are promising candidates to be delivered by means of liposomes and lipid nanoparticles, such as solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC). Several production procedures can be applied to achieve a high association efficiency between the bioactives and the carrier, depending on the physicochemical properties of both, as well as on the production procedure applied. Generally, this can lead to improved bioavailability, or in case of oral administration a more consistent temporal profile of absorption from the gastrointestinal tract. Advantages and drawbacks of such colloidal carriers are also pointed out. This article describes strategies used for formulation of peptides and proteins, methods used for assessment of association efficiency and practical considerations regarding the toxicological concerns.

Oral insulin delivery by means of solid lipid nanoparticles.

Abstract: The aim of this work was to produce and characterize cetyl palmitate-based solid lipid nanoparticles (SLN) containing insulin, and to evaluate the potential of these colloidal carriers for oral administration. SLN were prepared by a modified solvent emulsification-evaporation method based on a w/o/w double emulsion. The particle size, zeta potential and association efficiency of unloaded and insulin-loaded SLN were determined and were found to be around 350 nm, negatively charged and the insulin association efficiency was over 43%. After oral administration of insulin-loaded SLN to diabetic rats, a considerable hypoglycemic effect was observed during 24 hours. These results demonstrated that SLN promote the oral absorption of insulin.

Investigations of the effect of the lipid matrix on drug entrapment, in vitro release, and physical stability of olanzapine-loaded solid lipid nanoparticles.

Abstract: The purpose of this research was to study the effect of the lipid matrix on the entrapment of olanzapine (OL). OL-loaded solid lipid nanoparticles (SLNs) were prepared using lipids like glyceryl monostearate (GMS), Precirol ATO 5 (PRE), glyceryl tristearate (GTS), and Witepsol E85 (WE 85)—and poloxamer 407 and hydrogenated soya phosphatidylcholine as stabilizers—using a hot melt emulsification high-pressure homogenization technique, and then characterized by particle size analysis, zeta potential, differential scanning calorimetry (DSC), and powder X-ray diffraction (pXRD). Homogenization at 10 000 psi for 3 cycles resulted in the formation of SLNs with a mean particle size of ∼190 nm for the 4 lipids investigated. The highest partition coefficient for OL between the melted lipid and pH 7.4 phosphate buffer (pH 7.4 PB) was obtained with GTS. The entrapment efficiency was in the following order: GTS SLNs>PRE SLNs>WE 85 SLNs>GMS SLNs. DSC and pXRD showed that much of the incorporated fraction of OL existed in the amorphous state after incorporation into SLNs. A sharp increase in the flocculation of the SLN dispersions was observed upon addition of 0.6 M aqueous sodium sulfate solution. Nanoparticle surface hydrophobicity was in the following order: GTS SLNs>PRE SLNs>WE 85 SLNs>GMS SLNs. A significant increase in size and zeta potential was observed for GTS SLN and WE 85 SLN dispersions stored at 40°C. Release of OL from the SLNs was sustained up to 48 hours in pH 7.4 PB and obeyed Higuchi’s release kinetics.

Preparation, characterization, and in vitro and in vivo evaluation of lovastatin solid lipid nanoparticles.

Abstract: The purpose of this research was to study whether the bioavailability of lovastatin could be improved by administering lovastatin solid lipid nanoparticles (SLN) duodenally to rats. Lovastatin SLN were developed using triglycerides by hot homogenization followed by ultrasonication. Particle size and zeta potential were measured by photon correlation spectroscopy. The solid state of the drug in the SLN and lipid modification were characterized. Bioavailability studies were conducted in male Wistar rats after intraduodenal administration of lovastatin suspension and SLN. Stable lovastatin SLN having a mean size range of 60 to 119 nm and a zeta potential range of −16 to −21 mV were developed. More than 99% of the lovastatin was entrapped in the SLN. Lovastatin was dispersed in an amorphous state, and triglycerides were in {ieE162-1} form in the SLN. In vitro stability studies showed the slow release and stability of lovastatin SLN. The relative bioavailabilities of lovastatin and lovastatin hydroxy acid of SLN were increased by ∼173% and 324%, respectively, compared with the reference lovastatin suspension.

Cyproterone Acetate Loading to Lipid Nanoparticles for Topical Acne Treatment: Particle Characterisation and Skin Uptake

Abstract: Topical cyproterone acetate (CPA) treatment of skin diseases should reduce side effects currently excluding the use in males and demanding contraceptive measures in females. To improve skin penetration of the poorly absorbed drug, we intended to identify the active moiety and to load it to particulate carrier systems. CPA metabolism in human fibroblasts, keratinocytes and a sebocyte cell line as well as androgen receptor affinity of native CPA and the hydrolysis product cyproterone were determined. CPA 0.05% loaded solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC), a nanoemulsion and micropheres were characterized for drug-particle interaction and CPA absorption using human skin ex-vivo. Native CPA proved to be the active agent. Application of CPA attached to SLN increased skin penetration at least four-fold over the uptake from cream and nanoemulsion. Incorporation into the lipid matrix of NLC and microspheres resulted in a 2–3-fold increase in CPA absorption. Drug amounts within the dermis were low with all preparations. No difference was seen in the penetration into intact and stripped skin. With particulate systems topical CPA treatment may be an additional therapeutic option for acne and other diseases of the pilosebaceous unit.

Solid Lipid Nanoparticles for Targeted Brain Drug Delivery

Abstract: The present review discusses the potential use of solid lipid nanoparticles for brain drug targeting purposes. The state of the art on surfactant-coated poly(alkylcyanoacrylate) nanoparticles specifically designed for brain targeting is given by emphasizing the transfer of this technology to solid lipid matrices. The available literature on solid lipid nanoparticles and related carriers for brain drug targeting is revised as well. The potential advantages of the use of solid lipid nanoparticles over polymeric nanoparticles are accounted on the bases of a lower cytotoxicity, higher drug loading capacity, and best production scalability. Solid lipid nanoparticles physicochemical characteristics are also particularly regarded in order to address the critical issues related to the development of suitable brain targeting formulations. A critical consideration on the potential application of such technology as related to the current status of brain drug development is also given.

Nanostructured lipid carriers as novel carrier for sunscreen formulations

Abstract: Incorporation of sunscreens into lipid carriers with an increased sun protection factor (SPF) has not yet been fully accomplished. In the present paper, the effectiveness of a sunscreen mixture, incorporated into the novel topical delivery systems, i.e. solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC), used as ultraviolet (UV) protector enhancers with a distinctly higher loading capacity has been developed and evaluated. SLN and NLC were produced by hot high pressure homogenization technique in lab scale production. Size distribution and storage stability of formulations were investigated by laser diffractometry and photon correlation spectroscopy. Nanoparticles were characterized by their melting and recrystallization behaviour recorded by differential scanning calorimetry. Lipid nanoparticles produced with a solid matrix (SLN and NLC) were established as a UV protection system. The loading capacities for molecular sunscreens reported before now were in the range of 10-15%. It was possible to load NLC with up to 70% with molecular sunscreen, which is appropriate to obtain high SPFs with this novel UV protection system. The developed formulations provide a beneficial alternative to conventional sunscreen formulations. The UV protective efficacy of the lipid particles varied with the nature of lipid and UV wavelength.

Preparation and characterization of solid lipid nanoparticles containing silibinin.

Abstract: The study describes the development of stealth solid lipid nanoparticles (SLNs) as colloidal carriers for silibinin, a drug with very low solubility. Stealth SLNs were constituted mainly of bioacceptable and biodegradable lipids, such as stearic acid and surfactant Brij 78 (polyoxyethylene 20 stearyl ether) and can incorporate amounts of silibinin up to 7.55%. Stealth-loaded SLNs were in the nanometer size range. Thermal analysis (differential scanning calorimetry) showed that silibinin was dispersed in the stealth SLNs at an amorphous state. Release of silibinin from stealth SLNs was very slow. Stealth SLNs were stable without precipitation of silibinin on storage conditions and can be proposed for their parenteral administration.

Effect of solid lipid nanoparticles formulation compositions on their size, zeta potential and potential for in vitro pHIS-HIV-hugag transfection.

Abstract: Purpose This work was conducted to determine model equations describing the effect of solid lipid nanoparticles (SLN) formulation compositions on their size and zeta potential using the face-centered central composite design and to determine the effect of SLN formulation compositions on the potential for in vitro pHIS-HIV-hugag transfection.