ABSTRACT
In order to improve the pharmacological efficacy of recombinant human interleukin-11 (rhIL11) and to reduce the frequency of administration, we examined the feasibility of chemical modification of rhIL11 by polyethylene glycol. The rhIL11 was chemically modified by using branched type (PEG2), or linear type (PEG) polyethylene glycol-N-hydroxysuccinimide with various molecular weights. Plasma profiles of immunoreactive rhIL11 after i.v. injection of the 20 kDa PEG2 conjugated rhIL11 (PEG2 (20 K)-rhIL11) were determined by ELISA. Peripheral platelet counts after the administration of the various conjugates were measured. Pharmacokinetic analysis revealed that the mean residence time of PEG2 (20 K)-rhIL11 after i.v. injection extensively increased by a factor of ca 60 compared with the native rhIL11. Maximum peripheral platelet increase of 67% for PEG2 (20 K)-rhIL11 and that of 50% for PEG (20 K)-rhIL11 over the control was observed whereas no significant change was associated with the bolus i.v. injection of native rhIL11. On the other hand, the remaining biological activity of these PEGylated-rhIL11s was 14-16% of native rhIL11, suggesting that retention of rhIL11 in plasma is much effective in order to potentiate the pharmacological efficacy of the cytokine. Chemical modification of rhIL11 by PEG is a promising approach for improving the clinical efficacy of rhIL11 by prolonged retention in plasma.
Subject(s)
Antineoplastic Agents , Drug Carriers/chemistry , Interleukin-11 , Polyethylene Glycols/chemistry , Recombinant Proteins , Animals , Antineoplastic Agents/adverse effects , Antineoplastic Agents/blood , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Blood Platelets/cytology , Blood Platelets/drug effects , Cell Line, Tumor , Dose-Response Relationship, Drug , Enzyme-Linked Immunosorbent Assay , Humans , Injections, Intravenous , Interleukin-11/adverse effects , Interleukin-11/blood , Interleukin-11/chemistry , Interleukin-11/pharmacology , Male , Metabolic Clearance Rate , Mice , Mice, Inbred Strains , Molecular Weight , Platelet Count , Recombinant Proteins/adverse effects , Recombinant Proteins/blood , Recombinant Proteins/chemistry , Recombinant Proteins/pharmacologyABSTRACT
In order to improve the therapeutic efficacy of recombinant human interleukin 11 (rhIL11) and to reduce its frequency of administration, the feasibility of a sustained release formulation consisting of hyaluronic acid (HyA) was investigated. rhIL11 was mixed together with an aqueous solution of HyA or HyA and protamine, and the mixture was lyophilized. The resulting powder was compressed into pellet and was subcutaneously administered in the rats. The plasma profile of rhIL11 was determined by ELISA. The mean residence time and t(max) of rhIL11 were much prolonged by administration in an HyA pellet. The additional incorporation of protamine into the formulation further enhanced the plasma duration of the protein. Separately, peripheral platelet counts were measured for several rhIL11-containing solution and pellets. Platelet counts much increased after administration of rhIL11-containing pellets, whereas the effect of bolus subcutaneous administration of rhIL11 solution was limited. The degree of platelet increase in rats treated with the pellets was comparable to that for rats treated with 1- or 2-day continuous infusion from an osmotic mini-pump; these data reflect the importance of increased plasma duration of rhIL11. These data indicate that use of hyaluronic acid as a polymer matrix might enhance the therapeutic efficacy of rhIL11.
