Amulya K. Panda

Eudragit S100 entrapped insulin microspheres for oral delivery

The purpose of this research was to investigate whether Eudragit S100 microspheres have the potential to serve as an oral carrier for peptide drugs like insulin. Microspheres were prepared using water-in oil-in water emulsion solvent evaporation technique with polysorbate 20 as a dispersing agent in the internal aqueous phase and polyvinyl alcohol (PVA)/polyvinyl pyrrolidone as a stabilizer in the external aqueous phase. The use of smaller internal aqueous-phase volume (50 μL) and external aqueous-phase volume (25 mL) containing PVA in the manufacturing process resulted in maximum encapsulation efficiency (81.8%±0.9%). PVA-stabilized microspheres having maximum drug encapsulation released 2.5% insulin at pH 1.0 in 2 hours. In phosphate buffer (pH 7.4), microspheres showed an initial burst release of 22% in 1 hour with an additional 28% release in the next 5 hours. The smaller the volumes of internal and external aqueous phase, the lower the initial burst release. The release of drug from microspheres followed Higuchi kinetics. Scanning electron microscopy of PVA-stabilized microspheres demonstrated spherical particles with smooth surface, and laser diffractometry revealed a mena particle size of 32.51±20 μm. Oral administration of PVA stabilized microspheres in normal albino rabbits (equivalent to 6.6 IU insulin/kg of animal weight) demonstrated a 24% reduction in blood glucose level, with maximum plasma glucose reduction of 76±3.0% in 2 hours and effect continuing up to 6 hours. The area under the percentage glucose reduction-time curve was 93.75%. Thus, our results indicate that Eudragit S100 microspheres on oral administration can protect insulin from proteolytic degradation in the gastrointestinal tract and produce hypoglycemic effect.

Stabilization of Dichloromethane-Induced Protein Denaturation During Microencapsulation

This paper describes the denaturation of protein drugs by dichloromethane (DCM) during the primary emulsification step of the microencapsulation process using biodegradable polymer matrix for controlled-release application. It was found that interaction of proteins such as tetanus toxoid (TT), diphtheria toxoid (DT), ovine growth hormone (oGH), and human chorionic gonadotropin-based antifertility vaccine (beta-hCG-TT) with DCM during primary emulsification stages of particle formulation led to the precipitation of the proteins at the aqueous organic interface with concomitant reduction in their immunoreactivity. On the other hand, the B subunit of E. coli enterotoxin (LTB) was found to be comparatively stable toward the denaturing action of DCM. Attempts were made to overcome the DCM-induced denaturation by incorporation of stabilizers during the primary emulsification step of the particle formulation. Of the many additives tested to overcome the DCM-induced denaturation of proteins, serum albumins and polyvinyl alcohol (PVA) showed promising results in terms of retention of the immunoreactivity of the protein. TT stabilized by the incorporation of serum albumin during the primary emulsification step not only showed immunoreactivity in vitro, but also invoked antibody titers in rats comparable to those obtained for the native protein molecules. Incorporation of 2.5% of serum albumins in the internal aqueous phase not only protected the protein from the degradative action of DCM but also led to stabilized primary emulsion, which is necessary for uniform entrapment of protein drugs in the polymer matrix.

Development of enteric submicron particle formulation of papain for oral delivery

Background Particulate systems have received increasing attention for oral delivery of biomolecules. The objective of the present study was to prepare submicron particulate formulations of papain for pH-dependent site-specific release using pH-sensitive polymers. Methods Enteric submicron particle formulations of papain were prepared by w/o/w emulsion solvent evaporation using hydroxypropyl methylcellulose phthalate (HPMCP), Eudragit L100, and Eudragit S100, to avoid gastric inactivation of papain. Results Smaller internal and external aqueous phase volumes provided maximum encapsulation efficiency (75.58%–82.35%), the smallest particle size (665.6–692.4 nm), and 25%–30% loss of enzyme activity. Release studies in 0.1 N HCl confirmed the gastroresistance of the formulations. The anionic submicron particles aggregated in 0.1 N HCl (ie, gastric pH 1.2) due to protonation of carboxylic groups in the enteric polymer. Aggregates < 500 μm size would not impede gastric emptying. However, at pH > 5.0 (duodenal pH), the submicron particles showed deaggregation due to restoration of surface charge. HPMCP submicron particles facilitated almost complete release of papain within 30 minutes at pH 6.0, while Eudragit L100 and Eudragit S100 particles released 88.82% and 53.00% of papain at pH 6.8 and pH 7.4, respectively, according to the Korsmeyer–Peppas equation. Sodium dodecyl sulfate polyacrylamide gel electrophoresis and fluorescence spectroscopy confirmed that the structural integrity of the enzyme was maintained during encapsulation. Fourier transform infrared spectroscopy revealed entrapment of the enzyme, with powder x-ray diffraction and differential scanning calorimetry indicating an amorphous character, and scanning electron microscopy showing that the submicron particles had a spherical shape. Conclusion In simulated gastrointestinal pH conditions, the HPMCP, Eudragit L100, and Eudragit S100 submicron particles showed good digestion of paneer and milk protein, and could serve as potential carriers for oral enzyme delivery. Stability studies indicated that formulations with approximately 6% overage would ensure a two-year shelf-life at room temperature.

Insulin loaded eudragit L100 microspheres for oral delivery: preliminary in vitro studies.

Eudragit L100 microspheres were prepared using water-in-oil-in water (w/o/w) emulsion-solvent evaporation with polysorbate 20 as dispersing agent in the internal aqueous phase, and PVA/PVP as stabilizer in the external aqueous phase. Smaller internal and external aqueous phases provided higher drug encapsulation. The PVA-stabilized microspheres having maximum drug encapsulation (84.5 2.8%) released 7% insulin at pH 1.0 in 2 h. In phosphate buffer (pH 7.4), microspheres showed an initial burst release of 21% in 1 h with additional 35% release in the next 5 h. The smaller the volumes of internal and external aqueous phases, the lower the initial burst release. The release of drug from microspheres followed Higuchi kinetics. Scanning electron microscopy of PVA stabilized microspheres demonstrated spherical particles with smooth surface and laser diffractometry revealed a mean particle size (Vm) of 59.11 30 m.

Formulation and Characterization of Immunoreactive Tetanus Toxoid Biodegradable Polymer Particles

Poly lactide-co-glycolide and polylactide polymer particles entrapping immunoreactive tetanus toxoid (TT) were prepared with a view to developing a single shot controlled release vaccine formulation. Denaturation of TT by dichloromethane (DCM) during primary emulsification stage of particle formulation was minimized by incorporation of an optimal amount of rat serum albumin (RSA) in the internal aqueous phase. Incorporation of RSA as a stabilizer during the primary emulsification stage of polymer particle formulation protected the immunoreactivity of TT, enhanced its encapsulation efficiency and also led to uniform polymer particle formation. Use of sonication, both during primary and secondary emulsification processes, resulted in formation of nanoparticles whereas microparticles were formed when the secondary emulsion was carried out by homogenization. Immunoreactive TT particles made from different polymers incorporating stabilizers released antigen continuously for more than four months in vitro. Single injection of both type of particles encapsulating stabilized TT elicited anti-TT antibody titers in rats for more than five months, which was higher than that obtained with TT injected in saline. Anti-TT antibody titers in vivo were in accordance with the in vitro release characteristics of immunoreactive TT from the particles. Immune responses with hydrophobic polymer particles were better than those made using hydrophilic polymers. These results indicate the importance of protecting the immunoreactivity of TT during formation of polymer particles for sustained and improved antibody response.Poly lactide-co-glycolide and polylactide polymer particles entrapping immunoreactive tetanus toxoid (TT) were prepared with a view to developing a single shot controlled release vaccine formulation. Denaturation of TT by dichloromethane (DCM) during primary emulsification stage of particle formulation was minimized by incorporation of an optimal amount of rat serum albumin (RSA) in the internal aqueous phase. Incorporation of RSA as a stabilizer during the primary emulsification stage of polymer particle formulation protected the immunoreactivity of TT, enhanced its encapsulation efficiency and also led to uniform polymer particle formation. Use of sonication, both during primary and secondary emulsification processes, resulted in formation of nanoparticles whereas microparticles were formed when the secondary emulsion was carried out by homogenization. Immunoreactive TT particles made from different polymers incorporating stabilizers released antigen continuously for more than four months in vitro. Single injection of both type of particles encapsulating stabilized TT elicited anti-TT antibody titers in rats for more than five months, which was higher than that obtained with TT injected in saline. Anti-TT antibody titers in vivo were in accordance with the in vitro release characteristics of immunoreactive TT from the particles. Immune responses with hydrophobic polymer particles were better than those made using hydrophilic polymers. These results indicate the importance of protecting the immunoreactivity of TT during formation of polymer particles for sustained and improved antibody response.

Development and characterization of itraconazole-loaded solid lipid nanoparticles for ocular delivery

Abstract The purpose of this study was to investigate the feasibility of entrapping water-insoluble drug itraconazole into solid lipid nanoparticles (SLNs) for topical ocular delivery. The drug-loaded SLNs were prepared from stearic acid and palmitic acid using different concentrations of polyvinyl alcohol employed as emulsifier. SLNs were prepared by the melt-emulsion sonication and low temperature-solidification method and characterized for particle size, zeta potential, drug loading and drug entrapment efficiency. The mean particle size of SLNs prepared with stearic acid ranged from 139 to 199 nm, while the SLNs prepared with palmitic acid had particle size in the range of 126–160 nm. The SLNs were spherical in shape. Stearic acid-SLNs showed higher entrapment of drug compared with palmitic acid-SLNs. Differential scanning calorimetry (DSC) and X-ray diffraction measurements showed decrease in crystallinity of drug in the SLN formulations. The modified Franz-diffusion cell and freshly excised goat corneas were used to test drug corneal permeability. Permeation of itraconazole from stearic acid-SLNs was higher than that obtained with palmitic acid-SLNs. The SLNs showed clear zone of inhibition against Aspergillus flavus indicating antimicrobial efficacy of formulations.

Hyaluronic acid grafted PLGA copolymer nanoparticles enhance the targeted delivery of Bromelain in Ehrlich's Ascites Carcinoma.

Rapidly increasing malignant neoplastic disease demands immediate attention. Several dietary compounds have recently emerged as strong anti-cancerous agents. Among, Bromelain (BL), a protease from pineapple plant, was used to enhance its anti-cancerous efficacy using nanotechnology. In lieu of this, hyaluronic acid (HA) grafted PLGA copolymer, having tumor targeting ability, was developed. BL was encapsulated in copolymer to obtain BL-copolymer nanoparticles (NPs) that ranged between 140 to 281nm in size. NPs exhibited higher cellular uptake and cytotoxicity in cells with high CD44 expression as compared with non-targeted NPs. In vivo results on tumor bearing mice showed that NPs were efficient in suppressing the tumor growth. Hence, the formulation could be used as a self-targeting drug delivery cargo for the remission of cancer.

Development of enteric submicron particles formulation of α-amylase for oral delivery

Enteric submicron particles (SPs) formulations of α-amylase were prepared by w/o/w emulsion solvent evaporation using hydroxypropyl methylcellulose phthalate (HPMCP) and Eudragit L 100, to avoid gastric inactivation of α-amylase. Smaller internal and external aqueous phase volume provided maximum encapsulation efficiency (71.92–73.40%), least particle size (546.4–595.4 nm) and 23–26% loss of enzyme activity. Release studies in 0.1 N HCl confirmed the gastro-resistance of formulations. The anionic SPs aggregated in 0.1 N HCl (i.e. gastric pH 1.2), due to protonation of carboxylic groups of enteric polymer. The aggregates being < 500 µm size would not impede gastric emptying. However, at pH >5.0 (duodenal pH), SPs showed de-aggregation due to restoration of surface charge. HPMCP and Eudragit L 100 SPs facilitated almost complete release of α-amylase within 30 min at pH 6.0 and 6.8, respectively, following Higuchi kinetics. PXRD and DSC indicated amorphous character and scanning electron microscope showed spherical shape of SPs. In simulated gastro-intestinal pH condition, HPMCP and Eudragit L 100 SPs showed good digestion of cooked rice and could serve as potential carrier for oral enzyme delivery. Stability studies indicated the formulations as quite stable to ensure 2 years shelf life at room temperature.

Topical ocular delivery of a COX-II inhibitor via biodegradable nanoparticles

Abstract The present investigation strives to formulate nanoparticles of poly-ε-caprolactone (PCL), containing celecoxib (CXB), a non-steroidal anti-inflammatory agent. The CXB-PCL nanoparticles were formulated by solvent displacement method and optimized based on formulation variables like drug-to-polymer ratio and surfactant concentration. The formulations were characterized for particle dimensions, surface morphology, physicochemical features, percentage drug incorporation efficiency, in vitro drug release, in vitro trans-corneal permeation, in vivo efficacy against arachidonic acid-induced ocular inflammation, and stability study. The prepared nanoparticles were nearly spherical having particle sizes ranging from 89.16±8.2 nm to 191.27±12.1 nm with maximum entrapment efficiency of 97.03±0.20%. The drug release was in sustained fashion (<75% drug released after 8 h) and obeyed zero-order release kinetics. The trans-corneal permeation was significantly higher than the aqueous suspension of CXB (p=0.05). Further, % hydration level was observed within permissible ranges suggesting ocular tolerability. The anti-inflammatory activity was found better as there was observed an improvement in parameters like lid closure score, PMN counts, and protein content against CXB aqueous suspension. The formulations were stable as evident from accelerated stability testing results. Thus, the CXB-PCL nanoparticles may prove a viable alternative to conventional dosage forms offering enhanced ocular bioavailability and compatibility with ocular milieu.