Controversies with self-emulsifying drug delivery system from pharmacokinetic point of view

References

• Akimoto M, Nagahata N, Furuya A, et al. (2000). Gastric pH profiles of beagle dogs and their use as an alternative to human testing. Eur J Pharm Biopharm 49:99–102
   PubMed Web of Science ®Google Scholar
• An Y, Yan X, Li B, Li Y. (2014). Microencapsulation of capsanthin by self-emulsifying nanoemulsions and stability evaluation. Eur Food Res Technol 239:1077–85
   Web of Science ®Google Scholar
• Anton N, Vandamme TF. (2011). Nano-emulsions and micro-emulsions: clarifications of the critical differences. Pharm Res 28:978–85
   PubMed Web of Science ®Google Scholar
• Araya H, Tomita M, Hayashi M. (2005). The novel formulation design of O/W microemulsion for improving the gastrointestinal absorption of poorly water soluble compounds. Int J Pharm 305:61–74
   PubMed Web of Science ®Google Scholar
• Bahloul B, Lassoued MA, Seguin J, et al. (2015). Self-emulsifying drug delivery system developed by the HLB-RSM approach: characterization by transmission electron microscopy and pharmacokinetic study. Int J Pharm. http://dx.doi.org/10.1016/j.ijpharm.2015.04.018
   PubMed Web of Science ®Google Scholar
• Bahloul B, Lassoued MA, Sfar S. (2014). A novel approach for the development and optimization of self-emulsifying drug delivery system using HLB and response surface methodology: application to fenofibrate encapsulation. Int J Pharm 466:341–8
   PubMed Web of Science ®Google Scholar
• Balakrishnan P, Lee BJ, Oh DH, et al. (2009). Enhanced oral bioavailability of Coenzyme Q10 by self-emulsifying drug delivery systems. Int J Pharm 374:66–72
   PubMed Web of Science ®Google Scholar
• Bandyopadhyay S, Katare O, Singh B. (2012). Optimized self nano-emulsifying systems of ezetimibe with enhanced bioavailability potential using long chain and medium chain triglycerides. Colloids Surf B Biointerfaces 100:50–61
   PubMed Web of Science ®Google Scholar
• Beg S, Katare O, Saini S, et al. (2016). Solid self-nanoemulsifying systems of olmesartan medoxomil: formulation development, micromeritic characterization, in vitro and in vivo evaluation. Powder Technol 294:93–104
   Web of Science ®Google Scholar
• Borhade VB, Nair HA, Hegde DD. (2009). Development and characterization of self-microemulsifying drug delivery system of tacrolimus for intravenous administration. Drug Dev Ind Pharm 35:619–30
   PubMed Web of Science ®Google Scholar
• Cannon JB. (2011). LIPIDS-strategies to formulate lipid-based drug delivery systems. Am Pharm Rev 14:84
   Google Scholar
• Čerpnjak K, Zvonar A, Gašperlin M, Vrečer F. (2013). Lipid-based systems as a promising approach for enhancing the bioavailability of poorly water-soluble drugs. Acta Pharm 63:427–45
   PubMed Web of Science ®Google Scholar
• Chambin O, Jannin V. (2005). Interest of multifunctional lipid excipients: case of Gelucire 44/14. Drug Dev Ind Pharm 31:527–34
   PubMed Web of Science ®Google Scholar
• Chen ML. (2008). Lipid excipients and delivery systems for pharmaceutical development: a regulatory perspective. Adv Drug Deliv Rev 60:768–77
   PubMed Web of Science ®Google Scholar
• Chen Y, Li G, Wu X, et al. (2008). Self-microemulsifying drug delivery system (SMEDDS) of vinpocetine: formulation development and in vivo assessment. Biol Pharm Bull 31:118–25
   PubMed Web of Science ®Google Scholar
• Cheng G, Hu R, Ye L, et al. (2015). Preparation and in vitro/in vivo evaluation of puerarin solid self-microemulsifying drug delivery system by spherical crystallization technique. AAPS PharmSciTech 1–11. doi:10.1208/s12249-015-0469-8
   PubMed Web of Science ®Google Scholar
• Cherniakov I, Domb AJ, Hoffman A. (2015). Self-nano-emulsifying drug delivery systems: an update of the biopharmaceutical aspects. Expert Opin Drug Deliv 12:1121–33
   PubMed Web of Science ®Google Scholar
• Christiansen M, Holm R, Abrahamsson B, et al. (2016). Effect of food intake and co-administration of placebo self-nanoemulsifying drug delivery systems on the absorption of cinnarizine in healthy human volunteers. Eur J Pharm Sci 84:77–82
   PubMed Web of Science ®Google Scholar
• Christiansen ML, Holm R, Kristensen J, et al. (2014). Cinnarizine food-effects in beagle dogs can be avoided by administration in a self nanoemulsifying drug delivery system (SNEDDS). Eur J Pharm Sci 57:164–72
   PubMed Web of Science ®Google Scholar
• Chudasama A, Patel V, Nivsarkar M, et al. (2015). Role of lipid-based excipients and their composition on the bioavailability of antiretroviral self-emulsifying formulations. Drug Deliv 22:531–40
   PubMed Web of Science ®Google Scholar
• Cserháti T, Forgács E, Oros G. (2002). Biological activity and environmental impact of anionic surfactants. Environ Int 28:337–48
   PubMed Web of Science ®Google Scholar
• Dahan A, Hoffman A. (2008). Rationalizing the selection of oral lipid based drug delivery systems by an in vitro dynamic lipolysis model for improved oral bioavailability of poorly water soluble drugs. J Control Release 129:1–10
   PubMed Web of Science ®Google Scholar
• Dai WG. (2010). In vitro methods to assess drug precipitation. Int J Pharm 393:1–16
   PubMed Web of Science ®Google Scholar
• de Smidt PC, Campanero MA, Trocóniz IF. (2004). Intestinal absorption of penclomedine from lipid vehicles in the conscious rat: contribution of emulsification versus digestibility. Int J Pharm 270:109–18
   PubMed Web of Science ®Google Scholar
• Do TT, Van Speybroeck M, Mols R, et al. (2011). The conflict between in vitro release studies in human biorelevant media and the in vivo exposure in rats of the lipophilic compound fenofibrate. Int J Pharm 414:118–24
   PubMed Web of Science ®Google Scholar
• Eedara BB, Veerareddy PR, Jukanti R, Bandari S. (2014). Improved oral bioavailability of fexofenadine hydrochloride using lipid surfactants: ex vivo, in situ and in vivo studies. Drug Dev Ind Pharm 40:1030–43
   PubMed Web of Science ®Google Scholar
• Engel A, Oswald S, Siegmund W, Keiser M. (2012). Pharmaceutical excipients influence the function of human uptake transporting proteins. Mol Pharm 9:2577–81
   PubMed Web of Science ®Google Scholar
• Fagir W, Hathout RM, Sammour OA, ElShafeey AH. (2015). Self-microemulsifying systems of Finasteride with enhanced oral bioavailability: multivariate statistical evaluation, characterization, spray-drying and in vivo studies in human volunteers. Nanomedicine 10:3373–89
   PubMed Web of Science ®Google Scholar
• Fei Y, Kostewicz ES, Sheu MT, Dressman JB. (2013). Analysis of the enhanced oral bioavailability of fenofibrate lipid formulations in fasted humans using an in vitro–in silico–in vivo approach. Eur J Pharm Biopharm 85:1274–84
   PubMed Web of Science ®Google Scholar
• Fernandez-Tarrio M, Yañez F, Immesoete K, et al. (2008). Pluronic and tetronic copolymers with polyglycolyzed oils as self-emulsifying drug delivery systems. AAPS PharmSciTech 9:471–9
   PubMed Web of Science ®Google Scholar
• Gao P. (2012). Design and development of self-emulsifying lipid formulations for improving oral bioavailability of poorly water-soluble and lipophilic drugs. In: Williams III RO, Watts AB, Miller DA, eds. Formulating poorly water soluble drugs. New York: Springer, 243–66
   Google Scholar
• Garg B, Katare O, Beg S, et al. (2016). Systematic development of solid self-nanoemulsifying oily formulations (S-SNEOFs) for enhancing the oral bioavailability and intestinal lymphatic uptake of lopinavir. Colloids Surf B Biointerfaces 141:611–22
   PubMed Web of Science ®Google Scholar
• Generally Recognized as Safe (GRAS). (2016). Fda.gov. Available at: http://www.fda.gov/Food/IngredientsPackagingLabeling/GRAS/ [last accessed 3 May 2016]
   Google Scholar
• Gupta S, Chavhan S, Sawant KK. (2011). Self-nanoemulsifying drug delivery system for adefovir dipivoxil: design, characterization, in vitro and ex vivo evaluation. Colloids Surf A Physicochem Eng Asp 392:145–55
   Web of Science ®Google Scholar
• Gursoy RN, Benita S. (2004). Self-emulsifying drug delivery systems (SEDDS) for improved oral delivery of lipophilic drugs. Biomed Pharmacother 58:173–82
   PubMed Web of Science ®Google Scholar
• Hauss DJ. (2007). Oral lipid-based formulations: enhancing the bioavailability of poorly water-soluble drugs. (Vol. 170). New York: Informa Healthcare
   Google Scholar
• Heshmati N, Cheng X, Dapat E, et al. (2014). In vitro and in vivo evaluations of the performance of an indirubin derivative, formulated in four different self‐emulsifying drug delivery systems. J Pharm Pharmacol 66:1567–75
   PubMed Web of Science ®Google Scholar
• Hintzen F, Perera G, Hauptstein S, et al. (2014). In vivo evaluation of an oral self-microemulsifying drug delivery system (SMEDDS) for leuprorelin. Int J Pharm 472:20–6
   PubMed Web of Science ®Google Scholar
• Holm R, Tønsberg H, Jørgensen EB, et al. (2012). Influence of bile on the absorption of halofantrine from lipid-based formulations. Eur J Pharm Biopharm 81:281–7
   PubMed Web of Science ®Google Scholar
• Inugala S, Eedara BB, Sunkavalli S, et al. (2015). Solid self-nanoemulsifying drug delivery system (S-SNEDDS) of darunavir for improved dissolution and oral bioavailability: in vitro and in vivo evaluation. Eur J Pharm Sci 74:1–10
   PubMed Web of Science ®Google Scholar
• Kale AA, Patravale VB. (2008). Design and evaluation of self-emulsifying drug delivery systems (SEDDS) of nimodipine. AAPS PharmSciTech 9:191–6
   PubMed Web of Science ®Google Scholar
• Kang MJ, Jung SY, Song WH, et al. (2011). Immediate release of ibuprofen from Fujicalin®-based fast-dissolving self-emulsifying tablets. Drug Dev Ind Pharm 37:1298–305
   PubMed Web of Science ®Google Scholar
• Kang BK, Lee JS, Chon SK, et al. (2004). Development of self-microemulsifying drug delivery systems (SMEDDS) for oral bioavailability enhancement of simvastatin in beagle dogs. Int J Pharm 274:65–73
   PubMed Web of Science ®Google Scholar
• Kang JH, Oh DH, Oh YK, et al. (2012). Effects of solid carriers on the crystalline properties, dissolution and bioavailability of flurbiprofen in solid self-nanoemulsifying drug delivery system (solid SNEDDS). Eur J Pharm Biopharm 80:289–97
   PubMed Web of Science ®Google Scholar
• Katneni K, Charman SA, Porter CJ. (2007). Impact of cremophor‐EL and polysorbate‐80 on digoxin permeability across rat jejunum: Delineation of thermodynamic and transporter related events using the reciprocal permeability approach. J Pharm Sci 96:280–93
   PubMed Web of Science ®Google Scholar
• Khoo SM, Humberstone AJ, Porter CJ, et al. (1998). Formulation design and bioavailability assessment of lipidic self-emulsifying formulations of halofantrine. Int J Pharm 167:155–64
   Web of Science ®Google Scholar
• Kim MS, Ha ES, Choo GH, Baek IH. (2015). Preparation and in vivo evaluation of a dutasteride-loaded solid-supersaturatable self-microemulsifying drug delivery system. Int J Mol Sci 16:10821–33
   PubMed Web of Science ®Google Scholar
• Kim DW, Kang JH, Oh DH, et al. (2012). Development of novel flurbiprofen-loaded solid self-microemulsifying drug delivery system using gelatin as solid carrier. J Microencapsul 29:323–30
   PubMed Web of Science ®Google Scholar
• Kim DW, Kwon MS, Yousaf AM, et al. (2014). Comparison of a solid SMEDDS and solid dispersion for enhanced stability and bioavailability of clopidogrel napadisilate. Carbohydr Polym 114:365–74
   PubMed Web of Science ®Google Scholar
• Kim GG, Poudel BK, Marasini N, et al. (2013). Enhancement of oral bioavailability of fenofibrate by solid self-microemulsifying drug delivery systems. Drug Dev Ind Pharm 39:1431–8
   PubMed Web of Science ®Google Scholar
• Klein S, Dressman JB, Butler J, et al. (2004). Media to simulate the postprandial stomach I. Matching the physicochemical characteristics of standard breakfasts. J Pharm Pharmacol 56:605–10
   PubMed Web of Science ®Google Scholar
• Kohli K, Chopra S, Dhar D, et al. (2010). Self-emulsifying drug delivery systems: an approach to enhance oral bioavailability. Drug Discov Today 15:958–65
   PubMed Web of Science ®Google Scholar
• Kollipara S, Gandhi RK. (2014). Pharmacokinetic aspects and in vitro-in vivo correlation potential for lipid-based formulations. Acta Pharm Sin B 4:333–49
   PubMed Web of Science ®Google Scholar
• Kostewicz ES, Brauns U, Becker R, Dressman JB. (2002). Forecasting the oral absorption behavior of poorly soluble weak bases using solubility and dissolution studies in biorelevant media. Pharm Res 19:345–9
   PubMed Web of Science ®Google Scholar
• Kumar GP, Rambhau D, Apte SS. (2015). Improved oral pharmacokinetics of diclofenac sodium from SNEDDS in human volunteers. J Nanotechnol Diagn Treat 3:5–11
   Google Scholar
• Kyaw OM, Mandal UK, Chatterjee B. (2015). Polymeric behavior evaluation of PVP K30-poloxamer binary carrier for solid dispersed nisoldipine by experimental design. Pharm Dev Technol 1–11. doi:10.3109/10837450.2015.1116568
   Google Scholar
• Larsen AT, Åkesson P, Juréus A, et al. (2013b). Bioavailability of cinnarizine in dogs: effect of SNEDDS loading level and correlation with cinnarizine solubilization during in vitro lipolysis. Pharm Res 30:3101–13
   PubMed Web of Science ®Google Scholar
• Larsen AT, Ohlsson AG, Polentarutti B, et al. (2013a). Oral bioavailability of cinnarizine in dogs: relation to SNEDDS droplet size, drug solubility and in vitro precipitation. Eur J Pharm Sci 48:339–50
   PubMed Web of Science ®Google Scholar
• Li F, Song S, Guo Y, et al. (2015). Preparation and pharmacokinetics evaluation of oral self-emulsifying system for poorly water-soluble drug Lornoxicam. Drug Deliv 22:487–98
   PubMed Web of Science ®Google Scholar
• Li H, Tan Y, Yang L, et al. (2015). Dissolution evaluation in vitro and bioavailability in vivo of self-microemulsifying drug delivery systems for pH-sensitive drug loratadine. J Microencapsul 32:175–80
   PubMed Web of Science ®Google Scholar
• Morozowich W, Gao P. (2009). Improving the oral absorption of poorly soluble drugs using SEDDS and S-SEDDS formulations. In: Qiu Y, Chen Y, Zand GZ, Liu L, Porter WL, eds. Developing solid oral dosage forms: pharmaceutical theory and practice. Cambridge: Academic, 443–68
   Google Scholar
• Müllertz A, Ogbonna A, Ren S, Rades T. (2010). New perspectives on lipid and surfactant based drug delivery systems for oral delivery of poorly soluble drugs. J Pharm Pharmacol 62:1622–36
   PubMed Web of Science ®Google Scholar
• Narang AS, Delmarre D, Gao D. (2007). Stable drug encapsulation in micelles and microemulsions. Int J Pharm 345:9–25
   PubMed Web of Science ®Google Scholar
• O’Driscoll CM. (2002). Lipid-based formulations for intestinal lymphatic delivery. Eur J Pharm Sci 15:405–15
   PubMed Web of Science ®Google Scholar
• Oh DH, Kang JH, Kim DW, et al. (2011). Comparison of solid self-microemulsifying drug delivery system (solid SMEDDS) prepared with hydrophilic and hydrophobic solid carrier. Int J Pharm 420:412–18
   PubMed Web of Science ®Google Scholar
• Patil P, Patil V, Paradkar A. (2007). Formulation of a self-emulsifying system for oral delivery of simvastatin: in vitro and in vivo evaluation. Acta Pharm 57:111–22
   PubMedGoogle Scholar
• Porter CJ, Trevaskis NL, Charman WN. (2007). Lipids and lipid-based formulations: optimizing the oral delivery of lipophilic drugs. Nat Rev Drug Discov 6:231–48
   PubMed Web of Science ®Google Scholar
• Pouton CW. (1997). Formulation of self-emulsifying drug delivery systems. Adv Drug Deliv Rev 25:47–58
   Web of Science ®Google Scholar
• Pouton CW. (2000). Lipid formulations for oral administration of drugs: non-emulsifying, self-emulsifying and ‘self-microemulsifying’drug delivery systems. Eur J Pharm Sci 11:S93–8
   PubMed Web of Science ®Google Scholar
• Pouton CW. (2006). Formulation of poorly water-soluble drugs for oral administration: physicochemical and physiological issues and the lipid formulation classification system. Eur J Pharm Sci 29:278–87
   PubMed Web of Science ®Google Scholar
• Prajapati BG, Patel MM. (2007). Conventional and alternative pharmaceutical methods to improve oral bioavailability of lipophilic drugs. Asian J Pharm 1:1–8
   Google Scholar
• Quan Q, Kim DW, Marasini N, et al. (2013). Physicochemical characterization and in vivo evaluation of solid self-nanoemulsifying drug delivery system for oral administration of docetaxel. J Microencapsul 30:307–14
   PubMed Web of Science ®Google Scholar
• Ramasahayam B, Eedara BB, Kandadi P, et al. (2015). Development of isradipine loaded self-nano emulsifying powders for improved oral delivery: in vitro and in vivo evaluation. Drug Dev Ind Pharm 41:753–63
   PubMed Web of Science ®Google Scholar
• Sangsen Y, Wiwattanawongsa K, Likhitwitayawuid K, et al. (2016). Influence of surfactants in self-microemulsifying formulations on enhancing oral bioavailability of oxyresveratrol: studies in Caco-2 cells and in vivo. Int J Pharm 498:294–303
   PubMed Web of Science ®Google Scholar
• Savjani KT, Gajjar AK, Savjani JK. (2012). Drug solubility: importance and enhancement techniques. ISRN Pharm 2012:1–10
   Google Scholar
• Sek L, Boyd BJ, Charman WN, Porter CJ. (2006). Examination of the impact of a range of Pluronic surfactants on the in‐vitro solubilisation behaviour and oral bioavailability of lipidic formulations of atovaquone. J Pharm Pharmacol 58:809–20
   PubMed Web of Science ®Google Scholar
• Sermkaew N, Ketjinda W, Boonme P, et al. (2013). Liquid and solid self-microemulsifying drug delivery systems for improving the oral bioavailability of andrographolide from a crude extract of Andrographis paniculata. Eur J Pharm Sci 50:459–66
   PubMed Web of Science ®Google Scholar
• Sha X, Yan G, Wu Y, et al. (2005). Effect of self-microemulsifying drug delivery systems containing Labrasol on tight junctions in Caco-2 cells. Eur J Pharm Sci 24:477–86
   PubMed Web of Science ®Google Scholar
• Shah NH, Carvagal MT, Patel CI, et al. (1994). Self emulsifying drug delivery system (SEDDS) with polyglycolized glycerides for improving in-vitro dissolution and oral absorption of lipophilic drugs. Int J Pharm 106:15–23
   Web of Science ®Google Scholar
• Shanmugam S, Baskaran R, Balakrishnan P, et al. (2011). Solid self-nanoemulsifying drug delivery system (S-SNEDDS) containing phosphatidylcholine for enhanced bioavailability of highly lipophilic bioactive carotenoid lutein. Eur J Pharm Biopharm 79:250–7
   PubMed Web of Science ®Google Scholar
• Singh G, Pai RS. (2015). Trans-resveratrol self-nano-emulsifying drug delivery system (SNEDDS) with enhanced bioavailability potential: optimization, pharmacokinetics and in situ single pass intestinal perfusion (SPIP) studies. Drug Deliv 22:522–30
   PubMed Web of Science ®Google Scholar
• Sun M, Zhai X, Xue K, et al. (2011). Intestinal absorption and intestinal lymphatic transport of sirolimus from self-microemulsifying drug delivery systems assessed using the single-pass intestinal perfusion (SPIP) technique and a chylomicron flow blocking approach: linear correlation with oral bioavailabilities in rats. Eur J Pharm Sci 43:132–40
   PubMed Web of Science ®Google Scholar
• Suresh PK, Sharma S. (2011). Formulation and in-vitro characterization of self-nanoemulsifying drug delivery system of cinnarizine. Drugs 11:12
   Google Scholar
• Sweetman SC. (2009). Martindale: the complete drug reference. London: Pharmaceutical press
   Google Scholar
• Tang B, Cheng G, Gu JC, Xu CH. (2008). Development of solid self-emulsifying drug delivery systems: preparation techniques and dosage forms. Drug Discov Today 13:606–12
   PubMed Web of Science ®Google Scholar
• Tang Jl, Sun J, He ZG. (2007). Self-emulsifying drug delivery systems: strategy for improving oral delivery of poorly soluble drugs. Curr Drug Ther 2:85–93
   Google Scholar
• Tarr BD, Yalkowsky SH. (1989). Enhanced intestinal absorption of cyclosporine in rats through the reduction of emulsion droplet size. Pharm Res 6:40–3
   PubMed Web of Science ®Google Scholar
• Thomas N, Holm R, Müllertz A, Rades T. (2012). In vitro and in vivo performance of novel supersaturated self-nanoemulsifying drug delivery systems (super-SNEDDS). J Control Release 160:25–32
   PubMed Web of Science ®Google Scholar
• Trevaskis NL, Charman WN, Porter CJ. (2008). Lipid-based delivery systems and intestinal lymphatic drug transport: a mechanistic update. Adv Drug Deliv Rev 60:702–16
   PubMed Web of Science ®Google Scholar
• Uchino T, Yasuno N, Yanagihara Y, Suzuki H. (2007). Solid dispersion of spironolactone with porous silica prepared by the solvent method. Pharmazie 62:599–603
   PubMed Web of Science ®Google Scholar
• Wasylaschuk WR, Harmon PA, Wagner G, et al. (2007). Evaluation of hydroperoxides in common pharmaceutical excipients. J Pharm Sci 96:106–16
   PubMed Web of Science ®Google Scholar
• Wei Y, Ye X, Shang X, et al. (2012). Enhanced oral bioavailability of silybin by a supersaturatable self-emulsifying drug delivery system (S-SEDDS). Colloids Surf A Physicochem Eng Asp 396:22–8
   Web of Science ®Google Scholar
• Williams HD, Sassene P, Kleberg K, et al. (2013). Toward the establishment of standardized in vitro tests for lipid-based formulations, part 3: understanding supersaturation versus precipitation potential during the in vitro digestion of type I, II, IIIA, IIIB and IV lipid-based formulations. Pharm Res 30:3059–76
   PubMed Web of Science ®Google Scholar
• Woo JS, Song YK, Hong JY, et al. (2008). Reduced food-effect and enhanced bioavailability of a self-microemulsifying formulation of itraconazole in healthy volunteers. Eur J Pharm Sci 33:159–65
   PubMed Web of Science ®Google Scholar
• Yap SP, Yuen KH. (2004). Influence of lipolysis and droplet size on tocotrienol absorption from self-emulsifying formulations. Int J Pharm 281:67–78
   PubMed Web of Science ®Google Scholar
• Yi T, Wan J, Xu H, Yang X. (2008). A new solid self-microemulsifying formulation prepared by spray-drying to improve the oral bioavailability of poorly water soluble drugs. Eur J Pharm Biopharm 70:439–44
   PubMed Web of Science ®Google Scholar
• Zhang H, Yao M, Morrison RA, Chong S. (2003). Commonly used surfactant, Tween 80, improves absorption of P-glycoprotein substrate, digoxin, in rats. Arch Pharm Res 26:768–72
   PubMed Web of Science ®Google Scholar
• Zhu JX, Tang D, Feng L, et al. (2013). Development of self-microemulsifying drug delivery system for oral bioavailability enhancement of berberine hydrochloride. Drug Dev Ind Pharm 39:499–506
   PubMed Web of Science ®Google Scholar