Treatment of neuroblastoma and rhabdomyosarcoma using RGD-modified liposomal formulations of patupilone (EPO906).

BACKGROUND: Patupilone (EPO906) is a microtubule stabilizer with a potent antitumor effect. Integrin αVß3-binding (RGD) liposomes were loaded with EPO906, and their antitumor efficacy was evaluated in two pediatric tumor models, ie, neuroblastoma and rhabdomyosarcoma. METHODS: Integrin αVß3 gene expression, RGD-liposome cellular association, and the effect of EPO906 and liposomal formulations of EPO906 on cell viability were assessed in vitro in human umbilical vein endothelial cells (HUVEC), in the RH-30 rhabdomyosarcoma cell line, and in the Kelly neuroblastoma cell line. In vivo, mice bearing neuroblastoma or rhabdomyosarcoma tumors were treated with EPO906, EPO906-liposomes, or EPO906-RGD-liposomes. Tumor growth, cumulative survival, and toxicity were monitored. RESULTS: Integrin αVß3 was highly expressed in HUVEC and RH-30, but not in Kelly cells. Accordingly, RGD-liposomes were highly associated with HUVEC and RH-30 cells in vitro, but not with the Kelly cells. EPO906 and its liposomal formulations inhibited HUVEC, RH-30, and Kelly cell viability to the same extent. In vivo, EPO906 1.5 mg/kg and liposomal EPO906 potently inhibited tumor growth in both xenograft models without triggering major toxicity. At this dose, liposomal EPO906 did not enhance the antitumor effect of EPO906 in neuroblastoma, but tended to have an increased antitumor effect in rhabdomyosarcoma. Using a lower dose of EPO906-RGD-liposomes significantly enhanced cumulative survival in rhabdomyosarcoma compared with EPO906 alone. CONCLUSION: EPO906 shows a strong antitumor effect in neuroblastoma and rhabdomyosarcoma, without triggering major side effects. Its liposomal encapsulation does not alter its activity, and enhances cumulative survival when EPO906-RGD-liposomes are used at low dose in rhabdomyosarcoma.

Confocal Raman microscopy to probe content uniformity of a lipid based powder for inhalation: a quality by design approach.

In the present work confocal Raman microscopy was employed as a non-destructive tool to define the content uniformity and the polymorphic form of a drug substance distributed within a lipid based inhalable powder. Two spray dried powders with different active ingredient concentrations (1.55 and 7.3wt/wt%) and an additional placebo formulation were analyzed with confocal Raman microscopy and scanning electron microscopy to define the distribution of active substance within the lipid based particles as well as its polymorphic form. The formulation containing less drug substance was shown to have a high degree of content uniformity: a complete colocalization of the Raman signal for the lipids and the Raman signal for the drug substance was detected, implying that the active ingredient was homogenously distributed within the lipid particles. Within the higher concentrated preparation, in addition to the colocalized active ingredient, Raman signals of crystalline drug substance could be observed which were not matching with the location of the consistent lipid signal. Those observations gave evidence that a part of the active substance in this formulation was not molecularly dispersed within the powder. It could be shown that confocal Raman microscopy may be used as a fast and convenient method to define the content uniformity of an active ingredient within a lipid based spray dried powder for inhalation. Using this technique the distribution of an active ingredient can be characterized non-destructively, aiding in the understanding of complex drug delivery systems e.g. in the field of inhalable pharmaceutical powders. In addition analysis of solid state is available with confocal Raman microscopy.

Simple and precise detection of lipid compounds present within liposomal formulations using a charged aerosol detector.

In recent decades the use of liposomal preparations as drug delivery systems has become very attractive in pharmaceutical development. Therefore, thorough characterization and quantification of the lipids which form liposomes is wished from both investigators and regulatory authorities when the application in humans is being considered. In this study a new HPLC method for the detection of lipids in liposomal formulations was established using corona charged aerosol detection (CAD) which has the advantage to be independent of the chemical properties of the analytes. The superiority of this method over UV detection was demonstrated. Compared to UV detection no absorption effects of the organic solvent in the mobile phase interfering with the lipid signals were observed with CAD. CAD showed good linearity (R(2)>0.990) for all liposomal compounds. The acceptance criteria for precision including repeatability were met. The average recovery for each of the excipients of the liposomal formulation was in the range of 90.0-110%.

LC-MS characterization of trace impurities contained in calcium folinate.

An impurity present in calcium folinate (N5-formyl-5,6,7,8-tetrahydrofolic calcium salt) active pharmaceutical ingredient (API) was detected by high-performance liquid chromatography (HPLC). Through analysis by HPLC coupled with atmospheric-pressure chemical-ionization mass spectrometry (APCI-MS), a structure for this impurity was postulated and then proved by chemical synthesis.

Light-induced metastable states in oxalatenitrosylruthenium(II) and terpyridinenitrosylruthenium(II) complexes.

Two extremely long lived metastable states (SI and SII) can be accessed by irradiation with light in the blue-green spectral range at temperatures below 200 K in Cs(2)[Ru(ox)(NO)Cl(3)], [Ni(cyclam)][Ru(ox)(NO)Cl(3)].3H(2)O, and [Ru(terpy)(NO)(OH)Cl][PF(6)]. The crystal structures of the ground states of the oxalate-containing compounds are presented, and the influence of the atomic distances of the cations/anions is discussed with respect to the decay temperatures. The radiationless thermal decay of the metastable states is detected by differential scanning calorimetry (DSC) for the three compounds. Both metastable states decay exponentially in time under isothermal conditions. The excited states are energetically separated from the ground state by potential barriers given by the activation energy of the Arrhenius law. In [Ni(cyclam)][Ru(ox)(NO)Cl(3)].3H(2)O the enthalpy maximum of the thermal decay of SII appears at 182 K, which is a relatively high decay temperature for SII. The reason for this strong temperature shift compared to those of the other compounds could be due to the polarization effect of Ni(2+) on the electron density at the Ru site via the Cl atom.