Recent advances in the quantification of drug metabolizing enzymes and transporters by proteomic approach / 药学学报

With the advance of drug development and research techniques, the drug metabolic processes and mechanism can be more deeply achieved. As the drug metabolism and pharmacokinetics process are mediated by drug metabolizing enzymes and transporters, study of drug metabolizing enzymes and transporters has become an important part for drug development. The traditional immunoassays with low sensitivity and poor specificity can not reflect the accurate expression level of drug metabolizing enzymes and transporters. We now give a brief review on the quantitative study of drug metabolizing enzymes and transporters by mass spectrometry-based proteomic approach.

Fragmentation pathways of five estrogens using electrospray ionization quadrupole time-of-flight mass spectrometry / 药学学报

The fragmentation pathways of five estrogens (estradiol, estrone, equilin sulfate, 17 a-dihydroequilin sulfate and equilenin sulfate) have been studied with high resolution and high mass accuracy using electrospray ionization quadrupole time-of-flight mass spectrometry (ESI-Q-TOF/MS) in the negative ion mode. Molecular weights were obtained from [M-H](-) ions in the product ion spectra. The results indicate that the five structurally similar estrogens have similar fragmentation pathways. Using their stable isotope forms as internal reference compounds, the accurate mass and composition of the fragment ions were determined. During collision-induced dissociation (CID), cleavage is initiated by loss of oxygen atoms from carbon-17, after which D and C rings cleave sequentially and rearrange to finally form stable conjugate structures with highly abundant characteristic fragment ions at m/z 183 (accompanied by m/z 181), m/z 169 and m/z 145 (accompanied by m/z 143). Understanding these characteristic fragmentation pathways of estrogens will be helpful in identifying the structures of steroid hormones in general.

Fragmentation behaviors of taxanes drugs using electrospray ionization with quadrupole time-of-flight mass spectrometry / 药学学报

The fragmentation pathways of two taxanes drugs have been studied in positive ion mode by Q-TOF with the advantages of high mass accuracy and high resolution analysis. The [M+H] + ions were observed by ESI-MS, from which the molecular weights were obtained. Using the protonated pseudo-molecular ions [M+H]+ as internal reference compounds, the accurate mass and element composition of the fragment ions were determined. The collision induced dissociation (CID) data of the [M+H] ions provided fragmentation pathways of related compounds. Results showed that the major cleavage pathways of paclitaxel and docetaxel were the same that the cleavage of C-O bond between the side chain and taxol skeleton easily occurred, then stripping of the functional groups on the parent ring. Some common fragments were formed, such as m/z 105.033 7, 291.137 3, 309.148 5, 327.159 7, 387.181 2 and 509.217 4, which would provide a basis for future qualitative and quantitative analysis of taxanes in vitro and in vivo.

Multidimensional spatial triangular area as an index for the evaluation of the release-absorption correlation of multiple component traditional Chinese medicines / 药学学报

The paper is aimed to provide a novel index, named as multidimensional spatial triangular area, for the evaluation of the release-absorption correlation of multiple component traditional Chinese medicines (TCMs). The applicability of the method was demonstrated by the example data. The method and standard practice for evaluation of the release-absorption correlation for western medicines with single compound could not be applied to TCMs with multiple components. The release percentage or absorption percentage of the multiple components for TCMs at the sampling time was a point in the multidimensional space. The area of the triangle formed byt the sequential three points represented the changing characteristics of the components' release and absorption kinetics. The side lengths of the triangle could be calculated from the spatial distances between each two of the sequential three points. Then the triangle area could be obtained by the side lengths. The in vitro release-in vivo absorption correlation of the multiple components could be represented by the correlation between the integrating values of the release triangle areas and that of the absorption triangle areas. The results of the examples indicated that the multidimensional spatial triangular area method could treat the multiple components in a holistic way, in line with the holism the hi he TCMs. Therefore, the multidimensional spatial triangular area method provided new methodology for the release-absorption correlation of the TCMs with multiple components.

Application of the theories of materiomic release kinetics to the evaluation of the sustained release kinetics and synchronicity of yinqiaojiedu honeyed pills / 药学学报

Yinqiaojiedu honeyed pills were equally divided into 1/4, 1/8, 1/12, and 1/16 parts. The materiomics release rates within 12 h of the intact Yinqiaojiedu honeyed pills and the divided granules were determined by the paddle method with a rotate speed at 100 r x min(-1), and the materiome was quantified by UV-scan and Kalman filter methods. The intact Yinqiaojiedu honeyed pills behaved typical sustained release profiles, while the well-divided portions also maintained a sustained release profile over 2-4 h. The release rates were well correlated with the extents for the divisions of the pills. The Weibull distribution parameters, Td and T50, were reduced in line with the particle size, indicating that the ways of administration of the pills may play a role in the in vivo pharmacokinetics of the pills. The visualization results showed obvious difference of materiomic release synchronicities between the intact pills and the equally divided particles, and the divisions enhanced the asynchronization. Therefore the novel theory of materiomic release/dissolution kinetics of traditional Chinese medicines (TCMs) quantitatively proved the traditional dosage form, namely, honeyed pills, as a prototype of the sustained-release dosage form with a visualization of the scientific connotation to the old saying in the classics of TCM, Pills, the moderate ones in action. In terms of materiome increase for each period of the release profiles, the materiomic release synchronicity was visually demonstrated. The novel theories provided methodological basis for the evaluation of traditional dosage forms and the design of the modern drug delivery systems for TCMs.

Novel method for the evaluation of the synchronicity of the chemomic release/dissolution of multi-component traditional Chinese medicines / 药学学报

Due to the diversity of components within the traditional Chinese medicines (TCMs), the release profiles of the components in the TCM dosage forms vary dramatically and no quantification method is available to determine the variance yet. Based upon the principles of Kalman filter method, the authors defined a new parameter, relative chemomic error (epsilon), to evaluate the asynchronous nature of the components in TCMs, and a derivative parameter as synchronization factor (SF) to quantify the synchronicity of the chemome of the TCMs. The average synchronization factor (SF(av)) was accordingly derived to simultaneously quantify the release/dissolution profiles of the multi-components in TCMs. Randomly generated simulation data were processed to demonstrate the chemomic data processing and the methodology. The results indicated that the novel parameter epsilon was well correlated (r = 0.996 8) with the coefficient of variation from the conventional release profiles of all the components. As the asynchronicity was the intrinsic characteristics of the multi-component TCMs, the synchronicity might be a new target of quality control of TCMs. The methods established by this report can be used a quantitative tool for the evaluation of the chemomic release synchronization of TCMs.

Identification of estazolam, alprazolam and triazolam in human urine by LC/MSn / 药学学报

<p><b>AIM</b>To investigate the fragmentation behavior of triazolobenzodiazepines and to develop a specific, sensitive and rapid LC/MSn assay for simultaneous determination of estazolam, alprazolam and triazolam in human urine.</p><p><b>METHODS</b>After oral administration of a single 4 mg dose of the drugs to each of three healthy volunteers, urine samples were purified by solid-phase extraction, and then injected into an ODS column (150 mm x 4.6 mm) with a mobile phase of methanol-water (8:2) for LC/MSn analysis. The structures of estazolam, alprazolam and triazolam in human urine were identified by direct comparison of the observed mass spectra and the chromatographic retention time with those of the reference substance. The mass spectrometer (Finnigan LCQ) was operated in positive mode and in two scan modes including SIM and full scan MS/MS mode. The obtained mass spectra was analyzed assisted with the software Mass Frontier 1.0 for their fragmentation pathways.</p><p><b>RESULTS</b>The full scan MS/MS spectra of each compound gave characteristic fragment ions of [M + H - N2]+ and [M + H - Cl]+. The detection limit was below 0.5 ng.mL-1 for estazolam, alprazolam and triazolam in human urine.</p><p><b>CONCLUSION</b>The method is useful in forensic and clinical toxicology in which unequivocal identification of eatazolam, alprazolam and triazolam is desired.</p>

Isolation and identification of a major metabolite of SFZ-47 in the rabbit urine / 药学学报

<p><b>AIM</b>To isolate and identify a glucuronide metabolite of SFZ-47 [3H-1,2-dihydro-2-(4-methyl-phenylamino)methyl-1-pyrrolizinone], which is difficult to synthesize because it undergoes hydrolysis and intramolecular acyl migration at physiological pH, in rabbit urine.</p><p><b>METHODS</b>Two rabbits were ig 200 mg doses of SFZ-47. Urine was collected for 24 h, adjusted to pH 4.0 with acetic acid and lyophilized. The residues were reconstituted in 25 mL methanol and centrifuged at 5,000 r.min-1 for 10 min. The supernatant was filtered (0.45 micron) and then isolated with semi-preparative reversed phase HPLC. The eluent collected from individual peaks was evaporated by rotary evaporation and freeze-drying. Compounds were then identified with electrospray ion trap mass spectrometry and 1HNMR spectroscopy.</p><p><b>RESULTS</b>The 1HNMR and ESI-MSn results indicate that the metabolite is the 1-O-acyl beta-D-glucuronide conjugate of 4-(3H-1,2-dihydro-1-pyrrolizinone-2-methylamino) benzoic acid.</p><p><b>CONCLUSION</b>This method was shown to be rapid and simple and gave excellent resolution from endogenous constituents in urine, and it is suitable for preparation of the glucuronide metabolites of SFZ-47 and its analogues.</p>