title: Cytotoxic activity of a new paclitaxel formulation, Pacliex, in vitro and in vivo.
abstract: BACKGROUND
  The paclitaxel formulation, Taxol (Bristol-Myers Squibb), is one of the most effective anticancer agents used today. However; it is associated with serious side effects believed to be caused by the Cremophor EL used for its formulation.
  
  
  OBJECTIVE
  To evaluate the cytotoxic activity of a new paclitaxel formulation, Pacliex (developed by Oasmia Pharmaceutical, Uppsala, Sweden), a mixed micelles preparation in which an amphiphilic synthetic derivative of retinoic acid replaced Cremophor EL/ethanol vehicle.
  
  
  METHODS
  In this study, three model systems were used to evaluate the cytotoxic activity of Pacliex and other paclitaxel preparations. The cytotoxic activities of Pacliex, Taxol and paclitaxel in ethanol were investigated against a panel of ten human tumor cell lines using the fluorometric microculture cytotoxicity assay (FMCA). Low- and high- proliferating in vitro hollow fiber model of two cell lines, the leukemia CCRF-CEM and the myeloma RPMI 8226/S cell lines, were used to assess the cytotoxic activity of the three formulations. The in vivo hollow fiber model of the two cell lines was used for assessment of Pacliex and Taxol activity. The [3-4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay was utilized to analyze the in vitro and in vivo hollow fiber data.
  
  
  RESULTS
  Pacliex was somewhat more effective than Taxol in the more sensitive cell lines. The activity of Taxol was more pronounced in the resistant cell lines due to an additive effect of the vehicle used. The three formulations showed similar activity in both the low- and high-proliferating in vitro hollow fiber cultures. The in vivo hollow fiber cytotoxic activity of Pacliex was similar to that of Taxol. Putting all the results together, it was found that all the three formulations had similar in vitro and in vivo activity.
  
  
  CONCLUSIONS
  The three in vitro and in vivo models confirmed the similarity of the cytotoxic activities of Pacliex and Taxol. Considering the above, Pacliex could be an interesting alternative Cremophor EL-free formulation of paclitaxel.
authors.affiliation: Division of Clinical Pharmacology, Department of Medical Sciences, University Hospital, 751 85, Uppsala, Sweden. sadia.hassan@medsci.uu.se
authors.forename: Saadia
authors.initials: S
authors.lastname: Hassan
authors.forename: Sumeer
authors.initials: S
authors.lastname: Dhar
authors.forename: Marie
authors.initials: M
authors.lastname: Sandström
authors.forename: Dzmitry
authors.initials: D
authors.lastname: Arsenau
authors.forename: Marina
authors.initials: M
authors.lastname: Budnikova
authors.forename: Igor
authors.initials: I
authors.lastname: Lokot
authors.forename: Nikolai
authors.initials: N
authors.lastname: Lobanov
authors.forename: Mats O
authors.initials: MO
authors.lastname: Karlsson
authors.forename: Rolf
authors.initials: R
authors.lastname: Larsson
authors.forename: Elin
authors.initials: E
authors.lastname: Lindhagen
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology* / Q000633:toxicity*; D002626:Chemistry, Pharmaceutical; D006801:Humans; D007938:Leukemia / Q000473:pathology; D008823:Micelles; D009101:Multiple Myeloma / Q000473:pathology; D017239:Paclitaxel / Q000031:analogs & derivatives* / Q000494:pharmacology* / Q000633:toxicity*; D014407:Tumor Cells, Cultured
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D008823:Micelles; C495179:Pacliex; D017239:Paclitaxel