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Tian F.,Shanghai Institute of Planned Parenthood Research | Wen C.-L.,Shanghai Institute of Planned Parenthood Research | Wen C.-L.,Fudan University | Wang Y.-Z.,Shanghai Institute of Planned Parenthood Research | And 4 more authors.
Chinese Journal of New Drugs | Year: 2014

Objectives: To characterize the stability and rheological properties of nifeviroc-loaded microemulsion thermosensitive in situ gel(NFVR/ME-TISG). Methods: To detect the changes of gel's appearance, pH value, partical size and Zata potentials in the fifth days and the tenth days, stability experiment were conducted. Rheological parameters of NFVR/ME-TISG were measured during phase transition at different temperature to evaluate rheological characteristics. Results: Stability experiment shows that there is no difference in the fifth days and the tenth days in the gel's appearance, pH value, partical size and Zata potentials. The sol-gel transition temperature(Ts-g)is 30 °C detected by rotational rheometer. The poloxamer solution below Ts-g(<25 °C)shows Newtonian fluid characteristics with comparatively low viscosity; with the increase of temperature, viscoelastic modulus rose, phase angle drooped, but there is no obvious change when the frequency increased, it shows characteristics of the pseudoplastic fluid. Conclusion: NFVR/ME-TISG has a desirable stability and will change its viscoelastic modulus as the tempetature changes. Source


Tian F.,Shanghai Institute of Planned Parenthood Research | Wang Y.-Z.,Shanghai Institute of Planned Parenthood Research | Yang K.,Malvern Instruments China Ltd. | Wen C.-L.,Shanghai Institute of Planned Parenthood Research | And 3 more authors.
Chinese Journal of New Drugs | Year: 2013

Objective: To characterize the rheological properties of thermosensitive in situ gels for predicting the behaviors of thermal gelation. Methods: Nifeviroc vaginal thermosensitive in situ gel (NFVR-TISG) was prepared using poloxamer407 and poloxamer188 as the gel matrix. Rheological parameters of NFVR-TISG and the NFVR-TISG diluted by stimulant vaginal fluid (SVF) were measured during phase transition at different temperatures, and gelation temperature was estimated by differential scanning calorimeter (DSC). Results: NFVR-TISG was Newtonian fluid with low viscoelasticity under room temperature and was converted to gel at 29°C. With the increase of temperature, the sol-gel transition process showed exponential increase and the phase angle showed decrease. The gelation temperature of NFVR-TISG detected by DSC was 30.4°C, similar to that measured by dynamic rheological studies. Conclusion: The rheological properties of NFVR-TISG meet the requirements for vaginal topical use. Dynamic rheological experiment may provide useful information for further in vitro evaluation of viscoelastic hydrodynamic properties of thermosensitive in situ gel. Source

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