{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,6]],"date-time":"2026-05-06T06:14:03Z","timestamp":1778048043959,"version":"3.51.4"},"reference-count":63,"publisher":"MDPI AG","issue":"5","license":[{"start":{"date-parts":[[2020,4,27]],"date-time":"2020-04-27T00:00:00Z","timestamp":1587945600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"FCT","doi-asserted-by":"publisher","award":["CESAM UIDB\/50017\/2020+UIDP\/50017\/2020"],"award-info":[{"award-number":["CESAM UIDB\/50017\/2020+UIDP\/50017\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001871","name":"FCT","doi-asserted-by":"publisher","award":["UID\/DTP\/04138\/2019"],"award-info":[{"award-number":["UID\/DTP\/04138\/2019"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"name":"DREAMS (ULHT)","award":["2020"],"award-info":[{"award-number":["2020"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Biomolecules"],"abstract":"<jats:p>Currently, insulin can only be administered through the subcutaneous route. Due to the flaws associated with this route, it is of interest to orally deliver this drug. However, insulin delivered orally has several barriers to overcome as it is degraded by the stomach\u2019s low pH, enzymatic content, and poor absorption in the gastrointestinal tract. Polymers with marine source like chitosan are commonly used in nanotechnology and drug delivery due to their biocompatibility and special features. This work focuses on the preparation and characterization of mucoadhesive insulin-loaded polymeric nanoparticles. Results showed a suitable mean size for oral administration (&lt;600 nm by dynamic laser scattering), spherical shape, encapsulation efficiency (59.8%), and high recovery yield (80.6%). Circular dichroism spectroscopy demonstrated that protein retained its secondary structure after encapsulation. Moreover, the mucoadhesive potential of the nanoparticles was assessed in silico and the results, corroborated with ex-vivo experiments, showed that using chitosan strongly increases mucoadhesion. Besides, in vitro and in vivo safety assessment of the final formulation were performed, showing no toxicity. Lastly, the insulin-loaded nanoparticles were effective in reducing diabetic rats\u2019 glycemia. Overall, the coating of insulin-loaded nanoparticles with chitosan represents a potentially safe and promising approach to protect insulin and enhance peroral delivery.<\/jats:p>","DOI":"10.3390\/biom10050675","type":"journal-article","created":{"date-parts":[[2020,4,28]],"date-time":"2020-04-28T10:30:58Z","timestamp":1588069858000},"page":"675","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":26,"title":["How Can Biomolecules Improve Mucoadhesion of Oral Insulin? A Comprehensive Insight using Ex-Vivo, In Silico, and In Vivo Models"],"prefix":"10.3390","volume":"10","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-4526-2157","authenticated-orcid":false,"given":"Mariana","family":"Amaral","sequence":"first","affiliation":[{"name":"Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal"}]},{"given":"Ana Sofia","family":"Martins","sequence":"additional","affiliation":[{"name":"Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal"}]},{"given":"Jos\u00e9","family":"Catarino","sequence":"additional","affiliation":[{"name":"Faculdade de Medicina Veterin\u00e1ria, Universidade Lus\u00f3fona de Humanidades e Tecnologias\/DNAtech Laborat\u00f3rio Veterin\u00e1rio, 1749-024 Lisboa, Portugal"}]},{"given":"Pedro","family":"Fa\u00edsca","sequence":"additional","affiliation":[{"name":"Faculdade de Medicina Veterin\u00e1ria, Universidade Lus\u00f3fona de Humanidades e Tecnologias\/DNAtech Laborat\u00f3rio Veterin\u00e1rio, 1749-024 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8640-4350","authenticated-orcid":false,"given":"Pradeep","family":"Kumar","sequence":"additional","affiliation":[{"name":"Department of Pharmacy and Pharmacology, School of Therapeutic Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg 2193, South Africa"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6499-310X","authenticated-orcid":false,"given":"Jo\u00e3o F.","family":"Pinto","sequence":"additional","affiliation":[{"name":"Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal"}]},{"given":"Rui","family":"Pinto","sequence":"additional","affiliation":[{"name":"Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal"},{"name":"JCS. Dr. Joaquim Chaves, Laborat\u00f3rio de An\u00e1lises Cl\u00ednicas, 1495-068 Miraflores-Alg\u00e9s, Portugal"}]},{"given":"Isabel","family":"Correia","sequence":"additional","affiliation":[{"name":"Centro de Qu\u00edmica Estrutural, Departamento de Engenharia Qu\u00edmica, Instituto Superior T\u00e9cnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7439-5912","authenticated-orcid":false,"given":"Lia","family":"Ascens\u00e3o","sequence":"additional","affiliation":[{"name":"Centro de Estudos do Ambiente e do Mar (CESAM), Faculdade de Ci\u00eancias, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5990-4539","authenticated-orcid":false,"given":"Ricardo A.","family":"Afonso","sequence":"additional","affiliation":[{"name":"CEDOC, NOVA Medical School\/Faculdade de Ci\u00eancias M\u00e9dicas (NMS\/FCM), Universidade Nova de Lisboa, 1150-082 Lisboa, Portugal"},{"name":"Ci\u00eancias Funcionais e Alvos Terap\u00eauticos, NOVA Medical School, Faculdade de Ci\u00eancias M\u00e9dicas (NMS|FCM), Universidade Nova de Lisboa, 1169-056 Lisboa, Portugal"},{"name":"Departamento de F\u00edsica, Faculdade de Ci\u00eancias e Tecnologia, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6814-7226","authenticated-orcid":false,"given":"M. Manuela","family":"Gaspar","sequence":"additional","affiliation":[{"name":"Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8817-4106","authenticated-orcid":false,"given":"Ad\u00edlia J.","family":"Charmier","sequence":"additional","affiliation":[{"name":"DREAMS, Universidade Lus\u00f3fona de Humanidades e Tecnologias, Campo Grande 376, 1749-024 Lisboa, Portugal"}]},{"given":"Isabel Vit\u00f3ria","family":"Figueiredo","sequence":"additional","affiliation":[{"name":"Pharmacology &amp; Pharmaceutical Care, Faculty of Pharmacy, Universidade de Coimbra, 3000-548 Coimbra, Portugal"},{"name":"Coimbra Institute for Clinical and Biomedical Research (iCBR), University de Coimbra, 3000-370 Coimbra, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1046-4031","authenticated-orcid":false,"given":"Catarina Pinto","family":"Reis","sequence":"additional","affiliation":[{"name":"Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal"},{"name":"IBEB, Biophysics &amp; Biomedical Engineering, Faculdade de Ci\u00eancias, Universidade de Lisboa, 1749-016 Lisboa, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2020,4,27]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","unstructured":"American Diabetes Association (2014). Diagnosis and Classification of Diabetes Mellitus. Diabetes Care, 37, 887.","DOI":"10.2337\/dc14-S081"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1016\/S0140-6736(13)60591-7","article-title":"Type 1 diabetes","volume":"383","author":"Atkinson","year":"2014","journal-title":"Lancet"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"2254","DOI":"10.1001\/jama.289.17.2254","article-title":"Outpatient Insulin Therapy in Type 1 and Type 2 Diabetes Mellitus","volume":"289","author":"DeWitt","year":"2003","journal-title":"JAMA"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"622","DOI":"10.1016\/j.jpeds.2007.10.006","article-title":"Dermatological Complications of Continuous Subcutaneous Insulin Infusion in Children and Adolescents","volume":"152","author":"Conwell","year":"2008","journal-title":"J. Pediatr."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"145","DOI":"10.1089\/dia.2013.0192","article-title":"Nonmetabolic Complications of Continuous Subcutaneous Insulin Infusion: A Patient Survey","volume":"16","author":"Pickup","year":"2014","journal-title":"Diabetes Technol. Ther."},{"key":"ref_6","unstructured":"Elsayed, A.M. (2012). Oral Delivery of Insulin: Novel Approaches. Recent Advances in Novel Drug Carrier Systems, InTech."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"74","DOI":"10.1186\/s12951-015-0136-y","article-title":"Nanoparticle based insulin delivery system: The next generation efficient therapy for Type 1 diabetes","volume":"13","author":"Sharma","year":"2015","journal-title":"J. Nanobiotechnol."},{"key":"ref_8","doi-asserted-by":"crossref","unstructured":"El\u00e7io\u011flu, H.K., and Sezer, A.D. (2014). Nanoparticle Insulin Drug Delivery\u2014Applications and New Aspects. Application of Nanotechnology in Drug Delivery, InTech.","DOI":"10.5772\/58538"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"5290","DOI":"10.1002\/jps.21347","article-title":"Nanoparticulate biopolymers deliver insulin orally eliciting pharmacological response","volume":"97","author":"Reis","year":"2008","journal-title":"J. Pharm. Sci."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"45","DOI":"10.1517\/17425247.5.1.45","article-title":"Nanoparticle strategies for the oral delivery of insulin","volume":"5","author":"Reis","year":"2008","journal-title":"Exp. Opin. Drug Deliv."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"163","DOI":"10.1016\/j.jconrel.2006.10.023","article-title":"Oral delivery of insulin associated to polymeric nanoparticles in diabetic rats","volume":"117","author":"Maincent","year":"2007","journal-title":"J. Control. Release"},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"520","DOI":"10.1177\/193229681300700228","article-title":"Oral Insulin Delivery: How Far are We?","volume":"7","author":"Fonte","year":"2013","journal-title":"J. Diabetes Sci. Technol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"619","DOI":"10.1021\/ar200234q","article-title":"pH-Responsive Nanoparticles Shelled with Chitosan for Oral Delivery of Insulin: From Mechanism to Therapeutic Applications","volume":"45","author":"Sung","year":"2012","journal-title":"Acc. Chem. Res"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"9826","DOI":"10.1016\/j.biomaterials.2011.08.087","article-title":"A review of the prospects for polymeric nanoparticle platforms in oral insulin delivery","volume":"32","author":"Chen","year":"2011","journal-title":"Biomaterials"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"249","DOI":"10.1016\/S0169-409X(98)00075-1","article-title":"Oral insulin delivery1Abbreviations: GI, gastrointestinal; IDDM, insulin-dependent diabetes mellitus; IU, international units; NIDDM, non-insulin-dependent diabetes mellitus; PIN, phase inversion nanoencapsulation; ZOT, zona occludens toxin.1","volume":"35","author":"Carino","year":"1999","journal-title":"Adv. Drug Deliv. Rev."},{"key":"ref_16","first-page":"743","article-title":"Oral insulin delivery by means of solid lipid nanoparticles","volume":"2","author":"Sarmento","year":"2007","journal-title":"Int. J. Nanomed."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"205","DOI":"10.1080\/17435390802398309","article-title":"Toxicological assessment of orally delivered nanoparticulate insulin","volume":"2","author":"Reis","year":"2008","journal-title":"Nanotoxicology"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"242","DOI":"10.1016\/j.jconrel.2006.05.013","article-title":"Biodegradable nanoparticles loaded with insulin\u2013phospholipid complex for oral delivery: Preparation, in vitro characterization and in vivo evaluation\u2019","volume":"114","author":"Cui","year":"2006","journal-title":"J. Control. Release"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"351","DOI":"10.1016\/j.jfda.2015.01.007","article-title":"Application of polymeric nanoparticles and micelles in insulin oral delivery","volume":"23","author":"Alai","year":"2015","journal-title":"J. Food Drug Anal."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"307","DOI":"10.1111\/cbdd.12318","article-title":"Synthesis, Characterization, and In vitro Studies of PLGA-PEG Nanoparticles for Oral Insulin Delivery Synthesis, Characterization, and In vitro Studies of PLGA\u2014PEG Nanoparticles for Oral Insulin Delivery","volume":"84","author":"Hosseininasab","year":"2014","journal-title":"Chem. Biol. Drug Des."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"29","DOI":"10.1016\/j.jconrel.2016.04.012","article-title":"Dual chitosan\/albumin-coated alginate\/dextran sulfate nanoparticles for enhanced oral delivery of insulin","volume":"232","author":"Lopes","year":"2016","journal-title":"J. Control. Release"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"127","DOI":"10.1080\/10717540801905165","article-title":"Polyelectrolyte Biomaterial Interactions Provide Nanoparticulate Carrier for Oral Insulin Delivery","volume":"15","author":"Reis","year":"2008","journal-title":"Drug Deliv."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Mohammed, M.A., Syeda, J.T.M., Wasan, K.M., and Wasan, E.K. (2017). An Overview of Chitosan Nanoparticles and Its Application in Non-Parenteral Drug Delivery. Pharmaceutics, 9.","DOI":"10.3390\/pharmaceutics9040053"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"3066","DOI":"10.1002\/adv.22077","article-title":"Surface modification of PLGA nanoparticles using chitosan: Effect of molecular weight, concentration, and degree of deacetylation","volume":"37","year":"2018","journal-title":"Adv. Polym. Technol."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"602","DOI":"10.1016\/j.ijpharm.2012.07.007","article-title":"Chitosan-based mucoadhesive tablets for oral delivery of ibuprofen","volume":"436","author":"Sogias","year":"2012","journal-title":"Int. J. Pharm."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"1837","DOI":"10.1021\/bm800276d","article-title":"Why is Chitosan Mucoadhesive?","volume":"9","author":"Sogias","year":"2008","journal-title":"Biomacromolecules"},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"630","DOI":"10.1021\/bm801361f","article-title":"Adsorption of Fucoidan and Chitosan Sulfate on Chitosan Modified PET Films Monitored by QCM-D","volume":"10","author":"Indest","year":"2009","journal-title":"Biomacromolecules"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"91","DOI":"10.1111\/j.1748-1716.1993.tb09596.x","article-title":"The effects of oestrogen and progesterone on insulin sensitivity in female rats","volume":"149","author":"Kumagai","year":"1993","journal-title":"Acta Physiol. Scand."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"392","DOI":"10.1016\/j.ejps.2006.12.007","article-title":"Nanoparticulate delivery system for insulin: Design, characterization and in vitro\/in vivo bioactivity","volume":"30","author":"Reis","year":"2007","journal-title":"Eur. J. Pharm. Sci."},{"key":"ref_30","first-page":"111","article-title":"Optimization of the encapsulation efficiency of a novel oral insulin delivery nanosystem","volume":"11","author":"Correia","year":"2014","journal-title":"Biomed. Biopharm. Res."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"1075","DOI":"10.1016\/0022-2836(92)90106-T","article-title":"Solution conformations and aggregational properties of synthetic amyloid \u03b2-peptides of Alzheimer\u2019s disease","volume":"225","author":"Barrow","year":"1992","journal-title":"J. Mol. Biol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"4108","DOI":"10.1021\/bi00838a031","article-title":"Computed circular dichroism spectra for the evaluation of protein conformation","volume":"8","author":"Greenfield","year":"1969","journal-title":"Biochemistry"},{"key":"ref_33","unstructured":"Reis, A.C.B.P. (2007). Encapsula\u00e7\u00e3o de F\u00e1rmacos Pept\u00eddicos pelo M\u00e9todo de Emulsifica\u00e7\u00e3o\/gelifica\u00e7\u00e3o Interna, Universidade de Coimbra."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"591751","DOI":"10.1155\/2013\/591751","article-title":"Development and Evaluation of Insulin Incorporated Nanoparticles for Oral Administration","volume":"2013","author":"Prusty","year":"2013","journal-title":"ISRN Nanotechnol."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"325","DOI":"10.1016\/j.ejpb.2008.09.002","article-title":"Mucoadhesion and drug permeability of free mixed films of pectin and chitosan : An in vitro and ex vivo study","volume":"71","author":"Hagesaether","year":"2009","journal-title":"Eur. J. Pharm. Biopharm."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"2384","DOI":"10.1007\/s11095-015-1631-4","article-title":"In Vitro, Ex Vivo and In Silico Mechanistic Elucidation of the Performance of an Optimized Porosity-Controlled Multi-Elemental Transbuccal System","volume":"32","author":"Adeleke","year":"2015","journal-title":"Pharm. Res."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"222","DOI":"10.1002\/btm2.10105","article-title":"In silico analytico-mathematical interpretation of biopolymeric assemblies: Quantification of energy surfaces and molecular attributes via atomistic simulations","volume":"3","author":"Kumar","year":"2018","journal-title":"Bioeng. Transl. Med."},{"key":"ref_38","first-page":"2207","article-title":"Novel PLGA-based nanoparticles for the oral delivery of insulin Novel PLGA-based nanoparticles for the oral delivery of insulin","volume":"10","author":"Malathi","year":"2016","journal-title":"Int. J. Nanomed."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"122","DOI":"10.1016\/j.colsurfa.2014.12.008","article-title":"Preparation and characterization of nickel chelating functionalized poly (lactic-co-glycolic acid) microspheres","volume":"468","author":"Rescignano","year":"2015","journal-title":"Colloids Surf. A Physicochem. Eng. Asp."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"726","DOI":"10.1590\/S0100-40422003000500017","article-title":"Caracteriza\u00e7\u00e3o e estabilidade f\u00edsico-qu\u00edmica de sistemas polim\u00e9ricos nanoparticulados para administra\u00e7\u00e3o de f\u00e1rmacos","volume":"26","author":"Schaffazick","year":"2003","journal-title":"Quim. Nova"},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Van Meerloo, J., Kaspers, G.J.L., and Cloos, J. (2011). Cell Sensitivity Assays: The MTT Assay, Humana Press.","DOI":"10.1007\/978-1-61779-080-5_20"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"547","DOI":"10.1515\/BC.2007.061","article-title":"Clinical chemistry reference database for Wistar rats and C57\/BL6 mice","volume":"388","author":"Boehm","year":"2007","journal-title":"Biol. Chem."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"555","DOI":"10.1016\/j.ijpharm.2017.09.018","article-title":"Physicochemical properties of mucus and their impact on transmucosal drug delivery","volume":"532","author":"Leal","year":"2017","journal-title":"Int. J. Pharm."},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"190","DOI":"10.1208\/s12249-019-1325-z","article-title":"Nanoparticles: Oral Delivery for Protein and Peptide Drugs","volume":"20","author":"Cao","year":"2019","journal-title":"AAPS PharmSciTech"},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"640","DOI":"10.1016\/j.ijbiomac.2014.08.040","article-title":"pH-sensitive chitosan\/alginate core-shell nanoparticles for efficient and safe oral insulin delivery","volume":"72","author":"Mukhopadhyay","year":"2015","journal-title":"Int. J. Biol. Macromol."},{"key":"ref_46","doi-asserted-by":"crossref","unstructured":"Brange, J., and Langkj\u0153r, L. (1993). Insulin Structure and Stability, Springer.","DOI":"10.1007\/978-1-4899-1236-7_11"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"349","DOI":"10.2174\/1389203003381315","article-title":"The Use of Circular Dichroism in the Investigation of Protein Structure and Function","volume":"1","author":"Kelly","year":"2000","journal-title":"Curr. Protein Pept. Sci."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"323","DOI":"10.1016\/S1016-8478(23)13808-8","article-title":"Role of disulfide bonds in the structure and activity of human insulin","volume":"16","author":"Chang","year":"2003","journal-title":"Mol. Cells"},{"key":"ref_49","first-page":"23","article-title":"Nanoemulsions coated with alginate\/chitosan as oral insulin delivery systems: Preparation, characterization, and hypoglycemic effect in rats","volume":"8","author":"Li","year":"2013","journal-title":"Int. J. Nanomed."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"430","DOI":"10.3109\/02652048.2011.576786","article-title":"Insulin-loaded PLGA microparticles: Flow focusing versus double emulsion\/solvent evaporation","volume":"28","author":"Holgado","year":"2011","journal-title":"J. Microencapsul."},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"198","DOI":"10.1016\/j.ijpharm.2009.07.023","article-title":"Improved cellular uptake of chitosan-modified PLGA nanospheres by A549 cell","volume":"382","author":"Tahara","year":"2009","journal-title":"Int. J. Pharm."},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"380","DOI":"10.1089\/ten.teb.2012.0443","article-title":"Physicochemical Properties and Applications of Poly(lactic-co-glycolic acid) for Use in Bone Regeneration","volume":"19","author":"Lanao","year":"2013","journal-title":"Tissue Eng. Part B Rev."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"632","DOI":"10.1016\/j.ejps.2012.01.002","article-title":"Preparation and characterization of insulin-loaded bioadhesive PLGA nanoparticles for oral administration","volume":"45","author":"Zhang","year":"2012","journal-title":"Eur. J. Pharm. Sci."},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"271","DOI":"10.1016\/j.ijpharm.2015.07.044","article-title":"Polymeric nanoparticles modified with fatty acids encapsulating betamethasone for anti-inflammatory treatment","volume":"493","author":"Silva","year":"2015","journal-title":"Int. J. Pharm."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"2084","DOI":"10.1016\/j.clinthera.2004.12.001","article-title":"Comparison of pharmacokinetic and pharmacodynamic properties of single-dose oral insulin spray and subcutaneous insulin injection in healthy subjects using the euglycemic clamp technique","volume":"26","author":"Cernea","year":"2004","journal-title":"Clin. Ther."},{"key":"ref_56","unstructured":"Kidron, M., Raz, I., Wolfensberger, M., Schwob, H., and Schruefer, C. (2008, January 6\u201310). Pharmacokinetics (PK) and Pharmacodynamics (PD) of Oral Insulin in Healthy Subjects. Proceedings of the ADA 68th Annual Scientific Sessions, San Francisco, CA, USA."},{"key":"ref_57","doi-asserted-by":"crossref","first-page":"1253","DOI":"10.1021\/bm900035u","article-title":"Preparation, Characterization, and Oral Delivery of Insulin Loaded Carboxylated Chitosan Grafted Poly(methyl methacrylate) Nanoparticles","volume":"10","author":"Cui","year":"2009","journal-title":"Biomacromolecules"},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"627","DOI":"10.1016\/j.ijpharm.2014.07.049","article-title":"Preparation and characterization of PEG-coated silica nanoparticles for oral insulin delivery","volume":"473","author":"Andreani","year":"2014","journal-title":"Int. J. Pharm."},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"341","DOI":"10.1016\/j.ijpharm.2012.06.054","article-title":"Thiolated Eudragit nanoparticles for oral insulin delivery: Preparation, characterization and in vivo evaluation","volume":"436","author":"Zhang","year":"2012","journal-title":"Int. J. Pharm."},{"key":"ref_60","doi-asserted-by":"crossref","unstructured":"Fonte, P., Andrade, F., Ara\u00fajo, F., Andrade, C., Neves, J.D., and Sarmento, B. (2012). Chitosan-Coated Solid Lipid Nanoparticles for Insulin Delivery, Academic Press.","DOI":"10.1016\/B978-0-12-391860-4.00015-X"},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"445","DOI":"10.1016\/j.ejps.2010.12.007","article-title":"Design and evaluation of novel pH-sensitive chitosan nanoparticles for oral insulin delivery","volume":"42","author":"Makhlof","year":"2011","journal-title":"Eur. J. Pharm. Sci."},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"299","DOI":"10.1007\/s13346-011-0023-5","article-title":"Chitosan-coated solid lipid nanoparticles enhance the oral absorption of insulin","volume":"1","author":"Fonte","year":"2011","journal-title":"Drug Deliv. Transl. Res."},{"key":"ref_63","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1016\/j.ejpb.2010.09.016","article-title":"Preparation and evaluation of alginate\u2013chitosan microspheres for oral delivery of insulin","volume":"77","author":"Zhang","year":"2011","journal-title":"Eur. J. Pharm. Biopharm."}],"container-title":["Biomolecules"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2218-273X\/10\/5\/675\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,13]],"date-time":"2025-10-13T14:09:18Z","timestamp":1760364558000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2218-273X\/10\/5\/675"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,4,27]]},"references-count":63,"journal-issue":{"issue":"5","published-online":{"date-parts":[[2020,5]]}},"alternative-id":["biom10050675"],"URL":"https:\/\/doi.org\/10.3390\/biom10050675","relation":{},"ISSN":["2218-273X"],"issn-type":[{"value":"2218-273X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,4,27]]}}}