FTIR and Raman analysis ofl-cysteine ethyl ester HCl interaction with dipalmitoylphosphatidylcholine in anhydrous and hydrated states

Abstract

Interactions of L-cysteine ethyl ester hydrochloride (CE), a bioactive cysteine derivative, with dipalmitoylphosphatidylcholine (DPPC) were investigated. To gain a deeper insight into analyzing L-cysteine ethyl ester HCl interaction with liposomes of DPPC in anhydrous and hydrated states, we performed experimental studies by infrared (Fourier transform infrared spectroscopy) and Raman spectroscopies. The results revealed that the interaction of CE with the phospholipid head groups was the same in absence or presence of water. In both states, the wavenumber of the PO 2 À group and C-N bond of the choline group decreased. This behavior can be ascribed to the replacement of hydration water and binding to the phosphate group. In the Raman spectrum results for the anhydrous and gel states, the S-H stretching band of the CE shifted to lower frequencies with a decrease in its force constant. Biologically active lipophilic molecules such as CE should be studied in terms of their interaction with lipid bilayers prior to the development of advanced lipid carrier systems such as liposomes. The results of these studies provide information on membrane integrity and physicochemical properties that are essential for the rational design of lipidic drug delivery systems.

Preparation and characterization of cysteine‐formaldehyde cross‐linked complex for CO2 capture

“…In order to examine the functional groups on the as‐prepared cross‐linked complex, FTIR measurements of L‐cysteine hydrochloride and the as‐prepared cross‐linked complex were carried out, and the results are presented in Figure . For L‐cysteine hydrochloride, the major intense bands were near 3422 cm −1 (free N‐H stretching vibration), near 3000 cm −1 (broad, O‐H stretching vibration from carboxylic acid with associated hydrogen bonds overlapped by C‐H stretching vibration from ‐CH 2 ‐ and ‐CH‐), 2600 cm −1 (sharp, S‐H stretching vibration), 1743 cm −1 (C = O stretching vibration from carboxyl), between 1600–1500 cm −1 (double peaks, bending vibration of NH 3 + ), between 1500–1400 cm −1 (O‐H bending vibration in plan from C‐O‐H and C‐H bending vibration from ‐CH 2 ), and 1200 cm −1 (C‐O stretching vibration from C‐O‐H) …”

“…For L-cysteine hydrochloride, the major intense bands were near 3422 cm −1 (free N-H stretching vibration), [42] near 3000 cm −1 (broad, O-H stretching vibration from carboxylic acid with associated hydrogen bonds overlapped by C-H stretching vibration from -CH 2and -CH-), 2600 cm −1 (sharp, S-H stretching vibration), [43] 1743 cm −1 (C = O stretching vibration from carboxyl), [44] between 1600-1500 cm −1 (double peaks, bending vibration of NH 3 + ), between 1500-1400 cm −1 (O-H bending vibration in plan from C-O-H and C-H bending vibration from -CH 2 ), and 1200 cm −1 (C-O stretching vibration from C-O-H). [45,46] In contrast, the as-prepared cross-linked complex exhibited different infrared spectra. The major intense bands near 1743 cm −1 (C = O stretching vibration) and 1200 cm −1 (C-O stretching vibration from C-O-H) disappeared, indicating the conversion from carboxylic acid to carboxylate due to the neutralization from potassium carbonate, along with the appearance of intense bands near 1620 and 1400 cm −1 (asymmetrical and symmetrical stretching vibration of COO -).…”

Recent advances in linear and non‐linear Raman spectroscopy. Part X

“…Aria and co‐workers have used FTIR and Raman to study the interaction of L‐cysteine ethyl ester HCl with dipalmitoylphosphatidylcholine in anhydrous and hydrated states. The results of their studies provide information on membrane integrity and physicochemical properties that are essential for the rational design of lipidic drug delivery systems . Bhunia et al .…”

“…The results of their studies provide information on membrane integrity and physicochemical properties that are essential for the rational design of lipidic drug delivery systems. [35] Bhunia et al have used Raman as a fingerprint of the interaction of K + with the COOgroup of zwitterionic alanine (ZAla). They find that the Raman bands at ∼ 529, 634, and 1079 cm À1 may be used as the Raman fingerprint for the interaction of K + with COOof the ZAla and ZAla -.…”

“…Gaynor and co-workers analysed the ν3 -ν4 difference band contribution to the CCl 4 symmetric stretch (ν1) mode. When these two patterns are modeled and subtracted from the experimental spectrum, a feature underlying almost exactly the C 35 Cl 4 (v = 0 → 1) band at 462.5 cm À1 becomes apparent., and they propose that this feature is the v3 -v4 difference band. [183] Roman et al carried out a vibrational analysis of cinchona alkaloids in the solid state and aqueous solutions with the aid of Raman optical activity (ROA).…”