Pharmacokinetic Profiling of Butylidenephthalide and Alisol B in Danggui-Shaoyao-San in Rats.

BACKGROUND AND OBJECTIVE: Danggui-Shaoyao-San (DSS), a famous Chinese formula, has been widely used to treat gynecological disorders since ancient times and has recently showed efficacy in treating Alzheimer's disease. Butylidenephthalide (BDPH) and alisol B (ALI) are recognized as the primary active ingredients of DSS. The objectives of the present study were to evaluate the pharmacokinetic comparative study of BDPH and ALI in herbal extracts and their purified forms. METHOD: A sensitive and specific high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) methodology was developed to determine the concentration level of BDPH and ALI in rat plasma. This approach enables a real-time pharmacokinetics profiling of BDPH and ALI in DSS extracts as well as their purified forms in rats after oral administration. RESULTS: The validated method showed an evident linearity over a wide range of dosages (r > 0.99) with sensitivity down to 1.0 ng/mL for each analyte. The extraction recovery of the analyte ranged from 80.8 to 99.1%. The pharmacokinetic parameters were significantly different in herbal extracts and their purified forms. The results showed that the absorption of both BDPH and ALI from DSS extracts was significantly greater compared with their purified forms. CONCLUSIONS: A highly specific, sensitive and rapid HPLC-MS/MS method was developed and applied for the determination of BDPH and ALI in rat plasma. It was found that BDPH and ALI had higher bioavailability in the DSS extract compared with their purified forms.

Liquid chromatography-tandem mass spectrometry evaluation of the pharmacokinetics of a diacid metabolite of norcantharidin loaded in folic acid-targeted liposomes in mice.

A previous study has reported diacid metabolite (DM) as the stable form of norcantharidin (NCTD), which is almost 100% metabolized to DM-NCTD. However, the unreliable pharmacokinetic characteristics of DM-NCTD could result in low bioavailability, hindering the clinical use of DM-NCTD in the treatment of diseases. A liposomal drug delivery system could overcome the shortcomings of DM-NCTD by improving the relative bioavailability (Fr), reducing drug toxicity, and increasing the therapeutic efficacy. However, there are no data concerning the pharmacokinetics of a DM-NCTD-loaded liposomal drug delivery system in animals, which is required for assessing its safety profile. Therefore, a rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of DM-NCTD in mouse plasma. Standard curves were linear (r=0.9966) over the range 10.0-1.00×10(4)ng/ml in mouse plasma with a lower limit of quantification (LLOQ) of 10ng/ml. This study successfully investigated the pharmacokinetics of DM-NCTD and DM-NCTD encapsulated in polyethylene glycol (PEG)-Liposomes (DM-NCTD/PEG-Liposome) or folic acid (FA)-PEG-Liposomes (DM-NCTD/FA-PEG-Liposome) in Kunming mice after a single intravenous dose of 2mg/kg. The plasma profile data of the three groups adhered to a two-compartment model. Compared with the DM-NCTD group, the Liposome groups had longer circulation times following intravenous administration in mice, and the Fr of DM-NCTD increased significantly (P<0.05). Furthermore, the area under the concentration-time curve (AUC) declined with an increase in the volume of distribution (Vd) from the PEG-Liposome to the FA-PEG-Liposome groups, which indicates a more efficient removal of the drug from the plasma of the FA-PEG-Liposome group. This result suggests a possible increased risk of DM-NCTD intoxication in normal tissues with FA-PEG-Liposomes. Based on this study, further investigation of the biodistribution of DM-NCTD/FA-PEG-Liposomes in healthy animals is warranted. In addition, the plausibility of formulating a safe DM-NCTD-loaded system without increasing toxicity against normal tissues needs to be determined.

Metabolic conversion from co-existing ingredient leading to significant systemic exposure of Z-butylidenephthalide, a minor ingredient in Chuanxiong Rhizoma in rats.

Pharmacokinetic (PK) study of medicinal herbs is a great challenge, because which component(s) is(are) the bioactive ingredients is largely unknown. Most of the reported PK studies of herbs focused on the major ingredients regardless of their in vivo bioactivities, while PK of components with low content in herbs is often ignored. The present study demonstrates how PK study can reveal potential importance of a low content ingredient to the herbal bioactivities using Z-butylidenephthalide (BuPh), a bioactive phthalide present in a significantly low quantity in medicinal herb Chuanxiong Rhizoma, as an example. PK of BuPh was investigated in rats using Chuanxiong extract, fraction containing BuPh and ligustilide, and pure BuPh, respectively. The results demonstrated that remarkable blood concentrations of BuPh were observed after administration of the herbal extract and its systemic exposure was significantly different between BuPh given in pure and mixed forms. More interestingly, AUC of BuPh via intake of fraction (9.3-fold) and extract (4.5-fold) was significantly greater than that obtained from pure BuPh, which was further evidenced to be mainly due to metabolic conversion from ligustilide, a major component in Chuanxiong. Our findings revealed that although it naturally occurred in low amount, BuPh reached significant systemic concentrations via metabolic conversion from ligustilide. Moreover, our results demonstrated that PK study is one of crucial and inevitable steps for revealing in vivo bioactive ingredients of herbal medicines, and such studies should be more appropriate to focus on in vivo profile of the ingredients co-existing in herbs rather than only studying them individually.

Evaluation of an immunoaffinity extraction column for enrichment of adducts between human serum albumin and hexahydrophthalic anhydride in plasma.

An immunoaffinity extraction (IAE) column was prepared for extraction of adducts between human serum albumin (HSA) and hexahydrophthalic anhydride (HHPA). HHPA is a strong sensitizer inducing immunoglobulin E antibodies in vivo. Polyclonal antibodies from a rabbit immunized with keyhole limpet hemocyananin-HHPA conjugate were purified using a Protein A Sepharose gel. To obtain antibodies with optimal affinity towards HHPA-protein adducts, HHPA-specific antibodies were selected using an N-hydroxysuccinimide-Sepharose column coupled with albumin-HHPA conjugate. Antibodies eluted from this column at pH 2.2 were selected to prepare the IAE column. The column was evaluated using 2 mL plasma spiked with HSA-HHPA conjugate. The column was eluted with glycine buffer at pH 2.0. The conjugates in the eluate were hydrolyzed to the corresponding HHP acid and quantified by mass spectrometry. The average recovery of HHPA adducts in 11 experiments was 68% with a coefficient of variation (CV) of 7%. The column's capacity to bind protein-HHPA adducts was found to be linear in the range of 0.15-1.2 nmol conjugate. The evaluation showed that the IAE column had adequate affinity towards the HHPA adducts and that the adducts could be extracted with good recovery and precision from a large volume of plasma.

LC-DAD-APCI-MS-based screening and analysis of the absorption and metabolite components in plasma from a rabbit administered an oral solution of danggui.

A valid chromatographic fingerprint method using liquid chromatography-diode array detection-atmospheric pressure chemical ionization mass spectrometry in negative mode (LC-DAD-APCI-MS) is proposed for studying the absorption and metabolites of a traditional Chinese medicine (TCM) Angelica sinensis (danggui) in rabbit plasma, after the rabbit is administered with danggui oral solution (DOS). More than thirty-two common components were detected in both DOS and rabbit plasma, which shows that the components in the DOS were absorbed into the body of the rabbit. Of these, senkyunolide I, senkyunolide H, Z-6,7-epoxyligustilide, 3-butylidene-7-hydroxyphthalide, Z-ligustilide, Z-butylidenephthalide, Diels-Alder dimers of ligustilide, linolenic acid, linoleic acid and falcarindiol were tentatively identified from their MS, UV spectra and retention behavior by comparing the results with the published literature. At least ten components were found in rabbit plasma but not in DOS, indicating that these components must be metabolites of some of the components in the original extract. The results prove that the proposed method can be used to rapidly analyze multiple constituents in TCMs, and to screen for bioactive compounds by comparing and contrasting the chromatographic fingerprints of DOS and plasma samples.

Serum albumins are the major site for in vivo formation of hapten-carrier protein adducts in plasma from humans and guinea-pigs exposed to type-1 allergy inducing hexahydrophthalic anhydride.

BACKGROUND: Organic acid anhydrides (OAAs) are highly allergenic compounds used in the chemical industry. The OAAs probably act as haptens but the proteins that form conjugates with OAAs in vivo are still unknown. Conjugates between the anhydrides and serum albumins (SAs) have routinely been used when testing for OAA-specific antibodies. However, the use of SA as the carrier-protein in these tests has never been evaluated. OBJECTIVE: The aim of this study was to identify major and also immunologically relevant protein conjugates of a particularly sensitizing OAA, hexahydrophthalic anhydride (HHPA), in plasma. METHODS: Plasma was obtained from a HHPA-exposed worker, from a guinea-pig (GP) exposed to HHPA in an exposure chamber for 2 weeks (8 h/day, 5 days/week) and from a GP exposed once, nose-only, to tritium-labelled HHPA for 8 h. The plasma was fractionated using ion exchange chromatography and gel filtration. These fractions and also aliquots of unfractioned plasma were hydrolysed, derivatized and analysed for anhydride adduct content using gas chromatography-mass spectrometry. Further, plasma from the tritium labelled HHPA-exposed GP was separated by SDS gel electrophoresis and analysed by autoradiography. In addition, immunologically relevant proteins were identified through specific IgE and IgG immunoblottings using sera from exposed workers. RESULTS: For humans > 85% and for GPs > 74% of the HHPA-adducts coeluted with SA in plasma. Autoradiography of GP-plasma shows a single 66 kDa protein that binds HHPA. IgE immunoblotting shows a major 66 kDa and a minor 28 kDa protein which could be inhibited by HHPA-SA conjugate. IgG immunoblotting showed a major 66 kDa protein and several minor protein bands. CONCLUSION: This study shows SA to be the major protein in plasma that forms adducts in vivo with HHPA. The results also show that in an in vitro synthesized HHPA plasma protein conjugate, HHPA-specific IgE and IgG antibodies bind preferably to the SA.

Total plasma protein adducts of allergenic hexahydrophthalic and methylhexahydrophthalic anhydrides as biomarkers of long-term exposure.

OBJECTIVES: The aim of this study was to evaluate the applicability of total plasma protein adducts (TPPA) of 2 sensitizing low-molecular-weight allergens, hexahydrophthalic anhydride (HHPA) and methylhexahydrophthalic anhydride (MHHPA), as biomarkers of long-term exposure. METHODS: Urine samples from occupationally exposed workers were analyzed for the levels of urinary metabolites of HHPA and MHHPA, and the levels were used as the index of exposure. In addition, blood samples were obtained from the same persons, and the levels of TPPA were determined. Reversed solid phase extraction, derivatization using pentafluorobenzyl bromide, and gas chromatography-mass spectrometry analysis in the negative ion chemical ionization mode were used to quantify the exposure. To assess the suitability of TPPA as a biomarker of exposure to the anhydrides, the TPPA levels were correlated to urinary metabolite levels and hemoglobin (Hb) adducts. The toxicokinetics of TPPA were also studied to determine the elimination half-time of the adducts. RESULTS: The levels of TPPA correlated exceptionally well with the metabolite levels in the urine sampled repeatedly, giving r=0.97 for HHPA and r=0.92 for MHHPA. The TPPA of HHPA correlated highly with the Hb adducts with r=0.86. There were also good correlations between single urinary determinations and the TPPA levels (r(s)=0.71 and 0.81, respectively, for HHPA and MHHPA). The in vivo decay of TPPA gave an elimination half-time of 22 days for HHPA and 24 days for MHHPA. CONCLUSIONS: TPPA levels of HHPA and MHHPA are excellent biomarkers of long-term exposure to anhydrides.

Quantification of protein adducts of hexahydrophthalic anhydride and methylhexahydrophthalic anhydride in human plasma.

Hexahydrophthalic anhydride (HHPA) and methylhexahydrophthalic anhydride (MHHPA) are two highly allergenic compounds used in the chemical industry. A method was developed for quantification of protein adducts of HHPA and MHHPA in human plasma. The plasma was dialysed and the anhydrides were hydrolysed from the proteins at mild acidic conditions. The released hexahydrophthalic acid (HHP acid) and methylhexahydrophthalic acid (MHHP acid) were purified by reversed solid phase extraction followed by derivatisation with pentafluorobenzyl bromide. The derivatives were analysed using GC-MS in negative ion chemical ionisation mode with ammonia as moderating gas. As internal standards, deuterium labelled HHP and MHHP acids were used. The detection limits were 0.06 pmol mL(-1) plasma for HHP acid and 0.03 pmol mL(-1) plasma for MHHP acid. The between-day precisions for HHP acid were 18% at 0.3 pmol mL(-1) and 8% at 4 pmol mL(-1). For MHHP acid, the precisions were 13% at 0.3 pmol mL(-1) and 9% at 4 pmol mL(-1). There were strong correlations (r=0.94 for HHPA and 0.99 for MHHPA) between total plasma protein adduct concentrations and serum albumin adduct levels. Workers exposed to time-weighted average air levels of HHPA between < 1 and 340 microg m(-3) and between 2 and 160 microg m(-3) for MHHPA had plasma adduct levels between the detection limits of the methods and 8.40 and 19.0 pmol mL(-1), respectively.

Human hemoglobin adducts following exposure to hexahydrophthalic anhydride and methylhexahydrophthalic anhydride.

Hexahydrophthalic anhydride (HHPA) and methylhexahydrophthalic anhydride (MHHPA) are highly allergenic compounds used in the chemical industry. The aim of this study was to characterize the protein adducts in erythrocytes following exposure to HHPA and MHHPA. Blood and urine samples were obtained from 51 HHPA- and MHHPA-exposed workers. Erythrocytic proteins from HHPA- and MHHPA-exposed workers were fractionated by gel filtration and ion exchange chromatography. In vitro synthesized conjugates between tritium-labeled and unlabeled HHPA and hemoglobin (Hb) were hydrolyzed by acid or digested by Pronase E. Levels of in vivo formed anhydride-Hb adducts and urinary/plasma levels of the corresponding acids were analyzed by gas chromatography-mass spectrometry (GC-MS) and correlated. The decay of adducts was studied in workers leaving employment or during vacation. More than 85% of the adduct forming protein in vivo coeluted with Hb in gel filtration and ion exchange chromatography. At least 70% of the HHPA in the in vitro formed adducts was found on lysine by GC-MS. Similar findings were obtained using Pronase E-digested tritium-labeled Hb-HHPA. The adduct levels in workers ranged 0-26 pmol/g Hb (mean 2. 7 pmol/g Hb) for HHPA, and the range for MHHPA was 0-55 pmol/g Hb (mean 4.1 pmol/g Hb). The Spearman's rank correlation coefficient between urine data and adducts was for HHPA rs = 0.80 and for MHHPA, rs = 0.78. For the plasma, the correlation using HHPA data was rs = 0.80 and for MHHPA, rs = 0.69. The adducts seemed to be stable in vivo. The adduct levels may be used as biomarkers of exposure to HHPA and MHHPA.

Biological monitoring of methylhexahydrophthalic anhydride by determination of methylhexahydrophthalic acid in urine and plasma from exposed workers.

OBJECTIVE: To investigate whether methylhexahydrophthalic acid (MHHP acid) in urine and plasma can be used as a biomarker for exposure to methylhexahydrophthalic anhydride (MHHPA). METHODS: MHHPA in air was sampled by Amberlite XAD-2 and analysed by gas chromatography (GC) with flame ionisation detection. MHHP acid in urine and plasma was analysed by GC with mass spectrometric detection. Workers occupationally exposed to MHHPA were studied. Air levels of MHHPA were determined by personal sampling in the breathing zone. Urinary levels of MHHP acid, a metabolite of MHHPA, were determined in 27 workers. In eight workers all urine was collected at intervals during 24 h. Plasma levels of MHHP acid were determined in 20 workers. RESULTS: The time-weighted average (TWA) air levels ranged from 5 to 60 micrograms MHHPA/m3 during 8-h workshifts. The urinary levels of MHHP acid increased during exposure and decayed after the end of exposure with an estimated half-life of about 6 h. A correlation was found between the TWA air levels of MHHPA and creatinine-adjusted MHHP acid levels in urine collected during the last 4 h of exposure. A correlation was also seen between the TWA air levels of MHHPA and the plasma concentrations of MHHP acid. An exposure to 20 micrograms MHHPA/m3 corresponded to about 140 nmol MHHP acid/mmol creatinine and about 40 nmol MHHP acid/l plasma. CONCLUSION: The results indicate that MHHP acid in urine or plasma may be used for biological monitoring of the exposure to MHHPA.

Determination of Z-butylidenephthalide in plasma by high-performance liquid chromatography.

An HPLC assay is described for the determination of Z-butylidenephthalide (Z-Bdph) in plasma. Plasma samples were cleaned up by extraction with 2% chloroform in n-hexane. Z-Bdph was separated on a normal-phase silica column with a mobile phase of chloroform-n-hexane (1:1). The limit of quantitation with UV detection at 254 nm for Z-Bdph in plasma was 0.01 microgram/ml. The recovery of Z-Bdph by organic solvent extraction of plasma was 99.5%. The intra-day and inter-day coefficients of variation and relative errors for Z-Bdph determination in plasma were both less than 10%. The present method was applied to pharmacokinetic studies of Z-Bdph in plasma after intravenous administration to rabbits.

Immunologic cross-reactivity of acid anhydrides with immunoglobulin E against trimellityl-human serum albumin.

The purpose of this study was to determine whether workers sensitized by one acid anhydride, trimellitic anhydride (TMA), would possibly react immunologically to two other acid anhydrides, phthalic anhydride (PA) or maleic anhydride (MA). We studied serum samples from four workers with TMA asthma and immunoglobin E (IgE) against TMA conjugated to human serum albumin (TM-HSA). In enzyme-linked immunosorbent assay (ELISA) cross-inhibition studies, TM-HSA inhibited IgE binding to TM-HSA, but when 100 times more P-HSA or M-HSA was used, no significant inhibition occurred. However, in ELISA studies of P-HSA and M-HSA, we saw binding of specific serum IgE. Finally, in passive transfer studies in rhesus monkeys with serum from an individual with antibodies to all three acid anhydrides, the following titers were obtained: TM-HSA (1:32), P-HSA (1:8), M-HSA (negative). We conclude that cross-inhibition studies may not be the best method for determining whether an individual sensitized to one antigen will react to a related antigen. The determination of biologic reactivity in a rhesus monkey model of passive cutaneous transfer makes it likely that biologic reactivity would also occur in a human sensitized to TMA and then exposed to another anhydride such as PA.

Determination of 4-methyl-cis-hexahydrophthalic anhydride in human blood by gas chromatography with electron-capture detection.

A gas-chromatographic technique using 63Ni electron-capture detection was applied to the determination of 4-methyl-cis-hexahydrophthalic anhydride in the blood of workers occupationally exposed to this airborne agent. The detection limit was 0.24 nmol ml-1. For occupational exposure to between 0.14 and 0.31 mg m-3 of the anhydride, the anhydride concentration in the workers' blood samples ranged from 3.4 to 10.7 nmol ml-1. The results are consistent with earlier findings in animal exposure experiments and support the view that the hydrolysis of the anhydride in a biological medium is not spontaneous, but might be an enzyme-catalysed reaction. The resulting dicarboxylic acid is excreted by the kidneys without further conjugation reactions.