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The critical micellar concentration (CMC) of the local anaesthetic agent heptacainium chloride in the solution of KBr was determined by the spectrophotometric method in the UV region of the spectrum at the temperature range of t = 20-40 degrees C and pH = 4.5-5.0. The dependence of CMC on the temperature T turned out forming the U-shape with the minimum at the temperature of t = 25 degrees C. The parabolic dependence of CMC on the temperature T was drawn by the fitting of the values using the polynomial function and the so-called power law equation. The CMC dependence on the temperature T was fitted by the second degree polynomial function. The obtained parabolic equations were applied to the "phase separation model", so the following thermodynamic parameters could be calculated: standard Gibbs free energy (deltaG), enthalpy (deltaH degrees), and entropy (deltaS degrees). The thermodynamic parameters were further used to determine the so-called entropy-enthalpy compensation of the systems under study. The compensation temperature was in the following range: (301 +/- 1-303 +/- 3)K. Then the temperature dependence of the enthalpy (deltaH degrees) and entropy (-TdeltaS degrees) contributions to the standard Gibbs free energy (deltaG degrees) for all prepared concentrations of the compound were calculated.

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The critical micelle concentrations (CMC), of heptacainium chloride in various 0.5 M alcohols (methanol, ethanol and n-propanol) were determined using spectrophotometric measurements. CMC values were determined through the change in the slope when the absorbance versus surfactant concentration was plotted at 234 nm. The CMC values show that micelle formation occurred more easily in methanol than in other higher alcohols.

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The paper presents the study of some physicochemical properties of 2-, 3-, 4-alkoxyphenylcarbamic acid derivatives with various substituted N-phenylpiperazin-1-yl moiety in the basic part of the molecule. Elemental analysis, melting point, solubility, surface activity, dissociation constant and some lipophilicity parameters i.e.--partition coefficient, capacity factor obtained from HPLC, and R(M) values from reversed-phase thin-layer chromatography were determined.

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We have studied the critical micellar concentration (c.m.c.) of the homologs of the local anesthetic heptacaine in the medium 0.1 mol/l NaCl, employing spectrophotometry in the UV region of the spectrum at T = 21 degrees C and pH = 4.5-5.0. On the basis of our experimental results, it is assumed that in the homologous series of amphiphilic compounds the quasi-parabolic dependence of biological potencies on the length of their hydrophobic substituent ("cut-off" effect) could be caused by c.m.c.

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Cell suspensions of gherkin (Cucumis sativus L.) were permeabilized by Tween-80, and immobilized by glutaraldehyde. Beta-galactosidase showed pH optimum at 4.9 and temperature optimum at 58 degrees C. The enzyme catalysed hydrolysis was linear for 3 h with 60-68% conversion of the substrate. The cells characterized by high beta-galactosidase activity and stability on long-term storage showed valuable technological properties.

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Local anesthetic monohydrochlorides of [2-(alkoxy)phenyl]-2-(1-piperidinyl)ethyl esters of carbamic acid (CnA, n = 2, 3, 4, 6, 8, 10, 12 is the number of carbon atoms in the alkyloxy substituent) increase the probability of formation of gauche isomers p(g) and decrease the effective energy difference between gauche and trans conformation E(g) in egg yolk phosphatidylcholine (EYPC) acyl chains, as determined by electron spin resonance spectroscopy using dipalmitoylphosphatidylcholines labeled with the paramagnetic dimethyloxazolidinyl group on the 12-th or 16-th carbon atoms of their sn-2 acyl chain, and oriented EYPC bilayers hydrated at 81% relative water vapour pressure. CnAs also increase the hydration of EYPC in non-oriented bilayers at the same relative water vapour pressure. At the molar ratio of CnA:EYPC = 0.4:1, the maximum effect on p(g), E(g) and hydration has been observed for intermediate alkyloxy chain lengths n approximately 4/6.

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Amphiphilic N,N-dimethylalkylamine N-oxides (abbreviation CnNO, n is the number of carbon atoms in the alkyl substituent) modulate the activity of the purified sarcoplasmic reticulum (Ca-Mg)ATPase. The phase of insensivity or slight stimulation of the activity at lower homologue concentrations is followed by the inhibition phase at higher concentrations. The potency to inhibit at high concentrations is maximal for the homologue with the alkyl chain length n = 16. The inhibition could be caused by the binding of homologues to binding sites at the protein/lipid bilayer interface.

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Local anesthetic [2-(alkyloxy)phenyl]-2-(1-piperidinyl)ethyl esters of carbamic acid modulate the activity of the purified sarcoplasmic reticulum (Ca-Mg)ATPase. The phase of insensitivity or slight stimulation of the activity at lower anesthetics concentrations is followed by the inhibition phase at higher concentrations. The potency to inhibit the activity at high concentrations is maximal for the homologue with the hexyloxy substituent and decreases for shorter and longer substituents. The inhibition of activity can be partially reversed by addition of n-decane. The inhibition could be caused by the binding of anesthetics to binding sites at the protein--lipid bilayer interface. The changed thickness of the hydrophobic part of this interface might be responsible for the n-decane reversible inhibition and its dependence on the alkyloxy substituent chain length, while the changed structure of the polar part of this interface could be the cause of the n-decane irreversible inhibiton.

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