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Ermolina I, Smith G, Ryabov Y, Puzenko A, Polevaya Y, Nigmatullin R, Feldman Y. Effect of Penetration Enhancers on the Dynamic Behavior of Phosphatidylcholine Headgroups in Liposomes. J Phys Chem B 2000. [DOI: 10.1021/jp9925482] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- I. Ermolina
- Department of Applied Physics, Hebrew University of Jerusalem, 91904 Jerusalem, Israel, Department of Theoretical Physics, Kazan State University, Kazan, Russia, and School of Pharmacy and Pharmaceutical Sciences, De Montfort University, Leicester, U.K
| | - G. Smith
- Department of Applied Physics, Hebrew University of Jerusalem, 91904 Jerusalem, Israel, Department of Theoretical Physics, Kazan State University, Kazan, Russia, and School of Pharmacy and Pharmaceutical Sciences, De Montfort University, Leicester, U.K
| | - Ya. Ryabov
- Department of Applied Physics, Hebrew University of Jerusalem, 91904 Jerusalem, Israel, Department of Theoretical Physics, Kazan State University, Kazan, Russia, and School of Pharmacy and Pharmaceutical Sciences, De Montfort University, Leicester, U.K
| | - A. Puzenko
- Department of Applied Physics, Hebrew University of Jerusalem, 91904 Jerusalem, Israel, Department of Theoretical Physics, Kazan State University, Kazan, Russia, and School of Pharmacy and Pharmaceutical Sciences, De Montfort University, Leicester, U.K
| | - Yu. Polevaya
- Department of Applied Physics, Hebrew University of Jerusalem, 91904 Jerusalem, Israel, Department of Theoretical Physics, Kazan State University, Kazan, Russia, and School of Pharmacy and Pharmaceutical Sciences, De Montfort University, Leicester, U.K
| | - R. Nigmatullin
- Department of Applied Physics, Hebrew University of Jerusalem, 91904 Jerusalem, Israel, Department of Theoretical Physics, Kazan State University, Kazan, Russia, and School of Pharmacy and Pharmaceutical Sciences, De Montfort University, Leicester, U.K
| | - Yu. Feldman
- Department of Applied Physics, Hebrew University of Jerusalem, 91904 Jerusalem, Israel, Department of Theoretical Physics, Kazan State University, Kazan, Russia, and School of Pharmacy and Pharmaceutical Sciences, De Montfort University, Leicester, U.K
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Smith G, Duffy AP, Shen J, Olliff CJ. Dielectric relaxation spectroscopy and some applications in the pharmaceutical sciences. J Pharm Sci 1995; 84:1029-44. [PMID: 8537878 DOI: 10.1002/jps.2600840902] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
With a few exceptions, dielectric relaxation spectroscopy (DRS) has been largely neglected by pharmaceutical scientists, despite the potential for this technique as a noninvasive and rapid method for the structural characterization and quality control of pharmaceutical materials. DRS determines both the magnitude and time dependency of electrical polarization (i.e. the separation of localized charge distributions) by either measuring the ability of the material to pass alternating current (frequency domain DRS) or by investigating the current that flows on application of a step voltage (time domain DRS). DRS is thus (i) sensitive to molecular mobility and structure, (ii) non-invasive, and (iii) employs only mild stresses (a weak electromagnetic field) in order to measure the sample properties. The technique covers a broad-band frequency window (from 10(-5) to 10(11) Hz) and therefore enables the investigation of a diverse range of processes, from slow and hindered macromolecular vibrations and restricted charge transfer processes (such as proton conductivity in nearly dry systems) to the relatively fast reorientations of small molecules or side chain groups. The dielectric response provides information on (i) structural characteristics of polymers, gels, proteins, and emulsions, (ii) the interfacial properties of molecular films, (iii) membrane properties, (iv) water content and states of water (and the effects of water as a plasticizer), and (v) lyophilization of biomolecules. This review article details the basis of dielectric theory and the principles of measuring dielectric properties (including a comprehensive account of measurement artifacts), and gives some applications of DRS to the pharmaceutical sciences.
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Affiliation(s)
- G Smith
- Department of Pharmaceutical Sciences, De Montfort University, Leicester, UK
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Abstract
The complex permittivities of L-alpha-lysolecithin in the absence and presence of the gramicidin A ion channel were measured over the temperature range 0-60 degrees C and over the frequency range 1-1000 MHz. One dielectric relaxation/loss has been observed. It is located at 103.3 MHz (1.54 ns) for a micellar 0.4 M L-alpha-lysolecithin solution at 20 degrees C, whereas it is shifted to 71.7 MHz (2.22 ns) for a lamellar L-alpha-lysolecithin-gramicidin A aqueous solution (0.4 M L-alpha-lysolecithin, 0.0308 M gramicidin A) at 20 degrees C. The dielectric relaxation decreases and the relaxation time increases when gramicidin A is incorporated into L-alpha-lysolecithin. These dielectric changes are related, in part, to the micellar-to-lamellar lipid phase transition induced by the incorporation of gramicidin A into lysolecithin. We suggest that the diffuse rotational motion of the polar head group of L-alpha-lysolecithin contributes to the dielectric relaxation/loss at around 100 MHz.
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Affiliation(s)
- R Buchet
- Department of Biochemistry and Molecular Biology State University of New York, Syracuse 13210
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