OBJECTIVETo evaluate polypropylenimine dendrimers (generations 1-5: DAB 4, DAB 8, DAB 16, DAB 32, and DAB 64) as gene delivery systems.METHODSDNA binding was evaluated by measuring the reduced fluorescence of ethidium bromide, and molecular modelling of dendrimer-DNA complexes also was performed. Cell cytotoxicity was evaluated against the A431 cell line using the MTT assay. In vitro transfection was evaluated against the A431 cell line using the beta-galactosidase reporter gene and N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium methylsulphate (DOTAP) served as a positive control.RESULTSMolecular modeling and experimental data revealed that DNA binding increased with dendrimer generation. Cell cytotoxicity was largely generation dependent, and cytotoxicity followed the trend DAB 64 > DAB 32 > DAB 16 > DOTAP > DAB 4 > DAB 8, whereas transfection efficacy followed the trend DAB 8 = DOTAP = DAB 16 > DAB 4 > DAB 32 = DAB 64.CONCLUSIONThe generation 2 polypropylenimine dendrimer combines a sufficient level of DNA binding with a low level of cell cytoxicity to give it optimum in vitro gene transfer activity.

01 Sep 1984·Die PharmazieQ4 · MEDICINE

[The ratio of free and fixed interlamellar water as quality criteria for O/W creams].

Q4 · MEDICINE

Article

Author: Junginger, H

O/W creams with crystalline gel structures are supposed to be four phase systems. Their dominant structural elements are the hydrophilic and lipophilic gel phases. The hydrophilic gel phases have - depending on the hydrophilic character of their polar groups - a very strong swelling capacity. Further, a dynamic equilibrium is maintained between the water interlamellarly inserted into the hydrophilic gel phase and the bulk water phase. The latter is mainly fixed mechanically by the hydrophilic gel phase. The lipophilic gel phases, however, which immobilize the dispersed phase, have no or only an extremely weak swelling capacity. By means of thermogravimetry (TG) a quantitative differentiation between water interlamellarly fixed in the hydrophilic gel phase and bulk water is possible. Using dynamic TG, the curves of water release and the results obtained are discussed. In the water-containing hydrophilic ointment DAB 8 and in the non-ionic hydrophilic ointment DAC the fractions of interlamellarly fixed water are substantially higher than those of the bulk water. In the investigated stearate creams, however, the fraction of the bulk water is much higher than the fraction of interlamellarly fixed water. Consequently the water release from these stearate creams is higher than that of the other O/W creams mentioned above. It is concluded that the ratio of interlamellarly fixed water and bulk water is an important criterion for the properties of such O/W creams and that TG can be suitably applied not only as in process control during product manufacturing but also as a useful tool in the development of O/W creams with a controlled water release.

01 Aug 1984·Pharmaceutisch Weekblad Scientific Edition

Colloidal structures of O/W creams

Article

Author: H. E. Junginger

O/W creams with crystalline gel structures (Water Containing Hydrophilic Ointment DAB 8, Non-ionic Hydrophilic Ointment DAC and a stearate cream) were investigated by means of small angle X-ray diffraction, differential scanning calorimetry, thermogravimetry and freeze fracture technique in combination with Transmission Electron Microscopy (TEM). It was found that these bases are building up two different colloidal gel structures, a hydrophilic gel phase and a lipophilic gel phase, each of them forming a coherent network. The hydrophilic gel phase is characterized by an interlamellar water layer; this interlamellarly fixed water is in a dynamic equilibrium with the bulk water phase. The lipophilic gel phase immobilizes mainly the inner (dispersed) phase. So the O/W creams presented here are supposed to be four-phase systems. The ratio of interlamellarly fixed water and bulk water, which may be determined easily by means of thermogravimetry, is found to be an important quality criterion for these O/W creams. The desired properties of water release of such a cream may be chosen by shifting the ratio of interlamellarly fixed water and bulk water.

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Indication	Highest Phase	Country/Location	Organization	Date
Hyperphosphatemia	Discovery	-	Deltanoid Pharmaceuticals, Inc.	-

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