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1.
目的:研究麝丹眼用即型凝胶中麝香酮与丹酚酸B经家兔离体角膜的渗透特性,为该制剂的开发提供参考。方法:以含1.0%聚山梨酯-80的生理盐水为释放介质,采用Franz扩散池法考察麝丹凝胶中麝香酮和丹酚酸B经家兔角膜的渗透性;以2,4-二硝基苯肼为衍生剂,衍生温度60℃,衍生时间30 min,对麝丹眼用即型凝胶剂家兔离体角膜渗透的接受液进行衍生,采用高效液相色谱法进行梯度洗脱,同时测定接收液中麝香酮、丹酚酸B的含量;考察不同p H和麝香酮质量分数对麝丹眼用即型凝胶中麝香酮、丹酚酸B离体角膜渗透性的影响,绘制累积释药曲线,建立动力学模型,计算表观渗透系数和稳态流量。结果:麝香酮和丹酚酸B通过角膜的扩散行为均符合零级动力学特征,麝丹凝胶中麝香酮离体角膜渗透特性对p H不敏感,丹酚酸B随p H降低而渗透速率增大;丹酚酸B渗透性随麝香酮质量分数增加而渗透量增加,在麝香酮质量分数为0.5%时,麝香酮表观渗透系数1.530×10-6cm·s-1,稳态渗透速率7.651×10-3μg·s-1·cm-2;在此质量分数下,丹酚酸B的表观渗透系数1.218×10-6cm·s-1,稳态渗透速率6.558×10-3μg·s-1·cm-2。结论:麝香酮可促进麝丹眼用即型凝胶中丹酚酸B的角膜渗透,该凝胶中麝香酮最佳用量0.5%。  相似文献   
2.
该实验采用中心组合设计-效应面法制备并优化了温敏型麝丹眼用即型凝胶,其处方最佳基质为18%的泊洛沙姆407(P407)和5%的泊洛沙姆188(P188);应用安东帕MCR302 流变仪对其进行了流变学考察,振幅扫描结果显示应控制其应变(γ)<0.5%,在高频区其弹性模量(G')大于黏性模量(G"),表现为凝胶特征,有较好的稳定性,通过温度扫描G',G"及相角(δ)的变化来确定了其相变温度(TSG)为33.25 ℃,触变性实验显示其结构恢复时间短于5 s;分别采用表面张力仪、露点渗透压仪分别测定了其表面张力和渗透压,结果分别为36.43 mN·m-1,320.6 mOsm·kg-1;荧光标记示踪法观察了其在眼角膜的滞留时间为180 min;其溶出实验表现为零级释放动力学特征,麝香酮和丹酚酸B的释放与药物溶蚀线性相关;眼部刺激性实验显示其无刺激性。麝丹即型凝胶有望为临床视网膜静脉阻塞治疗提供一种新型外用长效制剂。  相似文献   
3.
目的:建立九味防瘟散中麝香酮含量测定方法,以麝香酮为指标研究该制剂的稳定性.方法:以HPLC-MS法测定麝香酮的含量;研究九味防瘟散在不同温度和包装条件下的稳定性.结果:麝香酮浓度在0.2~20 mg·L-1线性关系良好(r =0.999 9),精密度、回收率、稳定性、重复性均符合实验要求.稳定性方面,去外包装组麝香酮损失速率>包装组,35℃时麝香酮损失速率>4℃,密闭包装组麝香酮损失速率>密封包装组.结论:HPLC-MS法测定九味防瘟散中的麝香酮含量灵敏、快捷、简便、准确.九味防瘟散须在冷处密封条件下保存.  相似文献   
4.
The vibrational theory of olfaction assumes that electron transfer occurs across odorants at the active sites of odorant receptors (ORs), serving as a sensitive measure of odorant vibrational frequencies, ultimately leading to olfactory perception. A previous study reported that human subjects differentiated hydrogen/deuterium isotopomers (isomers with isotopic atoms) of the musk compound cyclopentadecanone as evidence supporting the theory. Here, we find no evidence for such differentiation at the molecular level. In fact, we find that the human musk-recognizing receptor, OR5AN1, identified using a heterologous OR expression system and robustly responding to cyclopentadecanone and muscone, fails to distinguish isotopomers of these compounds in vitro. Furthermore, the mouse (methylthio)methanethiol-recognizing receptor, MOR244-3, as well as other selected human and mouse ORs, responded similarly to normal, deuterated, and 13C isotopomers of their respective ligands, paralleling our results with the musk receptor OR5AN1. These findings suggest that the proposed vibration theory does not apply to the human musk receptor OR5AN1, mouse thiol receptor MOR244-3, or other ORs examined. Also, contrary to the vibration theory predictions, muscone-d30 lacks the 1,380- to 1,550-cm−1 IR bands claimed to be essential for musk odor. Furthermore, our theoretical analysis shows that the proposed electron transfer mechanism of the vibrational frequencies of odorants could be easily suppressed by quantum effects of nonodorant molecular vibrational modes. These and other concerns about electron transfer at ORs, together with our extensive experimental data, argue against the plausibility of the vibration theory.In 1870, the British physician William Ogle wrote: “As in the eye and the ear the sensory impression is known to result not from the contact of material particles given off by the object seen or heard, but from waves or undulations of the ether or the air, one cannot but suspect that the same may be true in the remaining sense, and that the undulatory theory of smell… [may be] the true one” (1, 2). Of the 29 different “theories of odour” listed in the 1967 edition of The Chemical Senses (3), nine associate odor with vibrations, particularly those theories championed by Dyson (4, 5) and Wright (68). However, the premise that olfaction involves detection of vibrational frequencies of odorants remains highly speculative because neither the structures of the odorant receptors (ORs) nor the binding sites or the activation mechanisms triggered upon odorant binding to ORs have been established. In 1996–1997, Turin (912) elaborated on the undulatory theory of smell, as considered in more detail below, and suggested that a mechanism analogous to inelastic electron tunneling spectroscopy (13) may be involved, where tunneling electrons in the receptor probe the vibrational frequencies of odorants. In 2013, Gane et al. (14) commented that “whether olfaction recognizes odorants by their shape, their molecular vibrations, or both remains an open and controversial question” and that “a convenient way to address [this question] is to test for odor character differences between deuterated and nondeuterated odorant isotopomers since these have identical ground-state conformations but different vibrational modes.” Gane et al. (14) also stated that a particularly appropriate test case would involve odorants containing “more CH group… [such as] musks [which] are among the largest odorants and typically contain 15–18 carbons and 28 or more hydrogens.”In judging the plausibility of the vibration theory, we use a multipronged approach:
  • i)We consider the concepts of shape vs. vibration theory and odorant perception vs. reception.
  • ii)As a test of the vibration theory, we have prepared a series of isotopomers of musks and other compounds, containing up to 30 C–H or C–D bonds as test odorants, which are evaluated using in vitro activation of receptors identified by us and other groups as being highly responsive to these isotopomers.
  • iii)We consider the confounding effects of impurities and isotope effects in interpreting odorant perception, as well as the validity of requirements for specific IR bands for recognition of musks by their receptors.
  • iv)We examine the physical validity of the models developed to support the vibration theory.
  • v)We consider the specific limitations of our in vitro approach using isotopomers to evaluate the vibration theory, based primarily on results obtained with a single identified human musk OR, in addition to other OR/ligand pairs.
  • vi)We consider plausible nonvibration theory models for docking of musks to the human musk receptor, OR5AN1, where the musk carbonyl group functions as a hydrogen bond acceptor.
Gane et al. (14) have framed the argument for olfactory discrimination of hydrogen isotopomers as one of “shape” vs. “vibration.” However, neither the binding modes of isotopomers nor their activation mechanisms are known. ORs belong to the superfamily of class A G protein-coupled receptors (GPCRs), which are known to be activated through allosteric conformational changes induced upon ligand binding even without triggering any kind of electron transfer processes. Ligand–receptor interactions can be both attractive and repulsive, involving hydrogen bonding, van der Waals, cation–π, π–π, ion–ion, dipole–dipole, steric, and hydrophobic interactions with the receptor, with water channels and bridging water molecules mediating hydrogen bonds, as well as metal–ion coordination, as we have recently demonstrated in the latter case (15, 16). Therefore, molecular shape can be considered a “straw-man” alternative to the vibration theory when describing the differing affinities of ligands bound to GPCRs (17, 18), including isotopomers (19, 20). Some of these attractive and repulsive interactions were identified in 1940 by Pauling and Delbrück (21), who note that interacting biomolecules “must have complementary surfaces, like die and coin, and also a complementary distribution of active groups.” In addition, shape-related features are misrepresented by vibration theory proponents. For example, Franco et al. (17) stated: “Given that proteins are chiral, a shape-only theory cannot account for the identical odors of most enantiomeric pairs,” echoing similar comments by Turin (22): “One would therefore generally expect enantiomers to have completely different smells. This is emphatically not the case.” However, these assertions are clearly at odds with the highly developed ability of mice and other mammals to discriminate an array of nonpheromonal chiral odorant enantiomeric pairs (2325), with the divergent in vitro responses to enantiomers by different combinations of ORs (26) and, in particular, with the highly selective response of the musk-sensitive mouse receptor, MOR215-1, to (R)-muscone (“l-muscone”) compared with (S)-muscone (“d-muscone”) (27).In addition to our concerns regarding shape, a second issue relates to describing how different smells are perceived, that is, the perception of an odorant. It is known that in vivo perception of odorants reflects the totality of perireceptor events as well as odorant–OR interactions (reception). Volatile odorants enter the nasal passage, where they dissolve in the nasal mucus overlying the olfactory epithelium and are then rapidly detected by ORs on the cilia of the olfactory sensory neurons, ultimately leading to signaling (28, 29). It is the mechanism of odorant–OR interactions, the reception of the odorant, that we seek to examine with isotopomers to determine whether the vibration theory is plausible, displaying isotope effects, because perception could be influenced by isotope effects due to the perireceptor events involving mucosal components, such as enzymes, mucopolysaccharides, salts, and antibodies.Whether deuterated and nondeuterated odorant isotopomers can be distinguished by smell and, even if they can, whether this distinction validates the vibration theory is a matter of contention. A 2001 paper by Haffenden et al. (30) reported that benzaldehyde-d6 gave a statistically significant difference in odor perception relative to normal benzaldehyde, in support of the vibration theory. However, this study has been criticized for lacking double-blind controls to eliminate bias and because it used an anomalous version of the duo-trio test (31). Furthermore, the study failed to account for perireceptor events, namely, the enzyme-mediated conversion of odorants that has been shown to occur in nasal mucus. For example, benzaldehyde is converted to benzoic acid (32), a reaction potentially subject to significant primary isotope effects (2, 33, 34), which could explain the difference in odor perception for the benzaldehyde isotopomers. Earlier claims that human subjects can distinguish odors of acetophenone isotopomers (9, 35) have been shown to be untrue (14, 31). Recent studies indicate that Drosophila melanogaster can distinguish acetophenone isotopomers (36, 37) and that Apis mellifera L., the honey bee, can be trained to discriminate pairs of isotopomers (38). These studies differ from earlier insect studies in which isotopomer discrimination was not found. For example, systematic deuteration of 4-(p-hydroxyphenyl)-2-butanone acetate, a Dacus cucurbitae Coquillett (the male melon fly) attractant, did not affect the attractiveness of the compound to the fly (39); deuteration of alarm pheromones failed to alter the response toward these compounds by Pogonomyrmex badius worker ants (40); and honey bees could not distinguish between deuterated and nondeuterated nitrobenzene (41).Concerns have been raised (42) about aspects of the Drosophila study (36), which is “behavioural and not at the receptor level” (2) (also a concern with the Apis study). Also, given that the ORs and their downstream signaling in Drosophila and humans are completely unrelated, the Drosophila study should not be considered predictive of the ability of humans to distinguish isotopomers (2, 17). In view of the above discussion, it is interesting that in a blinded behavioral study, smell panelists distinguished between deuterated and nondeuterated isotopomers of cyclopentadecanone (1; Fig. 1A) and other musk odorants (14).Open in a separate windowFig. 1.(A) Preparation of deuterated 1–3. Deuterium could be selectively introduced, or selectively removed, adjacent to the carbonyl group using D2O/K2CO3 or H2O/K2CO3, respectively, at 130 °C; global replacement of all hydrogens could be achieved with Rh/C in D2O at 150 °C. Repetition led to more complete deuteration as well as reduction of 1 to 3 and 2; oxidation of 2 gave 1 with ∼98% deuteration. Chromatography of deuterated 1 with freshly distilled pentane followed by repeated recrystallization from methanol/water to constant melting point gave samples showing no new peaks in their 1H NMR spectra, other than very weak peaks corresponding to those peaks seen in undeuterated 1. (B) Deuterated (97%) muscone 4 was prepared via alcohol 5 as above. (C) 8-d5 and 2,4,5,7-tetrathiaoctane-d10, (9-d10; 98% deuterium) were prepared as shown. Details of these syntheses are provided in SI Appendix.Here, we study the response of human musk-sensitive OR5AN1, identified through screening of heterologously expressed human ORs, to cyclopentadecanone (1) and muscone (4) isotopomers. We also present pharmacological data on the response of mouse ORs to deuterated and nondeuterated acetophenone and benzaldehyde, as well as selected 13C isotopomers. In addition, we present related studies on the response of various human and mouse ORs to other deuterated and nondeuterated odorants, including (methylthio)-methanethiol (MTMT, 8; Fig. 1C) and bis(methylthiomethyl) disulfide (9), studied in connection with our investigation of the role of copper coordination in the recognition of both sulfur-containing odorants by the mouse (methylthio)methanethiol receptor, MOR244-3 (15, 16). Insofar as the ability to distinguish odors of isotopomers directly tests the predictions of the vibration theory, the comparative response of human and mouse ORs to isotopomers of these selected ligands in the heterologous OR expression system constitutes a robust test of the vibration theory. Finally, we discuss the basis for recent vibration theories of olfaction and supporting computational evidence (37, 4347) in light of well-established electron transfer theories (48). We point out that key assumptions underlying the vibration theory lack experimental support and are missing important physical features expected for biological systems.  相似文献   
5.
目的建立测定西黄胶囊中麝香酮的气相色谱法。方法色谱柱:OV-17毛细管柱(30.0m×0.32mm,1.0μm);初始柱温:150℃,保持26min;再以20℃.min-1的升温速率升至230℃,保持20min;进样口温度:200℃;检测器温度:250℃;载气:氮气;流速:2.0mL.min-1。结果回归方程线性关系良好,线性范围为1.5~299.2mg.L-1,平均回收率为94.7%,RSD1.3%。结论该方法准确、灵敏,能有效控制西黄胶囊的质量。  相似文献   
6.
麝香真伪的现场快速显微鉴别   总被引:1,自引:0,他引:1  
目的:运用显微鉴别技术,对麝香的真伪进行鉴别。方法:挑取麝香粉末用水合氯醛试液装片,置显微镜下观察。结果:野生国产麝香、进口俄罗斯麝香、家养国产麝香都与麝香对照药材具有相似的显微特征;而人工麝香和麝香伪品不具有麝香对照药材的显微特征。结论:通过对各地代表性样品进行显微鉴别分析,总结出天然麝香、家养麝香、人工麝香及麝香伪品的显微特征,为麝香的真伪鉴别提供简易快速的鉴别依据。  相似文献   
7.
麝香酮对谷氨酸所致PC12细胞损伤的保护及作用机制研究   总被引:2,自引:2,他引:0  
目的:考察麝香酮对谷氨酸引起PC12细胞损伤的保护作用及作用机制.方法:将大鼠嗜铬细胞瘤细胞株(pheochromocytoma,cells,PC12)分为正常组、模型组、麝香酮10.0,1.0,0.1 μmol·L~(-1)高、中、低剂量组和1μmol·L~(-1)尼莫地平组,用500μmol·L~(-1)谷氨酸造成PC12细胞损伤,采用药物预处理给药方法,MTT法测定细胞存活率,流式细胞仪测定细胞凋亡率,采用Fura3/AM为荧光指示剂,用Vector~2 1420多标记免疫分析仪研究麝香酮对谷氨酸所致损伤PC12细胞内Ca~(2+)的作用,流式细胞仪检测线粒体跨膜电位,考察不同浓度麝香酮对PC12细胞的保护作用.结果:麝香酮可明显提高谷氨酸诱导的PC12细胞还原能力,抑制该细胞LDH的释放,提高细胞存活率;抑制兴奋性氨基酸所引起的细胞内Ca~(2+)含量的升高;降低PC12细胞的凋亡百分率,并呈剂量相关性.结论:麝香酮可抑制谷氨酸诱导的PC12细胞凋亡,其作用机制可能与抑制细胞内钙超载,稳定细胞线粒体跨膜电位有关.  相似文献   
8.
目的建立人工麝香口崩片中麝香酮的含量测定方法。方法气相色谱法,样品以甲醇超声提取,Varian-3800型气相色谱仪,色谱柱:Cp-sil 8 cb low bleed/ms(30 m×0.25 mm,0.25μm);程序升温:160℃~250℃;检测器:氢火焰离子化检测器(FID),280℃,进样口温度260℃;载气为N_2,流速1.06mL/min,分流比10:1。结果麝香酮在56.7~226.8μg/mL线性良好(r=0.999 7),平均回收率100.14%,RSD=1.68%。结论本方法简便,快速、准确、重现性好,可作为本制剂的质量控制方法。  相似文献   
9.
气相色谱法测定穴贴定喘膏中麝香酮的含量   总被引:1,自引:0,他引:1  
目的用气相色谱法测定穴贴定喘膏中麝香酮的含量。方法样品用乙醚提取,氯仿溶解定容;HP-50 柱,采用程序升温150℃~200℃,升温速率10℃/min;氢火焰离子化检测器(FID),260℃;进样口温度260℃;载气为N2,柱前压5psi。结果麝香酮在5.12~81.84μg/mL线性良好(r=0.9999),平均回收率100.34%,RSD=1.64%。结论本法简便、快速、准确、重现性好,可作为本制剂的质量控制方法。  相似文献   
10.
目的建立保婴散中麝香酮的含量测定方法。方法气相色谱法。样品用乙醇浸渍提取后进样,采用HP-5石英毛细管色谱柱(5%PhenylMethyl Siloxane)(30.0 m×320 nm×0.25μm),柱温220℃,火焰离子化检测器(FID),进样分流比20∶1,外标法测定。结果方法的标准曲线方程A=886.18ρ-3.7,r=0.9998,线性范围:0.1~0.6 mg/mL;平均回收率为99.5%(n=9),RSD为2.2%。结论本方法准确、专属、灵敏度高,操作简便、快速,适用于保婴散中麝香酮的含量测定。  相似文献   
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