Safety, Tolerability, Pharmacokinetics, and Food Effects on TAC-302 in Healthy Participants: Randomized, Double-Blind, Placebo-Controlled, Single-Dose and Multiple-Dose Studies

TAC-302 stimulates neurite outgrowth activity and is expected to restore urinary function in patients with lower urinary tract dysfunction. We conducted 2 phase 1, randomized, placebo-controlled studies to confirm the safety and pharmacokinetics (PK) of TAC-302 in healthy adult Japanese male volunteers. In the first-in-human single-dose study (n = 60), TAC-302 was administered at doses from 100 to 1200 mg after an overnight fast. The effects of a meal on the PK of TAC-302 400 mg were also examined. A multiple-dose study (n = 36) evaluated the effects of meal fat content on the PK of single doses of TAC-302 (100, 200, or 400 mg) and multiple doses of TAC-302 administered for 5 days (100, 200, and 400 mg twice daily). TAC-302 showed linear PK up to doses of 1200 mg in the fasting state, and across the dose range of 100-400 mg in the fed state. No accumulation of TAC-302 was observed. Food, particularly with high fat content, increased TAC-302 plasma concentrations. No differences were observed in the adverse event incidence between the TAC-302 and placebo groups in either study. TAC-302 showed a wide safety margin.

Blood-brain barrier permeability study of ginger constituents

Ginger, the rhizome of Zingiber officinale Roscoe is of great importance in the traditional medicine for the treatment of various diseases. More than 400 constituents have been reported in the plant, the most important ones being the gingerol and shogaol derivatives. Positive effects of ginger extracts and isolated [6]-gingerol have been proved in animal models of anxiety, Alzheimer's disease, Parkinson's disease and epilepsy. Taken in consideration these promising positive effects of ginger and its constituents in the central nervous system, the isolation of gingerol and shogaol derivatives ([6]-gingerol (1), [8]-gingerol (2), [10]-gingerol (3), [6]-shogaol (4), [10]-shogaol (5), 1-dehydro-[6]-gingerdione (6), 1-dehydro-[10]-gingerdione (7)) and investigation of their transcellular passive diffusion across the blood-brain barrier (BBB) were carried out. For this purpose, a Parallel Artificial Membrane Permeability Assay for the Blood-Brain Barrier (PAMPA-BBB) was chosen that had previously been validated for natural compounds. Based on our results, [6]-gingerol, [8]-gingerol and [6]-shogaol were found to be able to penetrate the BBB via passive diffusion, suggesting them to contribute to the positive effects of ginger extracts in the central nervous system.

Pharmacokinetics and Tissue Distribution of Gingerols and Shogaols from Ginger (Zingiber officinale Rosc.) in Rats by UPLC⁻Q-Exactive⁻HRMS

Gingerols and shogaols are recognized as active ingredients in ginger and exhibit diverse pharmacological activities. The preclinical pharmacokinetics and tissue distribution investigations of gingerols and shogaols in rats remain less explored, especially for the simultaneous analysis of multi-components. In this study, a rapid, sensitive, selective, and reliable method using an Ultra-Performance Liquid Chromatography Q-Exactive High-Resolution Mass Spectrometer (UPLC-Q-Exactive⁻HRMS) was established and validated for simultaneous determination of eight compounds, including 6-gingerol, 6-shogaol, 8-gingerol, 8-shogaol, 10-gingerol, 10-shogaol, Zingerone, and 6-isodehydrogingenone in plasma and tissues of rats. The analytes were separated on a Syncronis C18 column (100 × 2.1 mm, 1.7 µm) using a gradient elution of acetonitrile and 0.1% formic acid in water at a flow rate of 0.25 mL/min at 30 °C. The method was linear for each ingredient over the investigated range with all correlation coefficients greater than 0.9910. The lowest Lower Limit of quantitation (LLOQ) was 1.0 ng/mL. The intra- and inter-day precisions (Relative Standard Deviation, RSD%) were less than 12.2% and the accuracy (relative error, RE%) ranged from -8.7% to 8.7%. Extraction recovery was 91.4⁻107.4% and the matrix effect was 86.3⁻113.4%. The validated method was successfully applied to investigate the pharmacokinetics and tissue distribution of eight components after oral administration of ginger extract to rats. These results provide useful information about the pharmacokinetics and biodistribution of the multi-component bioactive ingredients of ginger in rats and will contribute to clinical practice and the evaluation of the safety of a Chinese herbal medicine.

PEGylated Triacontanol Substantially Enhanced the Pharmacokinetics of Triacontanol in Rats

Triacontanol (TA), a natural compound with various health benefits, is extensively used as a nutritional supplement. The therapeutic and nutraceutical applications of TA are limited due to its poor aqueous solubility. PEGylated triacontanol (PEGylated TA) was designed to improve the solubility and pharmacokinetics of TA. After PEGylation, the solubility (∼250 g·L^-1 versus 9 × 10^-14 g·L^-1), body residence (MRT, 9.40 ± 2.03 h versus 2.59 ± 0.705 h, p < 0.001), and systemic exposure (AUC_0-inf, 29.1 ± 5.33 μM·h versus 0.529 ± 0.248 μM·h, p < 0.001) of TA were all significantly increased compared to pristine TA. When intravenously administered (6.85, 22.8, and 68.5 μmol·kg^-1) in rats, PEGylated TA exhibited a slow clearance (44.8 ± 8.62, 47.9 ± 5.18, and 46.9 ± 16.5 mL·h^-1·kg^-1), long elimination half-life (8.76 ± 0.96, 10.4 ± 1.66, and 11.1 ± 2.81 h), and abundant systemic exposure (AUC_{0- t}, 155 ± 24.2, 523 ± 56.2, and 1709 ± 245 μM·h). Meanwhile, its metabolite TA showed a high AUC_{0- t} (28.4 ± 5.14, 151 ± 25.4, and 797 ± 184 μM·h) and slow elimination ( t_1/2, 10.1 ± 2.03, 7.78 ± 1.74, and 6.82 ± 0.58 h). Our results demonstrated that PEGylated TA has superior pharmacokinetics, which enhanced its nutritional and pharmacodynamic potency, and thus warrants further investigations.

Quantitation of Gingerols in Human Plasma by Newly Developed Stable Isotope Dilution Assays and Assessment of Their Immunomodulatory Potential

In a pilot study with two volunteers, the main pungent and bioactive ginger (Zingiber officinale Roscoe) compounds, the gingerols, were quantitated in human plasma after ginger tea consumption using a newly established HPLC-MS/MS(ESI) method on the basis of stable isotope dilution assays. Limits of quantitation for [6]-, [8]-, and [10]-gingerols were determined as 7.6, 3.1, and 4.0 nmol/L, respectively. The highest plasma concentrations of [6]-, [8]-, and [10]-gingerols (42.0, 5.3, and 4.8 nmol/L, respectively) were reached 30-60 min after ginger tea intake. Incubation of activated human T lymphocytes with gingerols increased the intracellular Ca(2+) concentration as well as the IFN-γ secretion by about 20-30%. This gingerol-induced increase of IFN-γ secretion could be blocked by the specific TRPV1 antagonist SB-366791. The results of the present study point to an interaction of gingerols with TRPV1 in activated T lymphocytes leading to an augmentation of IFN-γ secretion.

Regioselective glucuronidation of gingerols by human liver microsomes and expressed UDP-glucuronosyltransferase enzymes: reaction kinetics and activity correlation analyses for UGT1A9 and UGT2B7

OBJECTIVES

To determine the reaction kinetics for regioselective glucuronidation of gingerols (i.e. 6-, 8- and 10-gingerol) by human liver microsomes and expressed UDP-glucuronosyltransferase (UGT) enzymes, and to identify the main UGT enzymes involved in regioselective glucuronidation of gingerols.

METHODS

The rates of glucuronidation were determined by incubating the gingerols with uridine diphosphoglucuronic acid-supplemented microsomes. Kinetic parameters were derived by fitting an appropriate model to the data. Activity correlation analyses were performed to identify the main UGT enzymes contributing to hepatic metabolism of gingerols.

KEY FINDINGS

Glucuronidation at the 4'-OH group was much more favoured than that at 5-OH. The degree of position preference was compound-dependent; the catalytic efficiency ratios of 4'-O- to 5-O-glucuronidation were 9.1, 19.7 and 2.9 for 6-, 8- and 10-gingerol, respectively. UGT1A8 (an intestinal enzyme), UGT1A9 and UGT2B7 were the enzymes showing the highest activity towards gingerols. Formation of 5-O-glucuronide was mainly catalysed by UGT1A9. UGT2B7 was the only enzyme that generated glucuronides at both 4'-OH and 5-OH sites, although a strong position preference was observed with 4'-OH (≥80.2%). Further, activity correlation analyses indicated that UGT2B7 and UGT1A9 were primarily responsible for 4'-O-glucuronidation and 5-O-glucuronidation of gingerols in the liver, respectively.

CONCLUSIONS

Gingerols were metabolized by multiple hepatic and gastrointestinal UGT enzymes. Also, UGT1A9 and 2B7 were the main contributors to regioselective glucuronidation of gingerols in the liver.

Assay of 6-gingerol in CO2 supercritical fluid extracts of ginger and evaluation of its sustained release from a transdermal delivery system across rat skin

Ginger has been widely used as healthy food condiment as well as traditional Chinese medicine since antiquity. Multiple potentials of ginger for treatment of various ailments have been revealed. However, the biological half-life of 6-gingerol (a principal pungent ingredient of ginger) is only 7.23 minutes while taken orally. Delivery of ginger compositions by routes other than oral have scarcely been reported. Therefore, we studied a noninvasive transdermal drug delivery system (TDDS) of ginger to bypass hepatic first pass metabolism, avoid gastrointestinal degradation and achieve long persistent release of effective compositions. After establishment of a HPLC analysis method of 6-gingerol, assays of 6-gingerol were performed to compare two kinds of ginger extracts. Then, the characteristics of transdermal delivery of 6-gingerol in TDDS were exhibited. The results showed that the contents of 6-gingerol in two kinds of ginger extracts were significantly different. The maximal delivery percentage of 6-gingerol across rat skin at 20 h was more than 40% in different TDDS formulations. TDDS may provide long-lasting delivery of ginger compounds.

Synbiotic (probiotic and ginger extract) loaded floating beads: a novel therapeutic option in an experimental paradigm of gastric ulcer

OBJECTIVE

This study investigated the use of a bioactive phytochemical, namely ginger extract (GE), for its antioxidant and antiulcer effects, and also for supporting probiotic growth and activity. Use of probiotics is limited in therapy because of their transience and inability to survive the adverse physiological conditions of the gastrointestinal tract. Packaging probiotics in a suitably designed pharmaceutical system with GE may facilitate their establishment in the stomach mucosa.

METHODS

A probiotic (Lactobacillus acidophilus) and GE were simultaneously and individually encapsulated/immobilized in alginate floating beads. The developed system was evaluated for diameter, buoyancy, entrapment, porosity, in-vitro viability/release and pharmacodynamics in a cold restraint stress induced gastric ulcer model in rats.

KEY FINDING

The developed floating beads stayed in the stomach for more than 10 h and both agents were released slowly and over a prolonged period from these beads. Significant and promising results were obtained for the combination (synbiotic) system in terms of ulcer index, mucus secretion, oxidative stress and histopathological parameters, as compared with the individual agents. The developed system could completely revert the damage induced in ulcerated stomachs at physiological (ulcer index and mucus secretion), biochemical (oxidative stress) and histological levels.

CONCLUSION

This study establishes that suitable packaging of GE and Lactobacillus acidophilus together in floating beads can help exploit their prospects as therapeutic curative agents rather than potential preventive agents.

Preparation and evaluation of 5, 9-dimethyl-2-cyclopropyl-2-decanol as a penetration enhancer for drugs through rat skin

In the present study a new alcohol derivative of tetrahydrogeraniol (THG), an acyclic monoterpene, has been prepared by using Grignard reagent and methyl cyclopropyl ketone. Penetration enhancing effects of THG and the synthesized derivative 5,9-dimethyl-2-cyclopropyl-2-decanol (DICNOL) on the transdermal penetration of 5-fluorouracil (5-FU) and tramadol hydrochloride (tramadol HCl) across the excised rat skin were studied by an in vitro permeation technique using Franz diffusion cells. Azone was used as standard enhancer for comparison. DICNOL and THG significantly enhanced 5-FU and tramadol HCl penetration through rat skin compared with the control. DICNOL enhanced the permeability of 5-FU and tramadol HCl across full thickness skin by about 11 and 20 fold, respectively. Increased partition coefficient and diffusion coefficient values were obtained by these enhancers. The results suggest that the amount of DICNOL in the skin, especially in the stratum corneum, may be related to its penetration enhancing effects.

Examination of the pharmacokinetics of active ingredients of ginger in humans

Ginger extracts have been studied in various clinical trials for different indications. However, the pharmacokinetics of the ginger active constituents in human biological matrices is not well investigated. This study aims to develop a LC-MS/MS method for simultaneous measurement of 6-, 8-, and 10-gingerols and 6-shogaol and study their pharmacokinetics in human plasma and colon tissues. A sensitive LC-MS/MS method was established and validated with a low limit of quantification of 2-5 ng/mL. The intra- and inter-day accuracy ranged from -7.3% to 10.4% and from -9.4% to 9.8%, respectively. The intra- and inter-day precision ranged from 0.9% to 10.9% and from 2.0% to 12.4%, respectively. The glucuronide and sulfate metabolites of 6-, 8-, and 10-gingerols and 6-shogaol in plasma and colon tissues were quantified after hydrolysis with β-glucuronidase and sulfatase. After oral dosing of 2.0 g ginger extracts in human, free 10-gingerol and 6-shogaol were detected in plasma with peak concentrations (9.5 ± 2.2 and 13.6 ± 6.9 ng/mL, respectively) at 1 h after oral administration, but no free 6-gingerol and 8-gingerol were detected in plasma from 0.25 to 24 h. The peak concentrations of glucuronide metabolites of 6-, 8-, and 10-gingerols and 6-shogaol were 0.47 ± 0.31, 0.17 ± 0.14, 0.37 ± 0.19, and 0.73 ± 0.54 μg/mL at 1 h, respectively. The peak concentrations of the sulfate metabolites of 6-, 8-, and 10-gingerols and 6-shogaol were 0.28 ± 0.15, 0.027 ± 0.018, 0.018 ± 0.006, and 0.047 ± 0.035 μg/mL at 1 h, respectively. Very low concentrations (2-3 ng/mL) of 10-gingerol glucuronide and sulfate were found in colon tissues. Pharmacokinetic analysis showed that half-lives of these four analytes and their metabolites were 1-3 h in human plasma. No accumulation was observed for 6-, 8-, and 10-gingerols and 6-shogaol and their metabolites in both plasma and colon tissues after multiple daily dosing.

Adsorption of nonlamellar nanostructured liquid-crystalline particles to biorelevant surfaces for improved delivery of bioactive compounds

The adsorption of nanostructured lyotropic liquid-crystal particles, cubosomes and hexosomes, at surfaces was investigated for potential use in surface-specific agrochemical delivery. Adsorption of phytantriol (PHYT) and glyceryl monooleate (GMO)-based cubosomes and hexosomes, stabilized using Pluronic F127, at tristearin-coated (model leaf surface) and uncoated zinc selenide surfaces was studied using attenuated total reflectance Fourier transform IR (ATR-FTIR) spectroscopy, by quantifying the IR absorbance due to the lipid components of the particles over time. The delivery of an encapsulated hydrophobic model herbicide [dichlorodiphenyldichloroethylene (DDE)] was also examined on the model and real leaf surfaces. The adsorption behavior of the particles by ATR-FTIR was dependent on the internal nanostructure and lipid composition, with PHYT cubosomes adsorbing more avidly at tristearin surfaces than GMO-based cubosomes or hexosomes. There was a direct correlation between DDE associated with the surfaces and the particle adsorption observed in the ATR-FTIR study, strongly implicating particle adsorption with the delivery efficiency. Differences between the mode of interaction of the Pluronic stabilizer with the different lipids and particle nanostructures were proposed to lead to differences in the particle adsorption behavior.

Improved cellular uptake of functionalized single-walled carbon nanotubes

Single-walled carbon nanotubes (SWNTs) due to their unique structural and physicochemical properties, have been proposed as delivery systems for a variety of diagnostic and therapeutic agents. However, SWNTs have proven difficult to solubilize in aqueous solution, limiting their use in biological applications. In an attempt to improve SWNTs' solubility, biocompatibility, and to increase cell penetration we have thoroughly investigated the construction of carbon scaffolds coated with aliphatic carbon chains and phospholipids to obtain micelle-like structures. At first, oxidized SWNTs (2370 ± 30 nmol mg(-1) of SWNTs) were covalently coupled with an alcoholic chain (stearyl alcohol, C(18)H(37)OH; 816 nmol mg(-1) of SWNTs). Subsequently, SWNTs-COOC(18)H(37) derivatives were coated with phosphatidylethanolamine (PE) or -serine (PS) phospholipids obtaining micelle-like structures. We found that cellular uptake of these constructs by phagocytic cells occurs via an endocytotic mechanism for constructs larger than 400 nm while occurs via diffusion through the cell membrane for constructs up to 400 nm. The material that enters the cell by phagocytosis is actively internalized by macrophages and localizes inside endocytotic vesicles. In contrast the material that enters the cells by diffusion is found in the cell cytosol. In conclusion, we have realized new biomimetic constructs based on alkylated SWNTs coated with phospholipids that are efficiently internalized by different cell types only if their size is lower than 400 nm. These constructs are not toxic to the cells and could now be explored as delivery systems for non-permeant cargoes.

Human health risk assessment of long chain alcohols

Representative chemicals from the long chain alcohols category have been extensively tested to define their toxicological hazard properties. These chemicals show low acute and repeat dose toxicity with high-dose effects (if any) related to minimal liver toxicity. These chemicals do not show evidence of activity in genetic toxicity tests or to the reproductive system or the developing organism. These chemicals also are not sensitizers. Irritation is dependant on chain length; generally, alcohols in the range C(6-)C(11) are considered as irritant, intermediate chain lengths (C(12-)C(16)) alcohols are considered to be mild irritants and chain lengths of C(18) and above are considered non-irritants. These chemicals are broadly used across the consumer products industry with highest per person consumer exposures resulting from use in personal care products. Margins of exposure adequate for the protection of human health are documented for the uses of these chemicals.

Comparative effects of two gingerol-containing Zingiber officinale extracts on experimental rheumatoid arthritis

Ginger (Zingiber officinale) supplements are being promoted for arthritis treatment in western societies on the basis of ginger's traditional use as an anti-inflammatory in Chinese and Ayurvedic medicine. However, scientific evidence of ginger's antiarthritic effects is sparse, and its bioactive joint-protective components have not been identified. Therefore, the ability of a well-characterized crude ginger extract to inhibit joint swelling in an animal model of rheumatoid arthritis, streptococcal cell wall-induced arthritis, was compared to that of a fraction containing only gingerols and their derivatives. Both extracts were efficacious in preventing joint inflammation. However, the crude dichloromethane extract, which also contained essential oils and more polar compounds, was more efficacious (when normalized to gingerol content) in preventing both joint inflammation and destruction. In conclusion, these data document a very significant joint-protective effect of these ginger samples and suggest that nongingerol components are bioactive and can enhance the antiarthritic effects of the more widely studied gingerols.

Stability of [6]-gingerol and [6]-shogaol in simulated gastric and intestinal fluids

The degradation kinetics of [6]-gingerol and [6]-shogaol were investigated in simulated gastric (pH 1) and intestinal (pH 7.4) fluids at 37 degrees C. Degradation products were quantitatively determined by HPLC (Lichrospher 60 RP select B column, 5 microm, 125 mm x 4 mm; mobile phase: methanol-water-acetic acid (60:39:1 v/v); flow rate: 0.6 ml/min; detection UV: 280 nm). In simulated gastric fluid (SGF) [6]-gingerol and [6]-shogaol underwent first-order reversible dehydration and hydration reactions to form [6]-shogaol and [6]-gingerol, respectively. The degradation was catalyzed by hydrogen ions and reached equilibrium at approximately 200 h. In simulated intestinal fluid (SIF) both [6]-gingerol and [6]-shogaol showed insignificant interconversion between one another. Addition of amino acids glycine, 3-amino propionic acid (beta-alanine) and gamma-amino butyric acid (GABA), and ammonium acetate at a range of concentrations of 0.05-0.5mM had no effect on the rate of degradation of [6]-shogaol in SGF and 0.1M HCl solution. However, at exceedingly high concentration (0.5M) of ammonium acetate and glycine, significant amounts of [6]-shogaol ammonia and glycine adducts were detected. The degradation profile of [6]-gingerol and [6]-shogaol under simulated physiological conditions reported in this study will provide insight into the stability of these compounds when administered orally.

Comparison of composition and absorption of sugarcane policosanols

Policosanols (PC) exist as very-long-chain alcohols derived from sugarcane currently used in many countries as a cholesterol-lowering therapy. PC purity and relative percentage composition have been suggested as primary reasons why the original Cuban PC (OPC) supplements possess lipid-lowering efficacy. The purpose of the present study was, first, to compare the relative percentage purity and PC composition of both OPC and alternative sources of PC (APC). A second objective was to feed Syrian hamsters a diet containing 0.275 mg PC/g of either the OPC or an APC product (APC1) and compare subsequent tissue, plasma and faecal PC levels. Five animals from the APC1 dietary group received a diet containing ten times the original amount of PC. Results indicate that the APC formulations have a composition that is highly consistent with the OPC supplement, with octacosanol being present within the cited 60-70 % range. PC were undetectable in the small intestine, liver, adipose or plasma in animals fed either source. Hamsters fed OPC excreted octacosanol (C28) more rapidly (P < 0.05) than hamsters receiving APC1. If the cholesterol-lowering efficacy of PC mixtures is dependent on their purity and composition, then sugarcane-derived APC products should possess similar therapeutic properties as the OPC supplement.

Influence of terminal branching on the transdermal permeation-enhancing activity in fatty alcohols and acids

In order to investigate the effect of terminal chain branching in the skin permeation enhancers, seven alcohols and seven acids with the chain length of 8-12 carbons and terminal methyl or ethyl branching were prepared. Their transdermal permeation-enhancing activities were evaluated in vitro using theophylline as a model permeant and porcine skin, and compared to those of the linear standards. Terminal methyl branching increased the enhancing activity only in 12C acid, no effect was seen in the shorter ones. Terminal ethyl however produced a significant increase in activity. In the alcohols, the branching was likely to change the mode of action, due to a different relationship between the activity and the chain length.

Perfluorooctanoic Acid and Perfluorononanoic Acid in Fetal and Neonatal Mice Following In Utero Exposure to 8-2 Fluorotelomer Alcohol

8-2 Fluorotelomer alcohol (FTOH) and its metabolites, perfluorooctanoic acid (PFOA) and perfluorononanoic acid (PFNA), are developmental toxicants but metabolism and distribution during pregnancy are not known. To examine this, timed-pregnant mice received a single gavage dose (30 mg 8-2 FTOH/kg body weight) on gestational day (GD) 8. Maternal and neonatal serum and liver as well as fetal and neonatal homogenate extracts were analyzed using gas chromatography coupled with mass spectrometry. During gestation (GD9 to GD18), maternal serum and liver concentrations of PFOA decreased from 789 +/- 41 to 668 +/- 23 ng/ml and from 673 +/- 23 to 587 +/- 55 ng/g, respectively. PFOA was transferred to the developing fetuses as early as 24-h posttreatment with concentrations increasing from 45 +/- 9 ng/g (GD10) to 140 +/- 32 ng/g (GD18), while PFNA was quantifiable only at GD18 (31 +/- 4 ng/g). Post-partum, maternal serum PFOA concentrations decreased from 451 +/- 21 ng/ml postnatal day (PND) 1 to 52 +/- 19 ng/ml (PND15) and PFNA concentrations, although fivefold less, exhibited a similar trend. Immediately after birth, pups were cross-fostered with dams that had been treated during gestation with 8-2 FTOH (T) or vehicle (C) resulting in four treatment groups in which the first letter represents in utero (fetal) exposure and the second represents lactational (neonatal) exposure: C/C, T/C, C/T, T/T. On PND1, neonatal whole-body homogenate concentrations of PFOA from T/T and T/C groups averaged 200 +/- 26 ng/g, decreased to 149 +/- 19 ng/g at PND3 and this decreasing trend was seen in both neonatal liver and serum from PND3 to PND15. Based on detectible amounts of PFOA in neonatal serum in the C/T group on PND3 (57 +/- 11 ng/ml) and on PND15 (58 +/- 3 ng/ml), we suggest that the neonates were exposed through lactation. In conclusion, exposure of neonates to PFOA and PFNA occurs both pre- and postnatally following maternal 8-2 FTOH exposure on GD8.

[Effect of monohydric aliphatic alcohols on children's health]

To form the evidence base of the "environmental determination" of disease is a topical line in human ecology and environmental hygiene. The widespread use of monohydric aliphatic alcohols in industry has determined the necessity of making an in-depth study of their toxic effects on man, by taking into account their actual concentrations forming in the blood. The results of the studies have led to the conclusion that the real risk of toxic exposure of an organism to monohydric alcohols forms when the blood concentrations of butyl alcohols, propyl alcohols, and methyl alcohol are over 0.03, 1.0-1.5, and 0.5 microg/kg/cm3, respectively. Toxic exposure involves immunosuppressive, oxidative, hematoxic, and sensitizing effects and impaired hepatic etherifying function. With the higher toxicity of the compounds, the damaging action of monohydric alcohols on the organism increases and the spectrum of abnormal clinical and laboratory parameters expands.

The effect of water solubility of solutes on their flux through human skin in vitro

The Flynn database (n=97) for determining the effect of the physicochemical properties of solutes on their skin absorption has been edited to give a database for which the solubilities of the solutes in water, S(AQ), and their maximum fluxes from water through human skin in vitro, J(MAQ), are known or can be calculated (n=76). Data from the six major contributors to the original Flynn database have been included. Data for solutes, which were significantly ionized or for experiments using different thicknesses of skin were not excluded so that the edited database is as diverse as the original. The edited database was fit to five equations where the independent variables were solubility in octanol (S(OCT)) in water (S(AQ)) or molecular weight (MW), and combinations of those three variables; and the dependent variable was J(MAQ). The best fit was obtained from the Roberts-Sloan (RS) equation: logJ(MAQ)=x+ylogS(OCT)+(1-y)logS(AQ)-zMW, x=-3.00, y=0.73, z=0.0048, r(2)=0.934, S.D.=0.37 and F=274. This result is important because J (amount/area time) is the more clinically useful descriptor of permeation compared to P (distance/time); and because the identification of S(AQ) as a significant variable in predicting flux changes the design parameters for optimizing topical delivery of drugs from solubility in lipids (or partition coefficients between OCT and AQ, K(OCT:AQ)) and MW, to solubility in lipids, S(OCT), and in water, S(AQ), as well as MW.

Absorption, Distribution, Metabolism, and Elimination of 8-2 Fluorotelomer Alcohol in the Rat

The absorption, distribution, metabolism, and elimination of [3-14C] 8-2 fluorotelomer alcohol (8-2 FTOH, C7F1514CF2CH2CH2OH) following a single oral dose at 5 and 125 mg/kg in male and female rats have been determined. Following oral dosing, the maximum concentration of 8-2 FTOH in plasma occurred by 1 h postdose and cleared rapidly with a half-life of less than 5 h. The internal dose to 8-2 FTOH, as measured by area under the concentration-time curve to infinity, was similar for male and female rats and was observed to increase in a dose-dependent fashion. The majority of the 14C 8-2 FTOH (> 70%) was excreted in feces, and 37-55% was identified as parent. Less than 4% of the administered dose was excreted in urine, which contained low concentrations of perfluorooctanoate (approximately 1% of total 14C). Metabolites identified in bile were principally composed of glucuronide and glutathione conjugates, and perfluorohexanoate was identified in excreta and plasma, demonstrating the metabolism of the parent FTOH by sequential removal of multiple CF2 groups. At 7 days postdose, 4-7% of the administered radioactivity was present in tissues, and for the majority, 14C concentrations were greater than whole blood with the highest concentration in fat, liver, thyroid, and adrenals. Distribution and excretion of a single 125-mg/kg [3-14C] 8-2 FTOH dermal dose following a 6-h exposure in rats was also determined. The majority of the dermal dose either volatilized from the skin (37%) or was removed by washing (29%). Following a 6-h dermal exposure and a 7-day collection period, excretion of total radioactivity via urine (< 0.1%) and feces (< 0.2%) was minor, and radioactivity concentrations in most tissues were below the limit of detection. Systemic availability of 8-2 FTOH following dermal exposure was negligible.

Development and in vitro evaluation of furosemide transdermal formulations using experimental design techniques

The in vitro skin permeation of furosemide, a commonly used loop diuretic, through human epidermis, as a preliminary step towards the development of a transdermal therapeutic system, was examined. A screening study was carried out, in order to estimate the effects of the type, the concentration of enhancer and the concentration of gelling agent on the cumulative amount of furosemide permeated through human epidermis, using a 3(3) factorial design. The type and the concentration of enhancer were further evaluated as they were found to affect significantly furosemide permeation. In order to further increase the amount of the drug permeated, the combination of two enhancers, Azone and oleyl alcohol, at three concentration levels was employed, using an optimization technique. The results indicated that higher amounts of furosemide permeated were observed when Azone was used at 5.0-6.5% (v/v) and oleyl alcohol at 7.5-9% (v/v), in the gels used. These formulations seem to be suitable for possible transdermal delivery of furosemide for pediatric use.

Mechanistic Studies of Branched-Chain Alkanols as Skin Permeation Enhancers

As part of a long-term effort to understand the structure/function relationship between chemical permeation enhancers and skin permeation enhancement, the present study examined the influence of hydrocarbon chain branching on the effectiveness of skin permeation enhancers of the type that possesses a polar group (e.g., the hydroxyl group) attached to a hydrocarbon chain(s). The effects of x-hexanol, x-heptanol, x-octanol, and x-nonanol (where x is the position of the hydroxyl group ranging from 1 up to 5) on the transport of a probe permeant, corticosterone, across hairless mouse skin (HMS) were investigated. Isoenhancement concentrations are defined as the aqueous concentrations for which different enhancers induce the same extent of permeant transport enhancement, E, across the lipoidal pathway of stratum corneum (SC). The isoenhancement concentrations of 2-alkanol, 3-alkanol, 4-alkanol, and 5-alkanol to induce E = 10 were approximately 1.9-, 2.6-, 3.1-, and 3.9-fold higher, respectively, than those of the 1-alkanols of the same molecular formula. This suggested that the branched-chain alkanols have lower enhancer potency than the 1-alkanols of the same molecular formula; the potency decreases as the hydroxyl group moves from the end of the chain towards the center of the enhancer alkyl chain. To further investigate the mechanism(s) of action of the branched-chain alkanols as skin permeation enhancers, the equilibrium uptake of the enhancers into the hairless mouse skin stratum corneum (HMS SC) from aqueous enhancer solutions of E = 10 was determined. The data from these experiments provided a direct measure of the "intrinsic" potency of the enhancer. In the same experiments, the equilibrium partitioning (distribution) of a surrogate permeant, estradiol (E2beta), into the HMS SC was also determined and compared to the partitioning from PBS (no enhancer present). The uptake amounts (micromole/mg SC) for 1-alkanols into the intercellular lipids of the SC were found to be essentially the same at their isoenhancement concentrations. However, at their isoenhancement concentrations, the uptake amounts of the branched-chain alkanols into the intercellular lipids of HMS SC were higher than those of the 1-alkanols. These results support the view that: (1) the intrinsic potencies of the 1-alkanols are essentially the same and independent of their 1-alkyl chain length at their isoenhancement concentrations, (2) the intrinsic potencies of the branched-chain alkanols are lower than those of the normal alkanols, and (3) branching of the alkyl chain reduces the ability of the enhancer to effect lipid fluidization in the SC lipid lamellae at the target site(s). The enhancement effects of the branched-chain alkanols and the 1-alkanols at their isoenhancement concentrations upon E2beta partitioning into the SC intercellular lipids were found to be approximately the same and in the range of five- to eight-fold enhancement. The constancy of this enhancement for E2beta partitioning suggests that the mechanism of enhancement action for the branched-chain alkanols and the 1-alkanols are the same. Additionally, a good correlation of the intercellular lipid/PBS partition coefficients of both the branched-chain alkanols and the 1-alkanols with the n-octanol/PBS partition coefficients was found. This supports the view that the chemical microenvironment of the polar head group and the alkyl group of the studied enhancers at the site of skin permeation enhancer action in the SC lipid lamellae can be represented by water-saturated n-octanol for both the branched-chain alkanols and the 1-alkanols.

Relationship between internal phase volume and emulsion stability: the cetyl alcohol/stearyl alcohol system

The main objective of this study was to optimize the stability of cetyl alcohol/stearyl alcohol emulsions in terms of percentage of internal phase volume, emulsifier type and concentration, and amount of external phase (water). Creams (o/w emulsions) were prepared by phase inversion and physical properties as particle size of the internal phase, apparent viscosity, and sedimentation volume evaluated. Stability was performed at room temperature, 40 degrees C, 50 degrees C, and under stress conditions. High hydrophilic lipophilic balance (HLB) nonionic surfactants as tween 80, tween 20, Myrj 52, Brij 35, and low HLB span 60 were used as emulsifying agents. The percentage of internal phase components (cetyl alcohol and stearyl alcohol), percentage of emulsifying agents, and percentage of aqueous external phase were varied, and stability was investigated. As the level of emulsifier agent (tween 80 and span 60) increased from 3% to 15%, and the percent of the internal phase remained constant at 30%, the particle size of the internal phase decreased and the cream became more stable. Formulations of the same composition, but prepared using Myrj 53 and tween 20 as emulsifiers, showed a larger particle size than formulations prepared using tween 80 and Brij 35. As the level of the internal phase volume increased and consequently the amount of water decreased, emulsion viscosity increased. The best formulation containing 30% internal phase (50% cetyl alcohol, 35% stearyl alcohol), 15% emulsifying agents (tween 80/span 60 ratio of 3:1), and 70% water was selected, and effects of process temperature and cooling rate on emulsion stability investigated. This formulation was further investigated in terms of stability of a 1% hydrocortisone addition by varying the percentage (30%, 35%, 40%, and 45%) of internal phase and percentage of water (70%, 65%, 60%, and 55%). The best formulation contained 45% internal phase (22.5 g cetyl alcohol, 15.75 g stearyl alcohol, 15% emulsifying agent, which is equivalent to 5 g tween 80 and 1.7 g span 60), and 55% w/w water, was manufactured under different manufacturing processes. Emulsions prepared by homogenization at the beginning of the process of emulsification were stable with small internal phase particle diameter. This study demonstrates that at every cetyl alcohol/stearyl alcohol ratio there is a phase volume/emulsifier HLB ratio, which results in optimum stability.

Skin permeation enhancement effect and skin irritation of saturated fatty alcohols

Though the skin permeation enhancement effect of chemical penetration enhancers has been studied extensively, their skin irritation potential has not been adequately investigated. The objective of this study was to evaluate the skin permeation enhancement effect and skin irritation of saturated fatty alcohols using melatonin as a model compound. A saturated solution of melatonin in a mixture of water and ethanol (40:60) containing 5% w/v of saturated fatty alcohol was used in the skin permeation studies using Franz diffusion cells. For skin irritation studies, 230 microl of fatty alcohol solution was applied on the dorsal surface of the hairless rats using Hill top chamber. The skin irritation was evaluated by visual scoring method and bioengineering methods such as measurement of transepidermal water loss (TEWL) and skin blood flow. The flux of melatonin across hairless rat skin was found to be dependent on the carbon chain length of the fatty alcohols, with decanol showing the maximum permeation of melatonin. All fatty alcohols increased the TEWL and skin blood flow significantly compared with the vehicle. The fatty alcohols (decanol, undecanol and lauryl alcohol), which showed greater permeation of melatonin, also produced greater TEWL, skin blood flow and erythema. Tridecanol and myristyl alcohol showed lower permeation enhancement effect but caused greater skin irritation. Octanol and nonanol may be the most useful enhancers for the transdermal delivery of melatonin considering their lower skin irritation and a reasonably good permeation enhancement effect. However, further studies are needed to ascertain their safety as skin penetration enhancers. Skin permeation and skin irritation in experimental animals such as rats are generally higher compared with human skin. Further studies in human volunteers using fatty alcohols at the concentrations of 5% or lower may provide useful information on the utility of these fatty alcohols as permeation enhancers.

Metabolism of [6]-gingerol in rats

The metabolic fate of [6]-gingerol, one of the active constituents of Zingiber officinale Roscoe, was investigated using rats. The bile of rats orally administered [6]-gingerol was shown to contain a major metabolite (1) by HPLC analysis. Although the metabolites derived from [6]-gingerol were not detected in the urine, the ethyl acetate extract of the urine after enzymatic hydrolysis was shown to contain six minor metabolites (2-7). Their structures were determined to be (S)-[6]-gingerol-4'-O-beta-glucuronide (1), vanillic acid (2), ferulic acid (3), (S)-(+)-4-hydroxy-6-oxo-8-(4-hydroxy-3-methoxyphenyl) octanoic acid (4), 4-(4-hydroxy-3-methoxyphenyl)butanoic acid (5), 9-hydroxy [6]-gingerol (6) and (S)-(+)-[6]-gingerol (7) based on spectroscopic and chemical data. The total cumulative amount of 1 excreted in the bile and 2-7 in the urine during 60 h after the oral administration of [6]-gingerol were approximately 48% and 16% of the dose, respectively. The excretion of 2-7 in the urine decreased after gut sterilization. On the other hand, the incubations of [6]-gingerol with rat liver showed the presence of 9-hydroxy [6]-gingerol, gingerdiol (8), and (S)-[6]-gingerol-4'-O-beta-glucuronide (1). These findings suggest that the gut flora and enzymes in the liver play an important part in the metabolism of [6]-gingerol.

Comparison of in vitro surface properties of clove oil-phospholipid suspensions with those of ALEC, Exosurf and Survanta

Dipalmitoyl phosphatidylcholine, the main component of lung surfactant is ineffective as a replacement surfactant due to its poor adsorption. We studied clove oil as a possible additive for improving the surface activity of protein-free phospholipid suspensions. We added low doses of clove oil, to phospholipid suspensions and studied the surface properties by in vitro analysis using a pulsating bubble surfactometer and a Wilhelmy balance. Survanta, ALEC and Exosurf were used as controls for comparison. The test surfactants, which were phospholipid-oil suspensions at 1% concentration, in buffer containing either 2 or 5 mM calcium, were pulsated at 40 cpm in a pulsating bubble surfactometer. The phospholipids studied were dipalmitoyl phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylglycerol (PG), binary mixtures of PC:PE (2:3) and PC:PG (2:3). The addition of clove oil (CO) to each of the above phospholipids was in the ratio of nine parts of phospholipid to one part of oil. The presence of CO caused a significant improvement in the adsorption and minimum surface tension of all the phospholipid suspensions studied. The mixtures PC with CO, both in the presence of 2 and 5 mM calcium, and PCPE with CO at 2 mM calcium concentration had surface properties significantly better than those of ALEC and Exosurf and equivalent to those of Survanta. The addition of clove oil helps improve the surface properties of phospholipids.

Effect of FITC-dextran molecular weight on its release from floating cetyl alcohol and HPMC tablets

The release mechanism of high molecular weight fluorescein isothiocyanate dextrans (FITC-dextrans) from HPMC hydrogel matrices was studied. An anomaly was noted in the release behaviour of a series of high molecular weight FITC-dextrans from a tablet formulation designed to float in stomach contents. The tablets contained sodium bicarbonate and hydroxypropylmethyl cellulose (HPMC) in a cetyl alcohol matrix. When hydrated in an acid medium, this tablet consisted of a mixed solid with a viscous surface layer containing carbon dioxide bubbles through which the active ingredient (FITC-dextran) was released into the aqueous environment. However, it was observed that, above a critical molecular weight (approx. 65 kDa), the FITC-dextran was only released into the medium by an erosion-type mechanism, whereas, below this value, both diffusion and erosion processes took place. The key constraint appeared to be the apparent gel pore-size of the hydrated HPMC that was approximately 12 nm in diameter, irrespective of the molecular weight of the HPMC samples evaluated. It was concluded that FITC-dextran release was controlled by both FITC-dextran molecular weight and the HPMC hydrogel structure.

Estimation of pulmonary deposition of aerosol using gamma scintigraphy

Following delivery of technetium 99m-labeled aerosols through a ventilator circuit, the amount of radioactivity in the lungs of 58 ventilated rabbits was estimated first by gamma scintigraphy via gamma camera and later by direct counting of the excised lungs (n = 116 specimens) with a gamma counter. The in situ radioactivity measured via scintigraphy was closely correlated with the gamma counter ex vivo tissue counts of the radioactivity (R2 = 0.997, P < 0.001). Overall, gamma scintigraphy gave slightly lower values of activity than the tissue counts from the gamma counter, but the limits of agreement between the two measurements were narrow enough for us to consider that the tissue and scintigraphy methods were in agreement. We conclude that gamma scintigraphy provides a convenient and noninvasive means for the accurate estimation of aerosol deposition in the lungs of small animals and possibly in small infants.

Effect of inhaled surfactant on pulmonary deposition and clearance of technetium-99m-DTPA radioaerosol

To establish the effect of an aerosolized synthetic surfactant (Exosurf) on pulmonary 99mTc-diethylenetriamine pentaacetic acid (DTPA) aerosol deposition and clearance, radioaerosol studies were performed at varying times and under varying conditions after surfactant inhalation in canine lungs.

METHODS

Twenty-three dogs had a baseline 99mTc-DTPA study; 2 days later the study was repeated after inhalation of a 1.5-ml/kg dose of Exosurf aerosolized by an ultrasonic nebulizer. The clearance half-time (T1/2) of 99mTc-DTPA from each lung was measured at different times (from 10 min to 3 hr) after Exosurf inhalation. For comparison, five animals had a 99mTc-DTPA study 10 min after inhalation of the same dose of saline as Exosurf. An additional five animals inhaled a 99mTc-DTPA-Exosurf mixture to investigate the distribution of Exosurf.

RESULTS

Technetium-99m-DTPA distributed uniformly without significant changes in penetration indexes before and after inhalation of Exosurf and the 99mTc-DTPA-Exosurf mixture. After Exosurf inhalation, 99mTc-DTPA clearance at 10 min (T1/2; 35.6 +/- 8.7 min; n = 6) and 40 min (29.4 +/- 6.3 min; n = 4) was significantly prolonged compared with the matched baseline values (24.7 +/- 6.4 min, p < 0.0001; and 21.7 +/- 8.9 min, p = 0.01, respectively). However, later clearance times were not prolonged. By contrast, after saline inhalation, 99mTc-DTPA distributed inhomogeneously, and clearance times T1/2) were not altered from the matched baseline values.

CONCLUSION

Aerosolized Exosurf distributes homogeneously in the lungs. Exosurf initially retards 99mTc-DTPA aerosol clearance, but 99mTc-DTPA transalveolar clearance returns to baseline rates within 1-2 hr. Technetium-99m-DTPA aerosol clearance measurements can be used to monitor the effect of inhaled Exosurf on pulmonary epithelial integrity.

Nebulisation of surfactants in an animal model of neonatal respiratory distress

AIMS

To evaluate pulmonary deposition and gas exchange following nebulisation of two surfactants by either a jet or an ultrasonic nebuliser.

METHOD

After bronchoalveolar lavage (BAL), 19 rabbits were ventilated in four groups. Group A1 (n = 5) and A2 (n = 6) received Technetium-99m labelled Exosurf, and groups B1 (n = 4) and B2 (n = 4) received radiolabelled Survanta. Groups A1 and B1 received jet nebuliser therapy, whereas groups A2 and B2 received ultrasonic nebuliser. Pulmonary deposition, distribution, and blood gases were determined.

RESULTS

Pulmonary deposition as per cent of initial dose and mg lipid) was 0.28(0.10)% or 0.59(0.21) mg in group A1, 1.05(0.23)% or 2.21(0.48) mg in group A2, 0.08(0.02)% or 0.30(0.08) mg in group B1, and 0.09(0.02)% or 0.34(0.08) mg in group B2. Deposition in group A2 was greater than in other groups (p = 0.001). Group A2 showed a small improvement in blood gases.

CONCLUSIONS

Even the highest deposition--ultrasonic nebuliser with Exosurf--achieved limited clinical effect. The aerosol route is currently not effective for surfactant treatment.

Susceptibility of exogenous surfactant to phospholipase A2 degradation

The inhibition of surfactant biophysical activity in vivo is potentially mediated by many factors, including serum proteins, particularly enzymatic proteins such as phospholipases. In the present study, we investigated the susceptibility of the phosphatidylcholine component of two exogenous surfactants, Exosurf and Survanta, to secretory-type phospholipase A2 (PLA2) deacylation in vitro. Lyophilized Exosurf and Survanta preparations were incubated at 37 degrees C for 120 min in the presence of bovine pancreatic PLA2, and the production of lysophosphatidylcholine was determined as a measure of the magnitude of phosphatidylcholine deacylation. The phosphatidylcholine component of Survanta was readily deacylated by PLA2, whereas the dipalmitoylphosphatidycholine (DPPC) component of Exosurf was resistant over the entire duration of the assay. To further evaluate this observed resistance the individual and combined effects of tyloxapol and hexadecanol, components of Exosurf, upon PLA2 deacylation of Survanta and DPPC were investigated. In both Survanta and DPPC preparations, PLA2-mediated deacylation was significantly inhibited in the presence of tyloxapol. We conclude that the presence of tyloxapol in the Exosurf preparation inhibits secretory type PLA2 mediated DPPC deacylation. This unique feature of Exosurf may be of clinical significance when this preparation is utilized in the treatment of surfactant-deficient infants.

Analytical procedure for the determination of 1-octacosanol in plasma by solvent extraction and capillary gas chromatography

A simple and rapid method for the determination of 1-octacosanol in plasma, based on an improved Folch extraction technique and capillary gas chromatography, has been developed taking into account the analytical criteria for the pharmacokinetic studies. The procedure was validated in the range of 50-2000 ng/ml. Despite the complexity of the obtained fingerprints, the efficiency and the separation power of GC allowed the determination of 1-octacosanol in plasma samples. The high recoveries (94.5-98.7%) and precision (1.8-5.8%) obtained are in accordance with the established validation criteria. The validity of this method for pharmacokinetic purposes was shown using an endovenous experiment in animals.

Physiologic response and lung distribution of lavage versus bolus Exosurf in piglets with acute lung injury

Despite evidence of surfactant dysfunction in the acute respiratory distress syndrome (ARDS), treatment with exogenous surfactant remains experimental. Uneven pulmonary distribution is one factor that may limit response. We investigated whether exogenous surfactant administered by lavage, consisting of a 35 ml/kg volume instilled by gravity and followed immediately by passive drainage (LAVAGE), would result in better lung distribution and physiologic response than with surfactant administered as a 5 ml/kg bolus (BOLUS). Exosurf, an artificial surfactant, was administered after acute lung injury induced by saline lung lavage in neonatal piglets. In the LAVAGE group (n= 9), 10.1 +/- 0.4 ml/kg of surfactant was retained, corresponding to a phospholipid dose of 136 +/- 5 mg/kg. In the BOLUS group (n = 9), the dose administered was 203 mg/kg phospholipid. Piglets in the LAVAGE group demonstrated greater improvement in pulmonary function, including PaO2, PaCO2, ventilation efficiency index, functional residual capacity (FRC), and pressure-volume curves than piglets in the BOLUS group. Some differences were found in lung distribution of surfactant. We conclude that Exosurf is more effective when administered by lavage in this lung injury model. We speculate that the lavage method of administration holds promise as an alternative method of surfactant administration in patients with ARDS.

A possible mechanism for the cytotoxicity of a polyacetylenic alcohol, panaxytriol: inhibition of mitochondrial respiration

A polyacetylenic alcohol, panaxytriol, isolated from Panax ginseng C. A. Meyer inhibits both tumor cell growth in vitro and the growth of B16 melanoma transplanted into mice. Our preliminary studies indicated that panaxytriol localizes to the mitochondria in human breast carcinoma cells (Breast M25-SF). This study focused on the effects of panaxytriol on mitochondrial structures and function in Breast M25-SF. The results indicate that panaxytriol rapidly inhibits cellular respiration and disrupts cellular energy balance in Breast M25-SF. At concentrations between 11.3 and 180 microM, panaxytriol causes a dose-dependent inhibition of the conversion of the tetrazolium (MTT assay) by mitochondrial dehydrogenase within 2 h. A 1-h treatment with 180 microM panaxytriol causes a significant loss of rhodamine-123 from cells with mitochondria prestained with rhodamine-123 (by flow cytometry). Specific toxic changes were observed by electron microscopy in the mitochondria of Breast M25-SF within 1 h after treatment with more than 180 microM panaxytriol. These data indicate that 180 microM panxytriol rapidly disrupts cellular energy balance and respiration in Breast M25-SF and suggest that panaxytriol may lower cellular ATP concentrations. After treatment with 180 microM panaxytriol, cellular ATP levels were 40% of those in control cells after 1 h. ATP depletion preceded the loss of cellular viability. Neither ATP depletion nor cytolysis was found in human erythrocytes that have no mitochondria. Thus, ATP depletion resulting from a direct inhibition of mitochondrial respiration is a critical early event in the cytotoxicity of panaxytriol.

Tissue distribution of (8-14C)-octacosanol in liver and muscle of rats after serial administration

The present study investigates the metabolic disposition of octacosanol in liver and muscle of rats after serial doses administration. Three groups of experimental animals received various doses of (8-14C)-octacosanol (2.0 microCi/dose) orally through a stomach tube. When expressed per organ, the highest amount of radioactivity was found in the liver (9.5% of administered dose), followed by the digestive tracts (8.2%) and the muscle (3.5%) at all doses of administration. The radioactivity in all other tissues examined was insignificant (< 0.9% in each) at any time during this period. The radioactivity in liver disappeared rapidly after 2-dose administration, even when the doses were increased. In contrast, the muscle seemed to be able to store a considerable amount of octacosanol in response to doses of administration. In case of 9-dose serial administration, after 3 and 9 days the accumulation of radioactivity in muscle was higher than that of the liver, possibly due to slow elimination of radioactivity from muscle. By the time when radioactivity in liver and muscle was low (after 6 and 10 doses), the radioactivity of octacosanol in plasma reached a maximum, particularly after administration of 6 doses. The plasma concentration and the fecal excretion of the radioactivity of octacosanol reached a maximum at the third day after the oral 6 doses, which reflected not only the saturation of radioactivity uptake by liver and muscle but also the metabolism and excretion of octacosanol with time at the same period. The results are discussed in the light of the role of octacosanol in increasing muscle endurance in exercise.

A highly sensitive enzyme-linked immunosorbent assay (ELISA) for antitumor polyacetylenic alcohol, panaxytriol

A new type of antitumor polyacetylenic alcohol, panaxytriol, was isolated from the roots of Panax ginseng C. A. Meyer. A highly sensitive enzyme-linked immunosorbent assay (ELISA) for the determination of panaxytriol was developed, which is capable of measuring as low as 25.6 pg/ml. Anti-panaxytriol antibody was obtained by immunizing rabbits with panaxytriol conjugated with bovine serum albumin using the N-succinimidyl ester method. An enzyme marker was similarly prepared by coupling panaxytriol with horseradish peroxidase. The specificity of this ELISA seems to be primarily toward both the glycol moiety and the diacetylene moiety of the panaxytriol, showing a slight cross-reaction with the other panaxytriol analogues which are structurally different only in C-9,10 positions, but no cross-reaction with the 1,2-decanediol or 3-nonyn-1-ol. The values for panaxytriol concentration detected by this assay were comparable with those detected by the gas chromatography method. The ELISA was about 5000 times more sensitive in detecting panaxytriol. Using this assay, panaxytriol levels were easily determined in the blood of rats. The ELISA may be a valuable tool for studies of the biological and pharmacological properties of the polyacetylenic alcohol, panaxytriol.

The first specific antibody against cytotoxic polyacetylenic alcohol, panaxynol

Antitumor polyacetylenic alcohol, panaxynol, was isolated and purified from a powder of the root of Panax ginseng C.A. Meyer. Panaxynol inhibited the growth of various kinds of cultured tumor cell lines in a dose-dependent manner. In this paper we demonstrated the first specific antibody production against panaxynol. Anti-panaxynol antibody was elicited in rabbits by immunization with panaxynol hemisuccinate-bovine serum albumin conjugate (panaxynol hemisuccinate-BSA conjugate). An enzyme immunoassay (EIA) for the determination of panaxynol was established using a double-antibody technique. The EIA was highly specific against panaxynol although the antibody showed a minimal cross-reactivity with other types of polyacetylenic alcohol, i.e. panaxydol (12.0%) and panaxytriol (0.77%). Panaxynol at a concentration as low as 6.4 ng/ml can be detected. Using this assay we reconfirmed the rapid consumption of panaxynol by target tumor cells in an in vitro-culture system. The anti-panaxynol antibody may be a valuable tool for studies of the biological properties of polyacetylenic compounds.

Biodistribution and metabolism of orally administered octacosanol in rats

The biodistribution and metabolism of [8-14C]-octacosanol in rats were investigated to understand the mechanism of increased physical exercise and motor endurance by octacosanol. After 14C-octacosanol administered, radioactivity of octacosanol was mainly found in adipose tissue, especially in brown adipose tissue. Absorption of octacosanol is very low and mainly excreted through feces. The radioactivity of octacosanol was also partly expired as 14CO2. About 49% of the administered dose were excreted through different pathways. Metabolites of octacosanol are present in the urine. Octacosanol may be partly oxidized and degraded to fatty acids through beta-oxidation.

Pharmacokinetics of [6]-gingerol after intravenous administration in rats with acute renal or hepatic failure

The pharmacokinetics of [6]-gingerol were investigated in rats with acute renal failure induced by bilateral nephrectomy, or those with acute hepatic failure induced by a single oral administration of carbon tetrachloride (CCl4), to clarify the contribution of the kidney and liver to the elimination process of [6]-gingerol. After bolus intravenous administration, a plasma concentration-time curve of [6]-gingerol was illustrated by a two-compartment open model. There was no significant difference in either the plasma concentration-time curve or any pharmacokinetic parameters between the control and nephrectomized rats. It is suggested, therefore, that renal excretion does not contribute at all to the disappearance of [6]-gingerol from plasma in rats. In contrast, hepatic intoxication with CCl4 elevated the plasma concentration of [6]-gingerol at the terminal phase. Its elimination half-life increased significantly, from 8.5 to 11.0 min, in CCl4-intoxicated rats. The extent of [6]-gingerol bound to serum protein was more than 90% and was affected very slightly by the CCl4-intoxication. These aspects indicate that [6]-gingerol is eliminated partly by the liver.

Enhancement of propranolol hydrochloride and diazepam skin absorption in vitro. II: Drug, vehicle, and enhancer penetration kinetics

The fluxes of representative hydrophilic (propranolol hydrochloride) and lipophilic (diazepam or indomethacin) drugs, administered as ethanolic solutions containing putative penetration enhancers (n-nonane, 1-nonanol, and 1-decanol), were measured across hairless mouse skin in vitro. Propranolol transport was augmented significantly by the presence of 4% (v/v) alkane or alkanol in the vehicle; diazepam and indomethacin, on the other hand, were enhanced only by n-nonane. Experiments with saturated solutions of the drugs as the donor phase revealed that the actions of the enhancers were taking place in the skin and were not a result of an alteration of solute thermodynamic activity in the vehicle. In separate runs, the impact of n-nonane and 1-nonanol on the percutaneous penetration of ethanol was determined. Temporal effects identical to those on the flux of propranolol were observed. A further measurement revealed that the penetration of 1-decanol, when administered as a 4% (v/v) solution in ethanol, followed a profile similar to that of the solvent (which, in turn, was comparable with that of the independently assessed propranolol hydrochloride). Thus, considerable linkage exists between the transport of a hydrophilic drug and the major vehicle component in the presence of n-nonane and 1-nonanol. The lipophilic drugs, conversely, were promoted only by n-nonane and only after most of the ethanol had been absorbed. The results show that an apparent synergy of transport between a putative enhancer and a cosolvent may not always lead to augmented drug flux. Study of the transport of all key formulation components is recommended, therefore, to optimize vehicles for transdermal drug delivery.

Importance of hydrophobic apoproteins as constituents of clinical exogenous surfactants

The biophysical properties and physiologic effects of a series of clinical exogenous pulmonary surfactants was compared to determine the importance of the hydrophobic apoproteins (SP-B and C) as constituents of these preparations. The three exogenous surfactants studied, calf lung surfactant extract (CLSE), Survanta (Surfactant-TA), and Exosurf, all contain dipalmitoyl phosphatidylcholine (DPPC) as their major constituent. CLSE and Survanta also contain 1 to 2% of SP-B,C but Exosurf has the additives hexadecanol and tyloxapol instead to enhance the activity of DPPC. In adsorption experiments, CLSE reached a final surface tension of 22 mN/m, and Survanta and Exosurf reached 28 and 38 mN/m, respectively. Addition of 1% by weight of an apoprotein isolate containing both SP-B and C to Exosurf slightly improved its adsorption. In oscillating bubble studies, CLSE and Survanta decreased surface tension to low values of less than 1 and 2 mN/m, respectively, but Exosurf achieved a minimum value of only 29 mN/m. Addition of SP-B,C to Exosurf improved this minimum to 1 mN/m and approached the behavior of mixtures of synthetic DPPC with SP-B,C. In both adsorption and pulsating bubble experiments, the minimum surface tensions found for Exosurf were almost identical to those generated by tyloxapol alone. In studies of physiologic activity, 20 mg of CLSE or Survanta restored the pressure-volume mechanics of lavaged, surfactant-deficient excised rat lungs to 95 and 50%, respectively, of normal prelavage levels. Instillation of Exosurf (37.5 mg) produced a minimal improvement of only 10% compared to 70% for mixtures containing 1% SP-B,C with either Exosurf or DPPC.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacokinetics of [6]-gingerol after intravenous administration in rats

A high-performance liquid chromatographic method to determine [6]-gingerol, a pungent constituent of ginger, in rat plasma was developed and a pharmacokinetic study was performed in rats. Quantitative analysis with high reproducibility was achieved for [6]-gingerol over the concentration range of 0.2-40 micrograms/ml. After bolus intravenous administration at a dose of 3 mg/kg, the plasma concentration-time curve was described by a two-compartment open model. [6]-Gingerol was rapidly cleared from plasma with a terminal half-life of 7.23 min and a total body clearance of 16.8 ml/min/kg. Serum protein binding of [6]-gingerol was 92.4%.

The toxicity of acetylenic alcohols to the fathead minnow, Pimephales promelas: narcosis and proelectrophile activation

1. The 96-h LC50 values for 16 acetylenic alcohols in the fathead minnow (Pimephales promelas) were determined using continuous-flow diluters. The measured LC50 values for seven tertiary propargylic alcohols agreed closely with the QSAR predictions based upon data for other organic non-electrolytes acting by a narcosis mechanism. 2. Four primary and four secondary propargylic alcohols were 7 to 4600 times more toxic than the respective narcotic toxicity estimated by QSAR. Metabolic activation to electrophilic alpha,beta-unsaturated propargylic aldehydes or ketones is proposed to account for the increased toxicity. 3. 3-Butyn-1-ol and 4-pentyn-2-ol, primary and secondary homopropargylic alcohols, were 320 and 160, respectively, times more toxic than predicted. In this case an activation step involving biotransformation to an allenic electrophile intermediate was proposed.

Selachyl alcohol as an oral antihypertensive agent: a preliminary note

Selachyl alcohol (SA) is a mono-oleyl glyceryl ether. It has certain biologic activities similar to those of the antihypertensive neutral renomedullary lipid (ANRL) derived from the renal papilla and its renomedullary interstitial cells (RIC). These include a vaso-depressor effect following bolus injection and a requirement for hepatic activation for the development of biological activity. In view of this similarity to ANRL, it appeared worthwhile to test the antihypertensive action of SA when given via the GI tract. Accordingly, pure SA was given either by gavage or by tube into the stomach or duodenum of one-kidney, one-clip hypertensive rats (5-10 mg per dose). The role of hepatic activation was demonstrated by comparing the BP response to bolus injection of SA and ANRL with and without the presence of an intact circulation to the liver. Administration of SA via the GI tract resulted in a significant decline in BP without tachycardia or weight loss. In the absence of a circulation to the liver, neither SA nor ANRL was active. SA appears to be an effective antihypertensive agent when given via the GI tract.