Investigation Of Dual Drug Delivery System Based On Poly(lactic Acid) Electrospun Fibers

Electrospun fibers, with diameters ranging from several microns to100nm, haveoutstanding characteristics such as flexible morphology, large surface area to volumeratio and unique nanometescale architecture, and therefore have been widely used inmany biomedical fields. Particularly, electrospun fibers have been intensivelyinvestigated for drug delivery systems because they confer higher drug encapsulationefficiency and better structural stability than other drug carriers. Presently, moststudies focus on single drug delivery systems which often could not satisfy therequirements in clinical therapies. Hence, various dual-drug delivery systems havebeen developed to improve therapy efficacy, in which two drugs with differenttherapeutic effects are loaded.In this study, novel electrospun poly(L-lactic acid)(PLLA) fiber mats wereprepared by spray-dryiny and electrospinning process for the controllable co-deliveryof hydrophobic benzoin and hydrophilic bovine serum albumin (BSA). The releasebehaviors of the drugs were studied and modulated by adding polyvinylpyrrolidone(PVP) to the electrospun PLLA fiber mats. The characterizations confirmed thatchitosan microspheres were encapsulated and uniformLy distributed in theelectrospun fiber mats.The dual release in vitro showed a short-term BSA release buta 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 byincreasing PVP/PLLA ratio.The most disadvantage of electrospun fiber is its lower the mechanical strength,in this study novel electrospun poly (L-lactic acid)(PLLA) fiber mats containing withhalloysites (HNTs) were prepared by electrospinning process for the controllableco-delivery of hydrophobic dexamethasone (DEX) and hydrophilic polymyxin b(PMB), forming a excellent mechanical strength and biocompatibility material. Thecharacterizations confirmed that HNTs were encapsulated and uniformLy distributed in the electrospun fiber mats. The dual release in vitro showed a short-term PMBrelease but a sustained long-term DEX release in all the dual-drug delivery systems.Moreover, the release rate of PMB and DEX from the systems was significantlyaccelerated by increasing HNTS/PLLA ratio. Antibacterial experiments confirmedthat electrospun poly(L-lactic acid)(PLLA) fiber mats containing with halloysites(HNTs) has good antibacterial properties. The antibacterial experiment ofstaphylococcus aureus and e. coli showed that with the dosage of loaded HNTsincrease in the nanofibers, the bacteriostatic circle diameter of fiber membranesincrease. The bacteriostatic effect of electrospun poly (L-lactic acid)(PLLA) fibermats containing with HNTs for escherichia coli bacteriostatic is better thanstaphylococcus aureus, and the increase content of HNTs can improve theirantibacterial properties. In conclusion, electrospun poly (L-lactic acid)(PLLA) fibermats containing with HNTs including polymyxin b all has very good antibacterialeffect to escherichia coli, the less effect to staphylococcus aureus, thus electrospunpoly (L-lactic acid)(PLLA) fiber mats containing with HNTs can be used in thewound dressing.