Solution thermodynamics of methocarbamol in some ethanol + water mixtures

Abstract

Recebido em 26/2/12; aceito em 16/6/12; publicado na web em 21/9/12 Apparent thermodynamic functions, Gibbs energy, enthalpy and entropy of solution and mixing, for methocarbamol in ethanol + water mixtures, were evaluated from solubility data determined at temperatures from 293.15 K to 313.15 K and from calorimetric values of drug fusion. The drug solubility was greatest in the mixtures with 0.70 or 0.80 mass fraction of ethanol and lowest in neat water across all temperatures studied. Non-linear enthalpy-entropy compensation was found for the dissolution processes. Accordingly, solution enthalpy drives the respective processes in almost all the solvent systems analyzed.

Acetaminophen, Methocarbamol, Guaifenesin and Mephenesin in Propylene Glycol: Solubility and Phase Behaviour for Use in Medical Industry

“…Unfortunately, experimental values of μ0 are not available for neat drugs and the values estimated using density functional theory (DFT) are found to be very unreliable for the purpose of calculations, as discussed in our previous publication [15]. However, it is interesting to note that the discomfort experienced by patients, administrated with the liquid drugs intravenously where PG is treated as excipient [2,[6][7][8][9], may be due to the above-observed * T0 values have an error of (±) 5% due to the short range of data points. heterogeneity.…”

“…In a few formulations, the maximum amount of PG is reported to be up to 55% by weight in oral solutions and nearly 80% in injectable formulation [2,6]. Common medicines used as drug solution with PG are acetaminophen, methocarbamol, guaifenesin, amprenavir, oxytetracycline, pentobarbital sodium, etomidate, lormetazepam, lorazepam, cotrimoxazole, amoxicillin, omeprazole, temazepam, etc., where PG is treated as excipient [2,[6][7][8][9]. For orally administered drugs solubility is the most important parameter.…”

“…Therefore, solubility behavior of drugs in PG is useful for pharmaceutical dose design. There are many methods in use to study the solubility [5,[7][8][9]17] but these methods do not explain the exact phase behavior of the mixtures. For these reasons, it is important to determine the complete information about physicochemical data of pharmaceutical systems.…”

Antibacterial, antifungal, and antiviral activities of chalcone-bearing tetrahydropyranyl and 2,4-dihydroxyl moieties

“…Changes in the free energy landscape upon tethering can be attributed to changes in entropy or enthalpy [33][34][35]. Very often, the changes in entropy and enthalpy are coupled.…”

“…The main advantage that the Abraham model is that can be used to predict other solute properties such as the toxicity of organic compounds towards different aquatic organisms. Yue et al [35], has compiled Abraham model equation coefficients for predicting the median lethal molar concentration of organic compounds towards five species of fish (fathead minnow, guppy, bluegill, golden orfe and Medaka high-eyes) [43][44] and three species of water fleas (Daphnia magna, Ceriodaphnia dubia and Daphnia pulex) [45].…”