Hyoscyamine extractabilities

The separate determination of hyoscine, hyoscyamine and atropine in a mixture is of considerable interest. Rowson has investigated this problem and has proposed the following method based on the observation that at pH 8-5 hyoscine is quickly and completely extracted by chloroform whereas atropine is extracted with difficulty the hyoscyamine extracted is calculated from the optical rotation of the mixed alkaloids after correction for the hyoscine content. The specific rotation of /-hyoscyamine was taken as —22° and /-hyoscine as —18°,... 

Atropa Belladonna Linn. Leaves, 0-4 roots, 0-5 seeds, 0-8 whole plant, 0-2 to 1-0 h5mscyamine with some hyoscine atropine has been found but may have resulted from racemisation during extraction apoatropine and possibly belladonnine (Kreitmair Atropa bcetica. Leaves, 0-82-1-06 roots, 0-94 fruit, 1-09 hyoscyamine and atropine. 

The alkaloid may be separated from accompanying hyoscyamine by extracting most of it with ether and then crystallising the mixed oxalates from water, that of norhyoscyamine separating first. It crystallises in colourless prisms, m.p. 140°, [a]j, — 23-0° (50 per cent. EtOH), is soluble in alcohol or chloroform, less so in ether or acetone, and sparingly in water... 

By extraction of Solanacean drugs, especially Atropa belladonna, Hyoscyamus niger or other species. On careful extraction L-hyoscyamine is obtained first, which can be racemized to atropine by addition of alkali in ethanolic solution. 

The base-catalysed racemization of the alkaloid (-)-hy oscy amine to ( )-hyoscyamine (atropine) is an example of enolate anion participation. Alkaloids are normally extracted from plants by using base, thus liberating the free alkaloid bases from salt combinations. (—)-Hyoscyamine is found in belladonna Atropa belladonna) and stramonium Datura stramonium) and is used medicinally as an anticholinergic. It competes with acetylcholine for the muscarinic site of the parasympathetic nervous system, thus preventing the passage of nerve impulses. However, with careless extraction using too much base the product isolated is atropine, which has only half the biological activity of (—)-hyoscyamine, since the enantiomer (+)-hyoscyamine is essentially inactive. 

Liquid oral antidiarrhoeals or any other dosage form for paediatric use containing diphenoxylate or atropine or belladonna including their salts and esters or metabolites, hyoscyamine or their extracts or their alkaloids. 

Opium alkaloids such as codeine, thebaine, papaverine, and noscapine exhibit high solubility (0.09-0.9 mg/g) in supercritical fluids including CO N,0, CHF, [37]. However, in spite of their high solubilities, they were not extracted from plant material by pure CO, to the degree expected [29], possibly because these alkaloids exist as their salt forms in plant tissue. In this chapter, the examples that show the difference of the solubilities between alkaloidal free bases and salts are presented. For this comparison, the solubilities of the free bases of hyoscyamine (1), scopolamine (2), pseudoephedrine (6) were measured and compared with those of their hydrochloride salts (Figures 3 and 4). 

Figure 3. Solubilities of hyoscyamine (I) and scopolamine (2) free bases in supercritical CO, [39]. Reprinted from J. Chromatogr. A, 863, Y. H. Choi et al., Strategies for supercritical fluid extraction of hyoscyamine and scopolamine salts using basified modifiers, 47-55 (1999), with permission from Elsevier Science.

Although there were some differences on the effects of temperature and pressure according to each particular compound, the free bases of hyoscyamine (1), scopolamine (2), and pseudoephedrine (6) were all found to be highly soluble in supercritical CO,. However, the hydrochloride salts of these compounds were scarcely extracted by pure CO, under any conditions employed. These results were consistent with preliminary evidence indicating that these alkaloids are not extracted from plant materials by pure CO,. This means that the alkaloids in living cells in the plant are not in the form of their free bases but rather as water-soluble salts in the cell vacuole [40]. Therefore, it was necessary to develop a procedure to enhance the solubilities of alkaloidal salts in CO,. 

To improve supercritical C02 solubilities of target alkaloidal salts, an appropriate modifier to raise the polarity of C02 had to be used. As previously mentioned, the most common modifier used in SFE is methanol because of its high solvation parameters, which can greatly increase the resultant polarity of C02. Water has been chosen as another modifier because some alkaloidal salts are freely soluble in water as well as methanol. Moreover, the addition of water into C02 has been reported to improve the extraction yield of some alkaloids [29]. Methanol or water as a modifier was added into the extractor at the concentration levels of 1, 5 and 10% (v/v), respectively. The effect of methanol and water on the solubilities of hyoscyamine (1) and scopolamine (2) is shown in Figure 5. Analogous information on ephedrine derivatives such as methylephedrine (3), norephedrine (4), ephedrine (5), and pseudopehedrine is illustrated in Figure 6. 

Generally, alkaloidal salts are insoluble in nonpolar solvents but their free bases are quite soluble in the solvents. Therefore, the basified modifier should be introduced into the SFE to solubilize alkaloids in CO,. For the evaluation of the effects of basified modifiers, diethylamine was added to methanol or water at a 10% (v/v) concentration level. Then, the basified modifiers were continuously incorporated into the extraction cell at concentrations of 1, 5, and 10 % (v/v). The effects of methanol basified with diethylamine as a modifier on the solubilities of hyoscyamine (1) and scopolamine (2) are shown in Figure 8. The addition of diethylamine (10% v/v) into methanol dramatically enhanced the solubilities of the alkaloidal hydrochloride salts compared with those of pure methanol alone. This may be due to the fact that methanol basified with diethylamine changed the salts to the free bases. 

When the extractabilities using diethylamine/methanol as a modifier were compared with diethylamine/water, the former was more effective on the extractabilities of hyoscyamine (1) and scopolamine (2) salts than the latter, as seen in the comparison of pure methanol and water. Although the water with added diethylamine was less effective than basifled methanol, it could largely increase the solubilities wben compared with pure water, similar to the comparison of basic methanol with pure methanol (Figure 9). 

In both results of solubility and desorption from filter papers, diethylamine in methanol as a modifier was found to offer greater efficiency for SFE of the alkaloids than any other modifiers employed. The yields of hyoscyamine (1) and scopolamine (2) from the roots and aerial parts by SFE and conventional organic solvent extraction are listed in Tables 2 and 3. The SFE yields from both plant parts were greatly enhanced by the addition of methanol basified with diethylamine. From the results of solubility and desorption from filter paper, methanol and diethylamine/methanol (10% v/v) were much more efficient for both compounds than water and diethylamine/water (10% v/v) because of their low miscibility with C02. The extraction profile of hyoscyamine (1) when present in plant material was in good agreement with that when extracted as a pure compound. However, in the case of scopolamine (2), there... 

Although there are some differences in the degree of enhancement of extractability, among the modifiers employed in this study, 10% methanol basified with diethylamine was found to be optimal for the extraction of hyoscyamine (1) and scopolamine (2) from both the roots and aerial parts of Scopolia japonica. While the recoveries from the roots and aerial parts of S. 

The alkaloids of this group are derived from a combination of a piperidine and a pyrrolidine ring, designated as tropane (Figure 14.2). The 3-hydroxy derivative of tropane is known as tropine and is the basic component of atropine. When atropine is hydrolyzed, it forms tropine and tropic acid (a-phenyl-p-hydroxy-propionic acid). Atropine is the tropic acid ester of tropine. It has been prepared synthetically. Tropic acid contains an asymmetric carbon atom. The racemic compound (atropine) as obtained naturally or as synthesized may be resolved into its optically active components, d- and /-hyoscyamine. Atropine is racemic hyoscyamine that is, it consists of equal parts of /-hyscyamine and plant cells and also in the process of extraction, so that the relative proportion of the isomers in the plants and in the preparations varies. However, atropine itself does exist in small amounts in the plants, although most of it is formed from the /-hyoscyamine in the process of extraction. 

Anisodamine is a natural derivative of hyoscyamine mono-hydroxylated at the tropane skeleton (Fig. 1). The compound was extracted from traditional Chinese medicine Anisodus tanguticus evoking typical non-specific effects of cholinergic antagonists (spasmolysis, anaesthesia, mydriasis, analgesia) in combination with... 

Atropine is the racemic mixture of R- and S-hyoscyamine produced during the pharmaceutical plant extraction process. R-hyoscyamine is nearly inactive on MR (distomer) whereas S-hyoscyamine exhibits high affinity (eutomer). Nevertheless, due to economic reasons atropine is typically administered even though only half of the applied dose (S-hyoscyamine) is pharmacologically active on MR. Surprisingly, there is still little information about different pharmacokinetic behaviour of both enantiomers anyhow [46,47],... 

Supercritical fluid extraction (SEE) has become a method of choice for the extraction of plant material [14]. It represents an interesting alternative technique compared to conventional liquid-solid extraction, with lower solvent consumption and working temperature. The free bases of hyoscyamine and scopolamine are extractable with... 

A GC-MS method was developed for the determination of hyoscyamine and scopolamine in blood semm [91,92]. Extraction was carried out using aqueous basic solution followed by a purification step on an Extrelut column. Derivatization was done with N,0-bis(trimethylsilyl)trifluoroacetamide/trimethylchlorosilane (99 1). GC-MS was performed on a HP-5 MS column (30m x 0.25 mm i.d. with a 0.25 p,m film thickness). The linearity was good between 10 and 5000ng/mL. The limit of detection (LOD) was 5ng/mL for each compound. 

The on-line coupling of CE with electrospray ionization mass spectrometry (CE-ESI-MS) allows high separation efficiency together with high sensitivity and selectivity as well as molecular structural information. A CE-UV-ESI-MS method was developed for the analysis of hoscyamine, scopolamine, and other tropane derivatives [131]. The differentiation of hyoscyamine from littorine, commonly encountered in plant material, was demonstrated using in-source collision-induced dissociation. The developed method was applied to the analysis of these alkaloids in Belladonna leaf extract and in Datura Candida x D. awreahairy root extract. Recently, CE coupled with electrochemiluminescence detection has been used for the determination of atropine and scopolamine in Flos daturae [132]. 

Tropane alkaloids are an important class of natural products possessing different and interesting pharmacological activities. Hyoscyamine (atropine in the racemate form), scopolamine, and cocaine are the major representatives of this class. They are commonly found in plant materials, mainly in genera belonging to three families Solanaceae, Erythroxylaceae, and Convolvulaceae. The importance of these compounds requires that there are accurate analytical methods for their determination in plants and in biological matrices. This chapter describes the state-of-the-art of analytical procedures (extraction and analysis) for analyzing tropane alkaloids. 

In their physiological action atropine and hyoscyamine are similar and exert what is termed a mydriatic action causing dilation of the pupil of the eye. This action may be produced eithef by external application or by taking internally. As little as i part atropine in 130,000 parts of water will exert a distinct action on the eye. They decrease body secretions and also affect the heart. Taken internally they are poisonous in as little as o.i gm. Tropine exerts no mydriatic action when applied to the eye but in large doses internally it does produce dilation. In addition to the use of these alkaloids in the pure form, extracts of belladonna are also used. 

Plasma proteins were precipitated with methanol, and the methanol extract was evaporated before analysis. The sensitivity of the assay was 300 fmol in the assay tube (equivalent to 87 pg of atropine), and plasma samples could be measured down to 1,4 ng/mL (60), The assay in general responded to muscarinic antagonists and was reportedly considerably more sensitive to (-)-hyoscyamine (S-atropine) (60) than an RIA procedure (36). 

---