title: Microcalorimetric studies to determine the enthalpy of solution of diclofenac sodium, paracetamol and their binary mixtures at 310.15 K.
abstract: A sensitive and selective microcalorimetric technique has been used to determine the enthalpy of solution of diclofenac sodium (DS), paracetamol (PC) and their binary mixtures over a wide range of composition in the pH range 4-12. The systems showed endothermic behavior. The molar enthalpies of solutions of DS vary between 42.26+/-0.16 and 50.48+/-0.03 kJ mol(-1) at pH 4-9 and for PC from 24.28+/-0.05 to 36.03+/-0.01 kJ mol(-1) at pH 5-12. The excess molar enthalpy of their mixtures has also been determined. The values of excess molar enthalpy of solutions are negative and very low in magnitude indicating no specific interaction between DS and PC in solution.
authors.affiliation: Pharmaceutical Chemistry Division, University Institute of Pharmaceutical Sciences, Panjab University, Chandigarh, India. renukchadha@rediffmail.com
authors.forename: R
authors.initials: R
authors.lastname: Chadha
authors.forename: N
authors.initials: N
authors.lastname: Kashid
authors.forename: D V S
authors.initials: DV
authors.lastname: Jain
mesh_terms: D000082:Acetaminophen / Q000737:chemistry*; D002152:Calorimetry, Differential Scanning / Q000379:methods; D004008:Diclofenac / Q000737:chemistry*; D006358:Hot Temperature; D019999:Pharmaceutical Solutions
chemical_list: D019999:Pharmaceutical Solutions; D004008:Diclofenac; D000082:Acetaminophen