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ABSTRACT
Berbamine loaded quaternized chitosan/agarose microspheres were prepared using a water-inoil emulsion technique. Optimum preparing parameters were determined by orthogonal experiments as follows: ratio of berbamine to quaternized chitosan (w/w), 1:10; percentage of emulsifier (span 80, v/v), 1%; volume of glutaraldehyde, 3 mL; and reaction temperature, 70°C. Under these optimal conditions, the encapsulation efficiency and loading capacity of microspheres are 86.01% and 7.52%, respectively. Swelling test showed that the microspheres possessed higher swelling ratio at pH 7.4 than at pH 1.2. FTIR indicated that berbamine had been successfully loaded in the quaternized chitosan/agarose microspheres by physical entrapment. In vitro release studies showed that berbamine was released from microspheres in a significantly sustained fashion.
KEY WORDS: Quaternized chitosan, agarose, microspheres, berbamine.
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INTRODUCTION
Berbamine, a well-known bisbenzylisoquinoline alkaloid, is a natural compound isolated from traditional Chinese herbal medicines such as Berberis amurensis (Fig.1). Berbamine has been widely used in China for leukopenia treatment over the past decades. Clinical studies showed that berbamine could stimulate normal hematopoiesis of cancer patients undergoing chemotherapy or radiotherapy and has been used to protect tumor patients from cytotoxic effects of chemotherapeutic agents on bone marrow. Meanwhile, berbamine has anti-inflammatory, anti-arrhythmic effects and antineoplastic activity[1, 2]. However, on oral administration, berbamine may produce some side effects, such as jaundice, stomach upset, lethargy, nose bleed, skin and eye irritation, kidney irritation, and so on. Therefore, it is essential to deliver berbamine at the intended therapeutic concentrations to the target sites to elicit its activity. Sustained delivery of berbamine may reduce the systemic side effects and provide effective and safe therapy of leukopenia that may reduce the dose and duration of therapy when compared with the conventional treatment.
Recently, microspheres have received great attention because of a variety of applications such as delivery vesicles for drugs, DNA, antigens, and protection proteins and enzymes, especially for controlled or sustained drugdelivering systems[3, 4]. There has been considerable interest in developing microspheres prepared from chitosan matrices as effective drug delivery devices. Owing to its nontoxicity, biodegradability, biocompatiblity, mucoadhesion and antibacterial, chitosan, a natural polysaccharide, has been extensively applied in various areas, especially in the pharmaceutical and biomedical fields, such as drug delivery, wound dressing and antimicrobial agents[5, 6]. It is reported...