The invention discloses a preparation method of a hard-core soft-membrane type nano slow-release
drug delivery system for injection. The preparation method comprises the following steps of: S1, preparing hydroxyapatite; S2, preparing a soft-membrane material PEG-PSI; S3, mixing a
drug to be delivered with the prepared hydroxyapatite in a solution, then adding the PEG-PSI dissolved in
dimethyl sulfoxide for injection, uniformly mixing, and then centrifuging a preparation at a high speed; and S4, washing, then re-suspending in pure water, and carrying out
freeze drying to obtain a final product. According to the preparation method disclosed by the invention,
polyethylene glycol modified polysuccinimide with different molecular weights is used as an organic
coating material, the hydroxyapatite is used as a
drug carrying core, the drug is adsorbed, and a nano preparation form with a hard-core soft-
membrane structure is formed through a
coating effect of the polysuccinimide on the hydroxyapatite, so that the drug
carrying capacity of a nano preparation is increased, the burst release of the nano preparation is avoided, the aggregation of nano particles is reduced, and the physical and
chemical stability is improved.