Elsevier

Materials Letters

Volume 65, Issues 17–18, September 2011, Pages 2800-2803
Materials Letters

Controlled dual release of hydrophobic and hydrophilic drugs from electrospun poly(l-lactic acid) fiber mats loaded with chitosan microspheres

https://doi.org/10.1016/j.matlet.2011.06.018Get rights and content

Abstract

This work is to develop novel electrospun poly(l-lactic acid) (PLLA) fiber mats for controllable delivery of hydrophobic and hydrophilic drugs. For this aim, bovine serum albumin (BSA, used as a hydrophilic model drug) was firstly enveloped into chitosan microspheres by spray drying. Benzoin (used as a hydrophobic model drug) was directly dissolved in PLLA solution and then the chitosan microspheres were suspended into the PLLA solution, which was used to prepare PLLA fiber mats by electrospinning. Polyvinylpyrrolidone (PVP) was added into the PLLA solution to tune the drug release behaviors. The results showed that the chitosan microspheres were uniformly distributed in the fibers. BSA had a short-term release while benzoin had a long-term and sustained release in all the dual drug delivery systems, and the release of both hydrophobic and hydrophilic drugs could be adjusted by changing the ratio of PVP/PLLA.

Introduction

Electrospun fibers, with diameters ranging from several microns to 100 nm [1], have outstanding characteristics such as flexible morphology, large surface area to volume ratio and unique nanometer scale architecture, and therefore have been widely used in many biomedical fields [2], [3]. Particularly, electrospun fibers have been intensively investigated for drug delivery systems because they confer higher drug encapsulation efficiency and better structural stability than other drug carriers [4], [5].

Presently, most studies focus on single drug delivery systems [6], [7], which often could not satisfy the requirements in clinical therapies [8]. Hence, various dual-drug delivery systems [9], [10] have been developed to improve therapy efficacy, in which two drugs with different therapeutic effects are loaded. Recently, coaxial or emulsion electrospinning has been reported for preparing core-shell type fibers, but a special apparatus and operation parameters are necessary [11] and some surfactants are used [12]. In this study, novel electrospun poly(l-lactic acid) (PLLA) fiber mats were prepared by spray-drying and electrospinning process for the controllable co-delivery of hydrophobic benzoin and hydrophilic bovine serum albumin (BSA). The release behaviors of the drugs were studied and modulated by adding polyvinylpyrrolidone (PVP) to the electrospun PLLA fiber mats.

Section snippets

Experimental

Benzoin and BSA were purchased from Beijing Dingguo Biotechnology Co., Ltd. (China). PLLA (Mw = 100 kDa) and PVP (k30) were purchased from Jinan Daigang Biological Technology Co., Ltd. (China). Chitosan (Mw = 50 kDa, the degree of deacetylation of 95%) was purchased from Jinan Haidebei Ocean Biological Engineering Co., Ltd. (China). Other chemicals and solvents were of analytical grade.

With high-speed stirring, aqueous sodium tripolyphosphate solution (1%, w/v) as crosslinking agent was added into 2%

Results and discussion

From Fig. 1 A, the diameter of BSA-loaded chitosan microspheres was about 1–3 μm. The smaller microspheres have a quicker evaporation during spray drying than the larger ones, probably leading to the smoother surface compared to that of the larger ones. The smaller chitosan microspheres were separated by an 800-mesh standard sieve. From Fig. 1B, C and D, the electrospun fiber mats looked uniform and presented porous structure on their surfaces. This morphology is attributed to the rapid

Conclusion

In this paper, we prepared a dual-drug delivery system of chitosan microspheres-loaded, electrospun PLLA fiber mats. The characterizations confirmed that chitosan microspheres were encapsulated and uniformly distributed in the electrospun fiber mats. The dual release in vitro showed a short-term BSA release but a sustained long-term benzoin release in all the dual-drug delivery systems. Moreover, the release rate of BSA and benzoin from the systems was significantly accelerated by increasing

Acknowledgment

This work was financially supported by the National Natural Science Foundation of China and Guangdong Province (Grant no. 50903039; 9451063201002459), the Research Fund for the Doctoral Program of Higher Education of China (Grant no. 20094401120006), the Project of Science and Technology of Guangdong Province (Grant no. 2010A040302004; 2010B090301007) and the Fundamental Research Funds for the Central Universities.

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