Duman, G. | Aslan, I. | Özer, A.Y. | Inanc¸, I. | Taralp, A.

Article | 2014 | Journal of Liposome Research24 ( 4 ) , pp.259 - 269

The moisture-imparting effect of sodium hyaluronate (Na-HA) was investigated in liposome, gel and lipogelosome topical formulations. Sixteen liposome formulations were prepared with or without Na-HA (45 kDa) using various ratios of dimyristoylphosphatidylcholine, 1,2-dimyristoyl-sn-glycero-3-phosphatidylglycerol, dipalmitoylphosphatidylcholine and phospholipon 100H. The liposomes were characterized in terms of their structure, composition, zeta potential, Na-HA-entrapment capacity and stability. In particular, scanning electron microscopy, polarized light microscopy, dynamic light scattering and atomic force microscopy were utilized . . . to probe appearance, size and size distribution and lamellarity. The work was then extended to gels using the gelling agents poloxamer (PXM 188 or 407) and Carbopol or Ultrez 21 (U-21), yielding liposome-loaded gel formulations (i.e. lipogelosomes). The in vitro release kinetics of Na-HA from liposomes, lipogelosomes and commercial Na-HA reference formulations were studied via a flow-through cell method. Among the liposomal formulations tested, L6, comprising of Na-HA-loaded phospholipon 100H:stearylamine:cholesterol (7:1:2), displayed optimal traits. The mean particle size, zeta potential and entrapment capacity of L6 were determined as 1900 nm, -20.9mV and 15.0%. The optimum lipogelosome, LG4, was obtained by incorporating liposome L6 into a U-21 gel at a ratio of 1:1 (w/w). In clinical trials, in-house formulations were applied twice daily to 15 female volunteers. The two-week benefits were assessed against a commercial product; and in all cases, changes of skin humidity, sebum content, pH and wrinkle depth were promising. In particular, the LG4 lipogelosome-based formulation had significantly improved skin hydration and compliance, as evidenced by a moisture content gain of 30.4%. © 2014 Informa Healthcare USA, Inc Daha fazlası Daha az

Rouf, M.A. | Vural, I. | Renoir, J.M. | Hincal, A.A.

Article | 2009 | Journal of Liposome Research19 ( 4 ) , pp.322 - 331

Rapamycin (Sirolimus) is a macrolide lactone with antifungal, immunosuppressant, and antiproliferative actions. The mechanism of rapamycin action involves the inhibition of mTOR and subsequent cytostasis. Rapamycin also prevents angiogenesis in tumors and can prevent cancer cells' resistance to other chemotherapeutic agents. However, very poor water solubility, bioavailability, only slight solubility in acceptable parenteral excipients, chemical instability, and major sequestration (95%) of free rapamycin into the erythrocytes have prevented its development as an anticancer drug. To address these problems, it was attempted to develo . . .p liposomal rapamycin delivery systems in this study. Conventional and pegylated liposomes were prepared with various lipid and cholesterol ratios. They were then characterized; these liposomes contained 0.680.90mg of rapamycin per milliliter of liposome suspension. Having suitable particle size, these liposomes successfully retained the entrapped drug. Both types of liposomes were found to be effective; however, conventional liposomes showed better antiproliferative activity against MCF-7 cells than pegylated liposomes. But, pegylated liposome showed better stability than conventional liposomes. In conclusion, the enhanced permeability and retention effercts of tumors should provide the opportunity for pegylated liposomal rapamycin to be applied as an intravenous drug-delivery system for targeted delivery to cancer cells, avoiding the major sequestration of free rapamycin into the erythrocytes Daha fazlası Daha az