The present invention relates to linear oligo- or poly-ε-caprolactones di-blockcopolymers, in solid form at room temperature, comprising monoalkyl oligoethyleneglycol residues. The present invention further relates to a drug delivery formulation comprising above materials and a process for the preparation of the drug delivery formulation. The oligoethyleneglycol residues are preferably selected from the group consisting of methyl diethylene glycol, methyl triethyleneglycol or methyl tetraethylene glycol. The oligo- or poly-ε-caprolactone derivatives are prepared via the reaction of mono-hydroxy-oligoethyleneglycol with ε-caprolactone, whereby the mono-hydroxy-oligoethyleneglycol acts as an initiator.
