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KMID : 0614020030180010054
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Journal of Pharmaceutical Sciences (C.N.U.)
2003 Volume.18 No. 1 p.54 ~ p.65
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Preparatioina and Evaluation of Bupivacaine-loaded Microspheres by Solvent Extraction Method
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Kim Min-Soo
Hwang Sung-Joo
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Abstract
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Various bupivacaine-loaded microspheres were prepared with poly (d,l-lactide) (PLA) by solvent extraction method. The internal solution of polymer(PLA R104) and drug in glacial acetic acid was introduced into the external phase of polyvinylpyrrolidone (PVP K-30) in polyethyleneglycol (PEG), and emulsified to be an oil-in-oil (o/o) emulsion. The o/o emulsion was poured to the buffer solution. During this process, microspheres were precipitated because the buffer solution is miscible with PEG and glacial acetic acid. The microspheres were acquired by filtration, redispersion, washing and lyophihzation. The effects of process conditions such as drug loading, emulsification speed. emulsifier concentration. external phase, internal/external phase ratio and temperature on the characteristics of microspheres were investigated. And bupivacaine-loaded microspheres were also prepared when citric acid or meglumine was added into the internal polymer solution, and/or when meglumine or bupivacaine was added into the external PEG phase. Itraconazole was used as a water insoluble model drug. Itraconazole-loaded microspheres were prepared by the same method as the above to compare the characteristics of microspheres between the bupivacaine microspheres. The prepared microspheres were characterized for their drug loading efficiency, particle size distribution and surface morphology. Drug loading efficiency was higher in the itraconazole-loaded microspheres than the bupivacaine-loaded microspheres, because itraconazole has a very low solubility. The average number mean diameters of bupivacaine-loaded microspheres were 27.64~47.92μm, while those of itraconazole-loaded microspheres were 16.18~25.74pm. In morphology studies, bupivacaine-loaded microspheres showed an irregular shape and had a rough surface.
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KEYWORD
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Bupivacaine, PLA, Microspheres, Solvent extraction method
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