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1、The professional English of pharmaceutical engineeringWang XinliangEast China University of Science and Technology 概 念 簡 介手性藥物: 具有手性結構及藥理活性的具有治療疾病作用的手性化合物。藥理作用:通過其余體內大分子進行手性識別和匹配產生活性而起到治療的作用。一對對映體的手性藥物在手性結構上的差異往往會導致它們在藥理活性、藥物代謝及毒性等方面產生不同的體內的藥理活性。v根據一對對映體的手性藥物藥理作用和藥效,可分為: 一個有藥理活性,而它的對映體沒有藥理活性; 一對對映體有
2、相反的藥理活性,一個有活性,對映體甚至可能顯毒性; 一對對映體藥理活性相同,但有差別; 一對對映體有迥乎不同的藥理活性; 一對對映體藥理活性完全相同。 2 Wordsencompasschirality (a. chiral)enantiomerdiastereomermesomerracemateunwantedclear-cuttolerabilityimpetusbuilding blockcholesterolmentholstationary/mobile phase assaychiral selectortartaric acidensuingembryoscountercloc
3、kwise vt. 包含;包圍,環(huán)繞n. 手(征)性 (a. 手(征)性的)n. 對映(異構)體n.非對映(異構)體n. 內消旋體n. 外消旋體(化合物)a. 有害的;不需要的a.清晰的;輪廓鮮明的n.耐受性; 容忍度n. 動力;促進;沖力n. 砌塊;積木;構件n.膽固醇;膽甾醇n. 薄荷醇,薄荷腦固定相/流動相n.化驗,試驗;vt. 分析,測試手性選擇試劑酒石酸a. 跟著發(fā)生的 n. 胚胎;晶胎adv. 逆時針地 手性幾乎并不是化學中的新概念,但在過去的幾年里手性技術的進步已對制藥研究和開發(fā)產生了越來越大的影響。如今,手性技術對合理的藥物設計正起著強大的影響。 Chirality is ha
4、rdly a new concept in chemistry, yet advances in chiral technology have had a growing impact on pharmaceutical research and development over the past few years. Chiral technology now exerts a strong influence on rational drug design. 尤其在尋求高選擇性作用(機制)時,手性技術有助于新受體為基礎的或酶抑制的小分子藥物的構思(概念的形成)和發(fā)現。手性技術被人們所認可主
5、要是因為現在已有大量可用于制造單一對映體手性藥物的技術。 It aids the conception and discovery of new receptor-based or enzyme-inhibiting small molecule drugs, especially where high selectivity of action is sought. Its acceptance is largely because there is now an abundance of technology in place for the manufacture of single-e
6、nantiomer chiral drugs. 對那些不熟悉手性技術的人們而言,該術語包括生產單一手性形式(對映體)化合物的技術,具有足夠復雜性的分子結構的化合物是手性的;也就是說,這時分子不能與其鏡像疊加(重合)。隨著分子變得更加復雜,藥品的特異作用性增加;對更具特異性作用的藥品的追求將導致更大比例的藥品為手性。 For those unfamiliar with chiral technology, the term encompasses the range of techniques for producing the single-handed forms (enantiomers)
7、 of compounds that have sufficient molecular complexity to be chiral, that is, when molecules cannot be superimposed on their mirror images. Since the specificity of drugs increases as the molecules become more complex, the drive for more specific drugs will lead to a greater proportion being chiral
8、. 如果某一藥物是手性的,在生物學范疇里其對映體總具有不同的活性。一種藥物可能會與細胞受體發(fā)生特異性的相互作用而產生期望的結果,而另外一種藥物則可能產生無用的作用,或通過某些其他的相互作用而可能導致有害的作用。 If a drug is chiral, then in biological terms the enantiomers invariably differ in activity. One may specifically interact with a cell receptor to produce the desired outcome while the other mig
9、ht have no useful application or might have an unwanted effect through some other interaction. 在明確的例子中,手性化合物的一個異構體是“對人體有益的”,而另一個異構體則是“對人體有害的”,發(fā)展單一異構體的藥物以加強其安全性和耐受性,可以獲得顯而易見的利潤。此外,這也可以通過監(jiān)管渠道加快藥品的發(fā)展,從而節(jié)省研發(fā)成本。 In the clear-cut example where one isomer of a chiral compound is good and the other bad, the
10、re is obvious benefit from developing the drug as the single isomer to enhance its safety and tolerability. In addition, this can also speed the progress of the drug through regulatory channels, thereby saving R u拆分方法,其中的前體或物料提供一種消旋體混合物,必須經過分離而得到需要的異構體。在較有利的情況下,不需要的異構體可用于通過把它重新變回消旋體而再進行拆分,或將其構型轉化使得也
11、能提供需要的異構體;或 u不對稱合成,其中的單一異構體產品源自將不對稱性直接引入非手性材料。u resolution methods, where the precursor or material is provided as a racemic mixture and has to be separated to give the required isomer. In favourable cases the undesired isomer can be used either by turning it back into racemate which can be resolved
12、 again or inverting its configuration so that it too provides the required isomer; oru asymmetric synthesis, where the single-isomer product is derived by introducing the asymmetry directly into a non-chiral material. 手性池 最簡單的獲得單一異構體的途徑是直接天然資源中分離得到,在所有情況下,在植物、動物或微生物的自然界中所固有的手性不貴且易得,也已被使用。一個例子就是抗癌藥物紫
13、杉醇,存在于太平洋紫杉中。紫杉醇的結構復雜性使得采用化學全合成來供應藥物不切合實際。但是,合成化學可以幫助從樹上得到的豐富的中間體上附上一個對紫杉醇活性起關鍵作用的側鏈。 Chirality pool methods The simplest access to single isomers is their direct isolation from natural sources and in all cases the inherent chirality of Nature - in plants, animals or microorganisms which are inexpen
14、sive and readily available- has been used. An example is the anticancer drug Taxol, present in the Pacific Yew tree. Taxols structural complexity makes total chemical synthesis impractical for drug supply. However, synthetic chemistry can help by attaching a side chain that is key to Taxols activity
15、 onto a more abundant intermediate from the tree. Other examples are the penicillins and Mercks cholesterol lowering agent lovastatin which are derived by microbial fermentation. In both cases synthetic chemistry has also been applied to modify the fermentation products to give better drugs (such as
16、 amoxicillin (阿莫西林) and simvastatin (辛伐他丁), respectively, which have modified side chains). 其他的例子,如青霉素和默克公司的降膽固醇藥洛伐他汀都是源自微生物發(fā)酵。在這兩種情況下合成化學也適用于修飾發(fā)酵產品,以提供更好的藥物(例如,阿莫西林和辛伐他丁就是分別修飾側鏈而成的)。 Apart from the production of complete drugs, Nature also makes available to the chirality pool useful building block
17、s like the natural amino acids or sugars. (L-Aspartic acid (天冬氨酸), for example, is used by Monsanto to give the sweetener Aspartame (阿斯巴甜). Nowadays, some chemically produced chiral materials are becoming commodities and they too can be considered to have entered the chirality pool - (S)-malic acid
18、(蘋果酸) and the (R)- and (S)-glycidols (縮水甘油) are examples of this. 除了成藥的生產,自然界也能夠提供像天然氨基酸或糖類的有用砌塊作為手性池。 (例如,L-天冬氨酸就被孟山都公司用來生產甜味劑阿斯巴甜) 。目前,一些化工生產的手性物質正成為商品,它們也可被認為已成為手性池(例如(S)-蘋果酸,(R)- 和 (S)-縮水甘油)。 Resolution methods Racemates are easy to make and there are many ways to separate them into enantiomers.
19、 The oldest route, classical resolution, uses a chiral acid or base that forms a salt with the racemate. A great many drugs are made in this way. For instance, Syntex has developed a resolution for the (S)-enantiomer anti-inflammatory drug naproxen using an alkylglucamine resolving agent. A related
20、method covalently binds an auxiliary like menthol or further purification of the separated diastereoisomers.光 學 拆 分 法 外消旋體容易制備,并有很多方法可將它們分離得到其對映體。 最古老的路線經典拆分,就是利用手性酸或堿與外消旋體生成鹽。許多藥物都是以這種方式生產的。例如,Syntex(美國先達公司)發(fā)展了一種使用烷基葡胺拆分劑,拆分得到(s)-對映體抗炎藥萘普生。相關的方法還需采用薄荷醇作共價鍵合的助 劑或進一步純化已分離得到的對映異構體。 Both of these appro
21、aches need stoichiometric amounts of another agent but resolution can be done directly by physical methods. Chromatography on a chiral stationary phase is one, especially useful for providing pre-clinical and early-clinical quantities (as well as, of course, assaying enantiomeric composition). Simil
22、ar physical separations can be achieved by membrane or extraction systems where one phase contains the racemate and another a chiral selector which will selectively draw out one of the isomers. 這兩種方法都需要化學計量的另一種試劑,但拆分也可直接采用物理方法來實現。色譜法中手性固定相方法就是其一,尤其適合提供有用的臨床前和早期臨床用的(藥品)數量(當然也包括測定對映體組成)。類似的物理分離,可通過膜或提
23、取系統來實現,其中一相含有消旋體,而另一相中含有可選擇性分離出其中一個異構體的手性選擇試劑。 v When Drug Molecules Look in the Mirror從鏡子中看藥物分子 When Drugs Molecules Look in the Mirror 從Louis Pasteur分離出酒石酸的對映異構體已經過了大約150年了。從希臘文字“enantio”派生出來,意為相反的,對映異構體是不可重疊的鏡像結構。因為這對“雙胞胎(孿晶)”除了偏振光的旋轉方向不同外,擁有完全相同的物理性質,它們通常被認為是單一實體這一點被全世界的藥品監(jiān)管機構所特別認可的。但對映異構體受到手性環(huán)境(即環(huán)境由一個孿晶構成,而非另外一個)的影響會表現出明顯不同的化學行為。 24 數十種外消旋體藥物的單個對映異構體在生物活性上的差異已經被報道。雖然治療活性往往存在于一個孿晶中,而另一個可能會導致不期望的副作用。沙利度胺(反應停)慘劇就是一個令人警示的例子。在二十世紀六十年代里,許多服用外消旋體的沙利度胺的孕婦產下了畸形嬰兒。隨后的調查顯示只有該藥品的右旋體會對老鼠的胚胎造成同樣的生育缺陷。如果這一鎮(zhèn)靜劑是以L-沙利度胺(即偏振光逆時針旋轉的單一對映異構體)的形式予以服藥(或給藥)的話,那場災難也許將從不會發(fā)生。 26 27