Solvent Effects on Chemical Processes. 8. Demethylation Kinetics of Aspartame in Binary Aqueous-Organic Solvents

Solubility of Acetaminophen and Ibuprofen in the Mixtures of Polyethylene Glycol 200 or 400 with Ethanol and Water and the Density of Solute-Free Mixed Solvents at 298.2 K

“…Usually one organic solvent is able to solve the solubility problem; however, in some cases, the addition of the second and even third cosolvent is also required to achieve the desired drug concentration in a given solution volume. In addition to enhancing the aqueous solubility of drugs, cosolvents can alter other drug properties such as chemical stability 2 and skin permeability. 3 In a detailed report, the effects of ethanol concentration on the solubility, ionization, and permeability characteristics of ibuprofen were investigated.…”

Simultaneous formation and detection of the reaction product of solid-state aspartame sweetener by FT-IR/DSC microscopic system

“…The ® rst DSC endothermic peak at 1238C and the second TGA weight loss step from 1108C might be due to the dehydration of the hemihydrate from the APM crystal lattice. The second DSC endothermic peak at 1818C and its corresponding TGA curve from 1538C were attributed to the intramolecular cyclization of APM molecules to form DKP (Skwierczynski andConnors 1994, Leung andGrant 1997). The dehydration process and cyclization pathway will be discussed below in detail.…”

“…The stability of APM has been extensively studied both in solution and the solid state, and determination by many sophisticated methods has shown it to cause physical transformation (polymorphic transition and desolvation ) and chemical reaction (racemization, ester and peptide hydrolysis, and aminolysis ) (Gund and Veber 1979, Smith and Sol 1980, Boehm and Bada 1984, Gaines and Bada 1988, Bell and Labuza 1991, Langguth et al 1991, Sanyude et al 1991, Skwierczynski and Connors 1994, Leung and Grant 1997, Leung et al 1998). Factors such pH, ionic strength, bu er type, relative vapour pressure and temperature have been reported to signi® cantly a ect its stability in solution or in the solid state.…”

“…However, the analysis of the degraded products of APM after chemical reaction can only be undertaken using a complicated chromatographic system. As an example of the stability studies of APM in solid state, several complex steps including thermal pretreatment at various temperatures and separation processes were carried out to determine the degraded products using a complicated HPLC analytical system, and the pathway of degradation was then proposed (Gaines and Bada 1988, Langguth et al 1991, Skwierczynski and Connors 1994, Leung and Grant 1997. We are very interested in the establishment of an analytical method to enable a one-step study of the solid state stability of APM during thermal treatment.…”

Stability Challenges in Drug Discovery

“…Common cosolvents used in solution-stability studies include DMSO, MeCN, MeOH, EtOH, and others. Cosolvents can have complicated effects on the stability by changing the dielectric constant of the buffer, solvation of the compound and its transition state, and the apparent pH of the buffer solution [23] [24]. Cosolvents can both accelerate and decelerate degradation of drug molecules.…”