What's the difference between levorotatory and racemic?
Levorotatory
Definition:
(a.) Turning or rotating the plane of polarization towards the left; levogyrate, as levulose, left-handed quartz crystals, etc.
Example Sentences:
(1) In addition, the inhibitory activity of these acyclic analogues was enantioselective, exhibiting a preference, similar to the parent vesamicol, for the levorotatory isomer [(-)-11a vs (+)-11a].
(2) The levorotatory form of 5-hydroxytryptophan significantly improved the ataxia score.
(3) The stereochemistry of this material was established by conversion to levorotatory methyl 4-phthalimido [4(-2)H] butyrate.
(4) Extraction and fractionation of Frullania tamarisci has given, as the only allergenic component isolated, a levorotatory crystalline sutbstance, the structure of which is demonstrated.
(5) As several reports in literature confirmed the greatest antineoplastic activity of L-form in animals, the suggestion of further clinical investigation of levorotatory form as a separate preparation has been put forward.
(6) The dextrorotatory enantiomer of fluoxetine was slightly more potent than the levorotatory enantiomer in antagonizing the depletion of brain serotonin by p-chloroamphetamine in rats.
(7) The levorotatory compounds of R configuration showed stronger protective and also therapeutic effect in different experimental arrhythmias.
(8) These data indicate that the beta 2-receptor agonistic and anti-permeability actions of terbutaline are found solely in the levorotatory enantiomer.
(9) In five cases in which the levorotatory form of 5-hydroxytryptophan therapy was maintained for 12 months, the effect continued progressively.
(10) Some features of cerebellar ataxia have been reported to regress partially with long-term administration of 5-hydroxytryptophan or levorotatory form of 5-hydroxytryptophan.
(11) The racemic N-alkyl derivatives are more active than the racemic or even the levorotatory N-benzyl compound.
(12) By the consecutive oxidation and hydrolysis reactions a levorotatory intermediate was formed, presumably (-)-2-oxo-4-hydroxy-4-carbohydroxy-5-ureido-imidazoline.
(13) It was shown that the stereodifferentiation of anti-tumor effect of enantiomers was not outstanding although quite consistently in favour of levorotatory forms.
(14) A similar, but less potent neuron-protective effect, was seen with the opioid levorotatory enantiomer of DX, levorphanol (ED50, 40 microM).
(15) Treponemycin is a crystalline light-yellow compound with an mp of 93 to 95 degrees C, levorotatory, and soluble in most organic solvents.
(16) In this report, we identify that a major cortical receptor alteration in these disorders is a reduction in nicotinic receptors measured using both tritiated acetylcholine and levorotatory tritiated nicotine binding.
(17) The therapeutic index of the racemic 13 and its levorotatory enantiomer was about 1.7 times higher than that for ifosfamide and about 2.7 times higher than that for cyclophosphamide.
(18) In a separate experiment, 100 micrograms of dextrorotatory and levorotatory gossypol was administered to male mice.
(19) Among these compounds, the levorotatory 3-acetyl-N-(cyclopropylmethyl)morphinan (12) was found to be an orally active analgesic, comparable in potency to morphine (1), yet only weakly able to substitute for morphine (1) in morphine-dependent rats.
(20) The dextrorotatory gossypol, both in rat and mice, had less pronounced effect on the histoarchitecture of the testis in comparison to racemic and levorotatory gossypol.
Racemic
Definition:
(a.) Pertaining to, or designating, an acid found in many kinds of grapes. It is also obtained from tartaric acid, with which it is isomeric, and from sugar, gum, etc., by oxidation. It is a sour white crystalline substance, consisting of a combination of dextrorotatory and levorotatory tartaric acids.
Example Sentences:
(1) These results indicate that both racemic and L-baclofen inhibit trigeminal transmission in man, probably because they interfere with excitatory transmission through the interneurons of the lateral reticular formation.
(2) In contrast to the enantiomeric discrimination observed with racemic amine, the individual isomers were metabolized at approximately the same rate.
(3) Routine enantiomeric analyses were successfully carried out on samples taken from animals dosed orally with the racemic drugs, providing important data on the possible levels of exposure to individual enantiomers during toxicity testing.
(4) Racemic verapamil and the L- and D-isomer increased cellular vincristine accumulation to the same extent.
(5) By this method, about 5.0 mg of racemic HCZ could be resolved completely in one run.
(6) The racemization-suppressing effect of other compounds were also evaluated by employing one of these model couplings to be at best only limitedly effective.
(7) The antihypertensive and pulse-slowing effects of racemic propranolol, oxprenolol, pindolol, practolol and d-propranolol were assessed in 54 hypertensive patients.
(8) The assay is reliable to 0.1% racemate with a detection limit of approximately 100 pmol.
(9) The allene oxide also opens to a zwitterion, which undergoes charge delocalization to form a planar intermediate; this structure is the achiral precursor of the stable end product of pericyclic ring closure, viz., racemic cis-12-oxo-PDA.
(10) Decreasing the water concentration in the reaction medium by adding methanol at 0 degrees C drastically reduces the rate of racemization without affecting the rate of transamination.
(11) Racemization of aspartic acid in dentin protein during the human lifetime progresses with age.
(12) Five diammine-Pt(II) or Pt(IV) coordination compounds, namely cis-diammine-dichloro-platinum (II) "cis-DDP", transdihydroxy-cis-diammine-dichloro-platinum (IV) "trans-ODDP", and derived substitution products of lactic acid (racemates or L-forms) with diminished toxicity in comparison to cis-DDP have been tested against mouse leukemia P388, and partly on melanoma B16 for antineoplastic activity.
(13) The racemic drug has unusual pharmacokinetic properties because of its concentration-dependent binding to plasma proteins in the therapeutic plasma concentration range.
(14) The vasodilating potency of d-alprenolol and d-propranolol was not significantly different from that of the respective racemic mixtures.
(15) High-pressure liquid chromatographic (HPLC) methods have been developed for the determination of drug content, racemate A and related compounds in nadolol raw materials.
(16) The effects of the d- and l-isomers of pentazocine were compared to that of racemic pentazocine on contractions of the mouse isolated vas deferens.
(17) Our results indicate that racemic EM 12 as well as its enantiomers are chemically and metabolically more stable than thalidomide; however, extensive racemisation occurs both in vivo and in vitro.
(18) These data, coupled with the equilibrium fractionation factor for the 2-position of proline (which has been determined to be 1.17), provide the transition-state factors for each of the in-flight protons, and delineate the nature of the transition state(s) for the enzyme-catalyzed racemization.
(19) Consequently, racemic compounds showed approximately half potency of the corresponding enantiomers.
(20) S(+)-ibuprofen and R(-)-ibuprofen given alone more rapidly reached significantly higher maximal plasma concentrations than after the same doses of the racemic compound.