Biopharmaceutical characterisation of insulin and recombinant human growth hormone loaded lipid submicron particles produced by supercritical gas micro-atomisation.
Homogeneous dispersions of insulin and recombinant human growth hormone (rh-GH) in tristearin/phosphatidylcholine/PEG mixtures (1.3:1.3:0.25:0.15 w/w ratio) were processed by supercritical carbon dioxide gas micro-atomisation to produce protein-loaded lipid particles. The process yielded spherical particles, with a 197+/-94 nm mean diameter, and the insulin and rh-GH recovery in the final product was 57+/-8% and 48+/-5%, respectively. In vitro, the proteins were slowly released for about 70-80 h according to a diffusive mechanism. In vivo, the insulin and glucose profiles in plasma obtained by subcutaneous administration of a dose of particles containing 2 microg insulin to diabetic mice overlapped that obtained with 2 microg of insulin in solution. Administration of a dose of particles containing 5 microg insulin resulted in faster and longer glycaemia reduction. Oral administration of 20 and 50 microg insulin equivalent particles produced a significant hypoglycaemic effect. The glucose levels decreased since 2h after administration, reaching about 50% and 70% glucose reduction in 1-2h with the lower and higher dose, respectively. As compared to subcutaneous administration, the relative pharmacological bioavailability obtained with 20 and 50 microg equivalent insulin particles was 7.7% and 6.7%, respectively. Daily subcutaneous administration of 40 microg of rh-GH-loaded particles to hypophysectomised rats induced similar body weight increase as 40 microg rh-GH in solution. The daily oral administration of 400 microg rh-GH equivalent particles elicited a slight body weight increase, which corresponded to a relative pharmacological bioavailability of 3.4% compared to subcutaneous administration.
Salmaso
Stefano
S
Department of Pharmaceutical Sciences, University of Padua, Via F. Marzolo, 5, 35131 Padua, Italy.
Bersani
Sara
S
Elvassore
Nicola
N
Bertucco
Alberto
A
Caliceti
Paolo
P
D000818:Animals; D001682:Biological Availability; D001786:Blood Glucose / Q000187:drug effects; D001835:Body Weight / Q000187:drug effects; D002245:Carbon Dioxide / Q000737:chemistry; D003692:Delayed-Action Preparations; D003921:Diabetes Mellitus, Experimental / Q000188:drug therapy*; D004305:Dose-Response Relationship, Drug; D005260:Female; D019382:Human Growth Hormone / Q000008:administration & dosage*; D006801:Humans; D007004:Hypoglycemic Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics; D007328:Insulin / Q000008:administration & dosage* / Q000493:pharmacokinetics; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010713:Phosphatidylcholines / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014280:Triglycerides / Q000737:chemistry
D001786:Blood Glucose; D003692:Delayed-Action Preparations; D007004:Hypoglycemic Agents; D007328:Insulin; D010713:Phosphatidylcholines; D014280:Triglycerides; D019382:Human Growth Hormone; D002245:Carbon Dioxide; D011092:Polyethylene Glycols; C022618:tristearin