title: Influence of storage time and temperature on the stability of indomethacin Pluronic F-127 gels.
abstract: The stability of 20 topical gel formulations containing drug, 1% w/w indomethacin (IND), and 20% w/w Pluronic (PF-127) as a gel-forming agent, hexylene glycol (HG) and polyethylene glycol 300 (PEG) in different amounts (16, 20 and 24% w/w) as solvents and 1% w/w polyvinyl pyrrolidone (PVP, K-25) and Tween as excipients was determined by appearance and consistency of the gels, microscopy, pH and rheological measurements after 1 and 4 weeks storage, at 6 degrees C, 20 +/- 2 degrees C and 45 degrees C. Viscosity values were determined from rheograms by a Haake Rotovisco sensor at shear rates of 1000 to 10,000 l/s. The relationship between effectors (temperature and storage time) and response (viscosity) was determined using multiple regression analysis. All formulations were stable at room temperature (20 +/- 2 degrees C). The consistency of the gels containing HG and PEG decreased during storage at 6 degrees C. Storing the gels at 6 degrees C resulted in the precipitation of IND, but when PVP was incorporated into the IND-PF-127 gels, the stability of the gels was improved. All IND gels sustained their pseudoplastic flow behaviour. The viscosity decreased as storage time increased. A statistically significant model was obtained, showing that the effect of storage temperatures on the viscosity was much less than the effect of storage time.
authors.affiliation: Pharmaceutical Technology Division, University of Helsinki, Finland. amna_S86@yahoo.ca
authors.forename: A
authors.initials: A
authors.lastname: Shawesh
authors.forename: S
authors.initials: S
authors.lastname: Kallioinen
authors.forename: O
authors.initials: O
authors.lastname: Antikainen
authors.forename: J
authors.initials: J
authors.lastname: Yliruusi
mesh_terms: D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003460:Crystallization; D004355:Drug Stability; D004356:Drug Storage; D005079:Excipients; D007213:Indomethacin / Q000032:analysis*; D010316:Particle Size; D020442:Poloxamer; D013696:Temperature; D013997:Time Factors; D014783:Viscosity
chemical_list: D005079:Excipients; D020442:Poloxamer; D007213:Indomethacin