Fabrication and optimization of itraconazole-loaded zein-based nanoparticles in coated capsules as a promising colon-targeting approach pursuing opportunistic fungal infections

Drug Delivery and Translational Research - Tập 13 Số 12 - Trang 2982-3002 - 2023
Shery Adel1, Rania Samir Fahmy1, Ibrahim Elsayed2, M. I. Mohamed2, Reem R. Ibrahim3
1Department of Pharmaceutics, Faculty of Pharmacy, Ahram Canadian University, 6th of October City, Egypt
2Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Cairo University, Kasr El-Aini Street, Cairo, 11562, Egypt
3Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmacy, Helwan University, Ain Helwan, Egypt

Tóm tắt

AbstractItraconazole (ITZ), a broad-spectrum antifungal drug, was formulated into colon-targeting system aiming to treat opportunistic colonic fungal infections that commonly infect chronic inflammatory bowel diseases (IBD) patients due to immunosuppressive therapy. Antisolvent precipitation technique was employed to formulate ITZ-loaded zein nanoparticles (ITZ-ZNPs) using various zein: drug and aqueous:organic phase ratios. Central composite face-centered design (CCFD) was used for statistical analysis and optimization. The optimized formulation was composed of 5.5:1 zein:drug ratio and 9.5:1 aqueous:organic phase ratio with its observed particle size, polydispersity index, zeta potential, and entrapment efficiency of 208 ± 4.29 nm, 0.35 ± 0.04, 35.7 ± 1.65 mV, and 66.78 ± 3.89%, respectively. ITZ-ZNPs were imaged by TEM that revealed spherical core–shell structure, and DSC proved ITZ transformation from crystalline to amorphous form. FT-IR showed coupling of zein NH group with ITZ carbonyl group without affecting ITZ antifungal activity as confirmed by antifungal activity test that showed enhanced activity of ITZ-ZNPs over the pure drug. Histopathological examination and cytotoxicity tests ensured biosafety and tolerance of ITZ-ZNPs to the colon tissue. The optimized formulation was then loaded into Eudragit S100-coated capsules and both in vitro release and in vivo X-ray imaging confirmed the success of such coated capsules in protecting ITZ from the release in stomach and intestine while targeting ITZ to the colon. The study proved that ITZ-ZNPs is promising and safe nanoparticulate system that can protect ITZ throughout the GIT and targeting its release to the colon with effectual focused local action for the treatment of colon fungal infections. Graphical Abstract

Từ khóa


Tài liệu tham khảo

Manser CN, Maillard MH, Rogler G, Schreiner P, Rieder F, Bühler S. Vaccination in patients with inflammatory bowel diseases. Digestion. 2020;101(Suppl1):58–68.

Jansson-Knodell CL, Harris CE, Loftus EV, Walker RC, Enzler MJ, Virk A. Histoplasmosis in inflammatory bowel disease with tumor necrosis factor-alpha inhibitors: safe to continue biologics? Dig Dis Sci. 2021;66:190–8.

Praneenararat S. Fungal infection of the colon. Clin Exp Gastroenterol. 2014;415–26.

Conche C, Greten FR. Fungi enter the stage of colon carcinogenesis. Immunity. 2018;49(3):384–6.

Wang T, Fan C, Yao A, Xu X, Zheng G, You Y, et al. The adaptor protein CARD9 protects against colon cancer by restricting mycobiota-mediated expansion of myeloid-derived suppressor cells. Immunity. 2018;49(3):504–14.

Cosio T, Di Prete M, Campione E. Arsenic trioxide, itraconazole, all-trans retinoic acid and nicotinamide: a proof of concept for combined treatments with hedgehog inhibitors in advanced basal cell carcinoma. Biomedicines. 2020;8(6):156.

Alhowyan AA, Altamimi MA, Kalam MA, Khan AA, Badran M, Binkhathlan Z, et al. Antifungal efficacy of Itraconazole loaded PLGA-nanoparticles stabilized by vitamin-E TPGS: in vitro and ex vivo studies. J Microbiol Methods. 2019;161:87–95.

Brandi SL, Feltoft CL, Serup J, Eldrup E. Pseudohyperaldosteroism during itraconazole treatment: a hitherto neglected clinically significant side effect. BMJ Case Reports CP. 2021;14(6): e243191.

Lu L, Chen G, Qiu Y, Li M, Liu D, Hu D, et al. Nanoparticle-based oral delivery systems for colon targeting: principles and design strategies. Science Bulletin. 2016;61(9):670–81.

Guo Y, Zong S, Pu Y, Xu B, Zhang T, Wang B. Advances in pharmaceutical strategies enhancing the efficiencies of oral colon-targeted delivery systems in inflammatory bowel disease. Molecules. 2018;23(7):1622.

Jablan J, Jug M. Development of eudragit® s100 based pH-responsive microspheres of zaleplon by spray-drying: tailoring the drug release properties. Powder Technol. 2015;283:334–43.

Naeem M, Choi M, Cao J, Lee Y, Ikram M, Yoon S, et al. Colon-targeted delivery of budesonide using dual pH- and time-dependent polymeric nanoparticles for colitis therapy. Drug Des Dev Ther. 2015;9:3789–99.

El-Hady SM, AbouGhaly MHHH, El-Ashmoony MM, Helmy HS, El-Gazayerly ON. Colon targeting of celecoxib nanomixed micelles using pulsatile drug delivery systems for the prevention of inflammatory bowel disease. Int J Pharm. 2020;576:118982.

Karp F, Turino LN, Helbling IM, Islan GA, Luna JA, Estenoz DA. In situ formed implants, based on PLGA and Eudragit Blends, for novel florfenicol controlled release formulations. J Pharm Sci. 2021;110(3):1270–8.

Bakshi HA, Quinn GA, Aljabali AAA, Hakkim FL, Farzand R, Nasef MM, et al. Exploiting the metabolism of the gut microbiome as a vehicle for targeted drug delivery to the colon. Pharmaceuticals. 2021;14(12):1–14.

Bayan MF, Bayan RF. Recent advances in mesalamine colonic delivery systems. Future Journal of Pharmaceutical Sciences. 2020;6(1):1–7.

Tran PHL, Duan W, Lee B-J, Tran TTD. Drug stabilization in the gastrointestinal tract and potential applications in the colonic delivery of oral zein-based formulations. Int J Pharm. 2019;569: 118614.

Bisharat L, Alkhatib HS, Abdelhafez A, Barqawi A, Aljaberi A, Qi S, et al. Hot melt extruded zein for controlled delivery of diclofenac sodium: effect of drug loading and medium composition. Int J Pharm. 2020;585:119503.

Raza A, Hayat U, Bilal M, Iqbal HMN, Wang J-Y. Zein-based micro-and nano-constructs and biologically therapeutic cues with multi-functionalities for oral drug delivery systems. J Drug Deliv Sci Technol. 2020;58:101818.

Contado C, Caselotto L, Mello P, Maietti A, Marvelli L, Marchetti N, et al. Design and formulation of Eudragit-coated zein/pectin nanoparticles for the colon delivery of resveratrol. Eur Food Res Technol. 2020;246:2427–41.

Waghule T, Rapalli VK, Singhvi G, Manchanda P, Hans N, Dubey SK, et al. Voriconazole loaded nanostructured lipid carriers based topical delivery system: QbD based designing, characterization, in-vitro and ex-vivo evaluation. J Drug Deliv Sci Technol. 2019;52:303–15.

Krishna KV, Wadhwa G, Alexander A, Kanojia N, Saha RN, Kukreti R, et al. Design and biological evaluation of lipoprotein-based Donepezil nanocarrier for enhanced brain uptake through oral delivery. ACS Chem Neurosci. 2019;10(9):4124–35.

Tavares WS, Tavares-Júnior AG, Otero-Espinar FJ, Martín-Pastor M, Sousa FFO. Design of ellagic acid-loaded chitosan/zein films for wound bandaging. J Drug Deliv Sci Technol. 2020;59:101903.

Ramalho MJ, Bravo M, Loureiro JA, Lima J, Pereira MC. Transferrin-modified nanoparticles for targeted delivery of Asiatic acid to glioblastoma cells. Life Sci. 2022;296:120435.

Jiang Y, Zhu Y, Li F, Du J, Huang Q, Sun-Waterhouse D, et al. Antioxidative pectin from hawthorn wine pomace stabilizes and protects Pickering emulsions via forming zein-pectin gel-like shell structure. Int J Biol Macromol. 2020;151:193–203.

Gagliardi A, Voci S, Salvatici MC, Fresta M, Cosco D. Brij-stabilized zein nanoparticles as potential drug carriers. Colloids Surf, B. 2021;201:111647.

Abd-Elsalam WH, Ibrahim RR. Span 80/TPGS modified lipid-coated chitosan nanocomplexes of acyclovir as a topical delivery system for viral skin infections. Int J Pharm. 2021;609:121214.

Huang S, Yu X, Yang L, Song F, Chen G, Lv Z, et al. The efficacy of nimodipine drug delivery using mPEG-PLA micelles and mPEG-PLA/TPGS mixed micelles. Eur J Pharm Sci. 2014;63:187–98.

Ling X, Huang Z, Wang J, Xie J, Feng M, Chen Y, et al. Development of an itraconazole encapsulated polymeric nanoparticle platform for effective antifungal therapy. J Mater Chem B. 2016;4(10):1787–96.

Rao Q, Qiu Z, Huang D, Lu T, Zhang ZJ, Luo D, et al. Enhancement of the apparent solubility and bioavailability of tadalafil nanoparticles via antisolvent precipitation. Eur J Pharm Sci. 2019;128:222–31.

Ahuja M, Verma P, Bhatia M. Preparation and evaluation of chitosan–itraconazole co-precipitated nanosuspension for ocular delivery. J Exp Nanosci. 2015;10(3):209–21.

Sayed S, Elsayed I, Ismail MM. Optimization of β-cyclodextrin consolidated micellar dispersion for promoting the transcorneal permeation of a practically insoluble drug. Int J Pharm. 2018;549(1–2):249–60.

Helmy AM, Elsabahy M, Abd-Elkareem M, Ibrahim EA, Soliman GM. High-Payload chitosan microparticles for the colonic delivery of quercetin: development and in-vivo evaluation in a rabbit colitis model. J Drug Deliv Sci Technol. 2020;58:101832.

Pokharkar V, Suryawanshi S, Dhapte-Pawar V. Exploring micellar-based polymeric systems for effective nose-to-brain drug delivery as potential neurotherapeutics. Drug Deliv Transl Res. 2020;10(4):1019–31.

Ahmed S, Kassem MA, Sayed S. Co-polymer mixed micelles enhanced transdermal transport of Lornoxicam: in vitro characterization, and in vivo assessment of anti-inflammatory effect and antinociceptive activity. J Drug Deliv Sci Technol. 2021;62:102365.

McCartney F, Rosa M, Brayden DJ. Evaluation of sucrose laurate as an intestinal permeation enhancer for macromolecules: ex vivo and in vivo studies. Pharmaceutics. 2019;11(11):1–22.

Lim SM, Agatonovic-Kustrin S, Lim FT, Ramasamy K. High-performance thin layer chromatography-based phytochemical and bioactivity characterisation of anticancer endophytic fungal extracts derived from marine plants. J Pharm Biomed Anal. 2021;193:113702.

Srivastava S, Dewangan J, Mishra S, Divakar A, Chaturvedi S. Phytomedicine Piperine and Celecoxib synergistically inhibit colon cancer cell proliferation via modulating Wnt / β -catenin signaling pathway. 2021;84:153484.

Voigt W. Sulforhodamine B assay and chemosensitivity. Humana Press. 2005;110:39–48.

Afrashi M, Nasari M, Semnani D, Dehghan P, Maheronnaghsh M. Comparison of the antifungal activity of fluconazole- and ketoconazole-loaded PCL/PVP nanofibrous mat. Bull Mater Sci. 2021;44(2):166.

Broesder A, Berends JME, Scheepers SM, Nguyen DN, Frijlink HW, Hinrichs WLJ. Ileo-colon targeting of the poorly water-soluble drug celecoxib using a ph-dependent coating in combination with self-emulsifying drug delivery or solid dispersion systems. Pharmaceutics. 2021;13(5):731.

Ameeduzzafar, Qumber M, Alruwaili NK, Bukhari SNA, Alharbi KS, Imam SS, et al. BBD-based development of itraconazole loaded nanostructured lipid carrier for topical delivery: in vitro evaluation and antimicrobial assessment. J Pharm Innov. 2021;16(1):85–98.

Chickpetty SM, Raga BV. Formulation, in vitro drug release and in vivo human X-ray investigation of polysaccharide based drug delivery systems for targeting 5-fluorouracil to the colon. Braz J Pharm Sci. 2013;49(2):263–73.

Tung NT, Nguyen CH, Nguyen VD, Nguyen THT, Nguyen VL, Tran CS, et al. Formulation and in vivo imaging evaluation of colonic targeting tablets prepared by a simple dry powder coating technique. J Pharm Investig. 2020;50(4):383–98.

Erickson DP, Ozturk OK, Selling G, Chen F, Campanella OH, Hamaker BR. Corn zein undergoes conformational changes to higher β-sheet content during its self-assembly in an increasingly hydrophilic solvent. Int J Biol Macromol. 2020;157:232–9.

El-Dahmy RM, Elsayed I, Elshafeey AH, El GNAA, El-Gazayerly ON. Optimization of long circulating mixed polymeric micelles containing vinpocetine using simple lattice mixture design, in vitro and in vivo characterization. Int J Pharm. 2014;477(1):39–46.

Abd-Elsalam WH, El-Zahaby SA, Al-Mahallawi AM. Formulation and in vivo assessment of terconazole-loaded polymeric mixed micelles enriched with Cremophor EL as dual functioning mediator for augmenting physical stability and skin delivery. Drug Deliv. 2018;25(1):484–92.

Bisharat L, Berardi A, Perinelli DR, Bonacucina G, Casettari L, Cespi M, et al. Aggregation of zein in aqueous ethanol dispersions: effect on cast film properties. Int J Biol Macromol. 2018;106:360–8.

Nunes R, Baião A, Monteiro D, das Neves J, Sarmento B. Zein nanoparticles as low-cost, safe, and effective carriers to improve the oral bioavailability of resveratrol. Drug Deliv Transl Res. 2020;10(3):826–37.

Wang L, Zhang Y. Heat-induced self-assembly of zein nanoparticles: fabrication, stabilization and potential application as oral drug delivery. Food Hydrocoll. 2019;90:403–12.

Li F, Chen Y, Liu S, Qi J, Wang W, Wang C, et al. Size-controlled fabrication of zein nano/microparticles by modified anti-solvent precipitation with/without sodium caseinate. Int J Nanomed. 2017;12:8197–209.

Yu X, Afreen S, Kong Q, Wang J. Study on self-assembled morphology and structure regulation of α-zein in ethanol–water mixtures. Langmuir. 2020;36(40):11975–84.

Magne TM, Helal-Neto E, Correa LB, Alencar LMR, Piperni SG, Iram SH, et al. Rheumatoid arthritis treatment using hydroxychloroquine and methotrexate co-loaded nanomicelles: In vivo results. Colloids Surf, B. 2021;206:111952.

Aranda-Barradas ME, Trejo-López SE, Del Real A, Álvarez-Almazán S, Méndez-Albores A, García-Tovar CG, et al. Effect of molecular weight of chitosan on the physicochemical, morphological, and biological properties of polyplex nanoparticles intended for gene delivery. Carbohydrate Polymer Technologies and Applications. 2022;4:100228.

Gajera BY, Shah DA, Dave RH. Development of an amorphous nanosuspension by sonoprecipitation-formulation and process optimization using design of experiment methodology. Int J Pharm. 2019;559:348–59.

Danaei M, Dehghankhold M, Ataei S, Hasanzadeh Davarani F, Javanmard R, Dokhani A, et al. Impact of particle size and polydispersity index on the clinical applications of lipidic nanocarrier systems. Pharmaceutics. 2018;10(2):1–17.

Vogel R, Pal AK, Jambhrunkar S, Patel P, Thakur SS, Reátegui E, et al. High-resolution single particle zeta potential characterisation of biological nanoparticles using tunable resistive pulse sensing. Sci Rep. 2017;7(1):17479.

Joseph E, Singhvi G. Multifunctional nanocrystals for cancer therapy: a potential nanocarrier. In: Grumezescu AMBT-N for DD and T, editor. William Andrew Publishing; 2019:91–116.

Baidya D, Kushwaha J, Mahadik K, Patil S. Chrysin-loaded folate conjugated PF127-F68 mixed micelles with enhanced oral bioavailability and anticancer activity against human breast cancer cells. Drug Dev Ind Pharm. 2019;45(5):852–60.

Yousry C, Elkheshen SA, El-Laithy HM, Essam T, Fahmy RH. Studying the influence of formulation and process variables on Vancomycin-loaded polymeric nanoparticles as potential carrier for enhanced ophthalmic delivery. Eur J Pharm Sci. 2017;100:142–54.

Jiang Y, Zhang C, Yuan J, Wu Y, Li F, Waterhouse GIN, et al. Exploiting the robust network structure of zein/low-acyl gellan gum nanocomplexes to create Pickering emulsion gels with favorable properties. Food Chem. 2021;349:129112.

Cai T, Xiao P, Yu N, Zhou Y, Mao J, Peng H, et al. A novel pectin from Akebia trifoliata var. australis fruit peel and its use as a wall-material to coat curcumin-loaded zein nanoparticle. Int J Biol Macromol. 2020;152:40–9.

Ye W, Zhu F, Cai Y, Wang L, Zhang G, Zhao G, et al. Improved paclitaxel delivery with PEG-b-PLA/zein nanoparticles prepared via flash nanoprecipitation. Int J Biol Macromol. 2022;221:486–95.

Araiza-Aguilar JA, Rojas-Valencia MN, Aguilar-Vera RA. Forecast generation model of municipal solid waste using multiple linear regression. Glob J Environ Sci Manag. 2020;6(1):1–14.

Cui L, Wang H, Chen W. Trajectory planning of a spatial flexible manipulator for vibration suppression. Robot Auton Syst. 2020;123:103316.

Baltes L, Costiuc L, Patachia S, Tierean M. Differential scanning calorimetry—a powerful tool for the determination of morphological features of the recycled polypropylene. J Therm Anal Calorim. 2019;138(4):2399–408.

Alves-Silva I, Sá-Barreto LCL, Lima EM, Cunha-Filho MSS. Preformulation studies of itraconazole associated with benznidazole and pharmaceutical excipients. Thermochim Acta. 2014;575:29–33.

Wang TX, Li XX, Chen L, Li L, Janaswamy S. Carriers based on zein-dextran sulfate sodium binary complex for the sustained delivery of quercetin. Front Chem. 2020;8:1–12.

Piccinni P, Tian Y, McNaughton A, Fraser J, Brown S, Jones DS, et al. Solubility parameter-based screening methods for early-stage formulation development of itraconazole amorphous solid dispersions. J Pharm Pharmacol. 2016;68(5):705–20.

Patil P, Killedar S. Formulation and characterization of gallic acid and quercetin chitosan nanoparticles for sustained release in treating colorectal cancer. J Drug Deliv Sci Technol. 2021;63:102523.

Nakarani M, Misra AK, Patel JK, Vaghani SS. Itraconazole nanosuspension for oral delivery: formulation, characterization and in vitro comparison with marketed formulation. Daru: journal of Faculty of Pharmacy, Tehran University of Medical Sciences. 2010;18(2):84.

Lim WM, Rajinikanth PS, Mallikarjun C, Kang YB. Formulation and delivery of itraconazole to the brain using a nanolipid carrier system. Int J Nanomed. 2014;9:2117.

Chaunier L, Viau L, Falourd X, Lourdin D, Leroy E. A drug delivery system obtained by hot-melt processing of zein plasticized by a pharmaceutically active ionic liquid. J Mater Chem B. 2020;8(21):4672–9.

Gough CR, Bessette K, Xue Y, Mou X, Hu X. Air-jet spun corn zein nanofibers and thin films with topical drug for medical applications. Int J Mol Sci. 2020;21(16):5780.

Ahammed S, Liu F, Khin MN, Yokoyama WH, Zhong F. Improvement of the water resistance and ductility of gelatin film by zein. Food Hydrocoll. 2020;105:105804.

R I. Formulation and evaluation of herbal cream for arthritis. n: Int J Res Appl Sci Eng Technol. 2020;8(7):69–76.

Ali S, Khatri Z, Oh KW, Kim IS, Kim SH. Zein/cellulose acetate hybrid nanofibers: electrospinning and characterization. Macromol Res. 2014;22(9):971–7.

Bancila S, Ciobanu C-I, Murariu M, Drochioiu G. Ultrasound-assisted zein extraction and determination in some patented maize flours. Rev Roum Chim. 2016;61(10):725–31.

Medeiros GB, de Souza PR, Retamiro KM, Nakamura CV, Muniz EC, Corradini E. Experimental design to evaluate properties of electrospun fibers of zein/poly (ethylene oxide) for biomaterial applications. J Appl Polym Sci. 2021;138(36):50898.

Liu ZP, Zhang YY, Yu DG, Wu D, Li HL. Fabrication of sustained-release zein nanoparticles via modified coaxial electrospraying. Chem Eng J. 2018;334:807–16.

Lu Z, Hammond GB, Xu B. Revisiting the role of acids and hydrogen bond acceptors in enamine formation. Org Biomol Chem. 2020;18(35):6849–52.

Bauer L, Ferla S, Head SA, Bhat S, Pasunooti KK, Shi WQ, et al. Structure-activity relationship study of itraconazole, a broad-range inhibitor of picornavirus replication that targets oxysterol-binding protein (OSBP). Antiviral Res. 2018;156:55–63.

Lai LF, Guo HX. Preparation of new 5-fluorouracil-loaded zein nanoparticles for liver targeting. Int J Pharm. 2011;404(1–2):317–23.

Oh YK, Flanagan DR. Diffusional properties of zein membranes and matrices. Drug Dev Ind Pharm. 2010;36(5):497–507.

Oh YK, Flanagan DR. Swelling and permeability characteristics of zein membranes. PDA J Pharm Sci Technol. 2003;57(3):208–17.

Karthikeyan K, Vijayalakshmi E, Korrapati PS. Selective interactions of zein microspheres with different class of drugs: an in vitro and in silico analysis. AAPS PharmSciTech. 2014;15(5):1172–80.

Wang Y, Su CP, Schulmerich M, Padua GW. Characterization of core-shell structures formed by zein. Food Hydrocoll. 2013;30(2):487–94.

Amiry AF, Kigata T, Shibata H. Wall thickness and mucous cell distribution in the rabbit large intestine. J Vet Med Sci. 2019;81(7):990–9.

Wu Y, Luo Y, Wang Q. Antioxidant and antimicrobial properties of essential oils encapsulated in zein nanoparticles prepared by liquid–liquid dispersion method. LWT Food Sci Technol. 2012;48(2):283–90.

Sufi SA, Hoda M, Pajaniradje S, Mukherjee V, Coumar SM, Rajagopalan R. Enhanced drug retention, sustained release, and anti-cancer potential of curcumin and indole-curcumin analog-loaded polysorbate 80-stabilizied PLGA nanoparticles in colon cancer cell line SW480. Int J Pharm. 2020;588:119738.

Umerska A, Paluch KJ, Santos-Martinez MJ, Corrigan OI, Medina C, Tajber L. Freeze drying of polyelectrolyte complex nanoparticles: effect of nanoparticle composition and cryoprotectant selection. Int J Pharm. 2018;552(1–2):27–38.

Wong CY, Al-Salami H, Dass CR. Lyophilisation improves bioactivity and stability of insulin-loaded polymeric-oligonucleotide nanoparticles for diabetes treatment. AAPS PharmSciTech. 2020;21(3):1–20.

Zhang Y, Feng J, McManus SA, Lu HD, Ristroph KD, Cho EJ, et al. Design and solidification of fast-releasing clofazimine nanoparticles for treatment of cryptosporidiosis. Mol Pharm. 2017;14(10):3480–8.

Feng J, Zhang Y, McManus SA, Qian R, Ristroph KD, Ramachandruni H, et al. Amorphous nanoparticles by self-assembly: processing for controlled release of hydrophobic molecules. Soft Matter. 2019;15(11):2400–10.

Othman MH, Zayed GM, Ali UF, Abdellatif AAH. Colon-specific tablets containing 5-fluorouracil microsponges for colon cancer targeting. Drug Dev Ind Pharm. 2020;46(12):2081–8.

Rehman S, Ranjha NM, Shoukat H, Madni A, Ahmad F, Raza MR, et al. Fabrication, evaluation, in vivo pharmacokinetic and toxicological analysis of pH-sensitive eudragit S-100-coated hydrogel beads: a promising strategy for colon targeting. AAPS PharmSciTech. 2021;22(6):1–17.

Makhlof A, Tozuka Y, Takeuchi H. pH-Sensitive nanospheres for colon-specific drug delivery in experimentally induced colitis rat model. Eur J Pharm Biopharm. 2009;72(1):1–8.