两亲性壳聚糖包覆紫杉醇脂质体的制备及体外释放研究

目的:制备两亲性壳聚糖N-辛基-N,O-羧甲基壳聚糖包覆紫杉醇脂质体(PTX-LP-OCC),并考察其理化性质及体外释放行为。方法:采用基于乙醇的前体脂质体法制备紫杉醇脂质体并以OCC包覆,并以普通脂质体(PTX-LP)为对照,测定其包封率、粒径大小、电位,观测其形态及稳定性,然后采用全体液平衡反向透析法研究体外释放行为。结果:紫杉醇脂质体包封率为89.5%,粒径为236.5 nm,Zeta电位为-31.4 mV,多糖包覆修饰后药物包封率无显著变化,粒径及Zeta电位显著增加,脂质体稳定性显著提高,药物释放呈缓释特征,且突释显著降低。结论:两亲性壳聚糖包覆脂质体是一个有前景的抗肿瘤药物递送载体     

Formulation and evaluation of carnosic acid nanoparticulate system for upregulation of neurotrophins in the brain upon intranasal administration

To develop formulations of carnosic acid nanoparticles and to assess their in vivo efficacy to enhance the expression of neurotrophins in rat model. Carnosic acid loaded chitosan nanoparticles were prepared by ionotropic gelation technique using central composite design. Response surface methodology was used to assess the effect of three factors namely chitosan concentration (0.1–1% w/v), tri-poly phosphate concentration (0.1–1% w/v) and sonication time (2–10?min) on the response variables such as particle size, zeta potential, drug encapsulation efficiency and drug release. The neurotrophins level in the rat brain upon intranasal administration of optimized batch of carnosic acid nanoparticles was determined. The experimental values for the formulation were in good agreement with those predicted by the mathematical models. A single intranasal administration of the optimized formulation of carnosic acid nanoparticles was sufficient to result in comparable levels of endogenous neurotrophins level in the brain that was almost on par with four, once a day intranasal administration of solution in rats. The results clearly demonstrated the fact that nanoparticulate drug delivery system for intranasal administration of carnosic acid would require less number of administrations to elicit the required pharmacological activity owing to its ability to localize on the olfactory mucosal region and provide controlled delivery of carnosic acid for prolonged time periods.     

PEGylated thermo-sensitive poly(amidoamine) dendritic drug delivery systems

Development of efficient ocular delivery nanosystems remains a major challenge to achieve sustained therapeutic effect. The purpose of this work was to develop chitosan nanoparticles using sulfobutylether-β-cyclodextrin (SBE-β-CD) as polyanionic crosslinker and to investigate the potential of using those nanostructures as ocular drug delivery systems. Econazole nitrate (ECO) was chosen as model drug molecule. The influence of different process variables (chitosan molecular weight and the concentration of the two ionic agents) on particle size, polydispersity index, zeta potential, drug content, in vitro release and mucoadhesive properties was investigated. The results showed that the prepared nanoparticles were predominant spherical in shape having average particle diameter from 90 to 673 nm with positive zeta potential values from 22 to 33 mV and drug content values ranging from 13 to 45%. Drug release from optimized nanoparticles was controlled with approximately 50% of the original amount released over a 8h period. The release profile of nanoparticles followed a zero-order release kinetics. The optimized nanoparticles were tested for their use as ocular drug delivery systems on albino rabbits. The in vivo studies revealed that the prepared mucoadhesive nanoparticles had better ability in sustaining the antifungal effect of ECO than the ECO solution. Therefore, chitosan/SBE-β-CD nanoparticles developed showed a promising carrier for controlled delivery of drug to the eye.     

The design of biodegradable ofloxacin-based core-shell microspheres: influence of the formulation parameters on in vitro characterization

Ofloxacin (OFL), second-generation fluoroquinolone, is a broad-spectrum antibiotic which is active against both Gram-positive and Gram-negative bacteria. However, OFL has a short biological half life (8-9?h) and poor stability in serum and needs frequently repeated doses during the treatment. The objective of this study was to fabricate the fucospheres and chitosan microspheres containing a poorly soluble drug, OFL, and to compare the formulation parameters influencing the in vitro properties of microparticles such as size, zeta potential, encapsulation efficiency and drug release characteristics. Particle size of fucospheres and chitosan microspheres has been found to be 0.61-1.48 μm and 1.05-2.08 μm, respectively. The zeta potentials have changed between 5.6 mV and 28.0 mV for fucospheres; 22.3 mV and 42.4 mV for chitosan microspheres. The fucospheres have had higher drug encapsulation efficiency than those of chitosan microspheres. The particle size, surface charge, encapsulation efficiency and in vitro drug release from both fucospheres and chitosan microspheres have been affected by type and concentration of the polymers used. The release mechanism from most of the microsphere formulations has been fitted to Higuchi kinetic model. It can be concluded that OFL-encapsulated fucospheres can be a potential delivery system for antibiotics.     

大豆糖苷修饰阳离子脂质体的体外肝细胞靶向性

目的研究肝靶向物质大豆糖苷(soybean-derived sterylglucoside,SG)的加入对阳离子脂质体肝细胞靶向性的影响。方法以荧光素钠(FS)为模型药物，采用HepG₂ 2.2.15细胞模型和SD雄性大鼠，检测SG，SG/Brij-35(卞泽-35)和SG/PEG-DSPE(polyethylene glycol-distearoylphosphatidylethanolamine)修饰的阳离子脂质体的物理化学性质，在细胞培养水平和离体肝脏水平考察阳离子脂质体的转染和肝细胞选择性。结果未修饰以及SG，SG/Brij-35和SG/PEG-DSPE修饰的FS阳离子脂质体在中性溶液中的包封率分别为91.74%，88.46%，89.70%和83.12%，粒径分别为124.4，113.7，110.8和93.0 nm，空白脂质体在溶液中表面电荷为正。细胞培养和肝脏灌流结果说明，阳离子脂质体的转染率显著高于中性脂质体，SG单独修饰后的阳离子脂质体的细胞转染率较未修饰有显著提高，SG/Brij-35修饰的阳离子脂质体则表现出肝实质细胞选择性。结论阳离子脂质体可以促进FS进入肝脏细胞，具有较高的肝细胞摄取率，而SG/Brij-35的修饰可以提高脂质体的肝细胞选择性。     

复合碳酸钙空腔纳米粒的制备及性能评价

目的 制备甘草次酸/海藻酸钠修饰碳酸钙空腔纳米粒并进行体外评价。方法 以可溶性淀粉为模板剂制备中空球状碳酸钙纳米粒（CaCO3 Nps）;在非均相体系中合成了甘草次酸/海藻酸钠聚合物（GA-ALG）;并以聚合物（GA-ALG）为壳以中空结构的碳酸钙纳米粒为核,合成了壳核结构的GA-ALG-CaCO3 Nps。采用Malvern粒度分析仪测定纳米粒子的粒度分布和Zeta电位,并通过SEM对纳米粒的形态进行表征。应用荧光分光光度计评价载盐酸阿霉素（DOX）纳米粒的载药量、包封率及体外释放特征。结果 纳米粒分布均一,平均粒径为（425.4±31.1）nm,PDI为0.289,Zeta 电位为（-17.0±0.3）mV。药物的载药量为（13.06±0.51）%,包封率为（78.35±3.08）%。;体外释放结果显示,纳米粒具有一定的缓释作用。结论 GA-ALG-CaCO3 Nps作为新型的药物载体,具有良好的pH响应性,并能显著提高载药量,还具有明显的缓释效果,为新型的纳米给药系统的深入研究提供参考。     

The design of biodegradable ofloxacin-based core-shell microspheres: Influence of the formulation parameters on in vitro characterization

Ofloxacin (OFL), second-generation fluoroquinolone, is a broad-spectrum antibiotic which is active against both Gram-positive and Gram-negative bacteria. However, OFL has a short biological half life (8–9?h) and poor stability in serum and needs frequently repeated doses during the treatment. The objective of this study was to fabricate the fucospheres and chitosan microspheres containing a poorly soluble drug, OFL, and to compare the formulation parameters influencing the in vitro properties of microparticles such as size, zeta potential, encapsulation efficiency and drug release characteristics. Particle size of fucospheres and chitosan microspheres has been found to be 0.61–1.48 µm and 1.05–2.08 µm, respectively. The zeta potentials have changed between 5.6 mV and 28.0 mV for fucospheres; 22.3 mV and 42.4 mV for chitosan microspheres. The fucospheres have had higher drug encapsulation efficiency than those of chitosan microspheres. The particle size, surface charge, encapsulation efficiency and in vitro drug release from both fucospheres and chitosan microspheres have been affected by type and concentration of the polymers used. The release mechanism from most of the microsphere formulations has been fitted to Higuchi kinetic model. It can be concluded that OFL-encapsulated fucospheres can be a potential delivery system for antibiotics.     

A new drug nanocarrier consisting of chitosan and hydoxypropylcyclodextrin.

The objective of the present work was to develop a new drug nanocarrier consisting of nanoparticles made of chitosan and cyclodextrins. The rationale behind the design of this new nanosystem was to simultaneously implement the cyclodextrin drug complexation power and the inherent properties of chitosan nanoparticles, in a unique delivery system. The complexation with the cyclodextrin permits the solubilization as well as the protection for sensitive drugs, whereas the entrapment in the chitosan network is expected to facilitate their absorption. Chitosan nanoparticles including hydroxypropylcyclodextrins could be prepared by the ionic crosslinking of chitosan with sodium tripolyphosphate in the presence of cyclodextrins. Two hydrophobic drugs, triclosan and furosemide, were selected as models for complexation with the cyclodextrin and further entrapment in the chitosan nanocarrier. The resulting nanosystems were thoroughly characterized for their size and zeta potential and also for their ability to associate and deliver the complexed drugs. The results showed that the size of the nanoparticles was slightly affected by the incorporation of cyclodextrins, whereas the zeta potential did not suffer a significant modification. Moreover, the complexation of the drugs with the cyclodextrin facilitated their entrapment into the nanoparticles, increasing up to 4 and 10 times (for triclosan and furosemide, respectively) the final drug loading of the nanoparticles. These results led to the conclusion that the drug-cyclodextrin complex was efficiently retained in the nanoparticulate structure. Finally, the in vitro release profile observed for these nanoparticles was characterized by an initial fast release followed by a delayed release phase. In conclusion, this new nanosystem offers an interesting potential for the transmucosal delivery of hydrophobic compounds.     

Chitosan nanoparticles for plasmid DNA delivery: effect of chitosan molecular structure on formulation and release characteristics

Chitosan can be useful as a nonviral vector for gene delivery. Although there are several reports to form chitosan-pDNA particles, the optimization and effect on transfection remain insufficient. The chitosan-pDNA nanoparticles were formulated using complex coacervation and solvent evaporation techniques. The important parameters for the encapsulation efficiency were investigated, including molecular weight and deacetylation degree of chitosan. We found that encapsulation efficiency of pDNA is directly proportional with deacetylation degree, but there is an inverse proportion with molecular weight of chitosan. DNA-nanoparticles in the size range of 450-820 nm depend on the formulation process. The surface charge of the nanoparticles prepared with complex coacervation method was slightly positive with a zeta potential of +9 to +18 mV; nevertheless, nanoparticles prepared with solvent evaporation method had a zeta potential approximately +30 mV. The pDNA-chitosan nanoparticles prepared by using high deacetylation degree chitosan having 92.7%, 98.0%, and 90.4% encapsulation efficiency protect the encapsulated pDNA from nuclease degradation as shown by electrophoretic mobility analysis. The release of pDNA from the formulation prepared by complex coacervation was completed in 24 hr whereas the formulation prepared by evaporation technique released pDNA in 96 hr, but these release profiles are not statistically significant compared with formulations with similar structure (p > .05). According to the results, we suggest nanoparticles have the potential to be used as a transfer vector in further studies.     

Preparation, characterization, and drug release in vitro of chitosan-glycyrrhetic acid nanoparticles

A suitable carrier chitosan (CS) was used to prepare CS-Glycyrrhetic acid (GLA) nanoparticles under very mild conditions by polyelectrolyte complexation. These nanoparticles were well dispersed and stable in aqueous solution, and the physicochemical properties of which were investigated by FT-IR, dynamic light scattering, transmission electron microscope, fluorescence spectra and zeta potential. It was found that only when the weight ratio of CS to GLA was lower than 16.7, could the nanoparticles be formed. The prepared nanoparticles carried a positive charge and had the dried TEM-assessed size in the range from 20 to 30 nm. The mean hydrated diameter, size distribution and zeta potential of the nanoparticles could be controlled by some factors including the weight ratio of CS to GLA, the average molecular weight of CS and the pH value of the medium. It was also found that GLA encapsulation efficiency into the nanoparticles increased with the increase of the weight ratio of CS to GLA. The experiment of GLA release in vitro showed that the effect of CS encapsulation on GLA release was obvious and the CS-GLA nanoparticles system might be used to provide a continuous release.     

Chitosan nanoparticles as a new delivery system for the anti-Alzheimer drug tacrine

Tacrine-loaded chitosan nanoparticles were prepared by spontaneous emulsification. The particle size and zeta potential was determined by scanning probe microscopy and Zetasizer, respectively. The prepared particles showed good drug-loading capacity. The in vitro release studies showed that after the initial burst, all the drug-loaded batches provided a continuous and slow release of the drug. Coating of nanoparticles with Polysorbate 80 slightly reduced the drug release from the nanoparticles. Release kinetics studies showed that the release of drug from nanoparticles was diffusion-controlled, and the mechanism of drug release was Fickian. The biodistribution of these particles after intravenous injection in rats showed that of nanoparticles coated with 1% Polysorbate 80 altered the biodistribution pattern of nanoparticles.From the Clinical EditorIn this paper, chitosan nanoparticles are investigated in a pre-clinical study as an optimized delivery system for tacrin, a drug with potential significance in Alzheimer's disease. The preparation showed optimal pharmacokinetic characteristics in a rat model.     

2-Dioleoyl-sn-glycero-3-phosphocholine-based nanoliposomes as an effective delivery platform for 17β-estradiol

The high loading efficiency and controlled release of hydrophobic drugs is still an unmet goal in the development of drug delivery systems. In the present study, liposomes were developed to encapsulate 17β-estradiol (E2), which is a sex steroid shown to confer protective effects in the cardiovascular system. Egg phosphatidylcholine (EPC), 2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), or 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) were used to prepare liposomes by thin film hydration and tested for their ability to load E2 with a high efficiency. DOPC-based liposomes were found to improve E2 encapsulation efficiency and loading capacity compared to those composed of EPC and DPPC. In addition, neutral liposomes, liposomes prepared with the cationic charging agent DDAB, and liposomes prepared with the anionic charging agent DMPG, were characterized with regard to their E2 encapsulation efficiency, loading capacity, particle size, zeta potential, and in vitro drug release. A human coronary artery endothelial (HCAE) cell model was used to further evaluate liposome effects on cytotoxicity and relative cellular uptake efficiency of each formulation. Results showed that DOPC liposomes composed of DDAB had the highest E2 loading capacity and improved cellular uptake compared to uncharged and DMPG-based liposomes, demonstrating the greatest potential to be used in future cardiovascular therapeutic applications.     

Gel and solid matrix systems for the controlled delivery of drug carrier-associated nucleic acids

In order to achieve a sustained pharmacological activity of oligonucleotides (ODNs) and avoid repeated administrations, we have developed a new concept of delivery system that combine sustained release and improved intracellular penetration. These systems are designed for the intravitreal delivery of antisense ODNs. The first concept consisted in using liposomes dispersed in a thermosensitive gel (poloxamer 407). After intravitreal administration in a rabbit model, liposomes and liposomes-gel formulations provided, 1-day postinjection, significantly higher drug levels than the control solution of the oligothymidilate pdT16. In addition, there was no significant difference in the amounts of pdT16 found in the vitreous humor between the liposomes and liposomes-gel. Nevertheless, because of their better stability in the absence of poloxamer, liposomes alone allowed to a larger extent to control the delivery of ODNs as compared to liposome-gel formulations since 37% of the ODNs were still found in the vitreous 15 days after administration. In addition, the ODNs found in the vitreous humor were protected against degradation by their encapsulation within liposomes. The second approach consisted in designing microspheres allowing to release in a controlled fashion pdT16. The ODN was encapsulated within poly(lactide-co-glycolide) microspheres alone or associated with polyethylenimine (PEI) at different nitrogen/phosphate (N/P) ratios. The introduction of PEI in the internal aqueous phase resulted in a strong increase of the ODN encapsulation efficiency. PEI affected microsphere morphology inducing the formation of very porous particles yielding to an accelerated release of pdT16. Porosity and controlled delivery was prevented by introducing sodium chloride in the external preparation medium. When incubated with HeLa cells, microspheres encapsulating pdT16/PEI complexes allowed an improvement of the intracellular penetration of the released ODN. Both liposomes and microspheres are suitable for local delivery of ODNs.     

Magnolol-loaded core-shell hydrogel nanoparticles: drug release, intracellular uptake, and controlled cytotoxicity for the inhibition of migration of vascular smooth muscle cells

Encapsulation and release behavior of a water-insoluble drug, magnolol, using a core-shell polysaccharide-based nanoparticle, manipulating the cellular internalization and controlled cytotoxic effect of magnolol-loaded nanoparticles over the A10 vascular smooth muscle cells (VSMCs) was reported. A magnolol-polyvinylpyrrolidone (PVP) core phase was prepared, followed encapsulating by an amphiphilic carboxymethyl-hexanoyl chitosan (CHC) shell to form a magnolol-loaded core-shell hydrogel nanoparticles (termed magnolol-CHC nanoparticles). The resulting magnolol-CHC nanoparticles were employed for evaluation of drug release and controlled cytotoxic inhibition of VSMCs migration in vitro. A sustained release of the magnolol from the nanoparticles was determined. The magnolol-CHC nanoparticles exhibited outstanding cellular uptake efficiency, and under a cytotoxic evaluation, an increased antiproliferative effect and effective inhibition of VSMC migration as a result of efficient intracellular delivery of the encapsulated magnolol in comparison to free magnolol was achieved. We then envision a potential intracellular medication strategy with improved biological and therapeutic efficacy using the magnolol-CHC nanoparticles illustrated in this work.     

甘草酸表面修饰N-己酰化壳聚糖纳米粒的制备及其稳定性研究

目的:制备N-己酰化壳聚糖纳米粒(CCS-NPs)和甘草酸表面修饰N-己酰化壳聚糖纳米粒(CCS-NPs-GL),并考察其稳定性。方法:应用离子凝胶法制备CCS-NPs,高碘酸盐氧化法制备CCS-NPs-GL;考察各纳米粒在冷冻干燥前、后和不同pH缓冲盐中粒径、电位的变化以及不同温度对CCS-NPs-GL的粒径、药物包封率和甘草酸结合率的影响。结果:CCS-NPs和CCS-NPs-GL在冷冻干燥后粒径稍有增大,缓冲盐溶液中迅速分散,电位下降不明显;在生理pH条件下,两者易于分散且粒径无明显变化;不同温度下,CCS-NPs-GL的粒径、药物包封率和甘草酸结合率无明显变化。结论:CCS-NPs-GL作为潜在的肝靶向主动传输载体,其粒子的稳定性可满足后续静脉给药的体内靶向研究和药效学评价。     

Chitosan Nanoparticles for Plasmid DNA Delivery: Effect of Chitosan Molecular Structure on Formulation and Release Characteristics

Chitosan can be useful as a nonviral vector for gene delivery. Although there are several reports to form chitosan-pDNA particles, the optimization and effect on transfection remain insufficient. The chitosan-pDNA nanoparticles were formulated using complex coacervation and solvent evaporation techniques. The important parameters for the encapsulation efficiency were investigated, including molecular weight and deacetylation degree of chitosan. We found that encapsulation efficiency of pDNA is directly proportional with deacetylation degree, but there is an inverse proportion with molecular weight of chitosan. DNA-nanoparticles in the size range of 450–820 nm depend on the formulation process. The surface charge of the nanoparticles prepared with complex coacervation method was slightly positive with a zeta potential of +9 to +18 mV; nevertheless, nanoparticles prepared with solvent evaporation method had a zeta potential ～ +30 mV. The pDNA-chitosan nanoparticles prepared by using high deacetylation degree chitosan having 92.7%, 98.0%, and 90.4% encapsulation efficiency protect the encapsulated pDNA from nuclease degradation as shown by electrophoretic mobility analysis. The release of pDNA from the formulation prepared by complex coacervation was completed in 24 hr whereas the formulation prepared by evaporation tecnique released pDNA in 96 hr, but these release profiles are not statistically significant compared with formulations with similar structure p >. 05). According to the results, we suggest nanoparticles have the potential to be used as a transfer vector in further studies.     

Development of drug-loaded chitosan–vanillin nanoparticles and its cytotoxicity against HT-29 cells

Chitosan as a natural polysaccharide derived from chitin of arthropods like shrimp and crab, attracts much interest due to its inherent properties, especially for application in biomedical materials. Presently, biodegradable and biocompatible chitosan nanoparticles are attractive for drug delivery. However, some physicochemical characteristics of chitosan nanoparticles still need to be further improved in practice. In this work, chitosan nanoparticles were produced by crosslinking chitosan with 3-methoxy-4-hydroxybenzaldehyde (vanillin) through a Schiff reaction. Chitosan nanoparticles were 200–250?nm in diameter with smooth surface and were negatively charged with a zeta potential of???17.4?mV in neutral solution. Efficient drug loading and drug encapsulation were achieved using 5-fluorouracil as a model of hydrophilic drug. Drug release from the nanoparticles was constant and controllable. The in vitro cytotoxicity against HT-29 cells and cellular uptake of the chitosan nanoparticles were evaluated by methyl thiazolyl tetrazolium method, confocal laser scanning microscope and flow cytometer, respectively. The results indicate that the chitosan nanoparticles crosslinked with vanillin are a promising vehicle for the delivery of anticancer drugs.     

粒细胞-巨噬细胞集落刺激因子壳聚糖缓释纳米粒的制备

目的:研究以生物可降解壳聚糖纳米粒作为粒细胞-巨噬细胞集落刺激因子(GM-CSF)新型缓释系统的可行性。方法:以三聚磷酸钠为交联剂,采用离子交联法制备负载GM-CSF和牛血清白蛋白(BSA)的纳米粒。用透射电镜观测纳米粒径和形态;用紫外分光光度计、荧光分光光度计分别测定BSA和GM-CSF包封率,并考察制剂体外药物释放情况。结果:纳米粒形态多呈球形,平均粒径为201nm,GM-CSF和BSA包封率分别为62.1%、58.5% ,3d时体外累积释放率分别为69%、82%。结论:应用离子交联法可制备负载GM-CSF的壳聚糖缓释纳米粒。     

Preparation and evaluation of N(3)-O-toluyl-fluorouracil-loaded liposomes

This study was aimed at developing a liposome delivery system for a new and potential antitumor lipophilic prodrug of 5-fluorouracil (5-Fu)-N(3)-O-toluyl-fluorouracil (TFu), intended to improve the bioavailability and therapeutic efficacy of 5-Fu by oral and intravenous administration. TFu-loaded liposomes were prepared by a modified film dispersion-homogenization technique, the formulation and manufacture parameters were optimized concerning the drug encapsulation efficiency. TFu-loaded liposomes were characterized according to particle size, size distribution, zeta potential, drug entrapment efficiency, drug loading and physical stability, respectively. In vitro release characteristics, in vivo pharmacokinetic properties and bioavailabilities were also investigated. The formulated liposomes were found to be relatively uniform in size (400.5 +/- 9.6 nm) with a negative zeta potential (-6.4 +/- 0.8 mV). The drug entrapment efficiency and loading were (88.87 +/- 3.25%) and (8.89 +/- 0.19%), respectively. The physical stability experiments results indicated that lyophilized TFu-loaded liposomes were stable for at least 9 months at 4 degrees C. In vitro drug release profile of TFu-loaded liposomes followed the bi-exponential equation. The results of the pharmacokinetic studies in mice indicated that the bioavailability of TFu-loaded liposomes was higher than the suspension after oral administration, and was bioequivalent comparing with TFu 50% alcohol solution after intravenous (i.v.) administration. These results indicated that TFu-loaded liposomes were valued to develop as a practical preparation for oral or i.v. administration.     

Encapsulation and controlled release of recombinant human erythropoietin from chitosan-carrageenan nanoparticles

Novel chitosan-carrageenan nanoparticles were produced through the process of ionotropic gelation for the encapsulation and controlled release of recombinant human erythropoietin (rHu-EPO). The effects of chitosan concentration, chitosan to carrageenan mass ratio and solution pH on the nanoparticle diameter, polydispersity and surface charge were explored through both screening and response surface modeling (RSM) methods. The chitosan-carrageenan nanoparticles created had particle diameters between 200 and 1000nm, surfaces charges between 40 and 55mV, and polydispersity between 0.2 and 0.35. RSM optimized chitosan-carrageenan nanoparticles demonstrated an increased rHu-EPO encapsulation efficiency of 47.97?4.10% and a more sustained in vitro release of ~50% over a 2 week period when compared to previous nano/microparticle delivery systems. Studies on the effect of surface charge and chitosan molecular weight on the encapsulation and controlled release of rHu-EPO revealed that increasing either led to improved encapsulation efficiency and reduced release rate.