A novel method to eliminate the influence of absorbed lipids on the characterization of ultra-high molecular weight polyethylene using Fourier-transform infrared spectroscopy.

BACKGROUND: Fourier-transform infrared spectroscopy (FTIR) is one of the standard methods to analyze ultra-high molecular weight polyethylene (UHMWPE) in orthopedic implants. For retrieved components, lipid extraction using an organic solvent prior to the measurement is necessary to eliminate the influence of lipids absorbed in vivo. However, its influence on the measurement has not been substantially investigated. OBJECTIVE: To investigate the influence of lipid extraction on the FTIR analysis of UHMWPE and to develop a novel method to obtain reliable results without inconvenient lipid extraction. METHODS: FTIR analysis was repeatedly performed on UHMWPE specimens from retrieved components before and after lipid extraction under various conditions. A method to calculate the extent of influence of the absorbed lipids from the FTIR spectra was developed using a peak separation technique. RESULTS: An elevated temperature was necessary for lipid extraction; however, it had the potential to influence the results if the conditions were not properly controlled. The results obtained using the peak separation technique coincided with those obtained after lipid extraction. CONCLUSION: The use of the peak separation technique enables the efficient acquisition of reliable results without the need for lipid extraction.

O2-Cu/ZIF-8@Ce6/ZIF-8@F127 Composite as a Tumor Microenvironment-Responsive Nanoplatform with Enhanced Photo-/Chemodynamic Antitumor Efficacy.

Hypoxia and overexpression of glutathione (GSH) are typical characteristics of the tumor microenvironment, which severely hinders cancer treatments. Here, we design a novel biodegradable therapeutic system, O2-Cu/ZIF-8@Ce6/ZIF-8@F127 (OCZCF), to simultaneously achieve GSH depletion and O2-enhanced combination therapy. Notably, the doped Cu2+ doubles the O2 storage capacity of the ZIF-8 matrix, which makes OCZCF an excellent pH-sensitive O2 reservoir for conquering tumor hypoxia, enhancing the photodynamic therapy (PDT) efficiency of chlorin e6 (Ce6) under 650 nm laser irradiation. Moreover, the released Cu2+ can act as a smart reactive oxygen species protector by consuming intracellular GSH. The byproduct Cu+ will undergo highly efficient Fenton-like reaction to achieve chemodynamic therapy (CDT) in the presence of abundant H2O2. The accompanying O2 will further alleviate hypoxia. The in vitro and in vivo experimental data indicate that OCZCF could cause remarkable tumor inhibition through enhanced synergetic PDT and CDT, which may open up a new path for cancer therapy.

Supramolecular poly(acrylic acid)/F127 hydrogel with hydration-controlled nitric oxide release for enhancing wound healing.

Topical nitric oxide (NO) delivery has been shown to accelerate wound healing. However, delivering NO to wounds at appropriate rates and doses requires new biomaterial-based strategies. Here, we describe the development of supramolecular interpolymer complex hydrogels comprising PEO-PPO-PEO (F127) micelles embedded in a poly(acrylic acid) (PAA) matrix, with S-nitrosoglutathione (GSNO) molecules dissolved in the hydrophilic domain. We show that PAA:F127/GSNO hydrogels start releasing NO upon hydration at rates controlled by their rates of water absorption. SAXS measurements indicate that the supramolecular structure of the hydrogels retains long-range order domains of F127 micelles. The PAA/F1227 hydrogels displayed dense morphologies and reduced rates of hydration. The NO release rates remain constant over the first 200 min, are directly correlated with the hydration rates of the PAA:F127/GSNO hydrogels, and can be modulated in the range of 40 nmol/g h to 1.5 µmol/g h by changing the PAA:F127 mass ratio. Long-term NO-release profiles over 5 days are governed by the first-order exponential decay of GSNO, with half-lives in the range of 0.5-3.4 days. A preliminary in vivo study on full-thickness excisional wounds in mice showed that topical NO release from the PAA:F127/GSNO hydrogels is triggered by exudate absorption and leads to increased angiogenesis and collagen fiber organization, as well as TGF-ß, IGF-1, SDF-1, and IL-10 gene expressions in the cicatricial tissue. In summary, these results suggest that hydration-controlled NO release from topical PAA:F127/GSNO hydrogels is a potential strategy for enhancing wound healing. STATEMENT OF SIGNIFICANCE: The topical delivery of nitric oxide (NO) to wounds may provide significant beneficial results and represent a promising strategy to treat chronic wounds. However, wound dressings capable of releasing NO after application and allowing the modulation of NO release rates, demand new platforms. Here, we describe a novel strategy to overcome these challenges, based on the use of supramolecular poly(acrylic acid) (PAA):F127 hydrogels charged with the NO donor S-nitrosoglutathione (GSNO) from whereby the NO release can be triggered by exudate absorption and delivered to the wound at rates controlled by the PAA:F127 mass ratio. Preliminary in vivo results offer a proof of concept for this strategy by demonstrating increased angiogenesis; collagen fibers organization; and TGF-ß, IGF-1, SDF-1, and IL-10 gene expressions in the cicatricial tissue after topical treatment with a PAA:F127/GSNO hydrogel.

Poly(methyl vinyl ether-co-maleic acid) for enhancement of solubility, oral bioavailability and anti-osteoporotic effects of raloxifene hydrochloride.

Raloxifene HCl (RH) has poor water solubility and due to its extensive first pass metabolism; its bioavailability is only 2%. The purpose of the present study was to enhance the aqueous solubility, oral bioavailability and anti-osteoporotic effects of RH by electro-sprayed nanoparticles (NPs) in ovariectomized rats. NPs containing RH and different ratio of poly(methyl vinyl ether-co-maleic acid) (PMVEMA) were electrosprayed. The voltage, distance of needle to the collector, flow rate of the solution and polymeric percentage were optimized according to the size of NPs and drug solubility. The optimized formulation was characterized by SEM, XRD, DSC, and FTIR. The pharmacokinetic parameters were studies by oral administration of a single dose of 15mg/kg in Wistar rats. The anti-osteoporotic effects were studied in female ovariectomized rats. Animals were treated with 6mg/kg/day for 2months then serum calcium, phosphorous and alkaline phosphatase levels were measured. RH loaded electrosprayed NPs showed 10-fold enhanced solubility compared to the free drug. Moreover, the XRD and SEM tests displayed an amorphous state of drug in the NPs. FTIR and DSC tests revealed no interaction between the polymer and the drug. Serum calcium, phosphorous and alkaline phosphatase levels were significantly decreased in ovariectomized rats receiving oral RH NPs (P<0.05). No significant difference was detected between RH NPs and estradiol groups (P>0.05). Oral bioavailability of NPs showed 7.5-fold increase compared to the pure drug. The electrosprayed PMVEMA nanoparticles can enhance solubility, bioavailability and antiosteoporotic effects of RH.

Synergistic inhibition of migration and invasion of breast cancer cells by dual docetaxel/quercetin-loaded nanoparticles via Akt/MMP-9 pathway.

Metastasis impedes the successful chemotherapy for breast cancer. In this study, an Akt inhibitor (quercetin, Qu) was co-delivered with a chemotherapeutic agent (docetaxel, DTX) by using hyaluronic acid (HA)-modified nanoparticles (NPs) as vectors to block metastasis. Dual DTX/Qu-loaded HA/polylactic-co-glycolic acid-polyethyleneimine NPs (PP-HA/NPs) were prepared through a modified emulsion solvent evaporation technique. The particle size of PP-HA/NPs with narrow polydispersity was 209.8±10.8nm. Wound healing assay revealed that Qu co-delivery and HA modification elicited synergistic inhibitory effects on cell motility. The downregulation of p-Akt and matrix metalloproteinase-9 (MMP-9) expression contributed to the significant inhibition of cell migration and invasion with inhibition rates of 95.6% and 99.3%, respectively. Further studies indicated that PP-HA/NPs could be efficiently uptaken by 4T1 breast cancer cells and could further induce cytotoxicity, decrease colony formation and promote cell apoptosis. Biodistribution assay demonstrated PP-HA/NPs also enhanced drug accumulation in the tumor and lungs and predicted that PP-HA/NPs could be employed as an effective therapy for primary tumor and pulmonary metastasis. Therefore, PP-HA/NPs could be a promising delivery system to treat metastatic breast cancer effectively.

Oxidation and other property changes of a remelted highly crosslinked UHMWPE in retrieved tibial bearings.

This study examined retrieved UHMWPE tibial bearings made from a remelted highly crosslinked (HXL) UHMWPE to determine whether the material is chemically stable in vivo. Retrieved tibial components were measured for changes in ketone oxidation and crosslink density. Oxidation increased with in vivo duration, and a significant decrease in crosslink density with increased mean ketone oxidation index was observed. These results suggest that in vivo oxidation is causing material degradation. Furthermore, a subsurface whitened damage region was found below the articular surface of one bearing, indicating the possibility of a clinically relevant decrease in mechanical properties of this component. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 39-45, 2017.

Evaluation of the cytotoxicity, genotoxicity and mucus permeation capacity of several surface modified poly(anhydride) nanoparticles designed for oral drug delivery.

The main concerns with drugs designed for oral administration are their inactivation or degradation in the harsh conditions of the gastrointestinal tract, their poor solubility through the gastrointestinal mucus gel layer, the poor intestinal epithelium permeability that limits their absorption, and their toxicity. In this context, poly(anhydride) nanoparticles are capable of protecting the drug from the harsh environment, reduce the drug's toxicity and, by virtue of surface modification, to enhance or reduce their mucus permeability and the bioadhesion to specific target cells. The copolymer between methyl vinyl ether and maleic anhydride (commercialized as Gantrez® AN 119) are part of the poly(anhydride) nanoparticles. These biocompatible and biodegradable nanoparticles (NPs) can be modified by using different ligands. Their usefulness as drug carriers and their bioadhesion with components of the intestinal mucosa have been described. However, their toxicity, genotoxicity and mucus permeation capacity has not been thoroughly studied. The aim of this work was to evaluate and compare the in vitro toxicity, cell viability and in vitro genotoxicity of the bioadhesive empty Gantrez® AN 119 NPs modified with dextran, aminodextran, 2-hydroxypropyl-ß-cyclodextrin, mannosamine and poly-ethylene glycol of different molecular weights. Results showed that, in general, coated NPs exhibit better mucus permeability than the bare ones, those coated with mannosamine being the most permeable ones. The NPs studied did not affect cell metabolism, membrane integrity or viability of Caco-2 cells at the different conditions tested. Moreover, they did not induce a relevant level of DNA strand breaks and FPG-sensitive sites (as detected with the comet assay).

Facile fabrication of AIE-based stable cross-linked fluorescent organic nanoparticles for cell imaging.

An aggregation induced emission dye (RNH2) with two amino end-groups was facilely incorporated into stable cross-linked fluorescent organic nanoparticles via room temperature anhydride ring-opening polymerization and consecutive cross-linking with polyethylene polyamine. Thus obtained RO-OA-PEPA FONs were characterized by a series of techniques including (1)H nuclear magnetic resonance, Fourier transform infrared spectroscopy, UV-vis absorption spectrum, fluorescent spectroscopy and transmission electron microscopy. Biocompatibility evaluation and cell uptake behavior of RO-OA-PEPA FONs were further investigated to explore their potential biomedical application. We demonstrated that such FONs showed high-water dispersibility, strong red fluorescence, stable uniform morphology (100-200 nm) and excellent biocompatibility, making them promising for cell imaging application.

Intracellular degradation of multilabeled poly(ethylene imine)-mesoporous silica-silica nanoparticles: implications for drug release.

Mesoporous silica nanoparticles, MSNs, have emerged as an interesting carrier for drugs in vitro and in vivo. The particles are typically used in a surface functionalized form, where functional silanes or other covalently linked surface functions are used to provide anchoring sites for additional functionalities like targeting groups, imaging agents, and drugs. Here, we report results related to extra- and intracellular degradation of silica nanoparticles using multilabeled nonporous silica core-mesoporous silica shell-surface hyperbranched poly(ethylene imine) shell nanoparticles as model particles. Different fluorophores have been selectively covalently linked to different regions of the particles in order to study the particle degradation in detail under in vitro conditions in human SAOS-2 cells. A novel, quantitative method for nanoparticle degradation evaluation based on confocal fluorescence microscopy is applied. Our results suggest that the core-shell-shell MSNs degrade at a higher rate inside cells as compared to outside cells, which is of high importance for further application of this class of drug carriers.

PEG conjugation of a near-infrared fluorescent probe for noninvasive dual imaging of lung deposition and gene expression by pulmonary gene delivery.

Dual imaging of lung deposition and gene expression following the pulmonary delivery of a gene formulation is useful for a precise analysis of gene transfection efficiency in vivo. As a novel probe for evaluating lung deposition, in this study, a poly(ethylene glycol)-conjugated near-infrared fluorescent probe (PEG-NIRF) was newly synthesized, and compared with indocyanine green (ICG), for application to pDNA/polyethyleneimine (PEI) complex. PEG-NIRF had superior characteristics including a larger Stokes shift (absorption maximum, 662 nm; emission maximum, 772 nm) and relatively equivalent fluorescence intensity compared with ICG. ICG affected the physicochemical properties of pDNA/PEI complex with a loss of fluorescence intensity, while PEG-NIRF did not. Experiments in mice demonstrated that PEG-NIRF showed greater lung localization than ICG following pulmonary co-delivery with pDNA/PEI complex, indicating the possibility of accurately evaluating lung deposition. Moreover, it was clarified that the evaluation of lung deposition by PEG-NIRF even at 60 min could be significantly correlated with gene expression in each mouse following pulmonary co-delivery with pDNA/PEI complex. These results suggest that PEG-NIRF is widely applicable to the dual imaging of the lung deposition and gene expression of inhaled gene formulations.

Monitoring the viscoelastic properties of skin in liquid environments using quartz crystal microbalance.

Quartz crystal microbalance (QCM) with dissipation can be used to measure the response of the human stratum corneum (SC) attached to the QCM crystal, as it adsorbs or desorbs active ingredients from a liquid medium. The method was demonstrated with the sorption of poly(diallyl dimethyl ammonium chloride), a cationic polymer widely used in formulations for topical and transdermal applications. Using 14-mm diameter SC coupons attached to the QCM crystals with an adhesive, up to five overtones (up to 11th harmonic) were obtained and the response was analyzed using a Voigt model. The adhesive layer could be regarded as a rigid substrate, and the skin with overlaying fluid was modeled as a soft layer underneath a fluid medium. Limited modeling tools that are currently available were used to interpret the observed response in terms of physical parameters such as the changes in thickness, shear modulus, and viscosity. The high sensitivity of the technique demonstrates the possibility of using small samples of human skin for in vitro studies in a variety of topical and transdermal drug delivery applications and in the evaluation of skin care products.

The encapsulation and intracellular delivery of trehalose using a thermally responsive nanocapsule.

The thermally responsive wall permeability of an empty core-shell structured Pluronic nanocapsule (together with its temperature dependent size and surface charge) was successfully utilized for encapsulation, intracellular delivery, and controlled release of trehalose, a highly hydrophilic small (M(W) = 342 D) molecule (a disaccharide of glucose) that is exceptional for long-term stabilization of biologicals (particularly at ambient temperatures). It was found that trehalose can be physically encapsulated in the nanocapsule using a soaking-freeze-drying-heating procedure. The nanocapsule is capable of physically withholding trehalose with negligible release in hours for cellular uptake at 37 degrees C when its wall permeability is low. A quick release of the encapsulated sugar can be achieved by thermally cycling the nanocapsule between 37 and 22 degrees C (or lower). A significant amount of trehalose (up to 0.3 M) can be delivered into NIH 3T3 fibroblasts by incubating the cells with the trehalose-encapsulated nanocapsules at 37 degrees C for 40 min. Moreover, cytotoxicity of the nanocapsule for the purpose of intracellular delivery of trehalose was found to be negligible. Altogether, the thermally responsive nanocapsule is effective for intracellular delivery of trehalose, which is critical for the long-term stabilization of mammalian cells at ambient temperatures and the eventual success of modern cell-based medicine.

Silver absorption on burns after the application of Acticoat: data from pediatric patients and a porcine burn model.

Silver dressings have been widely used to successfully prevent burn wound infection and sepsis. However, a few case studies have reported the functional abnormality and failure of vital organs, possibly caused by silver deposits. The aim of this study was to investigate the serum silver level in the pediatric burn population and also in several internal organs in a porcine burn model after the application of Acticoat. A total of 125 blood samples were collected from 46 pediatric burn patients. Thirty-six patients with a mean of 13.4% TBSA burns had a mean peak serum silver level of 114 microg/L, whereas 10 patients with a mean of 1.85% TBSA burns had an undetectable level of silver (<5.4 microg/L). Overall, serum silver levels were closely related to burn sizes. However, the highest serum silver was 735 microg/L in a 15-month-old toddler with 10% TBSA burns and the second highest was 367 microg/L in a 3-year old with 28% TBSA burns. In a porcine model with 2% TBSA burns, the mean peak silver level was 38 microg/L at 2 to 3 weeks after application of Acticoat and was then significantly reduced to an almost undetectable level at 6 weeks. Of a total of four pigs, silver was detected in all four livers (1.413 microg/g) and all four hearts (0.342 microg/g), three of four kidneys (1.113 microg/g), and two of four brains (0.402 microg/g). This result demonstrated that although variable, the level of serum silver was positively associated with the size of burns, and significant amounts of silver were deposited in internal organs in pigs with only 2% TBSA burns, after application of Acticoat.

Comparison of silver-coated dressing (Acticoat), chlorhexidine acetate 0.5% (Bactigrass), and silver sulfadiazine 1% (Silverdin) for topical antibacterial effect in Pseudomonas aeruginosa-contaminated, full-skin thickness burn wounds in rats.

Acticoat (Smith and Nephew, Istanbul, Turkey), chlorhexidine acetate 0.5%, and silver sulfadiazine 1% were compared to assess the antibacterial effect of their application on experimental burn wounds in contaminated with Pseudomonas aeruginosa in rats. All treatment modalities were effective against P. aeruginosa because there were significant differences between treatment groups and control groups. The mean eschar concentrations did not differ significantly between Acticoat and chlorhexidine acetate groups, but there were significant differences between the silver sulfadiazine group and the other treatment groups, indicating that silver sulfadiazine significantly eliminated P. aeruginosa more effectively in the tissues than did the other two agents. All treatment modalities were sufficient to prevent the P. aeruginosa from invading to the muscle and from causing systemic infection. In conclusion, silver sulfadiazine is the most effective agent in the treatment of the P. aeruginosa-contaminated burn wounds; Acticoat can be considered as a treatment choice because of its peculiar ability of limiting the frequency of replacing wound dressings.

Failure property distributions for conventional and highly crosslinked ultrahigh molecular weight polyethylenes.

To make stochastic (probabilistic) failure predictions of a conventional or highly crosslinked ultrahigh molecular weight polyethylene (UHMWPE) material, not only must a failure criterion be defined, but it is also necessary to specify a probability distribution of the failure strength. This study sought to evaluate both parametric and nonparametric statistical approaches to describing the failure properties of UHMWPE, based on the Normal and Weibull model distributions, respectively. Because fatigue and fracture properties of materials have historically been well described with the use of Weibull statistics, it was expected that a nonparametric approach would provide a better fit of the failure distributions than the parametric approach. The ultimate true stress, true strain, and ultimate chain stretch data at failure were analyzed from 60 tensile tests conducted previously. The ultimate load and ultimate displacement from 121 small punch tests conducted previously were also analyzed. It was found that both Normal and Weibull models provide a reasonable description of the central tendency of the failure distribution. The principal difference between the Normal and Weibull models can be appreciated in the predicted lower-bound response at the tail end of the distribution. The data support the use of both parametric and nonparametric methods to bracket the lower-bound failure prediction in order to simulate the failure threshold for UHMWPE.

Topical application of ionic polymers affects skin permeability barrier homeostasis.

We previously demonstrated that the external electric potential affected skin barrier homeostasis. On the other hand, topical application of an ionic polymer formed a diffusion electric double layer on the surface of the skin. Thus, we evaluated effects of topical application of ionic polymers on the damaged skin barrier. Application of a nonionic polymer did not affect barrier recovery. Application of sodium salts of anionic polymers accelerated barrier recovery, while that of cationic polymers delayed it. Topical application of a sodium-exchange resin accelerated barrier recovery, but application of a calcium-exchange resin had no effect even when the resins had the same structure. Application of a chloride-exchange resin delayed barrier recovery. Topical application of ionic polymers influenced skin barrier homeostasis.

Development of novel 5-FU-loaded poly(methylidene malonate 2.1.2)-based microspheres for the treatment of brain cancers.

In order to treat malignant brain tumors by local delivery of antineoplastic agents, the feasibility of 5-fluorouracil (5-FU)-sustained release biodegradable microspheres with a novel material, poly(methylidene malonate 2.1.2), was investigated using an emulsion/extraction method. This polymer was expected to present a slow degradation rate, thus leading to a long term local delivery system. Microparticles were successfully obtained and characterized in terms of drug loading, size, morphology and release profile. The size of the particles was between 40 and 50 microm, which was compatible with a stereotactic injection through a needle. Sufficient drug loadings were obtained (i.e. compatible with the preparation of therapeutic 5-FU doses in a minimal volume of injection), and perfectly spherical microspheres were observed. The respective influences of the polymer molecular weight, the polymer concentration, and the emulsion time on the release profiles were studied using a 2(3) factorial design. In the same objective, the solvent extraction time was extended while keeping all the previous parameters fixed at their optimal values. The in vitro study of these different parameters allowed a reduction of the initial burst release, with a percentage of 5-FU released after 24 h that was lowered from 90 to 65%, and the achievement of a long term drug delivery system, since the release was still ongoing after 43 days. Moreover, the microparticles could be gamma-sterilized (25 kGy) without modification of the release kinetics. Thus, the requested specifications to perform animal experiments were attained.

Effects of sevelamer hydrochloride and calcium acetate on the oral bioavailability of ciprofloxacin.

BACKGROUND: The oral bioavailability of ciprofloxacin is significantly decreased when administered with calcium carbonate. Sevelamer hydrochloride is a phosphate-binding cationic polymer that is devoid of calcium. The authors conducted a 3-way, randomized, crossover study to determine the effects of sevelamer hydrochloride and calcium acetate on the relative oral bioavailability of ciprofloxacin. METHODS: Fifteen healthy volunteers were assigned randomly to receive each of the following oral regimens: ciprofloxacin 750 mg, alone (Arm A); ciprofloxacin 750 mg plus 7 sevelamer hydrochloride 403 mg capsules (Arm B); ciprofloxacin 750 mg plus 4 calcium acetate 667 mg tablets (Arm C). Serial blood and urine samples were obtained over 24 hours, and ciprofloxacin concentrations were determined by high-performance liquid chromatography. Pharmacokinetic data were analyzed using noncompartmental methods, and maximum serum concentration (Cmax) and area under the serum concentration time curve from 0 to infinity (AUC(0- infinity )) were tested for bioequivalence after log transformation of the data. The relative oral bioavailability of ciprofloxacin was calculated as AUC(0- infinity ), Arm B or Arm C/AUC(0- infinity ), Arm A. RESULTS: The Cmax and AUC(0- infinity ) of ciprofloxacin were significantly decreased when administered concomitantly with sevelamer hydrochloride or calcium acetate (P < 0.05), and bioequivalence was not achieved for either parameter. The relative oral bioavailability of ciprofloxacin was decreased by 48% with sevelamer hydrochloride and 51% with calcium acetate (P < 0.05). CONCLUSION: The relative oral bioavailability of ciprofloxacin is significantly decreased when administered with sevelamer hydrochloride or calcium acetate. Concomitant administration of these drugs may decrease clinical efficacy and promote bacterial resistance to ciprofloxacin.

Poly(D,L-lactide-co-ethyl ethylene phosphate)s as new drug carriers.

Many biodegradable polymers have been developed for controlled drug delivery. The plethora of drug therapies and types of drugs demand different formulations, fabrications conditions and release kinetics. No one single polymer can satisfy all the requirements. To extend the properties of poly(D,L-lactide) (PLA), we synthesized copolymers of PLA and poly(ethylethylene phosphate) (PEEP) by ring-opening polymerization using Al(Oipr)3 as the initiator. The copolymers were structurally characterized by IR and 1H NMR. DSC data confirmed the formation of random microphase structure in all the copolymers, and showed a decrease of Tg from 43.2 to -22.6 degrees C when the molar content of ethylethylene phosphate (EEP) increased from 5 to 40%. The hydrophilicity of the copolymers increased with EEP content. In contrast to the degradation behavior of PLA, disc samples made of PLAEEP90 showed a linear weight loss profile in PBS (pH 7.4) at 37 degrees C. BSA microspheres using PLAEEP90 were prepared by double-emulsion method, yielding a loading level of 4.3% and a loading efficiency of 75%. The BSA release profile consisted of an initial burst (9%) on the first day, followed by a daily 4% release for the following 40 days, resulting in 91% of the BSA release in a near linear manner. The released BSA remained intact according to SDS-PAGE data. Cytotoxicity and histopathology studies showed low toxicity in HeLa cells and good tissue biocompatibility in mouse brain, respectively. PLAEEP is a promising biodegradable polymer for controlled drug delivery.