Abstract

Poly(lactic-co-glycolic acid) Microspheres Containing a Recombinant Parathyroid Hormone (1-34) for Sustained Release in a Rat Model

Author(s): R. Baskaran, C. J. Lee, S. M. Kang, Y. Oh, S. E. Jin, D. H. Lee and S. G. Yang*
World Class Smart Lab, Department of New Drug Development, College of Medicine, Inha University, B-308, Chungsuk Bldg, 366, Seohae-Daero, Jung-Gu, Incheon 22332, Republic of Korea

Correspondence Address:
World Class Smart Lab, Department of New Drug Development, College of Medicine, Inha University, B-308, Chungsuk Bldg, 366, Seohae-Daero, Jung-Gu, Incheon 22332, Republic of Korea, E-mail: [email protected]


Recombinant parathyroid hormone (1-34), the drug of choice for treating severe osteoporosis, has a short half-life and requires daily subcutaneous injections. Controlled release formulation of recombinant parathyroid hormone (1-34) might prevent daily injections and improve therapeutic outcome. In this study, recombinant parathyroid hormone (1-34)-loaded poly(D,L-lactic-co-glycolic acid) microspheres using a double emulsion method were prepared. Scanning electron microscopy proved that the microspheres were spherical in shape with 2.0 to 5.0 µm diameter. A loading efficiency up to 84 % was achieved in the optimized formulation. Release study performed using microspheres of 10:1.0 polymer:drug ratio formulation revealed that the release of recombinant parathyroid hormone (1-34) was controlled over 22 days in a biphasic manner with an initial burst and a subsequent slow release. For pharmacokinetic study, recombinant parathyroid hormone (1-34)-loaded poly(D,L-lactic-co-glycolic acid) microspheres were subcutaneously injected to rats at 0.01 mg/kg dose of recombinant parathyroid hormone (1-34). Plasma drug concentration of recombinant parathyroid hormone (1-34)-loaded poly(D,L-lactic-co-glycolic acid) microspheres were maintained for a week whereas free recombinant parathyroid hormone (1-34) was quickly eliminated within a day. These results suggest that recombinant parathyroid hormone (1-34)-loaded poly(D,L-lactic-co-glycolic acid) microspheres appear to have the potential for further clinical development.



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