title: Characterization and release kinetics of nicotinamide microemulsion-based gels.
abstract: The aim of this study was to investigate physicochemical characteristics and to determine in vitro release kinetics of prepared nicotinamide microemulsion-based gels (MBGs). Nicotinamide microemulsions (ME) were composed of 3% w/w nicotinamide, 7% w/w water, 25% w/w soybean oil, and 65% w/w of 9:1 oleth-10:isopropyl alcohol mixture. A water-in-oil (w/o) type ME was converted to three MBGs. ME was combined with 5% w/w of colloidal silica to obtain MBG-1, with 5% w/w of 0.5% w/w carbomer solution to obtain MBG-2, or with a mixture of 3% w/w of 0.5% w/w carbomer solution and 2% w/w of PEG-40 hydrogenated castor oil to obtain MBG-3. The results indicated that MBG-1 was a clear gel with plastic flow while MBG-2 and MBG-3 were turbid gels with Newtonian flow. MBG-1 was physically and chemically stable at 4°C as well as at ambient temperature (approximately 30°C) during the 2-month study period. The color darkened when stored at 60°C. The release kinetics of MBG-1 was best fitted to zero order model. The in vitro release of nicotinamide from MBG-1 through cellulose membrane was compared with that from the ME and an oil-in-water (o/w) commercial cream (CC). The rank order of release rate of nicotinamide from different formulations was MBG-1 > ME > CC.
authors.affiliation: Department of Pharmaceutical Technology, Prince of Songkla University, Songkhla, Thailand.
authors.forename: Prapaporn
authors.initials: P
authors.lastname: Boonme
authors.forename: Nattiya
authors.initials: N
authors.lastname: Suksawad
authors.forename: Sarunyoo
authors.initials: S
authors.lastname: Songkro
mesh_terms: D019840:2-Propanol / Q000737:chemistry; D002368:Castor Oil / Q000737:chemistry*; D002482:Cellulose / Q000031:analogs & derivatives; D015194:Diffusion Chambers, Culture; D004355:Drug Stability; D005079:Excipients; D005782:Gels; D007700:Kinetics; D008567:Membranes, Artificial; D009536:Niacinamide / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry; D013024:Soybean Oil / Q000737:chemistry*; D014783:Viscosity; D014867:Water
chemical_list: D005079:Excipients; D005782:Gels; D008567:Membranes, Artificial; D014867:Water; D009536:Niacinamide; C005062:acetylcellulose; D011092:Polyethylene Glycols; D012822:Silicon Dioxide; D013024:Soybean Oil; D002368:Castor Oil; D002482:Cellulose; D019840:2-Propanol