Abstract: The invention describes complexes between VB12 analogues and either GCSF or EPO that retain both significant affinity for intrinsic factor (IF) in the VB12 portion of the complex and significant bioactivity of the GCSF or EPO portion of the complex. The invention also concerns a process for the synthesis of these complexes. This is achieved at least in part, by using a spacer compound, which is linked covalantly between the VB12 portion and the GCSF or EPO.

Abstract: There are disclosed complexes and compositions for oral delivery of a substance or substances to the circulation or lymphatic drainage system of a host. The complexes of the invention comprise a microparticle coupled to at least one carrier, the carrier being capable of enabling the complex to be transported to the circulation or lymphatic drainage system via the mucosal epithelium of the host, and the microparticle entrapping or encapsulating, or being capable of entrapping or encapsulating, the substance(s). Examples of suitable carriers are mucosal binding proteins, bacterial adhesins, viral adhesins, toxin binding subunits, lectins, Vitamin B.sub.12 and analogues or derivatives of Vitamin B.sub.12 possessing binding activity to Castle's intrinsic factor.

Abstract: The invention describes complexes between VB.sub.12 analogues and either GCSF or EPO that retain both significant affinity for intrinsic factor (IF) in the VB.sub.12 portion of the complex and significant bioactivity of the GCSF or EPO portion of the complex. The invention also concerns a process for the synthesis of these complexes. This is achieved at least in part, by using a spacer compound, which is linked covalantly between the VB.sub.12 portion and the GCSF or EPO. The complexes preferably have the formulaV--X--A--Y--ZwhereinV is vitamin B.sub.12 or a vitamin B.sub.12 analogue, or derivative, bonded to X either through a carboxylate group pendant to the corrin nucleus of VB.sub.12 or through the central cobalt atom or to a functional group introduced onto the VB.sub.12 molecule, X is selected from: --NHNH--, --NH--, --O--, --S--, --SS--or --CH.sub.2 --, and A is an optionally substituted, saturated or unsaturated, branched or linear, C.sub.