Reviewing the use of ethylcellulose, methylcellulose and hypromellose in microencapsulation. Part 2: Techniques used to make microcapsules

Drug Development and Industrial Pharmacy

Volumn 37, Issue 11, 2011, Pages 1259-1271

  Rogers, True L ^a   Wallick, Dave ^a  

^a DOW CHEMICAL COMPANY   (United States)

Author keywords

Encapsulation; HPMC; Hydroxypropyl methylcellulose; Microcapsule; Microparticle; Microsphere; Multiparticulate

Indexed keywords

ACETYLSALICYLIC ACID; ETHYL CELLULOSE; HYDROXYPROPYLMETHYLCELLULOSE; METHYLCELLULOSE; SOLVENT;

ELECTROSPRAY; EMULSION; EVAPORATION; MICROCAPSULE; MICROENCAPSULATION; PHASE SEPARATION; REVIEW; TEMPERATURE;

CAPSULES; CELLULOSE; DRUG COMPOUNDING; METHYLCELLULOSE; PARTICLE SIZE; SURFACE PROPERTIES;

EID: 80053976985     PISSN: 03639045     EISSN: 15205762     Source Type: Journal    
DOI: 10.3109/03639045.2011.567275     Document Type: Review

References (173)

1. Kitakoji T, Yoneda Y, Murakawa K. (1973). Double-wall microencapsulation for pressure-sensitive copying paper. JP 49121786 A2.
2. Samejima M, Hirata G, Ishibashi T. (1985). Process for preparing free-flowing ethyl cellulose microcapsules. US 4542042.
3. Amperiadou A, Georgarakis M. (1995). Controlled release salbutamol sulfate microcapsules prepared by emulsion solvent-evaporation technique and study on the release affected parameters. Int J Pharm, 115:1-8.
4. Moldenhauer MG, Nairn JG. (1991). The effect of rate of evaporation on the coat structure of ethylcellulose microcapsules. J Controlled Release, 17:49-60.
5. Lippold BH, Sutter BK, Lippold BC. (1989). Parameters controlling drug release from pellets coated with aqueous ethyl cellulose dispersion. Int J Pharm, 54:15-25. (Pubitemid 19198396)
6. D'Onofrio GP, Oppenheim RC, Bateman NE. (1979). Encapsulated microcapsules. Int J Pharm, 2:91-99. (Pubitemid 9114549)
7. Hasçiçek C, Gönül N, Erk N. (2003). Mucoadhesive microspheres containing gentamicin sulfate for nasal administration: preparation and in vitro characterization. Farmaco, 58:11-16. (Pubitemid 38365966)
8. Rao KR, Senapati P, Das MK. (2005). Formulation and in vitro evaluation of ethyl cellulose microspheres containing zidovudine. j Microencapsul, 22:863-876. (Pubitemid 43158188)
9. Witz I. (1982). Microcapsules for pressure sensitive recording materials. GB 2017624 B.
10. Chow AHL, Ho SSS, Tong HHY, Ma HHM. (1998). Parameters affecting in-liquid drying microencapsulation and release rate of cefaclor. Int J Pharm, 172:113-125. (Pubitemid 28430249)
11. Zhang Y, Chen L, Li B, Hua Z, Wu Y, Liu Z, Lu W. (2004). Effects of processing parameters on ethylcellulose microencapsulation using supercritical CO2 antisolvent precipitation. Shipin Kexue, 25:96-99.
12. Yalabik-Kas HS. (1983). Microencapsulation and in vitro dissolution of oxazepam from ethyl cellulose microcapsules. Drug Dev Ind Pharm, 9:1047-1060.
13. Trotta M, Cavalli R, Trotta C, Bussano R, Costa L. (2010). Electrospray technique for solid lipid-based particle production. Drug Dev Ind Pharm, 36:431-438.
14. Alam AS, Eichel HJ. (1980). Indoprofen - a continuous release pharmaceutical. DE 3001797 A1.
15. Lin S-Y, Yang JC. (1986). Studies on microencapsulation. Part IV. Effect of ethylene-vinyl acetate as a coacervation-inducing agent on the production and release behavior of chlorpromazine hydrochloride microcapsules and tabletted microcapsules. J Controlled Release, 3:221-228.
16. Vitkova M, Chalabala M, Rak J, Prochazka R. (1994). Ethylcellulose to prepare a matrix system of a hydrophilic drug by the microencapsulation process. S.T.P. Pharma Sciences, 4:486-491. (Pubitemid 24380410)
17. Kaltsatos V, Rollet M, Perez J. (1989). Optimization of a method of microencapsulation by phase separation. Role of the hydroxypropyl methyl cellulose as a nucleating agent. S.T.P. Pharma, 5:96-102. (Pubitemid 19077995)
18. Alam AS, Eichel HJ. (1982). Sustained release pharmaceutical formulation. US 4316884 A.
19. Lin SY, Chen FJ. (1992). Cooling rate affecting the formation and properties of theophylline ethylcellulose microcapsules prepared by phase separation method. Pharm Acta Helv, 67:91-96.
20. Whitaker Sr. DM. (1991). Stabilized perfume-containing microcapsules and method of preparing the same. US 5051305 A.
21. Anderson JL, Haines RC Jr, Powell TC. (1972). Minute capsules and their manufacture en masse. US 3694372 A.
22. Miller RE, Anderson JL. (1964). Minute polymeric capsules for drugs. US 3155590.
23. Wieland-Berghausen S, Schote U, Frey M, Schmidt F. (2002). Comparison of microencapsulation techniques for the watersoluble drugs nitenpyram and clomipramine HCl. J Control Release, 85:35-43. (Pubitemid 35476851)
24. Bettman MJ, Percel PJ, Powell TC. (1997). Effervescent microcapsules. US 5639475.
25. Morse LD. (1971). Microencapsulation form of antiinflammatory indomethacin. US 3557279 A.
26. Calanchi M, Gentilini L. (1985). Sustained release formulation of water-soluble components. EP 0177000 A1.
27. Morse LD, Hammes PA. (1974). Microencapsulated multivitamin compositions. GB 1371840 A.
28. Cameroni R, Coppi G, Forni F, Iannuccelli V, Bernabei MT. (1985). [Sulfadiazine: release from microcapsules]. Boll Chim Farm, 124:393-400.
29. Morse LD, Walker WG, Hammes PA. (1978). Microencapsulation. US 4123382 A.
30. Carpov A, Oita N, Tolea A. (1980). Microencapsulation of calcium rutin and magnesium rutin. RO 74767 B.
31. Motycka S, Nairn JG. (1979). Preparation and evaluation of microencapsulated ion-exchange resin beads. J Pharm Sci, 68:211-215. (Pubitemid 9117128)
32. Carpov A, Oita N, Tolea A, Pavelescu M. (1982). Antiinflammatory and antirheumatic composition containing acetylsalicylic acid and aminocaproic acid. RO 78211 B.
33. Nasa SL, Yadav S. (1989). Microencapsulation of metoprolol tartrate using phase separation coacervation techniques. Eastern Pharmacist, 32:133-134.
34. Chemtob C, Chaumeil JC, N'Dongo M. (1986a). Microencapsulation by ethyl cellulose phase separation: microcapsule characteristics. Int J Pharm, 29:1-7. (Pubitemid 16162490)
35. Manufacture of small capsules by coating with cellulose ethers or other polymers. (1967). NL 6611661.
36. Chemtob C, Chaumeil JC, N'Dongo M. (1986b). Tablets of metronidazole microcapsules: release characteristics. Int J Pharm, 29:83-92. (Pubitemid 16162499)
37. Nixon JR, Wong KT. (1990). Evaluation of drug permeation through polymeric membranes as a model for release. (II). Ethyl cellulosewalled microcapsules. Int J Pharm, 58:31-40. (Pubitemid 20034225)
38. Deasy PB, Brophy MR, Ecanow B, Joy MM. (1980). Effect of ethylcellulose grade and sealant treatments on the production and in vitro release of microencapsulated sodium salicylate. J Pharm Pharmacol, 32:15-20. (Pubitemid 10184746)
39. Powell TC. (1993). Controlled-release calcium channel blocker microcapsules. US 5252337 A.
40. Doshi HA, Nafde P, Shrivastava R. (1994). A study of microencapsulation by coacervation phase separation of ethylcellulose. Indian Journal of Pharmaceutical Sciences, 56:195-197.
41. Rak J, Vitkova M, Chalabala M, Heliova M. (1984). Study on drug microforms. X. Manufacture and in vitro evaluation of ethyl cellulose microcapsules with sulfamethoxydiazine. Farmaceuticky Obzor, 53:445-454. (Pubitemid 14018770)
42. El-Helw AER. (1987). Effect of microcapsule size on release and bioavailability of phenazopyridine hydrochloride from ethyl cellulose walled microcapsules. Acta Pharmaceutica Technologica, 33:145-148.
43. Safwat SM, El-Shanawany S. (1989). Evaluation of sustainedrelease suppositories containing microencapsulated theophylline and oxyphenbutazone. J Controlled Release, 9:65-73. (Pubitemid 19155973)
44. Fan G, Qu R, Zhou W, Yan Y, Zhao Q. (1996). Research on microencapsulation of water-soluble vitamins. Tianjin Daxue Xuebao, 29:592-597.
45. Samejima M, Hirata G, Koida Y. (1982). Studies on microcapsules. I. Role and effect of coacervation-inducing agents in the microencapsulation of ascorbic acid by a phase separation method. Chem Pharm Bull, 30:2894-2899. (Pubitemid 13235411)
46. Fekete P, Bezzegh D, Zukovics K, Jámbor Z, Tombor J. (1989). Process for preparing microcapsules comprising ethyl cellulose. GB 2226804 B2.
47. Friend DR, Ng S, Sarabia RE, Weber TP, Geoffroy J-M. (1997). Tastemasked microcapsule compositions and methods of manufacture. WO 9814179 A1.
48. Samejima M, Hirata G, Koida Y. (1983). Process for preparing pharmaceutically active compound-containing microcapsules. US 4389331.
49. Inoe N. (1992). Microencapsulated anti-AIDS virus agents. JP 06316524 A2.
50. Shin SC, Koh IB. (1989). Effect of polyisobutylene and sealant treatments on ethyl cellulose-walled methyldopa microcapsules. Yakche Hakhoechi, 19:29-37.
51. John PM. (1979). Controlled-release composition. US 4153677 A.
52. Singh J, Robinson DH. (1988). Controlled release captopril microcapsules: effect of non-ionic surfactants on release from ethyl cellulose microcapsules. J Microencapsul, 5:129-137.
53. Singh J, Robinson DH. (1990). Controlled release captopril microcapsules: effect of ethyl cellulose viscosity grade on the in vitro dissolution from microcapsules and tableted microcapsules. J Microencapsul, 7:67-76. (Pubitemid 20131656)
54. Kato T. (1981). Sustained-release pharmaceutical microcapsules. JP 58035110 A2.
55. Sveinsson SJ, Kristmundsdottir T. (1992). Naproxen microcapsules: preparation and in vitro characterization. Int J Pharm, 82:129-133.
56. Koida Y, Hirata G, Samejima M. (1983). Studies on microcapsules. II. Influence of molecular weight of ethylcellulose in the microencapsulation of ascorbic acid. Chem Pharm Bull, 31:4476-4482. (Pubitemid 14175612)
57. Szretter D, Zakrzewski Z. (1984). Microencapsulation of riboflavin by dispersion-congealing technique or by simple coacervation. Farmacja Polska, 40:275-279.
58. Koida Y, Kobayashi M, Samejima M. (1986). Studies on microcapsules. IV. Influence of properties of drugs on microencapsulation and dissolution behavior. Chem Pharm Bull, 34:3354-3361. (Pubitemid 17172400)
59. Uddin MS, Hawlader MN, Zhu HJ. (2001). Microencapsulation of ascorbic acid: effect of process variables on product characteristics. J Microencapsul, 18:199-209. (Pubitemid 32177838)
60. Kristl A, Bogataj M, Mrhar A, Kozjek F. (1991). Preparation and evaluation of ethyl cellulose microcapsules with bacampicillin. Drug Dev Ind Pharm, 17:1109-1130.
61. Vitkova M, Chalabala M, Rak J, Pikulikova Z. (1983). Study of drug microforms. IV. Preparation of microcapsules containing potassium chloride. Farmaceuticky Obzor, 52:531-538.
62. Lin SY. (1985). Influence of coacervation-inducing agents and cooling rates on the preparation and in vitro release of bleomycin hydrochloride microcapsules. J Microencapsul, 2:91-101.
63. Vitkova M, Chalabala M, Rak J, Heliova M. (1984). Drug microforms. VII. Microcapsules of chloramphenicol. Farmaceuticky Obzor, 53:241-250.
64. Abu-Izza KA, Garcia-Contreras L, Lu DR. (1996). Preparation and evaluation of sustained release AZT-loaded microspheres: optimization of the release characteristics using response surface methodology. J Pharm Sci, 85:144-149. (Pubitemid 26055794)
65. Morishita M, Inaba Y, Fukushima M, Hattori Y, Kobari S, Matsuda T. (1981). Microcapsule preparation. JP 56019324 B4.
66. Guyot M, Fawaz F. (1998). Nifedipine loaded-polymeric microspheres: preparation and physical characteristics. Int J Pharm, 175:61-74. (Pubitemid 28487016)
67. Mortada SM. (1982). Preparation of ethyl cellulose microcapsules using the complex emulsion method. Pharmazie, 37:427-429. (Pubitemid 12020046)
68. Bhalerao SS, Lalla JK, Rane MS. (2001). Study of processing parameters influencing the properties of diltiazem hydrochloride microspheres. J Microencapsul, 18:299-307. (Pubitemid 32285027)
69. Murthy TEGK, Chowdary KPR. (2004). Influence of polymer solvent on permeability and release of diclofenac from ethylcellulose films and microcapsules. International Journal of Pharmaceutical Excipients, April-June, 39-45.
70. Bodmeier R, Chen H. (1989). Preparation and characterization of microspheres containing the anti-inflammatory agents, indomethacin, ibuprofen, and ketoprofen. J Controlled Release, 10:167-175. (Pubitemid 19259948)
71. Murthy TEGK, Chowdary KPR. (2005). Formulation and evaluation of ethylcellulose-coated diclofenac sodium microcapsules: influence of solvents. Indian Journal of Pharmaceutical Sciences, 67:216-219.
72. Bodmeier R, Chen H. (1990). Indomethacin polymeric nanosuspensions prepared by microfluidization. J Controlled Release, 12:223-233. (Pubitemid 20162633)
73. Pérez-Martínez JI, Morillo E, Maqueda C, Ginés JM. (2001). Ethyl cellulose polymer microspheres for controlled release of norfluazon. Pest Manag Sci, 57:688-694. (Pubitemid 32737708)
74. Cheu SJ, Chen RR, Chen PF, Lin WJ. (2001). In vitro modified release of acyclovir from ethyl cellulose microspheres. J Microencapsul, 18:559-565. (Pubitemid 33150487)
75. Ravichandran V, Sivanand V, Raghuraman S, Velrajan G, Mohan SBN, Subash S, Bennitojohnson D, Sankar V. (2001). Microencapsulation of nimesulide for sustained release. Eastern Pharmacist, 44:111-114.
76. Das SK. (1991). In vitro dissolution profile of theophylline loaded ethylcellulose microspheres prepared by emulsification solvent evaporation. Drug Dev Ind Pharm, 17:2521-2528.
77. Ruiz R, Sakr A, Sprockel OL. (1990). A study on the manufacture and in vitro dissolution of terbutaline sulfate microcapsules and their tablets. Drug Dev Ind Pharm, 16:1829-1842. (Pubitemid 20230586)
78. Elbahri Z, Taverdet JL. (2005). Optimization of an herbicide release from ethylcellulose microspheres. Polymer Bulletin, 54:353-363. (Pubitemid 40997627)
79. Sheorey DS, Sai MS, Dorle AK. (1991). A new technique for the encapsulation of water insoluble drugs using ethyl cellulose. J Microencapsul, 8:359-368.
80. Goto S, Uchida T, Aoyama T. (1985). Preparation and biopharmaceutical evaluation of microcapsules of ampicillin. J Pharmacobio-Dyn, 8:270-277. (Pubitemid 15055785)
81. Sriwongjanya M, Bodmeier R. (1997). Entrapment of drug-loaded ion-exchange particles within polymeric microparticles. Int J Pharm, 158:29-38. (Pubitemid 27504471)
82. Uno K, Ohara Y, Arakawa M, Kondo T. (1984). A new method of preparing monocored water-loaded microcapsules using interfacial polymer deposition process. J Microencapsul, 1:3-8.
83. Huang HP, Ghebre-Sellassie I. (1989). Preparation of microspheres of water-soluble pharmaceuticals. J Microencapsul, 6:219-225. (Pubitemid 19122963)
84. Jones DS, Pearce KJ. (1995). An investigation of the effects of some process variables on the microencapsulation of propranolol hydrochloride by the solvent evaporation method. Int J Pharm, 118:199-205.
85. Yang CY, Tsay SY, Tsiang RC. (2000). An enhanced process for encapsulating aspirin in ethyl cellulose microcapsules by solvent evaporation in an O/W emulsion. J Microencapsul, 17:269-277. (Pubitemid 30235001)
86. Kentepozidou A, Kiparissides C. (1995). Production of watercontaining polymer microcapsules by the complex emulsion/ solvent evaporation technique. Effect of process variables on the microcapsule size distribution. J Microencapsul, 12:627-638.
87. Yang CY, Tsay SY, Tsiang RC. (2001a). Encapsulating aspirin into a surfactant-free ethyl cellulose microsphere using nontoxic solvents by emulsion solvent-evaporation technique. J Microencapsul, 18:223-236. (Pubitemid 32177840)
88. Kiritani M. (1973). Particle encapsulation. JP 50094112 A2.
89. Yang C-Y, Tsay S-Y, Chen B-K. (2001b). Application of gelatin for encapsulating aspirin into ethylcellulose microcapsule in an O/W emulsion. Chemical Engineering Communications, 186:241-255. (Pubitemid 34617049)
90. Lin WJ, Wu TL. (1999). Modification of the initial release of a highly water-soluble drug from ethyl cellulose microspheres. J Microencapsul, 16:639-646.
91. Yang F, Chu Y, Huo L, Yang Y, Liu Y. (2005). Fabrication of polyaniline/ethylcellulose composite microspheres by microencapsulation. Chemistry Letters, 34:388-389. (Pubitemid 40726595)
92. Morishita M, Inaba Y, Fukushima M. (1973). Microencapsulation of hydrogenated macrolide antibiotics. JP 49100216 A2.
93. Zandi M, Pourjavadi A, Hashemi SA, Arabi H. (1998). Preparation of ethylcellulose microcapsules containing perphenazine and polymeric perphenazine based on acryloyl chloride for physical and chemical studies of drug release control. Polymer International, 47:413-418.
94. Morishita M, Inaba Y, Fukushima M, Hattori Y, Kobari S, Matsuda T. (1976). Encapsulation of medicaments. US 3960757 A.
95. Andre-Abrant A, Taverdet J-L, Jay J. (2001). Microencapsulation by solvent evaporation. European Polymer Journal, 37:955-963.
96. Manekar NC, Puranik PK, Joshi SB. (1992b). Microencapsulation of terbutaline sulphate by the solvent evaporation technique. J Microencapsul, 9:481-487.
97. Arabi H, Hashemi SA, Fooladi M. (1996). Microencapsulation of allopurinol by solvent evaporation and controlled release investigation of drugs. J Microencapsul, 13:527-535. (Pubitemid 26283806)
98. Manekar NC, Puranik PK, Joshi SB. (1993). Microencapsulation of propranolol hydrochloride by the solvent evaporation technique. Eastern Pharmacist, 36:119-122.
99. Assimopoulou AN, Papageorgiou VP. (2004). Preparation and release studies of alkannin-containing microcapsules. J Microencapsul, 21:161-173. (Pubitemid 38401096)
100. Cristallini C, Enriquez de Grassi G, Guardines L, Gaussmann R. (1984). A controlled-release antiinflammatory drug. Studies on microcapsules. Appl Biochem Biotechnol, 10:267-272. (Pubitemid 15183363)
101. Moldenhauer MG, Nairn JG. (1992). The control of ethylcellulose microencapsulation using solubility parameters. J Controlled Release, 22:205-218.
102. Dubernet C, Rouland JC, Benoit JP. (1991). Ibuprofen-loaded ethylcellulose microspheres: analysis of the matrix structure by thermal analysis. J Pharm Sci, 80:1029-1033.
103. Moldenhauer MG, Nairn JG. (1994). Solubility parameter effects on microencapsulation in the presence of polyisobutylene. J Controlled Release, 31:151-162. (Pubitemid 24268161)
104. Elbary AA, El Razaz MA, El-Khateeb MM, Mohamed AI. (2001). Formulation and evaluation of controlled release ibuprofen granules and coprecipitates. Bulletin of the Faculty of Pharmacy (Cairo University), 39:83-102.
105. Rhee GJ, Do KC, Kim EH, Park JB, Whang SJ. (1997). Development of multiparticulate-system composed of sustained-release microspheres of pseudoephedrine hydrochloride and immediaterelease pellets of terfenadine using solvent evaporation method and spherically agglomerated crystallization process. Yakhak Hoechi, 41:305-311.
106. Ghorab MM, Zia H, Luzzi LA. (1990). Preparation of controlled release anticancer agents. I: 5-Fluorouracil-ethyl cellulose microspheres. J Microencapsul, 7:447-454.
107. Sarin JPS, Khanna NM, Gupta SK, Khanna M, Singh S. (1985). Subdermal drug implants. GB 2103927 B2.
108. Ibrahim SA, Sayed HA, Hafez E, El-Sayed AM, Ali SS. (1990). Preparation and evaluation of sustained release ethyl cellulose encapsulated aspirin. Bulletin of Pharmaceutical Sciences, Assiut University, 13:235-246.
109. Tsujiyama T, Suzuki N, Kawata M, Uchida T, Goto S. (1989). Preparation and pharmacokinetic and pharmacodynamic evaluation of hydroxypropyl cellulose-ethyl cellulose microcapsules containing piretanide. J Pharmacobiodyn, 12:311-323. (Pubitemid 19177280)
110. Khalil SAH, El-Gamal SS. (1973). Coating of pharmaceuticals by phase separation of cellulose derivatives. Preparation and in vitro release. Pharmazie, 28:385-388.
111. Uchida T, Fujimoto I, Goto S, Aoyama T. (1987). Preparation and evaluation of ethyl cellulose microcapsule containing cefadroxil or cephradine. Yakuzaigaku, 47:254-259.
112. Kosenko NV, Lebedenko VYa, Makharadze RV. (1986). Microencapsulation of ethmozin and microcapsule properties. Farmatsiya (Moscow, Russian Federation), 35:23-26.
113. Uchida T, Yasutake T, Goto S. (1992). Utility of mixture of commercially available polymers as constituents of sustainedrelease microcapsules containing cefadroxil or theophylline. Chem Pharm Bull, 40:463-466.
114. Kristmundsdottir T, Ingvarsdottir K. (1994). Ibuprofen microcapsules: the effect of production variables on microcapsule properties. Drug Dev Ind Pharm, 20:769-778. (Pubitemid 24141754)
115. Ku YS, Kang HH. (1991). Microencapsulation of propranolol hydrochloride with ethylcellulose by solvent evaporation method in liquid paraffin. Nonchong - Han'guk Saenghwal Kwahak Yonguwon, 48:109-128.
116. Yoshida NH. (1972). Preparation of minuscule capsules. US 3657144.
117. Manekar NC, Puranik PK, Joshi SB. (1992a). Microencapsulation of propranolol hydrochloride by the solvent evaporation technique. J Microencapsul, 9:63-66.
118. Zhu R, Xue F, Yang L, Zhao D. (1992). Microencapsulation of vitamin C by the solvent vaporation process. Gongneng Gaofenzi Xuebao, 5:175-180.
119. Becourt P, Boltri L, Cioloca N, Bruschi SDL, Mapelli LG, Rabaglia L, Schwabe D. (2002a). Taste masked oral composition of telithromycin. WO 2004009059 A1.
120. Zulkarnain AK. (1996). The effect of cellulose derivatives on lynestrenol release rate from microencapsulated dosage form and in vitro-in vivo correlation. Majalah Farmasi Indonesia, 7:180-190.
121. Becourt P, Cioloca N, Boltri L, Bruschi SDL, Mapelli LG, Rabaglia L, Schwabe D. (2002b). Taste masked oral composition of telithromycin. US 2004013737 A1.
122. Bruschi SDL, Mapelli LG, Rabaglia L, Boltri L. (2002). Process for the preparation of pharmaceutical microcapsules with enhanced taste-masking and high dissolution rate. WO 2004009058 A1.
123. Cordes G. (1972). Microencapsulation of pharmaceuticals. DE 2223896 A1.
124. Fukumori Y, Ichikawa H, Yamaoka Y, Akaho E, Takeuchi Y, Fukuda T, Kanamori R, Osako Y. (1991a). Microgranulation and encapsulation of pulverized pharmaceutical powders with ethyl cellulose by the Wurster process. Chem Pharm Bull (Tokyo), 39:1806-1812.
125. Fukumori Y, Ichikawa H, Yamaoka Y, Akaho E, Takeuchi Y, Fukuda T, Kanamori R, Osako Y. (1991b). Effect of additives on physical properties of fine ethyl cellulose microcapsules prepared by the Wurster process. Chemical & Pharmaceutical Bulletin, 39:164-169.
126. Giannini RP, Bashour DA. (1989). Amoxicillin microencapsulated granules. WO 9001932 A1.
127. Han M, Li K. (2001). Method for preparing microencapsulated multiple yeast enzyme composite for skin care. CN 1401314 A.
128. Ichikawa H, Fukumori Y. (2000). A novel positively thermosensitive controlled-release microcapsule with membrane of nano-sized poly(N- isopropylacrylamide) gel dispersed in ethyl cellulose matrix. J Controlled Release, 63:107-119. (Pubitemid 30046946)
129. Kassem AA, Badawy AA, El-Sayed AA, El-Mahrouk GM. (1978). Preparation of non-pareil seeds of thiamine hydrochloride. Pharmazeutische Industrie, 40:396-399. (Pubitemid 8335931)
130. Kim YJ, Yun CS, Seong KS. (1999). Preparation of microencapsulated ferrous sulfate. KR 211285 B1.
131. Knezevic Z, Gosak D, Hraste M, Jalsenjak I. (1998). Fluidbed microencapsulation of ascorbic acid. J Microencapsul, 15:237-252.
132. Persson NO, Lindblom G, Bogentoft C, Appelgren C. (1981). NMR diffusion measurement in polymeric membranes used for controlled drug release. Acta Pharm Suec, 18:35-44. (Pubitemid 11103369)
133. Senjkovic R, Jalsenjak I. (1984). Influence of the atomization time on the properties of ethylcellulose microcapsules of isoniazid prepared by a fluidized bed. J Microencapsul, 1:241-247.
134. Snipes WC, Wagner SJ. (1989). Controlled release potassium chloride composition. US 4832955.
135. Al-Omran MF, Al-Suwayeh SA, El-Helw AM, Saleh SI. (2002). Taste masking of diclofenac sodium using microencapsulation. J Microencapsul, 19:45-52. (Pubitemid 34083461)
136. Barik BB, Gupta BK, Pal M. (1993). Preparation and evaluation of rifampicin microcapsules. Eastern Pharmacist, 36:173-175.
137. Nixon JR, Meleka MR. (1984). The preparation and characterization of ethylcellulose-walled theophylline microcapsules. J Microencapsul, 1:53-64.
138. Barik BB, Sahoo SK, Chatterjee S, Dinda A (2004). Effect of a protective colloid in microencapsulation using ethylcellulose and Eudragit RS100. Journal of Teaching and Research in Chemistry, 11:53-57. (Pubitemid 39168208)
139. Nixon JR, Nimmannit U. (1985). Cellulose-walled microcapsules: 1. The effect of the solvent-non solvent proportions on the preparation of microcapsules from the system ethyl cellulosechloroform-ethane diol. J Microencapsul, 2:103-110. (Pubitemid 16092144)
140. El-Helw A-RM, Bayomi MA. (2000). Effect of core modification on the release of chlorpheniramine maleate from ethylcellulose and cellulose acetate propionate microcapsules. Saudi Pharmaceutical Journal, 8:31-38. (Pubitemid 30413227)
141. Salib NN, El-menshaway ME, Ismail AA. (1976). Ethyl cellulose as a potential sustained release coating for oral pharmaceuticals. Pharmazie, 31:721-723.
142. Itoh M, Nakano M, Juni K, Sekikawa H. (1980). Sustained release of sulfamethizole, 5-fluorouracil, and doxorubicin from ethylcellulose-polylactic acid microcapsules. Chem Pharm Bull (Tokyo), 28:1051-1055. (Pubitemid 10021813)
143. Wu JC, Jean WJ, Chen H. (1993). Preparation and release behavior of ethylcellulose microcapsules containing theophylline dispersed in cellulose triacetate matrixes. Journal of the Chinese Chemical Society (Taipei, Taiwan), 40:23-28.
144. Wu JC, Jean WJ, Chen H. (1994). Evaluation of the properties of ethylcellulose-cellulose triacetate microcapsules containing theophylline prepared by different microencapsulation techniques. J Microencapsul, 11:507-518. (Pubitemid 24276814)
145. Khanna NM, Gupta SK, Sarin JS, Singh S, Kanna M. (1982). Sustained-release pharmaceutical pellets for subcutaneous implantation. DE 3228533 A1.
146. Yazici E, Oner L, Kas HS, Hincal AA. (1996). Phenytoin sodium microcapsules: bench scale formulation, process characterization and release kinetics. Pharm Dev Technol, 1:175-183.
147. Zhang X, Lin T, Li X, Mei D, Li D, Gao H. (2000a). Studies on microcapsules of norfloxacin. Shenyang Yaoke Daxue Xuebao, 17:247-249.
148. Forni F, Coppi G, Vandelli MA, Cameroni R. (1991). Drug release from spray-dried and spray-embedded microparticles of diltiazem hydrochloride. Chemical & Pharmaceutical Bulletin, 39:2091-2095.
149. Du J, Ding X, Lin X, Zheng C, Zhang W, Peng Y. (2001). Microencapsulated powders containing vitamins and polymers for sustained-release. CN 1380056 A.
150. Lin Y, Zhu D, Ding F, Zan J, Jiang G. (2004). Reverse temperature sensitive in-situ formation type implanting agent for injection. CN 1631357 A.
151. Double-layered microcapsules (1981). JP 58035111 A2.
152. Wan LS, Heng PW, Chia CG. (1992). Plasticizers and their effects on microencapsulation process by spray-drying in an aqueous system. J Microencapsul, 9:53-62.
153. Liao C-W, Lin P, Weng C-N. (2003). An oral controlled-release formulation comprising ethylcellulose enteric encapsulant. US 2004208928 A1.
154. Mao L, Zhang R-H. (1994). Physicochemical properties and their influencing factors of microencapsulation of sulfadiazine with spray dry process. Zhongguo Yiyao Gongye Zazhi, 25:114-117.
155. Sfar S, Karoui M. (1989). Microencapsulation of potassium chloride by spray drying, and study of the release before and after treatment of the microcapsules by fats. Conference proceedings: Congr. Int. Technol. Pharm., Association de Pharmacie Galénique Industrielle.
156. Vo XM, Nguyen TL, Nguyen TMN. (2000). Pilot assay of the metronidazole microcapsules by separating the lyophilization phase from heating spray. Tap Chi Duoc Hoc, 15-17.
157. Yamada N, Nakamura H, Abe E. (1996). Preparation by spray drying of microcapsules with a core of a water soluble substance and a shell of ethylcellulose. Funtai Kogaku Kaishi, 33:632-337.
158. Zhang ZY, Ping QN, Xiao B. (2000b). Microencapsulation and characterization of tramadol-resin complexes. J Control Release, 66:107-113. (Pubitemid 30160849)
159. Chowdary KPR, Babu KVVS. (1988). A comparative evaluation of ethyl cellulose, gelatin and calcium alginate microcapsules prepared by complex emulsion methods. Indian Journal of Pharmaceutical Sciences, 50:173-175.
160. Chowdary KPR, Ratna JV. (1993). A comparative evaluation of ethylcellulose, methylcellulose, and cellulose acetate microcapsules prepared by a complex emulsion method. Indian Drugs, 30:179-184. (Pubitemid 23233652)
161. Jani GK, Chauhan GM, Gohel M, Patel J. (1992). Microencapsulation of indomethacin by complex emulsification. Indian Drugs, 29:450-452. (Pubitemid 23037115)
162. Morris NJ, Warburton B. (1982). Three-ply walled w/o/w microcapsules formed by a multiple emulsion technique. J Pharm Pharmacol, 34:475-479. (Pubitemid 12029561)
163. Yoshida H, Uesugi T, Noro S. (1980). [The effect of physical condition in first emulsification for yield of microcapsules (author's transl)]. Yakugaku Zasshi, 100:1203-1208. (Pubitemid 11134896)
164. Zhang R-C. (2002). Preparation of microcapsules by drying-in-liquid with a [(OI/WI)/OII]/WII multi-emulsion. Chemical Research in Chinese Universities, 18:438-440.
165. Chen H, Wu J-C, Chang C-L. (1994). Preparation and release behavior of cellulose triacetate-ethylcellulose microcapsules containing theophylline by using emulsion nonsolvent addition method. Huaxue, 52:301-310.
166. Chen H, Wu JC, Chen HY. (1995). Preparation of ethylcellulose microcapsules containing theophylline by using emulsion nonsolvent addition method. J Microencapsul, 12:137-147.
167. Chowdary KPR, Rao GN. (1984). Studies of a new technique of microencapsulation by ethyl cellulose. Indian Journal of Pharmaceutical Sciences, 46:213-215. (Pubitemid 15000028)
168. Chowdary KPR, Nageswara Rao G. (1985). Studies on a new technique of microencapsulation: Part II. Indian Drugs, 23:58.
169. Chowdary KPR, Rao GN. (1985). Studies on a new technique of microencapsulation. Part III: Effect of certain variables on size distribution of the microcapsules. Indian Drugs, 22:381-382.
170. Kaeser-Liard B, Kissel T, Sucker H. (1984). Manufacture of controlled release formulations by a new microencapsulation process, the emulsion-induction techniques. Acta Pharmaceutica Technologica, 30:294-301. (Pubitemid 15199271)
171. Chan LW, Heng PW. (1998). Effects of poly(vinylpyrrolidone) and ethylcellulose on alginate microspheres prepared by emulsification. J Microencapsul, 15:409-420. (Pubitemid 28288730)
172. Salib NN, El-Gholmy ZA, Hagar HHS. (1989). Controlled release indomethacin microcapsules. Part II: Utilizing the hydrophobic polymer ethyl cellulose. Alexandria Journal of Pharmaceutical Sciences, 3:183-186.
173. Mallick S, Roy K, Chakraborty A, Saha S. (2002). Mechanism of in vitro release kinetics of flurbiprofen loaded ethylcellulose micropellets. Acta Pol Pharm, 59:193-198.