Abdelkader H.Abdallah O.Y.Salem H.Alani A.W.G.Alany R.G.Department of PharmaceuticsFaculty of PharmacyMinia UniversityMiniaEgypt; Department of PharmaceuticsFaculty of PharmacyAlexandria UniversityAlexandriaEgypt; Analytical Chemistry DepartmentFaculty of PharmacyOctober University for Modern Science and ArtsCairoEgypt; Department of Pharmaceutical SciencesCollege of PharmacyOregon State UniversityCorvallisORUnited States; School of Pharmacy and ChemistryKingston University LondonKingston upon ThamesUnited Kingdom; School of PharmacyUniversity of AucklandAucklandNew Zealand2020-01-092020-01-092014223573https://doi.org/10.1111/jphp.12277PubMed ID 24944002https://t.ly/NXNwxScopusObjectives The solid-state interactions of fused mixtures nimesulide (ND) with polyethylene glycol (PEG) 4000, urea or mannitol were studied through constructing thaw-melt phase equilibrium diagrams. Methods The solid-state characteristics were investigated using differential scanning calorimetry (DSC) and X-ray diffraction (XRD). Various types of interactions were identified such as the formation of a eutectic system of ND-PEG 4000, monotectic system of ND-urea and complete solid immiscibility of ND with mannitol. The effects of carrier concentrations on the equilibrium solubility and in-vitro dissolution characteristics were studied. Key findings Linear increases (R2 > 0.99) in the aqueous solubility of ND in various concentrations of PEG 4000 and urea were obtained, whereas mannitol did not exhibit any effect on the solubility of ND. Similar trends were obtained with the dissolution efficiency of the fused mixtures of ND with PEG 4000 and urea compared with the corresponding physical mixtures and untreated drug. The analgesic effects of untreated ND and the selected formulations were investigated by evaluating the drug's ability to inhibit the acetic acid-induced writhing response. Conclusions The analgesic effect of ND in a eutectic mixture with PEG 4000 and a monotectic mixture with urea was potentiated by 3.2 and 2.7-fold respectively compared with the untreated drug. � 2014 Royal Pharmaceutical Society.Englishdissolution rateeutecticmonotecticnimesulidesolubilityacetic aciddrug carrierexcipientmacrogol derivativenimesulidepovidoneprostaglandin synthase inhibitorsulfonamideureawateranimalchemically inducedchemistrydifferential scanning calorimetrymedicinal chemistrymousepainsolubilityX ray diffractionAcetic AcidAnimalsCalorimetry, Differential ScanningChemistry, PharmaceuticalCyclooxygenase InhibitorsDrug CarriersExcipientsMicePainPolyethylene GlycolsPovidoneSolubilitySulfonamidesUreaWaterX-Ray DiffractionArticlehttps://doi.org/10.1111/jphp.12277PubMed ID 24944002