A Review of the Approved Data on Methods for Quantitative Determination of Sulfadiazine in Pharmaceutical Formulations
Abstract
Background: Recently, the consumption of pharmaceutical preparations and health products has increased to treat various diseases, such as urinary tract infections, treatment of some skin conditions, burns, Alzheimer's disease, streptococcal infection, bronchitis, and eye infections. Many of these preparations have the potential to harm patients or act as emergency pollutants in the environment. Sulfadiazine is one of the most commonly used antimicrobials for both human and animal infections. Aim: The purpose of this paper is to show how important it is to keep an eye on sulfadiazine using simple, accurate, precise, selective, and repeatable methods for estimation. Methods: For measuring pharmaceutical preparation amounts, spectrophotometry, chromatography, and electrochemical methods are best. Spectrophotometric techniques possess ease, accuracy with precision, and repeatability. Conclusion: Chromatographic techniques are selective, and they are more than their predecessors in that they possess speed and safety, but their drawback is that they are expensive. When compared to other methods, electrochemical techniques have very high sensitivity and selectivity. However, they are not very precise, and the sensors are affected by the current. Also, the supporting medium needs to be maintained all the time before it can be used.
References
- Abd, A. A.; Hamed, F. M.; and Khaleel, A. I. Spectrophotometric determination of sulphadiazine by oxidative coupling reaction with ortho-amino phenol as reagent. Tikrit Journal of Pure Science 2019; 24 (4): 40 45.
- Ahmed, N.A. and Khaleel, A.I. Spectrophotometric determination of sulphadiazine using 2,4dinitrophenylhydrazine as coupling reagent. Tikrit Journal of Pure Science 2018; 23(8): 7782.
- Ait Errayess, S., Idrissi, L., & Amine, A. Smartphone-based colorimetric determination of sulfadiazine and sulfasalazine in pharmaceutical and veterinary formulations. Instrumentation Science & Technology 2018; 46(6): 656-675.
- Ait Lahcen, A., Ait Errayess, S., Amine, A. Voltammetric determination of sulfonamides using paste electrodes based on various carbon nanomaterials. Microchimica Acta 2016; 183: 2169-2176.
- Al-Rufaie, M. M. (2016). New Spectrophotometric method for the assay of sulfadiazine drug based on diazotization coupling reaction. Acta Chemica Iasi 2016; 24(2): 88101.
- AL-Rufaie, M. M.; Taha, H.K.A.; Motaweq, Z. Y. ISM Analysis, evolution, human-type and validation of UV spectrophotometric techniques for assessment of sulfadiazine in bulk and cream dose forms. J. Microbiol 2020; 55: 95-105.
- Altunok, M. , Knig, A., Mahmoud, A. W. M. M. , Haddad, T., Vasconcelos, T. G., Kmmerer, K. Automated determination of sulfadiazine in water, fish Plasma and muscle by HPLC with on-line column-switching. Clean - Soil, Air, Water 2016 44(8): 967-974.
- Apaydn, S., & Trk, M. (2019). Sulfonamide derivatives as multi-target agents for complex diseases. Bioorganic & medicinal chemistry letters 2019; 29(16): 2042-2050.
- Avila, C. D., Ayala Gmez, R., Mazzieri, M. R., et al. Simultaneous determination of norfloxacin and sulfadiazine by first-derivative spectrophotometry. Journal of Chemistry Letters 2023; 4(3):130-135.
- Baby, J. N., Sriram, B., Wang, S. F., George, M. Integration of samarium vanadate/carbon nanofiber through synergy: An electrochemical tool for sulfadiazine analysis. Journal of Hazardous Materials 2021; 408: 124940.
- Baran, W., Adamek; E., Ziemiaska, J., et al. Effects of the presence of sulfonamides in the environment and their influence on human health. Journal of hazardous materials 2011; 196:1-15.
- Betz, J. M., Brown, P. N., & Roman, M. C. (2011). Accuracy, precision, and reliability of chemical measurements in natural products research. Fitoterapia 2011; 82(1):44-52.
- Bode, H. On Sandell's sensitivity. Fresenius J Anal Chem, 1991: 339, 898.
- Boltia, S. A., Ibrahim, M., Ibrahim, M. M., Ramadan, N. K. Development and Validation of a RP-HPLC Method for the Simultaneous Determination of Silver Sulfadiazine and Sodium Hyaluronate in the Presence of Methyl and Propyl Paraben in a Pharmaceutical Cream for Burns. Journal of Chromatographic Science, bmae028. 2024; 62(5): 399.
- Braga, O. C., Campestrini, I., Vieira, I. C., Spinelli, A. Sulfadiazine determination in pharmaceuticals by electrochemical reduction on a glassy carbon electrode. Journal of the Brazilian Chemical Society 2010; 21: 813-820.
- British Pharmacopoeia. vol3 London, 2009: 5729, 10070, 10071, 10072 p.
- Campestrini, I., de Braga, O. C., Vieira, I. C., Spinelli, A. Application of bismuth-film electrode for cathodic electroanalytical determination of sulfadiazine. Electrochimica Acta 2010; 55(17): 4970-4975.
- Caro, Y. S., Cmara, M. S., & De Zan, M. M. A review of bioanalytical methods for the therapeutic drug monitoring of -lactam antibiotics in critically ill patients: Evaluation of the approaches used to develop and validate quality attributes. Talanta 2020; 210: 120619.
- Carrazon, J. P., Corona, P. C., Diez, L. P. Electroanalytical study of sulphadiazine at solid electrodes. Determination in pharmaceutical preparations. Electrochimica Acta 1987; 32(11): 1573-1575.
- Center for Drug Evaluation and Research. Food and drug administration. Reviewer Guidance: Validation of Chromatographic Methods. Washington, DC: Department of Health and Human Services (accessed 4/09/10).
- Conde-Cid, M., Fernndez-Calvio, D., Nvoa-Muoz, J. C., et al. Degradation of sulfadiazine, sulfachloropyridazine and sulfamethazine in aqueous media. Journal of environmental management 2018; 228:239-248.
- Currie LA. IUPAC nomenclature in evaluation of analytical methods including detection and quantification capabilities. Pure Appl Chem 1995;67.1699723.
- Dhahir, S. A., & Mhemeed, A. H. Spectrophotometric determination of sulfamethoxazole and sulfadiazine in pure and pharmaceuticals preparation. Asian Journal of Chemistry 2012; 24(7): 3053.
- Diaz, T. G., Cabanillas, A. G., Valenzuela, M. A., & Salinas, F. Polarographic behaviour of sulfadiazine, sulfamerazine, sulfamethazine and their mixtures. Use of partial least squares in the resolution of the non-additive signals of these compounds. Analyst 1996; 121(4): 547-552.
- Doaa, Th. H. The poetic deviation in the poetic collection (Qabas al-Ilham) By the poet Abdul Hassan Khudair Obaid Al-Muhyawy. Sumer University Journal for humanity science 2024; (Special issue 3): 307-324.
- Dowd, P. A. Accuracy and Precision. In Encyclopedia of Mathematical Geosciences Cham: Springer International Publishing, 2023; 1-4p.
- Eshghi, H., Rahimizadeh, M., Zokaei, M., Eshghi, S., Eshghi, S., Faghihi, Z., et al . Synthesis and antimicrobial activity of some new macrocyclic bis-sulfonamide and disulfides. European Journal of Chemistry 2011; 2(1): 47-50.
- Ewelina Patyra., Kwiatek, K. Simultaneous determination of sulfonamides, trimethoprim, amoxicillin and tylosin in medicated feed by high performance liquid chromatography with mass spectrometry. J Vet. Res. 2024;68: 129-136.
- Ezabadi, I. R., Camoutsis, C., Zoumpoulakis, P., Geronikaki, A., Sokovi, M., Glamoilija, J., & iri, A. (2008). Sulfonamide-1, 2, 4-triazole derivatives as antifungal and antibacterial agents: Synthesis, biological evaluation, lipophilicity, and conformational studies. Bioorganic & Medicinal Chemistry 2008; 16(3): 1150-1161.
- Fan, J., Chen, Y., Feng, S., Ye, C., Wang, J. Flow-injection spectrophotometric determination of sulfadiazine and sulfamethoxazole in pharmaceuticals and urine. Analytical Sciences 2003;19(3): 419422.
- Findlay, J. W., Smith, W. C., Lee, J. W., Nordblom, G. D., Das, I., DeSilva, B. S., et al. Validation of immunoassays for bioanalysis: a pharmaceutical industry perspective. Journal of pharmaceutical and biomedical analysis 2000; 21(6): 1249-1273.
- Gaballah, M. S., Li, X., Zhang, Z., Al-Anazi, A., Sun, H., Sobhi, M., ... & Dong, R. Determination of tetracycline, oxytetracycline, sulfadiazine, norfloxacin, and enrofloxacin in swine manure using a coupled method of on-line solid-phase extraction with the uhplcdad. Antibiotics 2021; 10(11): 1397.
- Goth, A. (1981) . Medical Pharmacology , 10th Edn. , New York . 1981; 622.
- Handayani, Y. Development of a Simultaneous Sulfadiazine, Sulfamethoxazole, and Tetracycline Antibiotic Level Determination Method with High-Performance Liquid Chromatography. Natural Sciences Engineering and Technology Journal 2023; 3(1): 107-114.
- Hasan, A. F., & Mohammed, I. S. spectrophotometric determination and cloud point extraction of sulfadiazine in pure and pharmaceutical form. Biochemical & Cellular Archives 2021; 21(1).
- He, B. S., Chen, W. B. Voltammetric determination of sulfonamides with a modified glassy carbon electrode using carboxyl multiwalled carbon nanotubes. Journal of the Brazilian Chemical Society 2016; 27(12): 2216-2225.
- Henry, B., Foti, C., & Alsante, K. Can light absorption and photostability data be used to assess the photosafety risks in patients for a new drug molecule?. Journal of Photochemistry and Photobiology B: Biology 2009: 96(1): 57-62.
- Hong, X., Ma, J. Sensitive Sulfadiazine Sensor Based on Multiwalled Carbon Nanotubes Wrapped with Polystyrene Sulfonate Polymer Chain. International Journal of Electrochemical Science 2017; 12(7): 6779-6787.
- Hong, X., Zhu, Y., Ma, J. Application of multiwalled carbon nanotubes/ionic liquid modified electrode for amperometric determination of sulfadiazine. Drug testing and analysis 2012; 4(12): 1034-1039.
- Indian Pharmacopoeia. 9th Edition, Vol 4th Veterinary Monographs, The Indian Pharmacopoeia Commission Ghaziabad, 2022: 4924, 4925, 4926, 4927 pp.
- Injac, R., Kac, J., Karljikovic-Rajic, K., & Strukelj, B. Optimal conditions for extraction and simultaneous determination of sulfamethoxazole and trimethoprim in pharmaceuticals by micellar electrokinetic capillary chromatography. Journal of Food and Drug Analysis 2008;16(1): 18-25.
- International Conference on Harmonisation of Technical Requirements for Registration of Pharmaceuticals for Human Use. Validation of Analytical Methods: Denitions and Terminology. Geneva, Switzerland: ICH Secretariat (accessed 5/11/10).
- International Conference on Harmonization (ICH), Q2A: Federal Register, Vol. 60, March 1995, 11260 p.
- Ismail, B., & Nielsen, S. S. Basic principles of chromatography. Food analysis 2010; 27: 473-498.
- John, M.B. and John, H.B. Wilson and Gisvolds Textbook of Organic Medicinal and Pharmaceutical Chemistry ,12th Edn. Lippincott Williams & Wilkins, UK, 2004; p.237.
- Khalaf, R. A., Sheikha, G. A., Al-Sha'er, M., & Taha, M. Design, synthesis and biological evaluation of N4-sulfonamido-succinamic, phthalamic, acrylic and benzoyl acetic acid derivatives as potential DPP IV inhibitors. The Open Medicinal Chemistry Journal 2013; 7 (39).
- Kokulnathan, T., Kumar, E. A., Wang, T. J., Cheng, I. C. Strontium tungstate-modified disposable strip for electrochemical detection of sulfadiazine in environmental samples. Ecotoxicology and Environmental Safety 2021; 208, 111516.
- Lattanzio, G., Garca-Campaa, A. M., Soto-Chinchilla, J. J., Gmiz-Gracia, L., & Girotti, S. Chemiluminescence determination of sulphadiazine in drugs by flow injection analysis using the peroxyoxalate reaction in micellar medium. Journal of pharmaceutical and biomedical analysis 2008; 46(2): 381-385.
- Li, Z., Mo, Z., Meng, S., Gao, H., Niu, X., & Guo, R. (2016). The construction and application of chiral electrochemical sensors. Analytical Methods 2016; 8(46): 8134-8140.
- Liu, B., Ma, Y., Zhou, F., Wang, Q., & Liu, G. Voltammetric determination of sulfadiazine based on molecular imprinted electrochemical sensor. International Journal of Electrochemical Science 2020; 15(10): 9590-9596.
- Ma, J. Y., Hong, X. P. Simple Fabrication of Reduced Graphene OxideIonic Liquid Composite Modified Electrode for Sensitive Detection of Sulfadiazine. International Journal of Electrochemical Science 2020; 15(5): 3729-3739.
- Mahdi, M. I. and Kadim, K. H. (2015). Spectrophtometric determination of sulfadiazine in various sample by coupling with 2,5-dimethoxy aniline. Iraqi National Journal of Chemistry 2015; 15(1): 27 40.
- Malintan, N. T., Mohd, M. A. Determination of sulfonamides in selected Malaysian swine wastewater by high-performance liquid chromatography. Journal of Chromatography A 2006; 1127(1-2): 154-160.
- Maseer, A., Najem, M. Spectrophotometric Determination of Mesalazine in Pure Form and Pharmaceutical Formulations by Diazotization and Coupling With 2, 7-Dihydroxynaphthalene As a New Coupling Agent. Hacettepe University Journal of the Faculty of Pharmacy 2023; 43(3): 195-203.
- Mohamed, A. M. I., Askal, H. F., Saleh, G. A. Use of p-benzoquinone for the spectrophotometric determination of certain sulphonamides. Journal of pharmaceutical and biomedical analysis 1991; 9(7): 531-538.
- Mohammed, S. A. and Zebary, H. Y. S. Spectrophotometric determination of sulfadiazine via diazotization and coupling reaction - application to pharmaceutical. J. Sci. 2013; 24(6): 61-73.
- Mounir, M., Safwat, M. T., Abdelaleem, E. A. Chromatographic Analysis of Triple Veterinary Therapy; Erythromycin, Sulfadiazine and Trimethoprim in Different Edible Chicken Tissues. Available at SSRS 2023; 24.
- Msagati, T. A., Ngila, J. C. Voltammetric detection of sulfonamides at a poly (3-methylthiophene) electrode. Talanta 2002; 58(3): 605-610.
- Nagaraja, P., Naik, S. D., Shrestha, A. K., & Shivakumar, A. A sensitive spectrophotometric method for the determination of sulfonamides in pharmaceutical preparations. Acta Pharmaceutica 2007 57(3): 333-342.
- Nagaraja, P., Naik, S. D., Shrestha, A. K., & Shivakumar, A. A sensitive spectrophotometric method for the determination of sulfonamides in pharmaceutical preparations. Acta Pharmaceutica 2007;57(3): 333-342.
- Nejres, A. M., & Najem, M. A. Spectrophotometric determination of mesalazine in pure and pharmaceutical preparations by chelation method. AIP Conf. Proc. 2023; 2776 (1): 030003.
- Nejres, A. M., & Najem, M. A. Use of Mesalazine for the determination of dopamine and its pharmaceutical preparations by spectrophotometric method. Israa Univ. J. Appl. Sci 2022; 6(1): 228-245.
- Neumann, M. G., Miranda Jr, W. G., Schmitt, C. C., Rueggeberg, F. A., & Correa, I. C. Molar extinction coefficients and the photon absorption efficiency of dental photoinitiators and light curing units. Journal of dentistry 2005; 33(6): 525-532.
- Othman, N. S.and Kadder, R. M. Histidine as a new coupling agent for the spectrophotometric assay of sulphadiazine application to pharmaceutical preparations. Jour. Sci. 2006; 17 (4) :25 35.
- Ovung, A., & Bhattacharyya, J. Sulfonamide drugs: Structure, antibacterial property, toxicity, and biophysical interactions. Biophysical reviews 2021; 13(2): 259-272.
- Ozkan, S.A.; Kauffmann, J.M.; Zuman, P. Electroanalytical method validation in pharmaceutical analysis and their applications. Electroanalysis in Biomedical and Pharmaceutical Sciences: Voltammetry, Amperometry, Biosensors, Applications, HNB publishing; New York 2015; 235266.
- Ozkorucuklu, S. P., Ozcan, L., Sahin, Y., Alsancak, G. Electroanalytical determination of some sulfonamides on overoxidized polypyrrole electrodes. Australian Journal of Chemistry 2011; 64(7): 965-972.
- Papapanagiotou, E. P., Iossifidou, E. G., Psomas, I. E. and Photis, G. Simultaneous HPLC Determination of sulfadiazine and trimethoprime in cultured gilt head sea bream (Sparus Aurata L.) tissues. Journal of Liquid Chromatography & Related Technologies 2000; 23(18): 28392849.
- Patyra, E., Przenioso-Siwczy, M. and Kwiatek, K. Determination of sulfonamides in feeds by high-performance liquid chromatography after fluorescamine precolumn derivatization. Molecules 2019; 24(3): 452.
- Pokala, R. V., Kumari, K., Bollikola, H. B. UV Spectrophotometric method development and validation of sulfadiazine and trimethoprime in combined dosage form. International Journal of Pharmacy and Pharmaceutical Sciences 2018; 10(1): 103.
- Prass, S., St-Pierre, J., Klingele, M., Friedrich, K. A., Zamel, N. Hydrogen oxidation artifact during platinum oxide reduction in cyclic voltammetry analysis of low-loaded PEMFC electrodes. Electrocatalysis 2021; 12: 45-55.
- Ravisankar, P., Sulthana, M. S., Babu, P. S., Basha, S. A., Aswini, R., Swathi, V., ... & Thanuja, I. M. Comprehensive review of important analytical reagents used in spectrophotometry. Indo Am. J. Pharm. Res 2017; 7(5): 8716-8744.
- Richards, P., & Vishwanath, B. A. Analytical Method Development and Validation for the Simultaneous Estimation of Sulfadiazine and Pyrimethamine by RP-HPLC Method. RGUHS Journal of Pharmaceutical Sciences 2022; 12(1): 47-51.
- Romero, A. M., Benito, C. G., & Calatayud, J. M. Continuous-flow spectrophotometric determination of sulfadiazine by diazotisation with in situ preparation of nitrite. Analytica chimica acta 1995; 308(1-3): 451-456.
- Sadeghi, S., Garmroodi, A. Sensitive detection of sulfasalazine at screen printed carbon electrode modified with functionalized multiwalled carbon nanotubes. Journal of Electroanalytical Chemistry 2014; 727: 171-178.
- Sadeghi, S., Motaharian, A. Voltammetric sensor based on carbon paste electrode modified with molecular imprinted polymer for determination of sulfadiazine in milk and human serum. Materials Science and Engineering: C 2013; 33(8): 4884-4891.
- Sakthivel, R., Kubendhiran, S., Chen, S. M., Chen, T. W., Al-Zaqri, N., Alsalme, A., et al. Exploring the promising potential of MoS2RuS2 binary metal sulphide towards the electrocatalysis of antibiotic drug sulphadiazine. Analytica Chimica Acta, 2019; 1086: 55-65.
- Scozzafava, A., Mastrolorenzo, A., & Supuran, C. T. Sulfonamides and sulfonylated derivatives as anticancer agents. Current cancer drug targets 2002; 2(1): 55-75.
- Shabir, G. A. Validation of high-performance liquid chromatography methods for pharmaceutical analysis: Understanding the differences and similarities between validation requirements of the US Food and Drug Administration, the US Pharmacopeia and the International Conference on Harmonization. Journal of chromatography A 2003; 987(1-2): 57-66.
- Sharkawi, M. M., Safwat, M. T., & Abdelwahab, N. S. Ecofriendly UPLC-MS/MS method for simultaneous assay of veterinary drugs residues; erythromycin, sulfadiazine and trimethoprim in edible chicken tissues, evaluation of method greenness and whiteness.Microchemical Journal 2024; 204: 111060.
- Shu, Y. Z. Recent natural products-based drug development: a pharmaceutical industry perspective. Journal of natural products 1998;61(8): 1053-1071.
- Skoog, D.A. and Wast, D.M. Fundamentals of Analytical Chemistry. 9th Edn. Thomason learning, New York, 2013; 503-504,515-517,741-742,948p.
- Souza, C. D., Braga, O. C., Vieira, I. C., Spinelli, A. Electroanalytical determination of sulfadiazine and sulfamethoxazole in pharmaceuticals using a boron-doped diamond electrode. Sensors and Actuators B: Chemical 2008; 135(1): 66-73.
- Srivastava, A. K., Upadhyay, S. S., Rawool, C. R., Punde, N. S., Rajpurohit, A. S. Voltametric techniques for the analysis of drugs using nanomaterials based chemically modified electrodes. Current Analytical Chemistry 2019; 15(3): 249-276.
- Stock, R., & Rice, C. B. F. Chromatographic methods. 3rd edition, eBook ISBN: 978-1-4899-3360-7 Springer, Salisbury, Wiltshire, UK, 2010.
- Sun, Y., He, J., Waterhouse, G. I., Xu, L., Zhang, H., Qiao, X., & Xu, Z. A selective molecularly imprinted electrochemical sensor with GO@ COF signal amplification for the simultaneous determination of sulfadiazine and acetaminophen. Sensors and Actuators B: Chemical 2019; 300: 126993.
- Supuran, C. T., Casini, A., & Scozzafava, A. Protease inhibitors of the sulfonamide type: anticancer, anti-inflammatory, and antiviral agents. Medicinal Research Reviews 2003; 23(5): 535-558.
- Swetha, R., Kumar, D., Gupta, S. K., Ganeshpurkar, A., Singh, R., Gutti, G. et al. Multifunctional hybrid sulfonamides as novel therapeutic agents for Alzheimers disease. Future Medicinal Chemistry 2019; 11(24): 3161-3178.
- Talal Kh. S., Doaa T. H. Humanize nature in the poetry of childhood in Iraq (2003-2015). Journal of the College of Education for Women 2017; 28(2):400-409.
- United States pharmacopeia national formulary , Thirty-Third Edition. USP 38NF 33, USA, 2015: 5382,5383,5384,5385 pp.
- United States Pharmacopeia, Validation of Compendial Methods b1225N, in: The Official Compendia of Standards USP 32/NF29. Unite States Pharmacop -eial Convention, Rockville, MD, 2009.
- Uriel, M., Marro, D., et al. An AdequatePharmaceu-tical Quality System for Personalized Preparation. Pharmaceutics 2023; 15(3): 800.
- Vandana , K.: Dash , A.K. ; Kothapalli , U. ; Kishore ,T.S. ; Harika , L. and Pradhan , K.K. Method development and validation of sulphadiazine in bulk and pharmaceutical Dosage form by UV-spectrophotometric method . J Pharm. & Biol. 2011; 2(4):1167-1171.
- Vinoth, S., Govindasamy, M., Wang, SF. et al. Hydrothermally synthesized cubical zinc manganite nanostructure for electrocatalytic detection of sulfadiazine. Microchim Acta 2021; 188(131): 1-10.
- Vivekanandan, A. K., Muthukutty, B., Chen, S. M., Sivakumar, M., Chen, S. H. Intermetallic compound Cu2Sb nanoparticles for effective electrocatalytic oxidation of an antibiotic drug: sulphadiazine. ACS Sustainable Chemistry & Engineering 2020; 8(48): 17718-17726.
- Wilson C. O., Gisvold O., Block J. H.: Wilson and Gisvolds Textbook of Organic Medicinal and Pharmaceutical Chemistry, 11th ed., Block J., Beale J. M., Eds., Lippincott Williams and Wilkins: Philadelphia, 2004.
- Yu, L. X. Pharmaceutical quality by design: product and process development, understanding, and control. Pharmaceutical research, 25, 781-791.
- Zhou, Y., Wang, J., Gu, Z., Wang, S., Zhu, W., Acena, J. L., et al. Next generation of fluorine-containing pharmaceuticals, compounds currently in phase IIIII clinical trials of major pharmaceutical companies: new structural trends and therapeutic areas. Chemical reviews 2016; 116(2): 422-518.
- Zonaras, V., Tyrpenou, A., Alexis, M., and Koupparis, M. Determination of sulfadiazine, trimethoprim, and N4-acetyl-sulfadiazine in fish muscle plus skin by liquid chromatography-mass spectrometry. Withdrawal-time calculation after in-feed administration in gilthead sea bream (Sparus aurata L.) fed two different diets. Journal of Veterinary Pharmacology and Therapeutics 2016; 39(5): 504513.