Asian and Siberian ginseng as a potential modulator of immune function: an in vitro cytokine study using mouse macrophages

BACKGROUND: Ginseng is a widely used herbal product in China, other Asian countries, and in the Unites States. There is a traditional belief that ginseng stimulates immune functions. In this study, the innate effects of Asian and Siberian ginsengs on cytokines and chemokines produced by cultured macrophages were examined. MATERIALS AND METHODS: The effects of Asian and Siberian ginseng on cytokines and chemokines produced by cultured macrophages were examined. Mouse macrophages (J774A.1) were incubated with Asian or Siberian ginseng at varying concentrations (1, 10, 100, and 1000 microg/ml) for 24 h and then harvested for RNA isolation. The expression levels of IL-1beta, IL-12, TNF-alpha, MIP-1 alpha, and MIP-2 mRNA were measured by quantitative PCR. RESULTS: Our data showed that Asian ginseng induced a statistically significant increase in IL-12 expression at both mRNA and protein levels. However, the minor twofold increase is probably biologically insignificant. No significant increase of IL-12 by Siberian ginseng was observed at any dose level studied. No significant change in IL-1beta, IL-15, TNF-alpha, or MIP-1alpha mRNA was observed by either Asian or Siberian ginseng treatment. CONCLUSIONS: Our data showed statistically significant differential regulation of IL-12 by Asian ginseng. Siberian ginseng did not show a statistically significant increase. We conclude that both Asian ginseng and Siberian ginseng cannot significantly stimulate innate macrophage immune functions that influence cellular immune responses. Therefore, contrary to the popular belief, Asian and Siberian ginseng may not stimulate immune function.     

High-dose alpha-tocopherol therapy does not affect HDL subfractions in patients with coronary artery disease on statin therapy

BACKGROUND: Subfractions of HDL, particularly large HDL (HDL2), are inversely correlated with the severity of coronary artery disease (CAD). alpha-Tocopherol (AT) is the main lipid-soluble antioxidant in plasma. Results of a previous small study (n = 44) suggested that either a combination of an antioxidant cocktail [800 IU/day 2R,4'R,8'R-(RRR)-AT plus 1 g vitamin C, 25 mg beta-carotene, and 100 microg selenium] or individual antioxidant vitamins combined with simvastatin-niacin (S-N) therapy attenuated the protective increase in HDL2 seen with S-N alone. Few data are available on the effect of AT therapy alone on HDL subfractions, which we addressed in this study. METHODS: In a prospective placebo-controlled study, we randomized 127 patients with stable CAD to receive high-dose RRR-AT (1200 IU/day for 2 years) or placebo. HDL subfractions (small, medium, and large HDL particles) were analyzed by nuclear magnetic resonance spectroscopy. RESULTS: AT concentrations significantly increased in the AT arm but not with placebo. No differences were noted between AT and placebo groups in concentrations of total cholesterol, triglyceride, LDL-cholesterol, or HDL-cholesterol. AT therapy did not affect total, small, medium, or large HDL particles compared with baseline or placebo. Furthermore, serum apolipoprotein A1 concentrations did not change after 2 years AT therapy as compared with baseline. CONCLUSIONS: High-dose AT therapy administered for a 2-year period does not negatively affect either HDL subfractions or apolipoprotein A1 in patients with CAD on statin therapy. Thus the negative interaction previously proposed between antioxidant cocktail and statin therapy cannot be attributed to AT.     

Analytical performance evaluation of a new turbidimetric immunoassay for valproic acid on the ADVIA 1650 analyzer: effect of gross hemolysis and high bilirubin

Valproic acid is an anticonvulsant that requires careful therapeutic drug monitoring. Valproic acid is also used in psychiatric patients. Bayer Diagnostics (Tarrytown, NY) recently marketed a turbidimetric immunoassay for monitoring valproic acid concentrations in serum or plasma using the ADVIA 1650 analyzer. We evaluated the performance of this new assay by comparing it with a widely used fluorescence polarization immunoassay (FPIA) on the AxSYM analyzer (Abbott Laboratories, Abbott Park, IL). The total coefficient of variation (CV) for the low control of this new assay was 6.8% (mean = 30.7, SD = 2.1 microg/mL, n = 44) while the corresponding CVs for the medium and high controls were 3.3% (mean = 81.0, SD = 2.7 microg/mL, n = 44) and 5.9% (mean = 142.9, SD = 8.4 microg/mL, n = 44), respectively. The assay is linear up to a serum valproic acid concentration of 170 microg/mL, and the detection limit is 4.4 microg/mL. We observed an excellent correlation between the FPIA of valproic acid and the turbidimetric assay using specimens from 52 different patients who were receiving valproic acid. Using the valproic acid concentrations obtained by the FPIA as the x-axis, and the corresponding valproic acid concentrations obtained by the turbidimetric assay as the y-axis, we developed the following regression equation: y = 1.03 x+1.55 (r = 0.98). With this new assay, high concentrations of bilirubin (unconjugated 30 mg/dL and conjugated 30 mg/dL) and gross hemolysis (4+, hemoglobin: 1,500 mg/dL) have no effect on measurements of valproic acid concentration. We conclude that the new turbidimetric assay for valproic acid can be used for routine therapeutic drug monitoring of valproic acid in clinical laboratories.     

A Temporal Study on the Effects of TiO<Subscript>2</Subscript> Nanoparticles in a Fresh Water Microcosm

This study assesses the temporal changes in the physico-chemical behaviour of titanium dioxide nanoparticles (anatase and rutile phase) for a period of 120 h at environmentally relevant concentration of 1,000 µg/L, and the consequent impact on the microalgae population in a fresh water microcosm. The mean hydrodynamic size analysis in the medium revealed the differences in the aggregation behaviour of the two crystalline types of particles within first 12 h exposure before they had reached the micron size range. While the short term exposure (120 h) showed an immediate effect on the resident microalgae in the microcosm with respect to control, there were no significant differences in ecotoxicity effects of rutile and anatase phases of titania. The long term (90 days) exposure demonstrated a gradual recovery of the resident algal population. Summarizing the observations, the nanosized particles at low concentration may not retain the toxic potential for longer exposure time in a microcosm presumably owing to the complexity prevalent in the natural systems.     

Clinical utility of free drug monitoring.

Most drugs are bound to serum proteins to a various degree. Only unbound or free drug is pharmacologically active. Usually total drug is measured for therapeutic monitoring because there is equilibrium between bound and free drugs, and concentration of free drug can be predicted from total drug concentration. However, under certain conditions this equilibrium is disturbed and the measured free drug concentration can be significantly higher than expected from total drug concentrations, especially for strongly protein-bound drugs. In such case a patient may experience drug toxicity even if the total drug concentration is within the therapeutic range. Conditions like uremia, liver disease and hypoalbuminemia can lead to significant increases in free drug concentration. Therefore, monitoring free phenytoin and free valproic acid is recommended in these patients. Drug-drug interactions can also lead to a disproportionate increase in free drug concentration. One strongly protein-bound drug can significantly displace another strongly protein-bound drug if both drugs share the same binding site. Several over-the-counter pain medications such as salicylate, naproxen, and ibuprofen can cause significant displacement of both phenytoin and valproic acid from albumin binding site. Interestingly, such interactions are absent in uremic patients. Elderly patients may have increased free phenytoin or valproic acid due to hypoalbuminemia. Elevated free phenytoin concentrations have also been reported in patients with AIDS. Although digoxin is 25% bound to protein, monitoring free digoxin is useful in patients with elevated endogenous digoxin-like immunoreactive substances or in patients overdosed with digoxin and being treated with digibind. Monitoring free digoxin can also eliminate interference of Chinese medicines Chan Su and Danshen in serum digoxin measurement by certain immunoassays. However, free drug monitoring is not a routine procedure in clinical laboratories due to technical difficulties and lack of established reference ranges for free drugs.     

Summary Workshop Report: Facilitating Oral Product Development and Reducing Regulatory Burden Through Novel Approaches to Assess Bioavailability/Bioequivalence

This summary workshop report highlights presentations and over-arching themes from an October 2011 workshop. Discussions focused on best practices in the application of biopharmaceutics in oral drug product development and evolving bioequivalence approaches. Best practices leverage biopharmaceutic data and other drug, formulation, and patient/disease data to identify drug development challenges in yielding a successfully performing product. Quality by design and product developability paradigms were discussed. Development tools include early development strategies to identify critical absorption factors and oral absorption modeling. An ongoing theme was the desire to comprehensively and systematically assess risk of product failure via the quality target product profile and root cause and risk analysis. However, a parallel need is reduced timelines and fewer resources. Several presentations discussed applying Biopharmaceutics Classification System (BCS) and in vitro-in vivo correlations in development and in post-development and discussed both resource savings and best scientific practices. The workshop also focused on evolving bioequivalence approaches, with emphasis on highly variable products (HVDP), as well as specialized modified-release products. In USA, two bioequivalence approaches for HVDP are the reference-scaled average bioequivalence approach and the two-stage group-sequential design. An adaptive sequential design approach is also acceptable in Canada. In European Union, two approaches for HVDP are a two-stage design and an approach to widen C (max) acceptance limits. For some specialized modified-release products, FDA now requests partial area under the curve. Rationale and limitations of such metrics were discussed (e.g., zolpidem and methylphenidate). A common theme was the benefit of the scientific and regulatory community developing, validating, and harmonizing newer bioequivalence methodologies (e.g., BCS-based waivers and HVDP trial designs).     

Challenges and Opportunities in Achieving Bioequivalence for Fixed-Dose Combination Products

Fixed-dose combination (FDC) products are becoming a popular treatment option because of increased patient compliance and convenience, improved clinical effectiveness, and reduced cost to the patient, among several other reasons. A commonly applied approach for approval of a FDC product is demonstrating bioequivalence between the FDC and co-administration of individual mono-products, provided that there is adequate safety and efficacy data for co-administration of the individual agents. However, achieving bioequivalence between the FDC and individual mono-products can be very challenging, and sometimes not possible since combining multiple active ingredients, especially insoluble molecules, in a single drug product could complicate its biopharmaceutical and pharmacokinetic behavior. In this review, some of the major challenges often encountered while assessing bioequivalence during FDC development will be presented along with discussion of future opportunities to facilitate FDC development and approval.     

Bacterial tolerance to silver nanoparticles (SNPs): aeromonas punctata isolated from sewage environment

Use of silver nanoparticles (SNPs) is increasing in a large number of consumer products. Thus, the possible build-up of the nanoparticles in the environment is becoming a major concern. Aeromonas punctata isolated from sewage showed tolerance to 200 μg/ml SNPs. The growth kinetics data for A. punctata treated with nanoparticles were similar to those in the absence of nanoparticles. There was a reduction in the amount of exopolysaccharides (EPS) in bacterial culture supernatant after nanoparticle-supernatant interaction. EPS capping of the nanoparticles was confirmed by UV-visible, XRD and comparative FTIR analysis. The EPS-capped SNPs showed less toxicity to Escherichia coli, Staphylococcus aureus and Micrococcus luteus compared to the uncapped ones. The study suggests capping of nanoparticles by bacterially produced EPS as a probable physiological defense mechanism.