The present invention relates to a soluble hydrophobic-core carrier composition comprising (i) a linear polymeric backbone； (ii) a plurality of hydrophilic polymeric protective chains covalently linked and pendant to the polymeric backbone and (iii) at least one hydrophobic moiety covalently linked and pendant to the polymeric backbone. In certain embodiments, the weight ratio of hydrophilic protective chains to hydrophobic moieties in the carrier is at least 15:1. In other embodiments, at least 90% of the residues of the polymeric backbone are coupled to a hydrophilic polymeric protective chain or a hydrophobic moiety. In other embodiments, the composition further comprises (iv) a hydrophobic load molecule dissociably linked to the hydrophobic moiety of the carrier.
