Aspirin

A New 1:1 Drug-Drug Cocrystal of Theophylline and Aspirin: Discovery, Characterization, and Construction of Ternary Phase Diagrams

“…ASP is known to have three polymorphs, among which polymorph I is the stable phase under ambient condition. − Moreover, the ASP molecule contains the carboxylic acid functional group which acts as a hydrogen bond acceptor and donor. The Δp K a difference between the THP and ASP is −1.8 (p K a is 1.7 for protonated THP and 3.5 for ASP); hence, THP has the affinity to form a cocrystal with ASP through N–H···O and O–H···O intermolecular interactions.…”

Excited state dynamics of some nonsteroidal anti-inflammatory drugs: A surface-hopping investigation

“…Our computed semiempirical FOMO-CI vertical excitation energies for ASP in vacuum, reported in Table 2, match quite well the experimental results, especially if the shoulder at about 300 nm (4.13 eV) of the peak at 276 nm (4.49 eV) in the spectrum obtained by Govindasamy et al [15] in DMSO can be identified with the S 0 → S 1 transition. Other experimental absorption spectra of ASP recorded in various solvents [3,15,33] exhibit also maxima at 276 nm (4.49 eV) and 229 nm (5.41 eV). Although red-shifted, our AM1 vertical transitions are also in reasonable agreement with the B3LYP/6-311G** values reported in [16], the second absorption being the most sensitive to the level of theory employed in the calculations with a deviation amounting to ca.…”

“…The integration of the electronic time dependent Schrödinger equation was performed with the widely used Local Diabatization (LD) scheme Absorption spectrum in DMSO [15], shoulder. b Absorption spectrum in various solvents [3,15,33]. c Absorption spectrum in water [5].…”

“…The investigation of the photophysics of drugs or the photoreactive paths that might be activated upon photon absorption is crucial for identifying photoinitiated side effects, as well as in the design of novel and improved drugs. In the literature, there are a few experimental and computational studies on the photophysics of NSAIDs, most often based on steady state results [3,4,5,6,7,8,9,10,11,12,13,14], or on quantum chemical calculations on the energetics of their excited states, mainly at DFT/TD-DFT level of theory [2,15,16,17,18]. However, investigations of the excited state dynamics of these molecules are still lacking.…”

Modifier and Additive Effects in the Supercritical Fluid Extraction of Pseudoephedrine Hydrochloride from Spiked-Sand and Suphedrine Tablets

“…The IR of the pseudoephedrine hydrochloride standard is shown in Figure 4. IR studies of pseudoephedrine hydrochloride from a KBr pellet were previously performed by Benezra et al [6]. Several spectral assignments were made: 1) OH str.…”