Concomitant solubility-permeability increase: Vitamin E TPGS vs. amorphous solid dispersion as oral delivery systems for etoposide

Avital Beig, Noa Fine-Shamir, Daniel Porat, David Lindley, Jonathan M. Miller, Arik Dahan

Research output: Contribution to journalArticlepeer-review

44 Scopus citations


Vitamin E TPGS (TPGS) has both surfactant and P-glycoprotein (P-gp) inhibitory effects. While surfactants were previously found to cause solubility-permeability tradeoff, TPGS P-gp inhibitory effects may change this unfavorable interplay. The purpose of this research was to investigate the solubility-permeability interplay when using TPGS vs. amorphous solid dispersions (ASD) as oral drug delivery systems for the anticancer, P-gp substrate, lipophilic drug etoposide. The concentration-dependent effects of TPGS (0–100 mg/mL) vs. ASD on the solubility of etoposide, as well as the in-vitro (PAMPA) vs. in-vivo (intestinal rat perfusion) permeability of the drug were studied, and the resulting solubility-permeability interplay was analyzed. TPGS above CMC (0.3 mg/mL) increased etoposide solubility linearly, and ASD allowed significant supersaturation. Etoposide in-vitro PAMPA permeability decreased markedly with increasing TPGS levels, similarly to the solubility-permeability tradeoff previously defined for surfactants. In contrast, the presence of TPGS significantly increased etoposide in-vivo rat permeability, attributable to P-gp inhibition, similarly to the effect of the potent P-gp inhibitor GF120918 (10 µg/mL). High supersaturation achieved via ASD increased the drug's in-vivo permeability to the level obtained by TPGS or GF120918, supporting P-gp saturation. In conclusion, unique pattern of solubility-permeability interplay was found, involving concomitant increase of both the solubility and the permeability, as opposed to the previously reported tradeoff for solubilization methods and the unchanged permeability for supersaturation; P-gp inhibition/saturation by TPGS or by supersaturation allows simultaneous increase of both solubility and permeability, representing a significant advantage of such drug delivery approaches when suitable.

Original languageEnglish
Pages (from-to)97-103
Number of pages7
JournalEuropean Journal of Pharmaceutics and Biopharmaceutics
StatePublished - 1 Dec 2017


  • Drug absorption
  • Intestinal permeability
  • Oral drug delivery
  • P-glycoprotein inhibition
  • Solubility
  • Supersaturation

ASJC Scopus subject areas

  • Biotechnology
  • Pharmaceutical Science


Dive into the research topics of 'Concomitant solubility-permeability increase: Vitamin E TPGS vs. amorphous solid dispersion as oral delivery systems for etoposide'. Together they form a unique fingerprint.

Cite this