Disintegration and Dissolution Testing of Green Tea Dietary Supplements: Application and Evaluation of United States Pharmacopeial Standards.

Approved performance quality tests are lacking in the United States Pharmacopeia (USP) for dietary supplements (DSs) containing green tea extracts. We evaluated the applicability of USP <2040 > general chapter protocols for disintegration and dissolution testing of botanicals to GT DSs. Of 28 single-ingredient GT DSs tested in 2 to 4 lots, 9 (32.

Analytical ingredient content and variability of adult multivitamin/mineral products: national estimates for the Dietary Supplement Ingredient Database.

Background: Multivitamin/mineral products (MVMs) are the dietary supplements most commonly used by US adults. During manufacturing, some ingredients are added in amounts exceeding the label claims to compensate for expected losses during the shelf life. Establishing the health benefits and harms of MVMs requires accurate estimates of nutrient intake from MVMs based on measures of actual rather than labeled ingredient amounts.

Interlaboratory Trial for Measurement of Vitamin D and 25-Hydroxyvitamin D [25(OH)D] in Foods and a Dietary Supplement Using Liquid Chromatography-Mass Spectrometry.

Assessment of total vitamin D intake from foods and dietary supplements (DSs) may be incomplete if 25-hydroxyvitamin D [25(OH)D] intake is not included. However, 25(OH)D data for such intake assessments are lacking, no food or DS reference materials (RMs) are available, and comparison of laboratory performance has been needed. The primary goal of this study was to evaluate whether vitamin D3 and 25(OH)D3 concentrations in food and DS materials could be measured with acceptable reproducibility.

Feasibility of including green tea products for an analytically verified dietary supplement database.

The Dietary Supplement Ingredient Database (DSID) is a federally funded, publicly accessible dietary supplement database that currently contains analytically derived information on micronutrients in selected adult and children's multivitamin and mineral (MVM) supplements. Other constituents in dietary supplement products such as botanicals are also of interest and thus are being considered for inclusion in the DSID. Thirty-eight constituents, mainly botanicals were identified and prioritized by a federal interagency committee.

Tuning the self-assembling of pyridinium cationic lipids for efficient gene delivery into neuronal cells.

We are reporting a new set of biocompatible, low-toxicity pyridinium cationic lipids based on a dopamine backbone on which hydrophobic alkyl tails are attached via an ether linkage. Due to their optimized hydrophilic/hydrophobic interface and packing parameter, the new lipids are able to strongly self-assemble either alone or when coformulated with colipids DOPE or cholesterol. The supra-molecular assemblies generated with the novel pyridinium amphiphiles were characterized in bulk and in solution via a combination of techniques including DSC, nanoDSC, SAXS, TOPM, TEM, DLS, zeta potential, and electrophoretic mobility measurements.

Formation of lipid sheaths around nanoparticle-supported lipid bilayers.

High-surface-area nanoparticles often cluster, with unknown effects on their cellular uptake and environmental impact. In the presence of vesicles or cell membranes, lipid adsorption can occur on the nanoparticles, resulting in the formation of supported lipid bilayers (SLBs), which tend to resist cellular uptake. When the amount of lipid available is in excess compared with that required to form a single-SLB, large aggregates of SLBs enclosed by a close-fitting lipid bilayer sheath are shown to form.

Supported lipid bilayer nanosystems: stabilization by undulatory-protrusion forces and destabilization by lipid bridging.

Control of the stabilization/destabilization of supported lipid bilayers (SLBs) on nanoparticles is important for promotion of their organized assembly and for their use as delivery vehicles. At the same time, understanding the mechanism of these processes can yield insight into nanoparticle-cell interactions and nanoparticle toxicity. In this study, the suspension/precipitation process of zwitterionic lipid/SiO(2) nanosystems was analyzed as a function of ionic strength and as a function of the ratio of lipid/SiO(2) surface areas, at pH = 7.

Stabilization of soft lipid colloids: competing effects of nanoparticle decoration and supported lipid bilayer formation.

Stabilization against fusion of zwitterionic lipid small unilamellar vesicles (SUVs) by charged nanoparticles is essential to prevent premature inactivation and cargo unloading. In the present work, we examined the stabilization of DMPC and DPPC SUVs by monolithic silica (SiO(2)) nanoparticle envelopment, for SiO(2) with 4-6, 10-20, 20-30, and 40-50 nm nominal diameter. We found that for these soft colloids stabilization is critically dependent on whether fusion occurs between the charged nanoparticles and neutral SUVs to form supported lipid bilayers (SLBs), or whether the reverse occurs, namely, nanoparticle decoration of the SUVs.

Formation and colloidal stability of DMPC supported lipid bilayers on SiO2 nanobeads.

Supported lipid bilayers (SLBs) of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) were formed on 20-100 nm silica (SiO(2)) nanobeads, and the formation was accompanied by an 8 nm increase in diameter of the SiO(2), consistent with single nanobeads surrounded by a DMPC bilayer. Complete SLBs were formed when the nominal surface areas of the DMPC matched that of the silica, SA(DMPC)/SA(SiO2) = 1, and required increasing ionic strength and time to form on smaller size nanobeads, as shown by a combination of nano-differential scanning calorimetry (nano-DSC), dynamic light scattering (DLS), and zeta potential (zeta) measurements. For 5 nm SiO(2), where the nanoparticle and DMPC dimensions were comparable, DMPC fused and formed SLBs on the nanobeads, but it did not form single bilayers around them.