Conformation and electronic structure of Carbidopa. A QM/MD study

Abstract

Carbidopa (CD) is a drug used in combination with L-dopa (LD) in treatment of Parkinson's disease (PD). CD is an inhibitor for enzyme decarboxylase, yet its mode of action is not entirely known although it is believed to involve enzyme shape recognition. The present work attempts to investigate the conformational preferences of CD. Tight geometry optimization at the density functional theory (DFT)/B3LYP/6-311þþG** level of theory has been carried out. The shallow nature of the potential energy surface (PES) and the presence of several local minima within a small energy range necessitate the launching of DFT-based molecular dynamics (MD) simulations. Two MD experiments were submitted for 35,000 points each. The complete trajectory in time domain of 10.5 ps is analyzed and discussed. The global minimum energy structure of CD is localized and identi¯ed by subsequent frequency calculations. The quantum theory of atom in molecules (QTAIMs) is used to extract and compare the quantum chemical topology features of the electron density distribution in CD and LD. Bonding characteristics are analyzed and discussed within the natural bond orbital (NBO) framework.

Tricompartmental Microcarriers with Controlled Release for Efficient Management of Parkinson’s Disease

“…Raman spectra were used to confirm the presence of drugs in that specific localized compartment of the particles by remotely detecting the three compartments, as shown in the optical image displayed in Figure , and acquiring the spectra corresponding to that compartment. For LD, characteristics bands were at 785 cm –1 for C–H out-of-plane bending and C–O in-plane bending of a trisubstituted aromatic ring, and 1613 cm –1 for C–C stretching and C–H in-plane bending of the trisubstituted aromatic ring. − These bands were obtained while focusing in the middle of the polymeric particle at position ″1″ and its corresponding Raman micrograph was displayed as spectra-1 in Figure b. It exhibited the characteristic peaks of LD along with the matrix (PLA and PCL) in which LD was embedded.…”

A DFT Investigation on the Structure, Spectroscopy (FT‐IR and NMR), Donor‐Acceptor Interactions and Non‐Linear Optic Properties of (±)‐1,2‐Dehydroaspidospermidine

“…PED analysis implied that the scissoring (σCH2) modes for the rings of the compound were in the range of 1504 (76%)‐ 1447 cm −1 (83%), the wagging (ωCH2) modes were in the range of 1385 (41%)‐ 988 cm −1 (28%), the twisting (τCH2) frequencies were in the range of 1341–1064 cm −1 and the rocking (ρCH2) vibrations were in the range of 1170–179 cm −1 (Table S3). In agreement with the previous work reported in the literature, the CH2 bending vibrations were simulated in the order of σCH2> ωCH2> τCH2> ρCH2.…”