Abstract
Nanoemulsions are the versatile drug carriers with the combined benefits of a lipophilic carrier and nanoscale. It can be used for a range of purposes, i.e., from bioavailability enhancement to MDR modulation. In recent time it has also been investigated for its potential in drug targeting. The drug targeting through nanoemulsion can be due to the virtue of its physicochemical properties or imparted by surface modification. Nanoemulsions can be used for local targeting such as skin, lymphatic system, and lungs. Such targeting is due to size, surface charge, or lipophilicity of nanoemulsion but sometimes novel targeting ligands are also employed. The systemic targeting by nanoemulsions largely exploits EPR mechanism. However, ligand based targeting and in more recent targeting using physical stimuli is also getting popular. Apart from drug delivery, targeted nanoemulsions can also be unveiled for diagnostic purposes such as carrying radio contrast media for longer time.
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References
Solans C, Izquierdo P, Nolla J, Azemar N, Garcia-Celma MJ (2005) Nano-emulsions. Curr Opin Colloid Interface Sci 10:102–110
Anton N, Vandamme TF (2011) Nano-emulsions and micro-emulsions: clarifications of the critical differences. Pharm Res 28:978–985
Lovelyn C, Attama AA (2011) Current state of nanoemulsions in drug delivery. J Biomater Nanobiotechnol 2:626–639
Tiwari SB, Amiji MM (2006) Nanoemulsion formulations for tumor-targeted delivery. In: Amiji MM (ed) Nanotechnology for cancer therapy. Taylor and Francis Group, New York, pp 723–39
Sahoo S, Labhasetwar V (2003) Nanotech approach to drug delivery and imaging. Drug Discov Today 8:1112–1120
Mehra NK, Mishra V, Jain NK (2013) Receptor-based targeting of therapeutics. Ther Deliv 4:369–394
Biasis J, ClinB LP (1987) Microemulsions: Structure and Dynamics. CRC, Boca Raton
Azeem A, Khan ZI, Aqil M, Ahmad FJ, Khar RK, Talegaonkar S (2009) Microemulsions as a surrogate carrier for dermal drug delivery. Drug Dev Ind Pharm 35:525–547
Talegaonkar S, Akhter S, Jain GK, Ahmad FJ, Khar RK, Jain N, Khan ZI (2008) Investigation of nanoemulsion system for transdermal delivery of domperidone: ex-vivo and in vivo studies. Curr Nanosci 4:381–390
Karim A, Gokhale R, Cole M, Sherman J, Yeramian P, Bryant M, Franke H (1994) HIV protease inhibitor SC-52151: a novel method of optimizing bioavailability profile via a microemulsion drug delivery system. Pharm Res 11:S368
Constantinides PP (1995) Lipid microemulsions for improving drug dissolution and oral absorption and biopharmaceutical aspects. Pharm Res 12:1561–1572
Jumaa M, Mueller BW (2002) Formulation and stability of benzodiazepines in a new lipid emulsion formulation. Pharmazie 57:740–743
Anderson BD (1999) Chemical and related factors controlling lipid solubility. Bull Tech Gatt 92:11–18
Monsteqszia A, Haqqueniq S (2012) Surfactant science and technology. Wiley, New Jersey
Lawrence MJ, Rees GD (2000) Microemulsion-based media as novel drug delivery systems. Adv Drug Deliv Rev 45:89–121
Hait SK, Moulik SP (2002) Gemini surfactants: a distinct class of self-assembling molecules. Curr Sci 82:1101–1111
Ananthapadmanabhan KP et al (2009) A novel technology in mild and moisturizing cleansing liquids. Cosmet Dermatol 22:307–316
Griffin WC (1954) Calculation of HLB values of non ionic surfactants. J Soc Cosmet Chem 5:249–256
Ghosh PK, Murthy RSR (2006) Microemulsions: a potential drug delivery system. Curr Drug Deliv 3:167–180
Warisnoicharoen W, Lansley AB, Lawrence MJ (2000) Nonionic oil-in-water microemulsions: the effect of oil type on phase behavior. Int J Pharm 198:7–27
Yuasa H, Sekiya M, Ozeki S, Watanabe J (1994) Evaluation of milk fat globulemembrane (MFGM) emulsion for oral administration: absorption of α-linolenic acidin rats and the effect of emulsion droplet size. Biol Pharm Bull 17:756–758
Hauss DJ, Fogal SE, Ficorilli JV, Price CA, Roy T, Jayaraj AA, Keirns JJ (1998) Lipid-based delivery systems for improving the bioavailability and lymphatic transport of a poorly water-soluble LTB4 inhibitor. J Pharm Sci 87:164–169
Attwood D, Mallon C, Taylor CJ (1992) Phase studies on oil-in-water phospholipid microemulsions. Int J Pharm 84:R5–R8
Eccleston J (1994) Microemulsions. In: Swarbrick J, Boylan JC (eds) Encyclopedia of pharmaceutical technology. Marcel Dekker, New York, pp 375–421
Lawrence MJ (1996) Microemulsions as drug delivery vehicles. Curr Opin Colloid Interface Sci 1:826–832
OsborneDW MCA, Rogers RL (1988) Alcohol-free microemulsions. J Dispers Sci Technol 9:415–423
Aboofazeli R, Patel N, Thomas M, Lawrence MJ (1995) Investigations into the formation and characterisation of phospholipid microemulsions. IV. Pseudo-ternary phase diagrams of systems containing water–lecithin–alcohol and oil; the influence of oil. Int J Pharm 125:107–116
Aboofazeli R, Lawrence CB, Wicks SR, Lawrence MJ (1994) Investigations into the formation and characterisation of phospholipid microemulsions. III. Pseudo-ternary phasediagrams of systems containing water–lecithin–isopropylmyristate and either an alkanoic acid, amine, alkanediol,polyethylene glycol alkyl ether or alcohol as cosurfactant. Int J Pharm 111:63–72
Bouchemal K, Briancon S, Fessi H, Perrier E (2004) Nano-emulsion formulation using spontaneous emulsification: solvent, oil and surfactant optimization. Int J Pharm 280:241–251
Musa SH, Basri M, Masoumi HR, Karjiban RA, Malek EA, Basri H, Shamsuddin AF (2013) Formulation optimization of palm kernel oil esters nanoemulsion-loaded with chloramphenicol suitable for meningitis treatment. Colloids Surf B Biointerfaces 112:113–119
Chakraborty S, Shukla D, Vuddanda PR, Mishra B, Singh S (2010) Utilization of adsorption technique in the development of oral delivery system of lipid based nanoparticles. Colloids Surf B Biointerfaces 81:563–569
Marszall L (1987) HLB of nonionic surfactants: PIT and EIP methods. In: Schick MJ (ed) Nonionic surfactant: physical chemistry. Marcel Dekker, New York, pp 493–547
Shafiq-un-Nabi S, Shakeel F, Talegaonkar S, Ali J, Baboota S, Ahuj A, Khar RK, Ali M (2007) Formulation development and optimizationusing nanoemulsion technique: a technical note. AAPS Pharm Sci Tech 8:E1–E6
Alam MS, Ali MS, Alam N, Siddiqui MR, Shamim M, Safhi MM (2013) In vivo study of clobetasol propionate loaded nanoemulsion for topical application in psoriasis and atopic dermatitis. Drug Invent Today 5:8–12
Kumar S, Talegaonkar S, Negi LM, Iqbal Z (2013) Design and development of ciclopirox topical nanoemulsion gel for the treatment of subungual onychomycosis. Indian J Pharm Educ Res 46:303–314
Rhee YS, Choi JG, Park ES, Chi SC (2001) Transdermal delivery of ketoprofen using microemulsions. Int J Pharm 228:161–170
Elena P, Paola S, Maria RG (2001) Transdermal permeation of apomorphine through hairless mouse skin from microemulsions. Int J Pharm 226:47–51
Kreilgaard M (2002) Influence of microemulsion on cutaneous drug delivery. Adv Drug Deliv Rev 54:S77–S98
Hua L, Weisan P, Jiayu L, Ying Z (2004) Preparation, evaluation and NMR characterization of vinpocetine microemulsion for transdermal delivery. Drug Dev Ind Pharm 30:657–666
Trotta M, Pattarino F, Gasco MR (1996) Influence of counter ions on the skin permeation of methotrexate from water–oil microemulsion. Pharm. Acta Helv. 71:135–140
Baroli B, Lopez-Quintela MA, Delgado-Charro MB, Fadda AM, Blanco-Mendez J (2000) Microemulsions for topical delivery of 8-methoxsalen. J Control Release 69:209–218
Liu H, Li S, Wang Y, Han F, Dong Y (2006) Bicontinuous water-AOT/Tween 85-isopropyl myristate microemulsion: a new vehicle for transdermal delivery of cyclosporine A. Drug Dev Ind Pharm 32:549–557
Bernardi DS, Pereira TA, Maciel NR, Bortoloto J, Viera GS, Oliveira GC, Rocha-Filho PA (2011) Formation and stability of oil-in-water nanoemulsions containing rice bran oil: in vitro and in vivo assessments. J Nanobiotechnol 9:1–9
Alam MS, Ali MS, Alam N, Alam MI, Anwer T, Imam F, Shamim M (2012) Design and characterization of nanostructure topical gel of betamethasone dipropionate for psoriasis. J Appl Pharma Sci 2:148–158
Peira E, Carlotti ME, Trotta C, Cavalli R, Trotta M (2008) Positively charged microemulsions for topical application. Int J Pharm 346:119–123
Severino P, Fangueiro JF, Ferreira SV, Basso R, Chaud MV, Santana MH, Rosmaninho A, Souto EB (2013) Nanoemulsions and nanoparticles for non-melanoma skin cancer: effects of lipid materials. Clin Transl Oncol 15:417–424
Atrux-Tallau N, Delmas T, Han SH, Kim JW, Bibette J (2013) Skin cell targeting with self-assembled ligand addressed nanoemulsion droplets. Int J Cosmet Sci 35:310–318
O’Driscoll CM (2002) Lipid-based formulations for intestinal lymphatic delivery. Eur J Pharm Sci 15:405–415
Tortora GJ, Grabowski SR (2000) Introduction to the human body: the essentials of anatomy and physiology. Wiley, New York
Kiyasu JY, Bloom B, Chaikoff IL (1952) The portal transport of absorbed fatty acids. J Biol Chem 199:415–419
Wu H, Zhou A, Lu C, Wang L (2011) Examination of lymphatic transport of puerarin in unconscious lymph duct-cannulated rats after administration in microemulsion drug delivery systems. Eur J Pharm Sci 42:348–353
Griffin BT, O’Driscoll CM (2006) A comparison of intestinal lymphatic transport and systemic bioavailability of saquinavir from three lipid-based formulations in the anaesthetized rat model. J Phama Pharmacol 58:917–925
Karajgi JS, Vyas SP (1994) A lymphotropic colloidal carrier system for diethylcarbamazine: preparation and performance evaluation. J Microencapsul 11:539–545
Yoshimura K, Nunomura M, Takiguchi N, Oda K, Suzuki H, Furukawa R, Sarashina H, Kohda K, Saito N, Sugaya Y, Tiku T, Wakathuki K, Ishikawa H, Yasutomi J, Nakajima N (1996) Evaluation of endoscopic pirarubicin-Lipiodol emulsion injection therapy for gastric cancer. Gan To Kagaku Ryoho 23:1519–1522
Nasr M, Nawaz S, Elhissi A (2012) Amphotericin B lipid nanoemulsion aerosols for targeting peripheral respiratory airways via nebulization. Int J Pharm 436(1):611–616
Nesamony J, Kalra A, Majrad MS, Boddu SH, Jung R, Williams FE, Schnapp AM, Nauli SM, Kalinoski AL (2013) Development and characterization of nanostructured mists with potential for actively targeting poorly water-soluble compounds into the lungs. Pharm Res 30:2625–2639
Bae PK, Jung J, Lim SJ, Kim D, Kim SK, Chung BH (2013) Bimodal perfluorocarbon nanoemulsions for nasopharyngeal carcinoma targeting. Mol Imaging Biol 15:401–410
Maeda H, Matsumura Y, Kato H (1988) Purification and identification of [hydroxypropyl3] bradykinin in ascitic fluid from a patient with gastric cancer. J Biol Chem 263:16051–16054
Maeda H, Noguchi Y, Sato K, Akaike T (1994) Enhanced vascular permeability in solid tumor is mediated by nitric oxide and inhibited by both new nitric oxide scavenger and nitric oxide synthase inhibitor. Jpn J Cancer Res 85:331–334
Senger DR, Galli SJ, Dvorak AM, Perruzzi CA, Harvey VS, Dvorak HF (1983) Tumor cells secrete a vascular permeability factor that promotes accumulation of ascites fluid. Science 219:983–985
Leung DW, Cachianes G, Kuang WJ, Goeddel DV, Ferrara N (1989) Vascular endothelial growth factor is a secreted angiogenic mitogen. Science 246:1306–1309
Ichikawa H, Watanabe T, Tokumitsu H, Fukumori Y (2007) Formulation considerations of gadolinium lipid nanoemulsion for intravenous delivery to tumors in neutron-capture therapy. Curr Drug Deliv 4:131–140
Han M, He CX, Fang QL, Yang XC, Diao YY, Xu DH, He QJ, Hu YZ, Liang WQ, Yang B, Gao JQ (2009) A novel camptothecin derivative incorporated in nano-carrier induced distinguished improvement in solubility, stability and anti-tumor activity both in vitro and in vivo. Pharm Res 26:926–935
Pardridge WM (2007) Blood-brain barrier delivery. Drug Discov Today 12:54–61
Pardridge WM (2002) Drug and gene targeting to the brain with molecular Trojan horses. Nat Rev Drug Discov 1:131–139
Begley DJ, Brightman MW (2003) Structural and functional aspects of the blood–brain barrier. Prog Drug Res 61:39–78
Nies AT (2007) The role of membrane transporters in drug delivery to brain tumors. Cancer Lett 254:11–29
Deeken JF, Löscher W (2007) The blood–brain barrier and cancer: transporters, treatment, and Trojan horses. Clin Cancer Res 13:1663–1674
Gaoe H, Pang Z, Pan S, Cao S, Yang Z, Chen C, Jiang X (2012) Anti-glioma effect and safety of docetaxel-loaded nanoemulsion. Arch Pharm Res 35:333–334
Yao J, Zhou JP, Ping QN (2007) Characteristics of nobiletin-loaded nanoemulsion and its in vivo distribution in mice. Yao Xue Xue Bao 42:663–668
Talegaonkar S, Mishra P (2004) intranasal delivery: an approach to bypass the blood brain barrier. Indian J Pharmacol 36:140–147
Bahadur S, Pathak K (2012) Buffered nanoemulsion for nose to brain delivery of ziprasidone hydrochloride: preformulation and pharmacodynamic evaluation. Curr Drug Deliv 9:596–607
Kumar M, Misra A, Babbar AK, Mishra AK, Mishra P, Pathak K (2008) Intranasal nanoemulsion based brain targeting drug delivery system of risperidone. Int J Pharm 358:285–291
Vyas TK, Shahiwala A, Amiji MM (2008) Improved oral bioavailability and brain transport of Saquinavir upon administration in novel nanoemulsion formulations. Int J Pharm 347:93–110
Kumar M, Misra A, Pathak K (2009) Formulation and characterization of nanoemulsion of olanzapine for intranasal delivery. PDA J Pharm Sci Technol 63:501–511
Jogani VV, Shah PJ, Mishra P, Mishra AK, Misra AR (2008) Intranasal mucoadhesivemicroemulsion of tacrine to improve brain targeting. Alzheimer Dis Assoc Disord 22:116–124
Jain N, Akhter S, Jain GK, Khan ZI, Khar RK, Ahmad FJ (2011) Antiepileptic intranasal Amiloride loaded mucoadhesive nanoemulsion: development and safety assessment. J Biomed Nanotechnol 7:142–143
Murphy EA, Majeti BK, Barnes LA et al (2008) Nanoparticle-mediated drug delivery to tumor vasculature suppresses metastasis. Proc Natl Acad Sci U S A 105:9343–9348
Das M, Mohanty C, Sahoo SK (2009) Ligand-based targeted therapy for cancer tissue. Expert Opin Drug Deliv 6:285–304
Yukio K, Takeshi S, Takashi K et al (1996) Kinetic analysis of receptor-mediated endocytosis (RME) of proteins and peptides: use of RME as a drug delivery system. J Control Release 39:191–200
Sinha R, Kim GJ, Nie S et al (2006) Nanotechnology in cancer therapeutics: bioconjugated nanoparticles for drug delivery. Mol Cancer Ther 5:1909–1917
Vora T, Azambuja ED, Awada A, Piccart M (2009) Novel therapeutics in breast cancer: looking to the future. Update Cancer Ther 3:189–205
Alvarez RH, Valero V, Hortobagyi GN (2010) Emerging targeted therapies for breast cancer. J Clin Oncol 28:3366–3379.
Lee RJ, Armstrong AC, Wardley AM (2013) Emerging targeted combinations in the management of breast cancer. J Breast Cancer Targets Ther 14:505–515
Shaw RJ, Cantley LC (2006) Ras, PI(3)K and mTOR signalling controls tumour cell growth. Nature 441:424–430
Shih T, Lindley C (2006) Bevacizumab: an angiogenesis inhibitor for the treatment of solid malignancies. Clin Ther 28:1779–1802
Negi LM, Talegaonkar S, Jaggi M (2012) Role of CD44 in tumour progression and strategies for targeting. J Drug Target 20:561–573
Gao X, Cui Y, Levenson RM, Chung LWK, Nie S (2004) In vivo cancer targeting and imaging with semiconductor quantum dots. Nat Biotechnol 22:969–976
Bartlett DW, Su H, Hildebrandt IJ, Weber WA, Davis ME (2007) Impact of tumor-specific targeting on the biodistribution and efficacy of siRNA nanoparticles measured by multimodality in vivo imaging. Proc Natl Acad Sci U S A 104:15549–15554
Winkler J, Martin-Killias P, Pluckthun A, Zangemeister-Wittke U (2009) EpCAM targeted delivery of nanocomplexed siRNA to tumor cells with designed ankyrin repeat proteins. Mol Cancer Ther 8:2674–2683
Graf N, Bielenberg DR, Kolishetti N, Muus C, Banyard J, Farokhzad OC, Lippard SJ (2012) αVβ3 Integrin-targeted PLGA-PEG nanoparticles for enhanced anti-tumor efficacy of a Pt(IV) prodrug. ACS Nano 6:4530–4539
Kamaly N, Fredman G, Subramanian M, Gadde S, Pesic A, Cheung L, Fayad ZA, Langer R, Tabas I, Farokhzad OC (2013) Development and in vivo efficacy of targeted polymeric inflammation-resolving nanoparticles. Proc Natl Acad Sci U S A 110:6506–6511
Saw PE, Kim S, Lee IH, Park J, Yu M, Lee J, Kim JI, Jon S (2013) Aptide-conjugated liposome targeting tumor-associated fibronectin for glioma therapy. J Math Chem B 1:4723–4726
Werner ME, Karve S, Sukumar R, Cummings ND, Copp JA, Chen RC, Zhang T, Wang AZ (2011) Folate-targeted nanoparticle delivery of chemo- and radiotherapeutics for the treatment of ovarian cancer peritoneal metastasis. Biomaterials 32:8548–8554
Ohguchi Y, Kawano K, Hattori Y, Maitani Y (2008) Selective delivery of folate-PEG-linked, nanoemulsion-loaded aclacinomycin A to KB nasopharyngeal cells and xenograft: effect of chain length and amount of folate-PEG linker. J Drug Target 16:660–667
Talekar M, Ganta S, Singh A, Amiji M, Kendall J, Denny WA, Garg S (2010) Phosphatidylinositol 3-kinase inhibitor (PIK75) containing surface functionalized nanoemulsion for enhanced drug delivery, cytotoxicity and pro-apoptotic activity in ovarian cancer cells. Pharm Res 29:2874–2886
Tiwari S, Tan Y, Amiji M (2006) Preparation and in vitro characterization of multifunctional nanoemulsions for simultaneous mr imaging and targeted drug delivery. J Biomed Nanotechnol 2:217–224
Watanabe M, Yoneda M, Morohashi A, Hori Y, Okamoto D, Sato A, Kurioka D, Nittami T, Hirokawa Y, Shiraishi T, Kawai K, Kasai H, Totsuka Y (2013) Effects of Fe3O4 magnetic nanoparticles on A549 cells. Int J Mol Sci 14:15546–15560
Hu SH, Hsieh TY, Chiang CS, Chen PJ, Chen YY, Chiu TL, Chen SY (2013) Surfactant-free lipo-polymersomes stabilized by iron oxide nanoparticles/polymer interlayer for synergistically targeted and magnetically guided gene delivery. Adv Healthc Mater 3:273–282. doi:10.1002/adhm.201300122
Huang HS, Hainfield JF (2013) Intravenous magnetic nanoparticle cancer hyperthermia. Int J Nanomedicine 8:2521–2532
Bakandritsos A, Zboril R, Bouropoulos N, Kallinteri P, Favretto ME, Parker TL, Mullertz A, Fatouros DG (2010) The preparation of magnetically guided lipid based nanoemulsions using self-emulsifying technology. Nanotechnology 21:055104–055112
Primo FL, Macaroff PP, Lacava ZGM, Azevedo RB, Morais PC, Tedesco AC (2007) Binding and photophysical studies of biocompatible magnetic fluid in biological medium and development of magnetic nanoemulsion: a new candidate for cancer treatment. J Magn Magn Mater 310:2838–2840
Fang JY, Hung CF, Hua SC, Hwang TL (2009) Acoustically active perfluorocarbon nanoemulsions as drug delivery carriers for camptothecin: drug release and cytotoxicity against cancer cells. Ultrasonics 49:39–46
Rapoport NY, Kennedy AM, Shea JE, Scaife CL, Nam KH (2009) Controlled and targeted tumor chemotherapy by ultrasound-activated nanoemulsions/microbubbles. J Control Release 138:268–276
Herman GT (2009) Fundamentals of computerized tomography: image reconstruction from projection, 2nd edn. Springer, Berlin
Osborne E, Sutherland C, Scholl A, Rowntree L (1923) Roentgenography of urinary tract during excretion of sodium iodide. J Am Med Assoc 80:368–373
Bourin M, Jolliet P, Ballereau F (1997) An overview of the clinical pharmacokinetics of x-ray contrast media. Clin Pharmacokinet 32:180–193
Hallouard F, Anton N, Choquet P, Constantinesco A, Vandamme T (2010) Iodinated blood pool contrast media for preclinical X-ray imaging applications—a review. Biomaterials 31:6249–6268
Henning T, Weber AW, Bauer JS, Meier R, Carlsen JM, Sutton EJ, Prevrhal S, Ziegler SI, Feussner H, Daldrup-Link HE, Rummeny EJ (2008) Imaging characteristics of DHOG, a hepatobiliary contrast agent for preclinical microCT in mice. Acad Radiol 15:342–349
Willekens I, Lahoutte T, Buls N, Vanhove C, Deklerck R, Bossuyt A, de Mey J (2009) Time-course of contrast enhancement in spleen and liver with Exia 160, Fenestra LC, and VC. Mol Imaging Biol 11:128–135
Weichert JP, Lee FT Jr, Chosy SG, Longino MA, Kuhlman JE, Heisey DM, Leverson GE (2000) Combined hepatocyte-selective and blood-pool contrast agents for the CT detection of experimental liver tumors in rabbits. Radiology 216:865–867
Hallouard F, Briançon S, Anton N, Li X, Vandamme T, Fessi H (2013) Iodinated nano-emulsions as contrast agents for preclinical X-ray imaging: impact of the free surfactants on the pharmacokinetics. Eur J Pharm Biopharm 83:54–62
Li X, Anton N, Zuber G, Zhao M, Messaddeq N, Hallouard F, Fessi H, Vandamme TF (2013) Iodinated α-tocopherol nano-emulsions as non-toxic contrast agents for preclinical X-ray imaging. Biomaterials 34:481–491
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Talegaonkar, S., Negi, L.M. (2015). Nanoemulsion in Drug Targeting. In: Devarajan, P., Jain, S. (eds) Targeted Drug Delivery : Concepts and Design. Advances in Delivery Science and Technology. Springer, Cham. https://doi.org/10.1007/978-3-319-11355-5_14
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