Effect of co-solvents on the controlled release of calcitonin polypeptide from in situ biodegradable polymer implants.
Drug Deliv
; 12(6): 393-8, 2005.
Article
en En
| MEDLINE
| ID: mdl-16253955
ABSTRACT
The objective of this study was to design an in situ biodegradable polymer implant controlled-release drug delivery system, using novel combinations of co-solvents and a model polypeptide, calcitonin (CT), and to assess the release of drug as a function of these co-solvents. Formulations were prepared by dissolving/ suspending CT polypeptide in poly-(lactic acid) (PLA) polymer solutions/suspensions containing combinations of a hydrophobic (benzyl benzoate, BB) and a hydrophilic (benzyl alcohol, BA) solvent. The CT-PLA mixtures were each injected into test tubes containing phosphate buffered saline solution to form the in situ implant and sampling was conducted over a 28-day period. The samples were analyzed for drug content using a modified Lowry protein assay procedure. Cumulative drug release demonstrated a rank-order correlation depending on the amount of the hydrophobic (BB) and hydrophilic (BA) solvents within each system. Increasing the amounts of the hydrophobic solvent, BB, in formulations demonstrated a 1.2-4.4-fold increase in CT release. Stability studies of all formulations over a 4-month period showed progressive increase in degradation of the CT polypeptide, especially at 37 degrees C, but a slower degradation pattern prevailed at 4 degrees and 20 degrees C. Differential scanning calorimetric studies revealed a homogenous mixture of drug in the polymer matrix. Overall, these studies demonstrated the feasibility of designing controlled release systems capable of releasing a polypeptide drug as a function of influence of different co-solvent combinations.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Polímeros
/
Solventes
/
Calcitonina
/
Ácido Láctico
/
Implantes Absorbibles
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
Drug Deliv
Asunto de la revista:
FARMACOLOGIA
/
TERAPIA POR MEDICAMENTOS
Año:
2005
Tipo del documento:
Article
País de afiliación:
Estados Unidos