IMPLANTS [CH. 17 191 release profiles. Increasing porosity ε or decreasing tortuosity τ may counteract the tendency for the release rate to decline. So, constant long-term release from matrix systems may preferably be realized under the following conditions: (i) hydrocolloids should be used as pore-forming excipients, (ii) excipients should be leached out very slowly and (iii) the matrix polymer should be elastic and permeable to water vapour in order to permit swelling and to yield homogeneous water uptake. Finally (iv) the swelling, drug-saturated excipient should be of higher osmotic activity than the surrounding medium in order to permit water uptake. The results show that this concept is capable of long-term ‘anomalous diffusion’ [17]. Further optimization may lead to matrix-type release systems capable of even longer and more constant drug release. REFERENCES 1 [] J.C.Fu, A.K.Kale, and D.L.Moyer, <strong>Drug</strong>-incorporated silicone discs as sustained release capsules. I.Chloroquione diphosphate, J. Biomed. Mater. Res., 7, 79–93 (1973). 2 [] Y.W.Chien, Novel <strong>Drug</strong> Delivery Systems, Dekker, New York, 1982. 3 [] D.N.Robertson, I.Sivin, H.A.Nash, J.Braun and J.Dinh, <strong>Release</strong> rates of levonorgestrel from silastic capsules, homogeneous rods and covered rods in humans, Contraception, 27, 483–495 (1983). 4 [] D.S.T.Hsieh, K.Mann and Y.W.Chien, Enhanced release of drugs from silicone elastomers (I-IV), <strong>Drug</strong> Dev. Ind. Pharm., 11, 1391–1446 (1985). 5 [] R.Langer, Biomaterials: new perspectives on their use in the controlled delivery of polypeptides, Pharm. Technol., 10 (October), 35–37 (1985). 6 [] L.R.Brown, C.L.Wei and R.Langer, In vivo and in vitro release of macromolecules from polymeric drug delivery systems, J. Pharm. Sci., 72, 1181–1185. 7 [] R.Burns, G.McRae and L.M.Sanders, A one year controlled release system for the LHRH agonist RS-49947, in: Proc. 15th Int. Symp. on <strong>Controlled</strong> <strong>Release</strong> of Bioactive Materials, Lincolnshire, 1988. 8 [] N.A.Peppas, and R.J.Haluska (eds.), Proc. 12th Int. Symp. on <strong>Controlled</strong> <strong>Release</strong> of Bioactive Materials, Lincolnshire, IL, 1985. 9 [] T.Higuchi, Mechanism of sustained action medication, J. Pharm. Sci., 52, 1145–1149 (1963). 10 [] S.J.Desai, A.P.Simonelli and W.J.Higuchi, Investigation of factors influencing release of solid drug dispersed in inert matrices I, J. Pharm. Sci., 54, 1459–1464 (1965). 11 [] H.Fessi, J.P.Marty, F.Puisieux and J.T.Carstensen,The Higuchi square root equation applied to matrices with high content of soluble drug substance, Int. J. Pharm., 1, 265–274 (1978). 12 [] J.W.McGinity, L.A.Hunke and A.B.Combs, Effect of water soluble carriers on morphine sulfate release from a silicone polymer, J. Pharm. Sci., 68, 662– 664 (1979). 13 [] R.Langer and J.Folkman, Sustained release of macromolecules from polymers, in R.J. Kostelnik (ed.), Polymeric Delivery Systems, Gordon and Breach, New York, 1978. 14 [] R.Langer, <strong>Controlled</strong> release of macromolecules, Chemtech, 3 (February), 98–105 (1982). 15 [] G.Di Colo, V.Campigli, V.Carelli, E.Nannipieri, M.F.Serafini and D. Vitale, <strong>Release</strong> of osmotically active drugs from silicone rubber matrices, Farmaco, Ed. Prat., 39, 377–389. 16 [] D.S.T.Hsieh, C.C.Chiang, D.S.Desai, <strong>Controlled</strong> release of macromolecules from silicone elatomer, Pharm. Technol., 6, 39–49 (1985). 17 [] P. Ritger and N.A. Peppas, A simple equation for description of solute release II, J. Control. <strong>Release</strong>, 5, 37–42 (1987). 18 [] B.W.Barry, Dermatological Formulations, Dekker, New York, 1983, pp. 81–85.
192
- Page 2 and 3:
PHARMACEUTICAL TECHNOLOGY Controlle
- Page 4 and 5:
3 TABLET MACHINE INSTRUMENTATION IN
- Page 6 and 7:
First published in 1991 by ELLIS HO
- Page 8 and 9:
7 10 Controlled delivery of theophy
- Page 10:
Slow and steady wins the race Poems
- Page 14 and 15:
1 Influence of drug solubility in t
- Page 16 and 17:
CH. 1] INFLUENCE OF DRUG SOLUBILITY
- Page 18 and 19:
CH. 1] INFLUENCE OF DRUG SOLUBILITY
- Page 20 and 21:
CH. 1] INFLUENCE OF DRUG SOLUBILITY
- Page 22:
CH. 1] INFLUENCE OF DRUG SOLUBILITY
- Page 25 and 26:
24 MATRIX FORMULATIONS [CH. 2 MATER
- Page 27 and 28:
26 MATRIX FORMULATIONS [CH. 2 Fig.
- Page 29 and 30:
28 MATRIX FORMULATIONS [CH. 2 Table
- Page 31 and 32:
30 MATRIX FORMULATIONS [CH. 2 The e
- Page 33 and 34:
32 MATRIX FORMULATIONS [CH. 2 Table
- Page 35 and 36:
34 CH. 3] THE FORMULATION OF SUSTAI
- Page 37 and 38:
36 CH. 3] THE FORMULATION OF SUSTAI
- Page 39 and 40:
38 CH. 3] THE FORMULATION OF SUSTAI
- Page 41 and 42:
40 CH. 3] THE FORMULATION OF SUSTAI
- Page 44 and 45:
4 Statistical optimization of a con
- Page 46 and 47:
MATRIX FORMULATIONS [CH. 4 45 (4) G
- Page 48 and 49:
MATRIX FORMULATIONS [CH. 4 47 Fig.
- Page 50 and 51:
Columns 1-4 lead to the matrix of e
- Page 52 and 53:
MATRIX FORMULATIONS [CH. 4 51 Table
- Page 54 and 55:
MATRIX FORMULATIONS [CH. 4 53 Fig.
- Page 56:
Fig. 5—Linearization of the relea
- Page 59 and 60:
58 MATRIX FORMULATIONS [CH. 5 Pevik
- Page 61 and 62:
60 MATRIX FORMULATIONS [CH. 5 The d
- Page 63 and 64:
62 MATRIX FORMULATIONS [CH. 5 Fig.
- Page 65 and 66:
64 MATRIX FORMULATIONS [CH. 5 Fig.
- Page 67 and 68:
66 MATRIX FORMULATIONS [CH. 5 Table
- Page 69 and 70:
68 MATRIX FORMULATIONS [CH. 5 Fig.
- Page 72 and 73:
6 Controlled release matrix tablets
- Page 74 and 75:
CH. 6] CONTROLLED RELEASE MATRIX TA
- Page 76 and 77:
CH. 6] CONTROLLED RELEASE MATRIX TA
- Page 78 and 79:
CH. 6] CONTROLLED RELEASE MATRIX TA
- Page 80 and 81:
7 A new ibuprofen pulsed release or
- Page 82 and 83:
CH. 7] A NEW IBUPROFEN PULSED RELEA
- Page 84 and 85:
CH. 7] A NEW IBUPROFEN PULSED RELEA
- Page 86 and 87:
CH. 7] A NEW IBUPROFEN PULSED RELEA
- Page 88:
CH. 7] A NEW IBUPROFEN PULSED RELEA
- Page 91 and 92:
90 CH. 8] TOPICAL RELEASE AND PERME
- Page 93 and 94:
92 CH. 8] TOPICAL RELEASE AND PERME
- Page 95 and 96:
94 CH. 8] TOPICAL RELEASE AND PERME
- Page 97 and 98:
96 CH. 8] TOPICAL RELEASE AND PERME
- Page 99 and 100:
98 CH. 8] TOPICAL RELEASE AND PERME
- Page 101 and 102:
100
- Page 103 and 104:
102
- Page 105 and 106:
104 MULTIPARTICULATES [CH. 9 parace
- Page 107 and 108:
106 MULTIPARTICULATES [CH. 9 (a) th
- Page 109 and 110:
108 MULTIPARTICULATES [CH. 9 Fig. 2
- Page 111 and 112:
110 MULTIPARTICULATES [CH. 9 Fig. 6
- Page 113 and 114:
112 MULTIPARTICULATES [CH. 9 Fig. 7
- Page 115 and 116:
114 MULTIPARTICULATES [CH. 9 Fig. 8
- Page 117 and 118:
116
- Page 119 and 120:
118 CH. 10] CONTROLLED DELIVERY OF
- Page 121 and 122:
120 CH. 10] CONTROLLED DELIVERY OF
- Page 123 and 124:
122 CH. 10] CONTROLLED DELIVERY OF
- Page 125 and 126:
124 CH. 10] CONTROLLED DELIVERY OF
- Page 127 and 128:
126 CH. 11] THE EFFECT OF FOOD ON G
- Page 129 and 130:
128 CH. 11] THE EFFECT OF FOOD ON G
- Page 131 and 132:
130
- Page 133 and 134:
132 CH. 12] BIODEGRADABLE POLYMERS
- Page 135 and 136:
134 CH. 12] BIODEGRADABLE POLYMERS
- Page 137 and 138:
136 CH. 12] BIODEGRADABLE POLYMERS
- Page 139 and 140:
138 CH. 12] BIODEGRADABLE POLYMERS
- Page 141 and 142: 140
- Page 143 and 144: 142 CH. 13] A COMPARISON OF DISSOLU
- Page 145 and 146: 144 CH. 13] A COMPARISON OF DISSOLU
- Page 147 and 148: 146 CH. 13] A COMPARISON OF DISSOLU
- Page 149 and 150: 148 CH. 13] A COMPARISON OF DISSOLU
- Page 151 and 152: 150 CH. 13] A COMPARISON OF DISSOLU
- Page 153 and 154: 152
- Page 155 and 156: 154
- Page 157 and 158: 156 OPHTHALMIC FORMULATION [CH. 14
- Page 159 and 160: 158 OPHTHALMIC FORMULATION [CH. 14
- Page 161 and 162: 160 OPHTHALMIC FORMULATION [CH. 14
- Page 163 and 164: 162 CH. 15] A SUSTAINED RELEASE OPH
- Page 165 and 166: 164 CH. 15] A SUSTAINED RELEASE OPH
- Page 167 and 168: 166 CH. 15] A SUSTAINED RELEASE OPH
- Page 169 and 170: 168 CH. 15] A SUSTAINED RELEASE OPH
- Page 171 and 172: 170
- Page 173 and 174: 172 IMPLANTS [CH. 16 The purpose of
- Page 175 and 176: 174 IMPLANTS [CH. 16 times with 5 m
- Page 177 and 178: 176 IMPLANTS [CH. 16 noted that the
- Page 179 and 180: 178 IMPLANTS [CH. 16 Fig. 1—The e
- Page 181 and 182: 180 IMPLANTS [CH. 16 Table 3—Tobr
- Page 183 and 184: 182
- Page 185 and 186: 184 CH. 17] SILICON MATRIX SYSTEMS
- Page 187 and 188: 186 CH. 17] SILICON MATRIX SYSTEMS
- Page 189 and 190: 188 CH. 17] SILICON MATRIX SYSTEMS
- Page 191: 190 CH. 17] SILICON MATRIX SYSTEMS
- Page 195 and 196: 194 INDEX dry granulation, 43 elect