Surfactant-polymer Nanoparticles: A Novel Platform for Sustained and Enhanced Cellular Delivery of Water-soluble Molecules

Purpose Nanoparticles, drug carriers in the sub-micron size range, can enhance the therapeutic efficacy of encapsulated drug by increasing and sustaining the delivery of the drug inside the cell. However, the use of nanoparticles for small molecular weight, water-soluble drugs has been limited by poor drug encapsulation efficiency and rapid release of the encapsulated drug. Here we report enhanced cellular delivery of water-soluble molecules using novel Aerosol OT™ (AOT)-alginate nanoparticles recently developed in our laboratory. Materials and Methods AOT-alginate nanoparticles were formulated using emulsion-crosslinking technology. Rhodamine and doxorubicin were used as model water-soluble molecules. Kinetics and mechanism of nanoparticle-mediated cellular drug delivery and therapeutic efficacy of nanoparticle-encapsulated doxorubicin were evaluated in two model breast cancer cell lines. Results AOT-alginate nanoparticles demonstrated sustained release of doxorubicin over a 15-day period in vitro. Cell culture studies indicated that nanoparticles enhanced the cellular delivery of rhodamine by about two–tenfold compared to drug in solution. Nanoparticle uptake into cells was dose-, time- and energy-dependent. Treatment with nanoparticles resulted in significantly higher cellular retention of drug than treatment with drug in solution. Cytotoxicity studies demonstrated that doxorubicin in nanoparticles resulted in significantly higher and more sustained cytotoxicity than drug in solution. Conclusions AOT-alginate nanoparticles significantly enhance the cellular delivery of basic, water-soluble drugs. This translates into enhanced therapeutic efficacy for drugs like doxorubicin that have intracellular site of action. Based on these results, AOT-alginate nanoparticles appear to be suitable carriers for enhanced and sustained cellular delivery of basic, water-soluble drugs.     

Solid Lipid Nanoparticles as Delivery Systems for Bromocriptine

PURPOSE: The present investigation describes a formulative study for the development of innovative drug delivery systems for bromocriptine. METHODS: Solid lipid nanoparticles (SLN) based on different lipidic components have been produced and characterized. Morphology and dimensional distribution have been investigated by electron microscopy and Photon Correlation Spectroscopy. The antiparkinsonian activities of free bromocriptine and bromocriptine encapsulated in nanostructured lipid carriers were evaluated in 6-hydroxydopamine hemilesioned rats, a model of Parkinson's disease. RESULTS: Tristearin/tricaprin mixture resulted in nanostructured lipid carriers with stable mean diameter up to 6 months from production. Bromocriptine was encapsulated with high entrapment efficiency in all of the SLN samples, particularly in the case of tristearin/tricaprin mixture. Bromocriptine encapsulation did not change nanoparticle dimensions. In vitro release kinetics based on a dialysis method demonstrated that bromocriptine was released in a prolonged fashion for 48 h. Tristearin/tricaprin nanoparticles better controlled bromocriptine release. Both free and encapsulated bromocriptine reduced the time spent on the blocks (i.e. attenuated akinesia) in the bar test, although the action of encapsulated bromocriptine was more rapid in onset and prolonged. CONCLUSIONS: It can be concluded that nanostructured lipid carriers encapsulation may represent an effective strategy to prolong the half-life of bromocriptine.     

A novel hybrid delivery system: Polymer-oil nanostructured carrier for controlled delivery of highly lipophilic drug all-trans-retinoic acid (ATRA)

Many recently developed drugs encounter delivery issues due to their high lipophilicity and poor aqueous solubility. This study reports the development of a novel hybrid nanocarrier known as polymer-oil nanostructured carrier (PONC), in which highly lipophilic drugs such as all-trans-retinoic acid (ATRA) and indomethacin pre-solubilized in oil phase were dispersed in a polymeric matrix of poly(d,l-lactic-co-glycolic acid) (PLGA). In comparison to the standard PLGA only nanoparticles, PONC substantially increased the encapsulation efficiency of ATRA and indomethacin by up to 259% and 124%, respectively. Differential scanning calorimetry analysis revealed that the inclusion of oil introduced nanostructure into the polymeric matrix of the carrier. This feature facilitated more uniform distribution of the drug molecules which subsequently led to improved drug release kinetics with significantly reduced burst release effects (p<0.05). PONC was lyophilizable, remained physically stable when stored at low temperatures, and demonstrated low non-specific carrier toxicity. Delivery of ATRA by PONC also significantly improved its anticancer activity over the standard PLGA only nanoparticles (p<0.05). Our findings have therefore validated a promising delivery system that integrates the advantages of lipid-based (e.g. efficient encapsulation of highly lipophilic drugs) and polymeric colloidal carriers (e.g. uniform size, good stability), plus potential therapeutic benefits for delivery of poorly water-soluble anticancer drugs like ATRA.     

Magnetic PECA nanoparticles as drug carriers for targeted delivery: synthesis and release characteristics

Magnetic poly(ethyl-2-cyanoacrylate) (PECA) nanoparticles containing anti-cancer drugs (Cisplatin and Gemcitabine) were prepared by inter-facial polymerization. The spherical nanoparticles (d = 250 +/- 15 nm) with smooth surfaces and moderately uniform size distributions were obtained. The amount of magnetite encapsulated inside the polymer matrix was increased up to 14.26% (w/w) by controlling the initial weight ratio of monomer/magnetite. It was found that the amount of Cisplatin encapsulated in the magnetic nanoparticle is much higher than that of Gemcitabine because Cisplatin (hydrophobic) is highly soluble in the oil phase and encapsulated easier inside nanoparticles compared to Gemcitabine (hydrophilic). The presence of magnetite and its super-paramagnetic characteristic were confirmed by FTIR spectra and VSM. In-vitro experiments of drug release and magnetic mobility under external magnetic field demonstrated that magnetic poly(ethyl-2-cyanoacrylate) (PECA) nanoparticles can be a highly versatile magnetic drug carrier with sustained release behaviour and sufficient magnetic susceptibility.     

BSA-PLGA-Based Core-Shell Nanoparticles as Carrier System for Water-Soluble Drugs

Purpose

Preparation, optimization and in vitro evaluation of core-shell nanoparticles comprising of a hydrophilic core of BSA surrounded by a hydrophobic shell of PLGA for loading water-soluble drugs.

Methods

A double emulsion method was optimized for preparation of BSA-PLGA based core-shell nanoparticles. Proof of concept for core-shell type structure was established by visual techniques like confocal microscopy and TEM. Characterization was done for particle size, encapsulation efficiency, drug loading and in vitro drug release. Cellular uptake was assessed using confocal microscopy, bio-TEM and HPLC assay, and cytotoxic activity was tested by MTT assay in MG-63 osteosarcoma cells.

Results

The optimized core-shell nanoparticles showed a particle size of 243 nm (PDI-0.13) and encapsulation efficiency of 40.5% with a drug loading of 8.5% w/w. In vitro drug release studies showed a sustained release for 12 h. Cellular uptake studies indicated a rapid and efficient uptake within 2 h. TEM studies indicated that the core-shell nanoparticles were localized in cytoplasm region of the cells. Gemcitabine loaded core-shell nanoparticles showed enhanced cytotoxicity against MG-63 cells as compared to marketed formulation of gemcitabine (GEMCITE®).

Conclusion

These results indicate that core-shell nanoparticles can be a good carrier system for delivering hydrophilic drugs like gemcitabine successfully to the cells with enhanced efficacy.

Nebulization performance of biodegradable sildenafil-loaded nanoparticles using the Aeroneb Pro: formulation aspects and nanoparticle stability to nebulization

Polymeric nanoparticles meet the increasing interest for drug delivery applications and hold great promise to improve controlled drug delivery to the lung. Here, we present a series of investigations that were carried out to understand the impact of formulation variables on the nebulization performance of novel biodegradable sildenafil-loaded nanoparticles designed for targeted aerosol therapy of life-threatening pulmonary arterial hypertension. Narrowly distributed poly(D,L-lactide-co-glycolide) nanoparticles (size: ～200 nm) were prepared by a solvent evaporation technique using poly(vinyl alcohol) (PVA) as stabilizer. The aerodynamic and output characteristics using the Aeroneb Pro nebulizer correlated well with the dynamic viscosity of the employed fluids for nebulization. The nebulization performance was mainly affected by the amount of employed stabilizer, rather than by the applied nanoparticle concentration. Nanoparticles revealed physical stability against forces generated during aerosolization, what is attributed to the adsorbed PVA layer around the nanoparticles. Sildenafil was successfully encapsulated into nanoparticles (encapsulation efficiency: ～80%). Size, size distribution and sildenafil content of nanoparticles were not affected by nebulization and the in vitro drug release profile demonstrated a sustained sildenafil release over ～120 min. The current study suggests that the prepared sildenafil-loaded nanoparticles are a promising pharmaceutical for the therapy of pulmonary arterial hypertension.     

PCL-PEG-PCL载姜黄素纳米粒子的制备以及体外药物释放的考察

目的 制备一种生物可降解、生物相容性良好的姜黄素纳米粒子,并对其体外药物释放行为进行考察。方法 采用开环聚合法制备生物可降解的PCL-PEG-PCL三嵌段聚合物,然后采用乳液挥发法制备负载姜黄素的PCL-PEG-PCL纳米粒子,通过透射电镜观察所制备纳米粒子的形貌特征,动态光散射(DLS)测定粒径,采用HPLC测定纳米粒子的包封率和载药量,同时考察其体外药物释放行为。结果 姜黄素纳米粒子具有球形结构,粒径在200 nm左右,载药量为(14.23±0.35)%,3 d体外累积释药量65%。结论 所制备的姜黄素纳米粒子具有较高的载药量和包封率,同时体外药物释放实验证实姜黄素纳米粒子具有良好的缓释功能。     

A fibrin encapsulated liposomes-in-chitosan matrix (FLCM) for delivering water-soluble drugs. Influences of the surface properties of liposomes and the crosslinked fibrin network

A depot drug delivery system, fibrin encapsulated liposome-in-chitosan matrix (FLCM), has been developed to deliver a water-soluble drug which is configured by a porous chitosan matrix containing a bovine fibrin network encapsulated different surface properties of liposomes. Quinacrine (QR), a water-soluble, low-molecular weight fluorescent marker, is used as a model drug to evaluate the delivery characteristics of the system. The SEM photographs show that the fibrin network adheres to the surfaces and pores of the chitosan matrix of a FLCM system. The QR release periods of the FLCM are sustained for about four times longer than those of QR encapsulated into the liposomes. However, the QR release periods and profiles of the FLCM are influenced by the surface properties of liposomes. The release of QR from FLCM is sustained for 9 days for neutral liposomes and only 5 days for PEG modified liposomes (PEG-liposome). After crosslinking the fibrin network of the FLCM with 0.5% of glutaldehyde, the release of QR is further sustained for 17 days with good linear profiles (e.g., 13 days) and with 50% of reduced burst release compared with those of without crosslinking, indicating that the stability of the fibrin network plays an important role on QR release of the system. More interestingly, the release periods and profiles of QR of the FLCM system are highly similar to those of Tirofiban, low-molecular weight of a water-soluble clinical cardiovascular drug, although the study has been done by human platelet poor plasma instead of bovine fibrinogen as a source of fibrin network. It suggests that the QR is a suitable model for investigating the drug delivery behaviors for water-soluble, low-molecular weight drugs of the FLCM. In conclusion, with QR as a model drug, FLCM with crosslinked fibrin network can effectively sustain the release of QR for 17 days but the release profiles are influenced by the surface properties of encapsulated liposomes. This study suggests that FLCM may have the potential as a depot drug delivery system for water-soluble drugs.     

Preparation and characterization of liposomes encapsulating chitosan nanoparticles

Liposomes are an important colloidal carrier system for controlled drug delivery. However some highly hydrophilic small molecules are difficult to entrap into liposomes and store stably, resulting in poor encapsulation efficiency and fast leakage. In the present work, fluorescein sodium (FS) was used as a model drug that was loaded into chitosan nanoparticles and then encapsulated into liposomes by reverse-phase evaporation (RPV). The encapsulation efficiency, particle size, zeta potential, release in vitro and pharmacokinetics in rats were determined in order to characterize the novel drug delivery system. The entrapment efficiency was above 80% in nanoparticles (Np) and 95% in liposomes encapsulating the nanoparticles (Lip-Np). The Lip-Np was composed of soybean phospholipids, cholesterol and chitosan, which the average diameter was 202.6 nm and zeta potential was -34.8 mV. The release rate of fluorescein sodium from Lip-Np was slower than from Np and liposomes. FS in Lip-Np administered to rats exhibited prolonged circulation and higher bioavailability than FS in Np. The results indicated that liposomal release kinetics can be controlled by encapsulating nanoparticles and thus solid-cored liposomes can be used as a potential drug delivery system.     

Discriminated effects of thiolated chitosan-coated pMMA paclitaxel-loaded nanoparticles on different normal and cancer cell lines

The aim of the present work was to prepare and characterize poly(methyl methacrylate) nanoparticles coated by chitosan–glutathione conjugate so as to encapsulate insoluble anticancer drugs. Nanoparticles were synthesized through radical polymerization of methyl methacrylate initiated by cerium (IV) ammonium nitrate. Paclitaxel (PTX), a model anticancer drug, was encapsulated in nanoparticles with a maximal encapsulation efficiency of 98.27%. These nanoparticles showed sustained in vitro release of the incorporated PTX (75% of the loaded dose was released in 10 days). All nanoparticles had positive charge and were spherical, with a size range of about 130–250 nm. The PTX-loaded nanoparticles showed cytotoxicity for NIH 3T3 and T47D breast carcinoma cells, along with no cytotoxicity for two colon cell lines (HT29, Caco2).From the Clinical EditorThe aim of this work was to prepare and characterize poly(methyl methacrylate) nanoparticles coated by chitosan–glutathione conjugate in an effort to encapsulate Paclitaxel as a model of insoluble anticancer drugs. These nanoparticles showed sustained in vitro drug release.     

Solid-state solubility influences encapsulation and release of hydrophobic drugs from PLGA/PLA nanoparticles

Biodegradable nanoparticles formulated from poly(D,L-lactide-co-glycolide) (PLGA) and polylactide (PLA) polymers are being extensively investigated for various drug delivery applications. In this study, we hypothesize that the solid-state solubility of hydrophobic drugs in polymers could influence their encapsulation and release from nanoparticles. Dexamethasone and flutamide were used as model hydrophobic drugs. A simple, semiquantitative method based on drug-polymer phase separation was developed to determine the solid-state drug-polymer solubility. Nanoparticles using PLGA/PLA polymers were formulated using an emulsion-solvent evaporation technique, and were characterized for size, drug loading, and in vitro release. X-ray powder diffraction (XRD) and differential scanning calorimetry (DSC) were used to determine the physical state of the encapsulated drug. Results demonstrated that the solid-state drug-polymer solubility depends on the polymer composition, molecular weight, and end-functional groups (ester or carboxyl) in polymer chains. Higher solid-state drug-polymer solubility resulted in higher drug encapsulation in nanoparticles, but followed an inverse correlation with the percent cumulative drug released. The XRD and DSC analyses demonstrated that the drug encapsulated in nanoparticles was present in the form of a molecular dispersion (dissolved state) in the polymer, whereas in microparticles, the drug was present in both molecular dispersion and crystalline forms. In conclusion, the solid-state drug-polymer solubility affects the nanoparticle characteristics, and thus could be used as an important preformulation parameter.     

Design of a Multifunctional PLGA Nanoparticulate Drug Delivery System: Evaluation of its Physicochemical Properties and Anticancer Activity to Malignant Cancer Cells

Purpose  Several individual approaches were combined to fabricate a novel nanoparticulate drug delivery system to achieve targeting and anticancer effects in various malignant cancer cells. Methods  Doxorubicin was conjugated to Poly(lactic-co-glycolic acid) (PLGA), which was formulated into nanoparticle via solvent-diffusion method. The surface of the nanoparticles was subsequently linked with Poly(ethylene glycol) (PEG) and Arg-Gly-Asp (RGD) peptide to realize both passive and active targeting functions. The multifunctional nanoparticles were then tested against several malignant cancer cell lines. Results  The conjugation increased loading efficiency of doxorubicin to PLGA nanoparticles (the encapsulation efficiency was over 85%) and alleviated the drug burst release effect substantially. The drug was released from the polymeric matrix in a sustained release manner over a period of 12 days. The resultant nanoparticles were spherically uniform and well-dispersed. The nanoparticle targeting ability was proven through strong affinity to various integrin-expressing cancer cells, and much less affinity to the low integrin expression cancer cells. The nanoparticles also showed high efficacy in inducing apoptosis in specific malignant cancer cell. Conclusion  The developed multifunctional nanoparticles hold potential to treat malignant integrin-expressing cancers.     

Purified and surfactant-free coenzyme Q10-loaded biodegradable nanoparticles

The intent of this work was to synthesize and comprehensively characterize ubiquinone-loaded, surfactant-free biodegradable poly(lactic-co-glycolic acid) (PLGA) nanoparticles in vitro. Surfactant-free, empty and ubiquinone (CoQ10)-loaded biodegradable nanoparticles were synthesized by nanoprecipitation, and the physicochemical properties of these nanoparticles were analyzed with a variety of techniques. Nanoprecipitation consistently yielded individual, sub-200nm, surfactant-free empty and CoQ10-loaded nanoparticles, where the physical and drug encapsulation characteristics were controlled by varying the formulation parameters. CoQ10 release was sustained for 2 weeks but then plateaued before 100% CoQ10 release. A novel, nondestructive purification protocol involving transient sodium dodecyl sulfate (SDS) adsorption to nanoparticles followed by centrifugation and dialysis was developed to yield purified, surfactant-free, CoQ10-loaded nanoparticles. This protocol permitted removal of unencapsulated CoQ10, prevented centrifugation-induced nanoparticle aggregation and preserved the surfactant-free and drug encapsulation properties of the nanoparticles. These CoQ10-loaded nanoparticles are promising as sustained drug delivery devices due to their extended CoQ10 release. Importantly, a surfactant-free nanoprecipitation procedure is presented that in combination with a novel purification step enables the synthesis of individual and purified CoQ10-loaded nanoparticles.     

Construction of amphiphilic copolymer nanoparticles based on hyperbranched poly (amine-ester) and 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine as drug carriers for cancer therapy

Novel amphiphilic copolymer nanoparticles (HPAE-co-PLA-DPPE) composed of hyperbranched poly (amine-ester), polylactide and 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE) segments were designed and synthesized that provided high encapsulation efficiency. These nanoparticles (NPs) were used to encapsulate an antitumor model drug, doxorubicin (DOX). The resulting NPs exhibited high encapsulation efficiency to DOX under an appropriate condition. In vitro release experiments revealed that the release of DOX from NPs was faster at pH 4.5 than that at pH 7.4 or pH 6.0. Confocal microscopy observation indicated that the DOX-loaded NPs can enter cells and localize in lysosomes that can be released quickly into the cytoplasm. The DOX-loaded NPs showed comparable anticancer efficacy with the free drug both in vivo and in vitro. These results demonstrate a feasible application of the hyperbranched copolymer, HPAE-co-PLA-DPPE, as a promising nanocarrier for intracellular delivery of antitumor drugs. FROM THE CLINICAL EDITOR: In this paper, the development of novel amphiphilic copolymer nanoparticles is discussed with the goal of establishing high encapsulation efficiency for chemotherapy drugs.     

Cetirizine dihydrochloride loaded microparticles design using ionotropic cross-linked chitosan nanoparticles by spray-drying method

To control the release rate and mask the bitter taste, cetirizine dihydrochloride (CedH) was entrapped within chitosan nanoparticles (CS-NPs) using an ionotropic gelation process, followed by microencapsulation to produce CS matrix microparticles using a spray-drying method. The aqueous colloidal CS-NPs dispersions with a drug encapsulation efficiency (EE) of <15%, were then spray dried to produce a powdered nanoparticles-in-microparticles system with an EE of >70%. The resultant spherical CS microparticles had a smooth surface, were free of organic solvent residue and showed a diameter range of 0.5∼5 μm. The in vitro drug release properties of CedH encapsulated microparticles showed an initial burst effect during the first 2 h. Drug release from the matrix CS microparticles could be retarded by the crosslinking agent pentasodium tripolyphosphate or the wall material. The technique of ‘ionotropic gelation’ combined with ‘spray-drying’ could be applicable for preparation of CS nanoparticlesin-microparticles drug delivery systems. CS-NPs based microparticles might provide a potential micro-carrier for oral administration of the freely water-soluble drug — CedH.     

Alginate encapsulated mesoporous silica nanospheres as a sustained drug delivery system for the poorly water-soluble drug indomethacin

We applied a combination of inorganic mesoporous silica material, frequently used as drug carriers, and a natural organic polymer alginate (ALG), to establish a sustained drug delivery system for the poorly water-soluble drug Indomethacin (IND). Mesoporous silica nanospheres (MSNs) were synthesized using an organic template method and then functionalized with aminopropyl groups through postsynthesis. After drug loading into the pores of aninopropyl functionalized MSNs (AP-MSNs), IND loaded AP-MSNs (IND-AP-MSNs) were encapsulated by ALG through the ionic interaction. The effects of surface chemical groups and ALG layer on IND release were systematically studied using scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption, zeta-potential analysis and TGA analysis. The surface structure and surface charge changes of the ALG encapsulated AP-MSNs (ALG-AP-MSNs) were also investigated. The results showed that sustained release of IND from the designed drug delivery system was mainly due to the blockage effect from the coated ALG. We believe that this combination will help designing oral sustained drug delivery systems for poorly water-soluble drugs.     

Preparation and in vitro evaluation of silk fibroin microspheres produced by a novel ultra-fine particle processing system

The objective of this study was to prepare silk fibroin SF microspheres containing the enhanced green fluorescent protein (EGFP) by using a novel ultra-fine particle processing system (UPPS) and to evaluate the microspheres as possible carriers for long-term delivery of sensitive biologicals. The drug content, encapsulation efficiency, and in vitro release were evaluated by Microplate Absorbance Reader. The particle size distribution and morphology of the microspheres were analyzed by Malvern Master Sizer 2000 and scanning electron microscopy. The distribution of EGFP and the interactions between SF and EGFP were investigated by Confocal Laser Scanning Microscopy, FTIP, Raman and NMR spectroscopy. The results showed that spherical microspheres with narrow size distribution, glossy and dense surface were successfully manufactured by using UPPS technology and over 95% of EGFP encapsulation efficiency and uniform drug distribution in the microspheres were achieved. Furthermore, a burst free and sustained release of encapsulated EGFP for a period of 50 days in deionized water was obtained. In conclusion, the novel UPPS technology could be used to manufacture SF matrix microspheres as a potential long-term protein delivery system to improve patient compliance and convenience.     

Sustained release of highly water-soluble drugs with micelle forming ability from polyionic matrix tablets

The aim of present study was to evaluate the application of a hydrophilic matrix tablet capable of polyion complex (PIC-tablet) to a controlled-release device for highly water-soluble drugs. The PIC-tablet was prepared from a mixture of dextran sulfate and [2-(diethylamino)ethyl] dextran chloride, and diltiazem hydrochloride was used as a model drug. Release tests revealed that the drug release was sustained even in 50% drug loading and was influenced by ionic strength but not by pH in medium. The drug release mechanism was thus investigated from the viewpoint of drug micelle forming property. The micelle forming ability of diltiazem was examined by the conductivity method, and was found to be influenced by ionic strength but not by pH value in accordance with the release tests. The results suggested that the drug's micelle interacted with the polyionic matrix. Further studies were conducted using metoprolol tartrate and thiamine hydrochloride as cationic drugs and sodium cloxacillin and sodium salicylic acid as anionic ones. The release profiles of the micelle-forming drugs metoprolol tartrate and sodium cloxacillin were also suppressed in spite of different solubility or opposite ionic charge from diltiazem hydrochloride. These findings demonstrated that the PIC-tablet is a promising device for oral controlled release delivery of water-soluble drugs with good micelle-forming ability.     

Influence of microencapsulation method and peptide loading on formulation of poly(lactide-co-glycolide) insulin nanoparticles

Insulin stability during microencapsulation and subsequent release is essential for retaining its biological activity. Therefore we investigated a novel solid/oil/water anhydrous encapsulation method with a combination of stabilizers for maintaining the integrity of insulin during formulation and delivery. Two methods were used for preparation of nanoparticles, namely water/oil/water solvent evaporation and s/o/w anhydrous encapsulation to study the influence of the microencapsulation method on nanoparticle characteristics such as size and morphology, drug content, encapsulation efficiency, and in vitro and in vivo release profile. Poly (lactic-co-glycolic) acid (PLGA) with co-polymer ratio 50:50 was selected to prepare drug-loaded nanoparticles. When nanoparticles were prepared by solvent evaporation higher encapsulation efficiencies could be obtained, e.g. 74 +/- 13 with 5% target loading, whereas with 12% target loading, encapsulation efficiency was 27 +/- 8.6. The s/o/w method has a direct influence on the evaluation parameters where very poor encapsulation efficiencies 11 +/- 6.8 (max) were observed. The presence of stabilizers in the nanoparticles resulted in an increase in particle size but a reduction of encapsulation efficiency. Insulin release rate was comparatively higher for the batches prepared by the w/o/w method containing stabilizers than the s/o/w method. Also the presence of stabilizers resulted in sustained release of insulin resulting in prolonged reduction of blood glucose levels in streptozotocin induced diabetic rats. From the in vitro and in vivo studies, it can be concluded that careful selection of processing conditions and combination of stabilizers also result in beneficial effects without compromising the advantages of these delivery systems.