Early postnatal development of the visual cortex in mice with retinal degeneration.

This study characterizes the early postnatal development of the visual neocortex in C3H/HeNRj mice. These mice are homozygous for the Pde6brd1 mutation, which causes retinal degeneration starting from postnatal day 7 (P7). To monitor the development of the visual cortex between P3 and P28 we used eight antigens known to be expressed at different developmental stages (Nestin, tau3, ß3- Tubulin, Calbindin, Doublecortin, MAP2, Parvalbumin and NeuN). Using semiquantitative analysis we traced the expression and localization of different developmental markers throughout the layers of the visual cortex. Cortical tissue sections corresponding to the first postnatal week (P3-P6) stained positively for Nestin, tau3, ß3-Tubulin and Calbindin. These proteins are known to be involved in the migration of neural progenitor cells (NPCs) within the cortical plate. At the time of eye-opening (P14), Doublecortin, MAP2 and NeuN, markers for developing and maturing neurons involved in NPC differentiation are present. Between P9 and P21 Nestin and Calbindin disappear while NeuN and Parvalbumin expression increases in the course of visual neocortex development. The findings of this study provide a snapshot of the dynamic changes in cortex formation during early postnatal development. So far, it is the first investigation on the postnatal development of the mouse visual cortex. Our results indicate that in C3H/HeNRj mice retinal degeneration during these early stages may not influence the maturation of the visual cortex. Until P28 in this mouse strain, the development of the visual neocortex is in accordance with data from other mice (C57BL/6) without retinal degeneration. Whether in older individuals of the C3H/HeNRj strain the visual neocortex will show signs of functional impairment has to be shown by future work.

The dolphin cochlear nucleus: topography, histology and functional implications.

Despite the outstanding auditory capabilities of dolphins, there is only limited information available on the cytology of the auditory brain stem nuclei in these animals. Here, we investigated the cochlear nuclei (CN) of five brains of common dolphins (Delphinus delphis) and La Plata dolphins (Pontoporia blainvillei) using cell and fiber stain microslide series representing the three main anatomical planes. In general, the CN in dolphins comprise the same set of subnuclei as in other mammals. However, the volume ratio of the dorsal cochlear nucleus (DCN) in relation to the ventral cochlear nucleus (VCN) of dolphins represents a minimum among the mammals examined so far. Because, for example, in cats the DCN is necessary for reflexive orientation of the head and pinnae towards a sound source, the massive restrictions in head movability in dolphins and the absence of outer ears may be correlated with the reduction of the DCN. Moreover, the same set of main neuron types were found in the dolphin CN as in other mammals, including octopus and multipolar cells. Because the latter two types of neurons are thought to be involved in the recognition of complex sounds, including speech, we suggest that, in dolphins, they may be involved in the processing of their communication signals. Comparison of the toothed whale species studied here revealed that large spherical cells were present in the La Plata dolphin but absent in the common dolphin. These neurons are known to be engaged in the processing of low-frequency sounds in terrestrial mammals. Accordingly, in the common dolphin, the absence of large spherical cells seems to be correlated with a shift of its auditory spectrum into the high-frequency range above 20 kHz. The existence of large spherical cells in the VCN of the La Plata dolphin, however, is enigmatic asthis species uses frequencies around 130 kHz.

Stereology of the neocortex in Odontocetes: qualitative, quantitative, and functional implications.

We investigated the quantitative morphology of the neocortex (gray matter) in 2 toothed whale (odontocete) species (harbor porpoise, Phocoena phocoena; bottlenose dolphin, Tursiops truncatus) with stereological methods. The 4 primary projection areas (motor, somatosensory, auditory, and visual fields) are analyzed for their cell densities in layers III and V with standard design-based stereology methods. Along cortical areas M1, S1, A1, and V1 in Tursiops, neuron density is always higher in layer III than in layer V, whereas the data in Phocoena are variable. Moreover, neuron density in layer III is generally around 1.5 times higher in Tursiops than in Phocoena. Maximal density values are seen in layer III of A1 and V1 in Tursiops and the ratio of layer III/layer V density is maximal in A1 of this species. Thus, layer III could have a higher capacity in the bottlenose dolphin with regard to intrinsic connectivity. Extant knowledge on toothed whale neurobiology and behavior suggests that quantitative/stereological differences between the 2 odontocete species regarding the neuron density of standard cortical units may be correlated with specific adaptations to their respective habitats. In contrast to layers V and VI which mainly serve as an executive system, layer III could represent an intermediate level in sensory and premotor processing which works more tangentially in the cortices via horizontal connections with other cortical areas, respectively. The generally higher density of cortical layer III in Tursiops suggests a higher connectivity of this layer in view of the more agile and complicated behavior of these gregarious animals including versatile phonation by complex sound and ultrasound signals.

Cetacean brain evolution: Dwarf sperm whale (Kogia sima) and common dolphin (Delphinus delphis) - An investigation with high-resolution 3D MRI.

This study compares a whole brain of the dwarf sperm whale (Kogia sima) with that of a common dolphin (Delphinus delphis) using high-resolution magnetic resonance imaging (MRI). The Kogia brain was scanned with a Siemens Trio Magnetic Resonance scanner in the three main planes. As in the common dolphin and other marine odontocetes, the brain of the dwarf sperm whale is large, with the telencephalic hemispheres remarkably dominating the brain stem. The neocortex is voluminous and the cortical grey matter thin but expansive and densely convoluted. The corpus callosum is thin and the anterior commissure hard to detect whereas the posterior commissure is well-developed. There is consistency as to the lack of telencephalic structures (olfactory bulb and peduncle, olfactory ventricular recess) and neither an occipital lobe of the telencephalic hemisphere nor the posterior horn of the lateral ventricle are present. A pineal organ could not be detected in Kogia. Both species show a tiny hippocampus and thin fornix and the mammillary body is very small whereas other structures of the limbic system are well-developed. The brain stem is thick and underlies a large cerebellum, both of which, however, are smaller in Kogia. The vestibular system is markedly reduced with the exception of the lateral (Deiters') nucleus. The visual system, although well-developed in both species, is exceeded by the impressive absolute and relative size of the auditory system. The brainstem and cerebellum comprise a series of structures (elliptic nucleus, medial accessory inferior olive, paraflocculus and posterior interpositus nucleus) showing characteristic odontocete dimensions and size correlations. All these structures seem to serve the auditory system with respect to echolocation, communication, and navigation.

The central vestibular complex in dolphins and humans: functional implications of Deiters' nucleus.

Toothed whales (Odontocetes; e.g., dolphins) are well-known for efficient underwater locomotion and for their acrobatic capabilities. Nevertheless, in relation to other mammals including the human and with respect to body size, their vestibular apparatus is reduced, particularly the semicircular canals. Concomitantly, the vestibular nerve and most of the vestibular nuclei are thin and small, respectively, in comparison with those in terrestrial mammals. In contrast, the lateral (Deiters') vestibular nucleus is comparatively well developed in both coastal and pelagic dolphins. In the La Plata dolphin (Pontoporia blainvillei) and the Common dolphin (Delphinus delphis), all of the vestibular nuclei are present and their topographic relations are similar to those in humans. Quantitative analysis, however, revealed that in the dolphin most of the nuclei (superior, medial, descending nucleus) are minute both in absolute and relative terms. Here, the only exception is the lateral vestibular nucleus, which is of comparable size in humans and Pontoporia and decidedly more voluminous in Delphinus. While the small size of the majority of the dolphin's vestibular nuclei correlates well with miniaturization of the semicircular canals, the size of Deiters' nucleus seems to support its relative independence from the vestibular system and a close functional relationship with the cerebellum. In comparison with findings in humans and other terrestrial mammals, both of these aspects seem to be related to the physical conditions of aquatic life and locomotion in three dimensions.

Morphology and evolutionary biology of the dolphin (Delphinus sp.) brain--MR imaging and conventional histology.

Whole brains of the common dolphin (Delphinus delphis) were studied using magnetic resonance imaging (MRI) in parallel with conventional histology. One formalin-fixed brain was documented with a Siemens Trio Magnetic Resonance scanner and compared to three other brains which were embedded in celloidin, sectioned in the three main planes and stained for cells and fibers. The brain of the common dolphin is large, with the telencephalic hemispheres dominating the brain stem. The neocortex is voluminous and the cortical grey matter thin but extremely extended and densely convoluted. There is no olfactory ventricular recess due to the lack of an anterior olfactory system (olfactory bulb and peduncle). No occipital lobe of the telencephalic hemisphere and no posterior horn of the lateral ventricle are present. A pineal organ could not be detected. The brain stem is thick and underlies a very large cerebellum. The hippocampus and mammillary body are small and the fornix is thin; in contrast, the amygdaloid complex is large and the cortex of the limbic lobe is extended. The visual system is well developed but exceeded by the robust auditory system; for example, the inferior colliculus is several times larger than the superior colliculus. Other impressive structures in the brainstem are the peculiar elliptic nucleus, inferior olive, and in the cerebellum the huge paraflocculus and the very large posterior interpositus nucleus. There is good correspondence between MR scans and histological sections. Most of the brain characteristics can be interpreted as morphological correlates to the successful expansion of this species in the marine environment, which was characterized by the development of a powerful sonar system for localization, communication, and acousticomotor navigation.

Markov-modeling for the administration of platinum analogues and paclitaxel as first-line chemotherapy as well as topotecan and liposomal doxorubicin as second-line chemotherapy with epithelial ovarian carcinoma.

PURPOSE: So far there is no analysis available on the cost effectiveness of the paclitaxel/platinum-analogue combination versus carboplatin monotherapy with ovarian cancer. Up-to-now only a cost-utility analysis on ovarian carcinoma has been published (Ortega et al. in Gynecol Oncol 66(3):454-463, 1997), which in addition to the first-line chemotherapy included second-line chemotherapy with effectiveness and cost data in the analysis. Therefore, within the scope of our study the cost effectiveness of platinum analogues and paclitaxel as first-line chemotherapy as well as topotecan and liposomal doxorubicin as second-lie chemotherapy was to be determined with epithelial ovarian carcinoma. METHODS: For this purpose a decision-making Markov model was developed which represents the medical and economic consequences of the administration of paclitaxel and platinum derivatives in first-line chemotherapy and the administration of topotecan and liposomal doxorubicin in second-line chemotherapy in the treatment of epithelial ovarian carcinoma by means of data from the literature. Patients were treated either in the early (FIGO stage I-IIa) or advanced stage (FIGO stage IIb-IV). RESULTS: The therapeutic strategy caboplatin followed by topotecan costs 20,123.91 euros, the therapeutic strategy carboplatin followed by liposomal doxorubicin 22,336.57 euros, the therapeutic strategy carboplatin/pactlitaxel followed by liposomal topotecan 29,820.64 euros and the therapeutic strategy carboplatin/paclitaxel followed by liposomal doxorubicin 31,560.47 euros from the time of diagnosis until death or survival within 5 years. With lives saved, accordingly of 2.55, 2.70, 2.60 and 2.65 years' costs amounted to 7,891 euros, 8,270.35 euros, and 11,453.62 euros per year of life saved. CONCLUSIONS: Based on the threshold value of social willingness to pay 45,500 euros per year of life saved, the therapeutic strategy carboplatin followed by topotecan, the therapeutic strategy carboplatin followed by liposomal doxorubicin, the therapeutic strategy carboplatin/paclitaxel followed by topotcan and the therapeutic strategy carboplatin/paclitaxel followed by liposomal doxorubicin can be evaluated to be cost effective.

[In vitro investigations of phase I metabolism of the fomocaine derivative Oe 9000 with pig liver homogenates]. / In-vitro-Untersuchungen zum Phase-1-Metabolismus des Fomocain-Derivats Oe 9000 mit Schweineleberhomogenaten.

2,2'-[4-(4-Phenoxymethylphenyl)butylimino]diethanol (Oe 9000) is a new, highly potent local anaesthetic related to fomocaine. It displays a long duration of action, low toxicity and is superior to fomocaine with regard to aqueous solubility and efficacy. In view of the development of new application forms, e.g. for the treatment of postoperative pain, the elucidation of the biotransformation of the drug is required. Therefore, experiments with 10000 x g supernatants and microsomes from pig liver homogenates were conducted. Using specifically synthesized reference compounds six phase I metabolites could be identified by LC-MS. Apart from the predominating oxidative desamination of the compound, that led after redox reactions to the corresponding butyric acid and butanol derivatives, oxygenation of the exocycle, oxidative N-desalkylation, and N-oxidation were observed. Thus, with the exception of one compound only metabolites are generated, that are expected to have no local anaesthetic activity due to their reduced basicity.

[Studies on the recovery of pharmaceutical drug substances from surfaces made of defined stainless-steel alloys]. / Wiederfindungsuntersuchungen von Arzneistoffen an definierten Edelstahloberflächen.

Facilities for the manufacturing of pharmaceutical drug substances on the pilot-plant and the industrial scale as well as chemical reactors and vessels used for chemical work-up mainly consist of alloyed stainless steel. The influence of the alloy composition and the surface condition, i.e. of the roughness of the stainless-steel materials, on the adsorption of structurally diverse steroidal substances and, hence, on the quality of the products was studied. In general, stainless-steel alloys with smooth, not so rough surfaces are to be favored as reactor material. However, it was demonstrated in this study that, on account of the weak interaction between active substances and steel materials, mechanically polished materials of a medium roughness up to approx. 0.4 microm can be employed instead of the considerably more cost-intensive electrochemically polished stainless-steel surfaces. The type of surface finishing up to a defined roughness, then, has no influence on the quality of these pharmaceutical products. Substances that, because of their molecular structure, can function as "anions" in the presence of polar solvents, are adsorbed on very smooth surfaces prepared by electrochemical methods, forming an amorphous surface film. For substances with this structural characteristics, the lower-cost mechanically polished reactor materials of a medium roughness up to approx. 0.5 microm should be used exclusively.

Mapping auditory cortex in the La Plata dolphin (Pontoporia blainvillei).

This study deals with the mapping of the primary and secondary auditory cortex. Due to their important role in echolocation they were the first areas to be examined [P.J. Morgane, M.S. Jacobs, in: R.J. Harrison (Ed.), Functional Anatomy of Marine Mammals, Comparative Anatomy of the Cetacean Nervous System, vol. 1, Academic Press, London, 1972, pp. 117-144]. We analysed the brain of a La Plata dolphin (Pontoporia blainvillei), which had been fixed in formaldehyde, embedded in paraffin, cut in sections of 20mum thickness and stained with cresyl violet. The experimental approach being impossible, we used cytoarchitectonic variations in the neocortex. Former electrophysiological data [T.F. Ladygina, A.Y. Supin, Localization of the projectional sensory areas in the cortex of the porpoise Tursiops truncates, Zh. Evol. Biokhim. Fiziol. 13 (1978) 712-718] [Sokolov, T.F. Ladygina, A.Y. Supin, Location of sensory zones in cerebral cortex of dolphin, Dokl. Biol. Sci., Russian Original 202 (1-6) (1972)] provided the framework for the exact determination of borders between functional cortical areas. We used a stereological observer-independent procedure based on changes in volume density of cell bodies throughout the neocortex [A. Schleicher, et al., Stereological approach to human cortical architecture: Identification and delineation of cortical areas, J. Chem. Neuroanat. 20 (2000) 31-47]. Due to the computer program's high sensitivity to changes in volume density it was possible to analyse the poorly laminated dolphin cortex. The 3D-reconstruction of the auditory cortex was processed using the AMIRA 3.0 Graphics software package comparing the main primary gyri in the histological sections with those in coronal magnetic resonance imaging scans of another intact Pontoporia brain.

Neuron numbers in sensory cortices of five delphinids compared to a physeterid, the pygmy sperm whale.

With its large mass and enormous gyrification, the neocortex of whales and dolphins has always been a challenge to neurobiologists. Here we analyse the relationship between neuron number per cortical unit in three different sensory areas and brain mass in six different toothed whale species, five delphinids and one physeterid. Cortex samples, including primary cortical areas of the auditory, visual, and somatosensory systems were taken from both hemispheres of brains fixed in 10% buffered formalin. The samples were embedded in paraffin, sectioned at 25 microm thickness and stained with cresyl violet. Because cortical thickness varies among toothed whale species, cell counts were done in cortical units measuring 150mum in width, 25 microm in thickness, and extending from the pial surface to the white matter. By arranging the delphinid brains according to their total mass, 834-6052 g, we found decreasing neuron numbers in the investigated areas with increasing brain mass. The pigmy sperm whale (Kogia breviceps), a physeterid with an adult brain weight of 1000 g had a distinctly lower neuron number per cortical unit. As had been expected, an increase in adult brain weight in delphinid cetaceans (family Delphinidae) is not correlated with an increase in neuron number per cortical unit.

Investigations on the thermal behavior of omeprazole and other sulfoxides.

Thermoanalytical and chromatographic investigations were performed to elucidate the reason for the uncommon thermal behavior of omeprazole prepared according to a newly developed route of synthesis. Differential scanning calorimetry revealed that the position of the melting endotherm of omeprazole strongly depended on the heating rate. High heating rates (20-30 degrees C/min) led to endothermic peaks at high temperatures (comparable to literature data), while lower rates induced a shift of the signal to lower temperatures. In thermogravimetric experiments weight loss was observed which started about 20 degrees C lower at the heating rate of 1 degrees C/min in comparison with the rate of 20 degrees C/min. Thermomicroscopic investigations indicated a decomposition prior to melting at low (1 degrees C/min) but not at high heating rates (20 degrees C/min). Investigation of the violet melt by HPLC and TLC showed that omeprazole was decomposed quantitatively. Decomposition started at 135 degrees C and depended on the rate of heating. The results indicate that eutectic behavior with decomposition products leads to a melting point depression of omeprazole upon slow heating. Similar behavior was observed for the related sulfoxides lansoprazole and pantoprazole which showed the same onset temperature for decomposition as omeprazole in chromatographic investigations. The heating rate dependent melting behavior was, however, much less pronounced for pantoprazole which has a melting range only slightly above the onset temperature for decomposition. In contrast, a constant value for the melting temperature could not be achieved for lansoprazole, the substance with the highest melting range under investigation, even at high heating rates up to 30 degrees C/min. In conclusion, a very dynamic method and exactly standardized measurement conditions, particularly with regards to heating rate, (e.g., in DSC) have to be employed to enable reliable determination of a melting point of these decomposable substances.

Investigations of interactions of chlormezanone racemate and its enantiomers on human keratinocytes and human leucoytes in vitro.

Chlormezanone is a centrally acting muscle relaxant introduced in human therapy as a racemic substance. The following investigation was performed in order to investigate whether the racemate and both enantiomers differ in their potential cytotoxicty in vitro. We investigated antiproliferative effects and cytotoxicity (PicoGreen and ATP assay) for human HaCaT keratinocytes, production of oxygen radicals (ROS) by human interleukin-3-stimulated leukocytes (Lucigenin assay) and production of sulfoleukotrienes (Cellular Antigen Stimulation Test - CAST) by human leukocytes. In the dosage range of 0.001 to 0.1 mg/ ml chlormezanone, no antiproliferative effects were measured with the racemate and both enantiomers. At 1.0 mg/ml, a decrease of proliferative activity was seen after 48 h incubation time of about 50% for the enantiomers and of about 80% for the racemate (PicoGreen) and 50% (enantiomers) or 21% (racemate) in the ATP assay, respectively. ROS production was significantly inhibited at concentrations < or =0.01 mg/ ml by the racemate and the (+)-enantiomer, whereas the (-)-enantiomer was less effective. There was no stimulation of sulfidoleukotrienes in human leukocytes by chlormezanone. Present data argue for absence of significant cytotoxicity against human HaCaT keratinocytes and a dose-dependent suppression of ROS production by human leukocytes that is not uniform among the racemate and its enantiomers.

[Photometric determination of iron contamination of drugs and biological matrices]. / Photometrische bestimmung von eisenkontaminationen in arzneistoffen und biologischen matrices.

The Ph. Eur. detects colorimetrically the limiting value of iron by formation of a complex with thioglycolic acid in ammoniacal solution. This reaction was rechecked by experiments. Contrary to the literature a solvated Fe(II)-complex will be formed due to the reduction of Fe(III) by the present thioglycolic acid. A supposed oxidation of the Fe(II)-complex by atmospheric oxygen does not occur. For the routine determination of traces of iron in medicinal substances and biological matrixes a VIS-method was developed based on the measurement of the absorption of the complex at 534 nm in the range of 10-100 ppm after graded oxidative decomposition with conc. sulfuric acid/H2O2 30%. This assay needs a calibration mixture or in the case of a higher demand of accuracy a calibration curve with at least five measuring points. Because of the contamination of commercially available reagents a blank value must be determined.

[New findings on the synthesis of the centrally acting muscle relaxant chlormezanone and its resolution of a gram scale using a Chiralcel OD column]. / Neue Befunde zur Synthese des chiralen Muskelrelaxans Chlormezanon und dessen Racematspaltung an einer präparativen Chiralcel OD-Säule.

2-(4-Chlorophenyl)-4-metathiazanone (2) is the intermediate product for the two step-synthesis of chlormezanone (1), a centrally acting muscle relaxant. The second step includes the oxidation of its sulfur atom. It has been found that the foregoing reaction of 4-chlorobenzaldehyde with methylamine forming the hemiaminale and the subsequent addition of beta-mercaptopropionic acid leads to a remarkable better yield (67% of th.) than the route via the hemimercaptale (42% of th.). 2 could be oxidized with sodium perborate superior to potassium permanganate. The racemic chlormezanone (1) is resolved quickly on a gram scale by preparative column chromatography on a Chiralcel OD column (tris(3,5-dimethyl-phenyl-carbamoyl)cellulose on silicagel). The resolution needed only 40 min, if flow rate, composition of the mobile phase and temperature as the most important factors are determined prior with an analytical column. Both dissociation constants could be determined for the first time with the aid of a log pKa-Titrator of the Sirius Co., which needs for the registration of the curves only 15-17 min in the pH range of 2-12. This speed outplayed the disturbing cleavage of the S-C bond of chlormezanone at strong acidic and alkaline pH values.

[Simultaneous photometric determination of covalently bound fluorine and fluoride ion contamination adsorbed on drugs in the low ppm range after alkaline pulping]. / Simultane photometrische Bestimmung von kovalent gebundenem Fluorund Arzneistoffen anhaftender Fluoridkontamination im ppm-Bereich nachalkalischem Aufschluss.

The simultaneous determination of fluorine resulting from inorganic fluoride as well as fluorine-containing solvents adsorbed to drugs was achieved in the 0.1-30 ppm range by a combination of decomposition with magnesium oxide at 800 degrees C and steam distillation of the resulting fluoride followed by photometric measurement of the aminomethylalizarindiacetic acid-cerium(III) complex at 620 nm. The inevitable loss of fluoride occurring during the decomposition and distillation processes was corrected using factors derived from authorized calibrations. The method was validated using glucose contaminated with dexamethasone which contains 4.84% fluorine per molecule.

[3,5-Dinitrobenzoic acid anhydride as reagent for the characterization of drugs and for the activation of polarographically inactive compounds]. / 3,5-Dinitrobenzoesäureanhydrid als Reagenz zur Charakterisierung von Arzneistoffen und zur Aktivierung polarographisch inaktiver Verbindungen.

Drugs with primary or secondary amino groups react with 3,5-dinitrobenzoic acid anhydride under catalysis of pyridine derivatives almost quantitatively to yield the corresponding amides which are reducible at the dropping mercury electrode (DME). 3,5-Dinitrobenzoic acid will be separated by thin layer chromatography. The limit of detection by DPP is in the range of 10(-8) M. The electrode reaction is irreversible.

Neuroanatomy of magnetoreception: the superior colliculus involved in magnetic orientation in a mammal.

The neural substrate subserving magnetic orientation is largely unknown in vertebrates and unstudied in mammals. We combined a behavioral test for magnetic compass orientation in mole rats and immunocytochemical visualization of the transcription factor c-Fos as a marker of neuronal activity. We found that the superior colliculus of the Zambian mole rat (Cryptomys anselli) contains neurons that are responsive to magnetic stimuli. These neurons are directionally selective and organized within a discrete sublayer. Our results constitute evidence for the involvement of a specific mammalian brain structure in magnetoreception.

[Synthesis and pharmacologic action of chiral fomocaine ((4-[2-methyl-3-(morpholin-4-yl)propyl)benzyl)-phenyl-ether and (4-(1-methyl-3-(morpholin-4-yl)propyl]benzyl)-phenyl-ether). 13. Synthesis of new compounds with local anesthetic action]. / Synthese und pharmakologische Wirkung chiraler Fomocaine ((4-[2-Methyl-3-(morpholin-4-yl)propyl]benzyl)-phenyl-ether und (4-[1-Methyl-3-(morpholin-4-yl)propyl]benzyl)-phenyl-ether). 13. Mitteilung zur Synthese neuer Verbindungen mit lokalanästhetischer Wirkung.

The syntheses of two chiral fomocaines namely rac ((4-[2-methyl-3-(morpholin-4-yl)propyl]-benzyl)-phenyl-ether (O/G 3) and rac (4-[1-methyl-3-(morpholin-4-yl)propyl]benzyl)-phenyl-ether) (O/G 5) are reported. These compounds are part of a new research program concerning the relation between chirality and local anaesthetic activity in the group of fomocaines. The yield over five steps is in the range of 9% (O/G 3) up to 19.2% (O/G 5). The racemates were resoluted via the diastereomeric salts formed with (+)- or (-)-camphersulfonic acid. The chromatographic resolution in analytical scale is successful using a Daicel OD-column. The enantiomers are stable. The surface anaesthesia of the racemates as well as of the enantiomeres is weaker in comparison with fomocaine. The rate of tissue irritation is higher. The LD50 (mouse i.v.) is in the range between 290-390 mg/kg, while fomocaine shows a LD50 value of 175 mg/kg.

Local anaesthetic effectivity and toxicity of fomocaine, five N-free fomocaine metabolites and two chiralic fomocaine derivatives in rats compared with procaine.

Until now, no optimal local anaesthetic drug with long lasting effect and low toxicity has been developed. Fomocaine (CAS 17692-39-6), introduced in the German extrapharmacopoela (DAC) in 1979, is a local anaesthetic, which is largely in accordance with these aspects. Now the basic ether fomocaine, its metabolites O/Se 9 (CAS 3006-96-0), O/Se 10 (CAS 31719-76-3), O/Se 11, O/Se 12 (CAS 64264-21-7) and M5 and its chiralic derivatives O/G 3 and O/G 5 were compared with procaine (CAS 59-46-1) and characterised more in detail in rats. The metabolism of fomocaine was investigated earlier with 14C-fomocaine in rats and beagle dogs. Rac-O/G 3 and Rac-O/G 5 could be separated into the enantiomers via the diastereomeric salts. Basing on standard methods for the testing of the local anaesthetic effects (estimation of infiltration and conduction anaesthesia in rat tail, measurement of corneal anaesthesia) and using a couple of tests characterising the side effects and toxicity of local anaesthetic (paresis of the N. ischiadicus, tissue irritation, determination of the approximative i.p. LD50) it can be concluded that: a) The very good surface anaesthesia caused by fomocaine could be stated, but, as expected, concerning conduction anaesthesia, procaine is better qualified for clinical use. b) Fomocaine is much more effective in conduction and surface anaesthesia than its chiralic derivatives O/G 3 and O/G 5. c) Differences between the two enantiomers of the O/G-substances have been found, but these little discrepancies are without practical relevance. In the case of O/G 5, agonistic effects of both enantiomers could be shown. d) Fomocaine undergoes extensive biotransformation with subsequent formation of 14 metabolites. Five of them (O/Se 9-O/Se 12; M5) are N-free and do not show any pharmacological activity. e) Compared to other local anaesthetics, fomocaine is relatively non-toxic (nearly no tissue irritation, high approximative LD50), however, surprisingly the toxicity of the reference substance procaine has been found to be lower after i.p. administration instead of i.v. administration in comparison with fomocaine.