Insulin Encapsulation Research Articles

Intestinal-Target and Glucose-Responsive Smart Hydrogel toward Oral Delivery System of Drug with Improved Insulin Utilization.

An intelligent insulin delivery system targeting intestinal absorption and glucose responsiveness can enhance the bioavailability through oral insulin therapy, offering promising diabetes treatment. In this paper, a glucose and pH dual-response polymer hydrogel using carboxymethyl agarose modified with 3-amino-phenylboronic acid and l-valine (CPL) was developed as an insulin delivery carrier, exhibiting excellent biocompatibility and effective insulin encapsulation. The insulin encapsulated in the hydrogel (Ins-CPL) was released in a controlled manner in response to the in vivo stimulation of blood glucose and pH levels with higher levels of intracellular uptake and utilization of insulin in the intestinal environment simultaneously. Notably, the Ins-CPL hydrogel effectively regulated blood sugar in diabetic rats over a long period by simulating endogenous insulin, responding to changes in plasma pH and glucose levels, and overcoming the intestinal epithelium barrier. This indicates a significant boost in oral insulin bioavailability and broadens its application prospects.

Insulin Conformation Changes in Hybrid Alginate-Gelatin Hydrogel Particles.

There is a strong need to develop an insulin delivery system suitable for oral administration and preserving natural (α-helix) insulin conformation. In this work, we fabricated alginate-gelatin hydrogel beads for insulin encapsulation. Altering matrix composition and crosslinking agents has resulted in various surface morphologies and internal spatial organization. The structures of the insulin-loaded matrices were studied using optical and field emission electronic microscopy. We use FTIR spectroscopy to identify insulin conformation changes as affected by the hydrogel matrices. It was found that blended alginate-gelatin matrices demonstrate better encapsulation efficiency and stronger swelling resistance to a simulated gastric environment than sodium alginate beads crosslinked with the CaCl2. FTIR measurements reveal conformation changes in insulin. It is also confirmed that in the presence of gelatin, the process of insulin fibrinogenesis ceases due to intermolecular interaction with the gelatin. Performed molecular modeling shows that dipole-dipole interactions are the dominating mechanism that determines insulin behavior within the fabricated matrix.

Microfluidic-assisted preparation of PLGA nanoparticles loaded with insulin: a comparison with double emulsion solvent evaporation method

Poly lactic-co-glycolic acid (PLGA) is an ideal polymer for the delivery of small and macromolecule drugs. Conventional preparation methods of PLGA nanoparticles (NPs) result in poor control over NPs properties. In this research, a microfluidic mixer was designed to produce insulin-loaded PLGA NPs with tuned properties. Importantly; aggregation of the NPs through the mixer was diminished due to the coaxial mixing of the precursors. The micromixer allowed for the production of NPs with small size and narrow size distribution compared to the double emulsion solvent evaporation (DESE) method. Furthermore, encapsulation efficiency and loading capacity indicated a significant increase in optimized NPs produced through the microfluidic method in comparison to DESE method. NPs prepared by the microfluidic method were able to achieve a more reduction of trans-epithelial electrical resistance values in the Caco-2 cells compared to those developed by the DESE technique that leads to greater paracellular permeation. Compatibility and interaction between components were evaluated by differential scanning calorimetry and fourier transform infrared analysis. Also, the effect of NPs on cell toxicity was investigated using MTT test. Numerical simulations were conducted to analyze the effect of mixing patterns on the properties of the NPs. It was revealed that by decreasing flow rate ratio, i.e. flow rate of the organic phase to the flow rate of the aqueous phase, mixing of the two streams increases. As an alternative to the DESE method, high flexibility in modulating hydrodynamic conditions of the microfluidic mixer allowed for nanoassembly of NPs with superior insulin encapsulation at smaller particle sizes.

Oral Delivery of Insulin from Trimethyl Chitosan/Tragacanth: In Vitro, MTT, and In Vivo Bioactivity Tests

: Insulin-loaded Trimethyl Chitosan (TMC)/tragacanth microspheres were prepared by microemulsion dispersion and triggered in situ gelation. Microspheres were characterized by their mean size and distribution by laser diffraction spectroscopy and Brunauer-Emmet-Teller theory. Insulin encapsulation efficiency and in vitro release were determined by Bradford protein assay, and bioactivity was assessed in vitro using an enzyme-linked immunoassay diagnostic kit and in vivo using Wistar diabetic rats. TMC/tragacanth particles suppressed insulin release in acidic media and promoted a sustained release at near-neutral conditions. Micro-capsulated insulin was bioactive, demonstrated by both in vivo and in vitro bioassays.

Injectable nanosized formulation for glucose-responsive insulin delivery

Glucose-responsive insulin (GRI) can tremendously facilitate insulin administration via expanding the safe dosage window and reducing injection frequency, as well as enhancing blood glucose control via actively adjusting the insulin release rate. We have previously prepared a robust ion complex-based GRI for type 1 diabetes treatment; however, this complex precipitates easily, which could cause difficulty of injection and inaccuracy of dosage. It remains elusive whether nanoparticulation of this complex could increase suspension stability and retain glucose responsiveness. Herein, we have linked poly (ethylene glycol) (PEG) to 4-carboxy-3-fluorophenylboronic acid (FPBA)-modified poly-ʟ-lysine to obtain PEG-PLL-FPBA. PEG-PLL-FPBA and insulin can form nanosized insulin complex (NIC) with a high insulin loading content and encapsulation efficiency. Of note, the size of the prepared NIC can keep stable for more than 7 days. The NIC showed glucose-stimulated insulin release in vitro with a maximal glucose-responsive index of 400 %. In a streptozotocin (STZ)-induced type 1 diabetic mouse model, the subcutaneously injected NIC could normalize hyperglycemia in 30 min and maintain it normally for 20 h, while minimal toxicity has been identified.

Insulin-Loaded Soybean Trypsin Inhibitor-Chitosan Nanoparticles: Preparation, Characterization, and Protective Effect Evaluation.

The aim of this work was to prepare insulin-loaded nanoparticles using soybean trypsin inhibitor (STI) and chitosan (CS) as a potential coating. The nanoparticles were prepared by complex coacervation, and characterized for their particle size, polydispersity index (PDI), and encapsulation efficiency. In addition, the insulin release and enzymatic degradation of nanoparticles in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) were evaluated. The results showed that the optimal conditions for preparing insulin-loaded soybean trypsin inhibitor-chitosan (INs-STI-CS) nanoparticles were as follows: CS concentration of 2.0 mg/mL, STI concentration of 1.0 mg/mL, and pH 6.0. The INs-STI-CS nanoparticles prepared at this condition had a high insulin encapsulation efficiency of 85.07%, the particle diameter size was 350 ± 5 nm, and the PDI value was 0.13. The results of the in vitro evaluation of simulated gastrointestinal digestion showed that the prepared nanoparticles could improve the stability of insulin in the gastrointestinal tract. Compared with free insulin, the insulin loaded in INs-STI-CS nanoparticles was retained at 27.71% after 10 h of digestion in the intestinal tract, while free insulin was completely digested. These findings will provide a theoretical basis for improving the stability of oral insulin in the gastrointestinal tract.

Design and Evaluation of Pegylated Large 3D Pore Ferrisilicate as a Potential Insulin Protein Therapy to Treat Diabetic Mellitus.

An iron-based SBA-16 mesoporous silica (ferrisilicate) with a large surface area and three-dimensional (3D) pores is explored as a potential insulin delivery vehicle with improved encapsulation and loading efficiency. Fe was incorporated into a framework of ferrisilicate using the isomorphous substitution technique for direct synthesis. Fe3+ species were identified using diffuse reflectance spectroscopy. The large surface area (804 m2/g), cubic pores (3.2 nm) and insulin loading were characterized using XRD, BET surface area, FTIR and TEM analyses. For pH sensitivity, the ferrisilicate was wrapped with polyethylene glycol (MW = 400 Daltons) (PEG). For comparison, Fe (10 wt%) was impregnated on a Korea Advanced Institute of Science and Technology Number 6 (KIT-6) sieve and Mesocellular Silica Foam (MSU-F). Insulin loading was optimized, and its release mechanism was studied using the dialysis membrane technique (MWCO = 14,000 Da) at physiological pH = 7.4, 6.8 and 1.2. The kinetics of the drug's release was studied using different structured/insulin nanoformulations, including Santa Barbara Amorphous materials (SBA-15, SBA-16), MSU-F, ultra-large-pore FDU-12 (ULPFDU-12) and ferrisilicates. A different insulin adsorption times (0.08-1 h), insulin/ferrisilicate ratios (0.125-1.0) and drug release rates at different pH were examined using the Korsmeyer-Peppas model. The rate of drug release and the diffusion mechanisms were obtained based on the release constant (k) and release exponent (n). The cytotoxicity of the nanoformulation was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay using human foreskin fibroblast (HFF-1) cells. A low cytotoxicity was observed for this nanoformulation starting at the highest concentrations used, namely, 400 and 800 μg. The hypoglycemic activity of insulin/ferrisilicate/PEG on acute administration in Wistar rats was studied using doses of 2, 5 and 10 mg/kg body weight. The developed facile ferrisilicate/PEG nanoformulation showed a high insulin encapsulation and loading capacity with pH-sensitive insulin release for potential delivery through the oral route.

Latest Development of Administration Routes for Anti-Diabetic Agents using Insulin Nanoparticles (NPs)

For the latest development for anti-diabetic agents, nanoparticles (NPs) have been in focus. Permeation enhancers (PEs) are known to increase the oral absorption of various kinds of macromolecules. One of PEs would be sodium N-[8-(2-hydroxybenzoyl) amino] caprylate (SNAC), which has been used for glucagon-like peptide-1 receptor agonist (GLP-1RA) as oral semaglutide (Rybelsus). For insulin encapsulation, polyelectrolyte nanocomplex (PEC) have been the promising carriers. Furthermore, spray drying technique has been an adequate and well-known industrial method for developing pharmaceutical industries, and aqueous polymer dispersions (APDs) have been applied. Consequently, self-nanoemulsifying drug delivery systems (SNEDDS) can be expected to improve future diabetic treatment.

Encapsulation of Insulin in Biodegradable Polymers

Encapsulation of insulin into alginate particles was carried out by the method of ionotropic gelation. To protect against the acidic, alkaline environment of the gastrointestinal tract, alginate particles were coated with gelatin. The optimal concentration of the solution of the crosslinking agent ‒ CaCl2 was determined during the optimization of the particle preparation method. The mechanism of interaction between alginate and gelatin was investigated using FTIR spectroscopy, FTIR spectra data confirm the formation of a polyelectrolyte complex between alginate an-d gelatin. The roughness and morphology of samples were determined by atomic force microscopy. The swelling of particles under simulated pH conditions of various parts of the human gastrointestinal tract was studied. The release of insulin from the particles was evaluated using UV spectroscopy, at pH 6.86; 9.18 the release of insulin reached 50%; 83% relatively.

Insight into molecular mechanism of human insulin encapsulation into the polyacrylic acid/deoxycholic acid-modified chitosan nanogel: An experimental and molecular dynamics investigation

Insulin is a therapeutic peptide used as a remedy for diabetes. However, it must be administered daily because of its high clearance rate and poor bloodstream stability. Due to its biocompatibility and high encapsulation efficacy, chitosan and its derivatives attracted attention as a suitable candidate for protein delivery vehicles. Herein, the Insulin polypeptide structure and dynamics were investigated during the encapsulation in the polyacrylic acid / deoxycholic acid-modified chitosan copolymers. The fluorescence and far-UV circular dichroism (CD) spectroscopies data showed the structural stability of Insulin in the presence of the copolymer and the possibility of hydrophobic interaction occurrence during the complex formation. The molecular dynamics (MD) simulation data confirmed the role of hydrophobic residues of Insulin in the adsorption process and revealed information on the main driving forces in interaction initiation. The present study results promise new designs and applications for chitosan nanoparticle-based protein delivery systems.

Leveraging Isothermal Titration Calorimetry to Explore Structure–Property Relationships of Protein Immobilization in Metal–Organic Frameworks

AbstractProteins immobilized in metal–organic frameworks (MOFs) often show extraordinary stability. However, most efforts to immobilize proteins in MOFs have only been exploratory. Herein, we present the first systematic study on the thermodynamics of protein immobilization in MOFs. Using insulin as a probe, we leveraged isothermal titration calorimetry (ITC) to investigate how topology, pore size, and hydrophobicity of MOFs influence immobilization. ITC data obtained from the encapsulation of insulin in a series of Zr‐MOFs reveals that MOFs provide proteins with a hydrophobic stabilizing microenvironment, making the encapsulation entropically driven. In particular, the pyrene‐based NU‐1000 tightly encapsulates insulin in its ideally sized mesopores and stabilizes insulin through π‐π stacking interactions, resulting in the most enthalpically favored encapsulation process among this series. This study reveals critical insights into the structure–property relationships of protein immobilization.

Leveraging Isothermal Titration Calorimetry to Explore Structure-Property Relationships of Protein Immobilization in Metal-Organic Frameworks.

Proteins immobilized in metal-organic frameworks (MOFs) often show extraordinary stability. However, most efforts to immobilize proteins in MOFs have only been exploratory. Herein, we present the first systematic study on the thermodynamics of protein immobilization in MOFs. Using insulin as a probe, we leveraged isothermal titration calorimetry (ITC) to investigate how topology, pore size, and hydrophobicity of MOFs influence immobilization. ITC data obtained from the encapsulation of insulin in a series of Zr-MOFs reveals that MOFs provide proteins with a hydrophobic stabilizing microenvironment, making the encapsulation entropically driven. In particular, the pyrene-based NU-1000 tightly encapsulates insulin in its ideally sized mesopores and stabilizes insulin through π-π stacking interactions, resulting in the most enthalpically favored encapsulation process among this series. This study reveals critical insights into the structure-property relationships of protein immobilization.

The enhanced encapsulation, release, and oral hypoglycemic performance of a biomacromolecule surface modified insulin-loaded halloysite nanocomposite: an in vitro and in vivo study

To overcome the drawbacks of oral administration of insulin, a surface-modified insulin-loaded nanocomposite was designed and prepared in this work. Halloysite nanotubes (HNTs) were employed to improve the insulin encapsulation, PEG-CS and hydroxypropyl methyl cellulose phthalate (HPMCP) were selected to surface modify the insulin-loaded HNTs to adjust the release of insulin. As a result, the insulin-loaded HNTs/PEG-CS/HPMCP NCs had good biocompatibility, relatively high drug loading, and pH-sensitive release properties. Oral administration of the NCs produced an effective and relative long-time hypoglycemic effect. Therefore, these NCs can be a promising delivery system to improve the oral bioavailability of insulin.

THE ELECTROSPRAYED INSULIN-LOADED POLYCAPROLACTONE MICROPARTICLES AS A DRUG CARRIER

Drug and protein encapsulated polymeric microparticles have been considered as the most effective delivery in pharmaceutical biotechnology. In this work, we report the fabrication of polycaprolactone microparticles (PCL MPs) containing insulin via an electrospraying method. The morphology, chemical composition, physicochemical properties, insulin encapsulation and release efficiency, degradation of PCL MPs, and cytotoxicity are systematically characterized and analyzed. The results indicate that insulin do not incorporate with PCL matrix leading to the deformation of PCL MPs’ structure. In addition, insulin can be loaded into the PCL MPs with high concentration up to 25 % while it remains chemical properties when releasing from the PCL MPs. Moreover, insulin demonstrates high burst release within the first day, subsequently the release become more stable during 2-7 days. The 80% viability of the cell suggests that PCL MPs are biocompartible to cells. As a consequence, the above mentioned material is proved to be has high potential for insulin carrier in controlled release application

Poly[(vinyl benzyl trimethylammonium chloride)]-based nanoparticulate copolymer structures encapsulating insulin

We report on the synthesis and preparation of four double hydrophilic polyelectrolytes and their complexation with insulin (INS). Specifically, two cationic-neutral poly[oligo(ethylene glycol) methacrylate]-b-poly[(vinyl benzyl trimethylammonium chloride)] (POEGMA-b-PVBTMAC) and two poly[oligo(ethylene glycol) methacrylate-co-vinyl benzyl trimethylammonium chloride] (P(OEGMA-co-VBTMAC)) copolymers are successfully synthesized by reversible-addition fragmentation chain transfer (RAFT) polymerization with different compositions. Based on light scattering techniques (DLS, ELS), the POEGMA81-b-PVBTMAC19, POEGMA46-b-PVBTMAC54 P(OEGMA90-co-VBTMAC10), P(OEGMA75-co-VBTMAC25) (subscripts denote wt.% composition of the components) copolymers are present as single chains and aggregates in aqueous media. A significant aggregation tendency of bare copolymers into well-defined spherical-shape particles is also noticed in cryogenic transmission electron microscopy measurements (Cryo-TEM) measurements. The synthesized copolymers were utilized as nanocarriers for insulin (INS) encapsulation. Nanocarriers were formed via electrostatic co-assembly, and the effects of copolymer structure on the properties of the formed hybrid copolymer-INS nanostructures are studied. Physicochemical results on the copolymer/INS complexes corroborated the efficient complexation of INS with copolymers. The determined characteristics and the morphology of the copolymer/INS complexes were found to depend on (−)INS/(+)polymer charge ratio. The copolymer/INS complexes retain the initial spherical shape of neat copolymer aggregates after the electrostatic complexation with INS, according to Cryo-TEM measurements, also uncovering the presence of aggregates and threadlike structures. FBS interactions between bare copolymers and copolymer/INS complexes manifested a good stability of the hybrid copolymer/INS assemblies into a simulated biological environment. Moreover, attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectroscopy shows physical interactions between INS and the respective polyelectrolytes. Fluorescence spectroscopy (FS) measurements indicated no significant changes on the conformation of complexed INS.

Exploring the potential of redispersible nanocomplex-in-microparticles for enhanced oral insulin delivery

Polyelectrolyte nanocomplex (PEC) is a promising carrier for insulin encapsulation. However, tenacious enzymatic degradation and insufficient penetration in mucus and enterocyte are the dominating obstacles for their oral insulin delivery. Besides, the rate of insulin release should be tuned to achieve desired therapeutic effect and meanwhile with scale-up potential. Thus, PEC embedded microparticles were fabricated in this study to solve the above dilemma. First of all, insulin loaded PEC with sodium dodecyl sulfate (SDS) coating was prepared by self-assembly method and then spray-dried using different ratio chitosan (CS)/ polyvinyl alcohol (PVA) as the matrix to obtain the microparticles. Influence of the CS/PVA ratio on the in vitro and in vivo properties of the redispersed PEC was investigated systemically. It was demonstrated that when CS 50 kDa was used in the matrix, all the PEC could be well redispersed with particle size less than 250 nm, and good stability in the gastrointestinal tract, further improved enzymatic stability was achieved by nanoparticles-in-microparticles design, with CS/PVA 1:1 and 4:1 groups showing better and comparable protection. Insulin release from the microparticles decreased with the increase of CS ratio in the CS/PVA matrix. Spray-dried microparticles had less influence on the mucus penetration of the in situ redispersed PEC, with enhanced insulin permeation observed in different intestinal segments in a CS/PVA ratio dependent manner. And the CS/PVA 1:1 group, which presented good enzymatic stability, enhanced mucus penetration and moderate insulin release rate, exhibited the highest relative pharmacological availability of 6.80%. In conclusion, PEC in microparticles design using CS/PVA as the composite matrix is a potential platform for enhanced oral insulin delivery.

Cubic and Hexagonal Mesophases for Protein Encapsulation: Structural Effects of Insulin Confinement

Monoolein-based cubic and hexagonal mesophases were investigated as matrices for insulin loading, at low pH, as a function of temperature and in the presence of increasing amounts of oleic acid, as a structural stabilizer for the hexagonal phase. Synchrotron small angle X-ray diffraction, rheological measurements, and attenuated total reflection-Fourier transform infrared spectroscopy were used to study the effects of insulin loading on the lipid mesophases and of the effect of protein confinement in the 2D- and 3D-lipid matrix water channels on its stability and unfolding behavior. We found that insulin encapsulation has only little effects both on the mesophase structures and on the viscoelastic properties of lipid systems, whereas protein confinement affects the response of the secondary structure of insulin to thermal changes in a different manner according to the specific mesophase: in the cubic structure, the unfolding toward an unordered structure is favored, while the prevalence of parallel β-sheets, and nuclei for fibril formation, is observed in hexagonal structures.

A new Glucose-Responsive delivery system based on Sulfonamide-phenylboronic acid for subcutaneous insulin injection

A novel glucose- and temperature-responsive random copolymer, poly sulfonamide-phenylboronic acid-co-N-vinylcaprolactam p(SAPBA-co-NVCL), was synthesised via the “one-pot” method. After the polymer was made into nanoparticles, their properties, including insulin loading capacity and encapsulation efficiency, were investigated; their cytotoxicity and treatment effectiveness were also explored. Thermogravimetric results confirmed that p(SAPBA-co-NVCL) had high stability. Performance test results showed that p(SAPBA-co-NVCL) nanoparticles had round morphology and good glucose sensitivity under physiological conditions. Concurrently, we found that the size of the nanoparticles and the amount of insulin released increased significantly with the increase of glucose concentration. In addition, cytotoxicity results suggested that p(SAPBA-co-NVCL) nanoparticles were non-toxic to normal cells, but had a certain lethality effect on tumour cells. Animal experiments showed that p(SAPBA-co-NVCL) nanoparticles stably lowered blood sugar within 12 h. Moreover, they did not cause toxic damage to the tissue; however, there was a small amount of bleeding at the injection site. In conclusion, our results suggested that p(SAPBA-co-NVCL) nanoparticles are safe and can be used for the subcutaneous injection of insulin or other hypoglycaemic proteins.

Preparation of Polylactic Acid/Glycolic Acid Copolymer Nanoparticles and Its Effect in the Treatment of Diabetes

Insulin (INS) is easily degraded when administered orally and loading it into polylactic acid/glycolic acid (PLGA) polymer nanoparticles can enhance the efficacy of the drug. The W/O/W double emulsion solvent volatilization method was adopted to prepare INS-loaded PLGA nanoparticles. The preparation formula of nanoparticles was determined according to the type, concentration, and PLGA concentration of the emulsifier. Then, the morphology, particle size, and drug encapsulation efficiency of nanoparticles were characterized. Phosphate buffered solution (PBS) with pH = 7.4 was utilized as the release medium, and the prepared nanoparticles were analyzed for in vitro release performance. In addition, the rat diabetes model was constructed, and subcutaneous injection of nanoparticle in vitro release solution was performed to observe its hypoglycemic effect, which was used for the treatment of diabetic patients. Patients were rolled into experimental group and control group. The changes of the patients’ HbA1c, blood lipids (total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C)), C peptide, and aminopeptidase N (APN) were observed before and after treatment. Through the test, the appearance of the prepared nanoparticles was round, the average particle size was 416.7 nm, and the INS encapsulation efficiency was (36.82±2.26)%. After 36 h, the cumulative release of INS reached (60.58 ±1.45)%, and then the release rate gradually slowed down. The drug release tended to be balanced after 72 h, and the best hypoglycemic effect was achieved after subcutaneous administration 3 h (P < 0.01). The blood glucose level of the rat diabetes model was greatly decreased after 3 h injection of 36.8 IU/kg PLGA polymer nanoparticles (P < 0.05), and the blood glucose dropped to the lowest at 8 h (P < 0.01), which was only (38.8 ± 3.72)% of the initial blood glucose. HbA1C of diabetic patients increased remarkably after treatment (P < 0.05), TG, TC, and LDL-C in blood lipids decreased, and HDL-C increased, without statistically considerable differences (P > 0.05). The serum APN level increased greatly (P < 0.01). In short, the prepared PLGA polymer nanoparticles can effectively reduce blood glucose, help diabetic patients to relieve the toxicity of high glucose in the body, and improve the secretion function of INS.

Preparation of snail cyst and PEG-4000 composite carriers via PEGylation for oral delivery of insulin: An in vitro and in vivo evaluation

Purpose: To develop PEGylated mucin as a carrier system for oral insulin delivery.
 Methods: Varied ratios of snail cyst were molecularly modified with polyethylene glycol 4000 (PEG 4000). Briefly, In each case, 20 g quantities of snail cyst and PEG 4000 were separately dispersed in distilled water, stirred and allowed to stand for 24 h to produce a homogeneous dispersion and clear solution, respectively. The solution of PEG was added to the snail cyst dispersion, stirred and allowed 12 h for molecular interaction. The mixture was added to a 250-mL beaker containing 100 mL of light liquid paraffin. The microparticles were obtained after stirring and removing the paraffin using chilled acetone. The obtained PEGylated mucin matrices, which were subsequently loaded with insulin using a diffusion method, characterized for particles size, drug loading, encapsulation efficiency, in vitro drug release and evaluated for oral application in diabetic rats.
 Results: The polymer hybrids improved insulin encapsulation efficiency (max 82.3 %), gave. polydispersity indices that ranged from 0.11 ± 0.1 to 0.24 ± 0.2, zeta potential values between 28 ± 0.3 and 38 ± 1.1 mV. Insulin release was highest (68 % in 6 h) for batch C and was sustained for 10 h in simulated intestinal fluid. The optimized batch (C-5) showed higher hypoglycaemic activity (56.5 %) than control (0.5 %) in diabetic rats.
 Conclusion: The results suggest that PEGylated mucin can potentially be developed as a platform for oral insulin delivery