Pharmaceutical Technology: Controlled Drug Release, Volume 2

More documents

Recommendations

Info

CH. 6] CONTROLLED RELEASE MATRIX TABLETS OF KETOPROFEN 75 Fig. 3—Glassy core volume decrease of tablets KET-R vs. time: ♦, pH 1.2; pH 6.8. from such a matrix tablet was practically independent of pH. The glassy core volume decrease was linear, as Fig. 3 shows, and the decrease rate was greater at pH 1.2 (20.363 mm 3 /min) than at pH 6.8 (12.985 mm 3 /min), even though it does not influence the drug release rate. Therefore this drug delviery system can be considered to follow a constant drug release. However, in spite of these positive characteristics, the drug release rate from KET-R tablets was to high for the desired twice-daily formulation to be obtained. Three different techniques for delaying drug release from these cores were then evaluated: (a) incorporation of a release retardant such as Precirol; (b) coating of 2/3 core surface with an impermeable covering by careful immersion in CAP; (c) a new approach based on pan-spray coating with a mixture of insoluble (Eudragit E 30D) and soluble (PEG 400) polymers. Precirol was successf ully used as a retardant in matrix tablet formulations [8]. The effect of Precirol incorporation into the hydroxypropylmethylcellulose matrix tablets was therefore investigated. Precirol: drug ratios of 1:3, 1:2 and 1:1 were used (tablets KET-R A, B, and C). No significant differences in the volume decrease profiles of glassy cores and in ketoprofen release profiles (Fig. 4) in comparison with original core were obtained, even with increased Precirol. In order to reduce further the ketoprofen release rate from matrix tablets, the partial coating of the cores with CAP was assayed. This technique was successfully applied to obtain a progammable zero-order drug delivery system [5]. The release profile of ketoprofen from the 2/3 CAP coated core (KET-R CAP tablet) was of zero order (y=0.037 x −1.263, r=0.99) and the drug release rate was clearly lower than the original core, as is shown in Fig. 5. However, the technique of preparation of KET-R CAP tablets was somewhat complex, requiring considerable accuracy in the partial coating phase, and not easily applicable on an industrial scale. In view of the above results a new approach based on core panspray coating was experimented with a mixture of Eudragit E 30D and PEG 400 was chosen as a coating: Eudragit, completely
76 MATRIX FORMULATIONS [CH. 6 Fig. 4—<strong>Release</strong> profile of ketoprofen from tablets containing Precirol (50 rev/min; pH 1.2): KET-R A; ■. tablet KET-R B; ♦, tablet KET-R C. tablet KET-R; ♦, tablet Fig. 5—<strong>Release</strong> profile of ketoprofen from tablet 2/3 CAP coated (50 rev/min; pH 1.2): ♦, tablet KET-R: R CAP. , tablet KET- insoluble in water, was the retardant, while PEG 400 was added in order to form ionophorous pores, thus allowing the drug release rate to be controlled. Tablets coated with the Eudragit-PEG 400 mixture were made with three different polymer film thicknesses: 6, 10 and 15 mg (KET-R, 10 and 15 tablets). For these tablets it was not possible to obtain swelling measurements because this was prevented by the lake coating. The ketoprofen release profiles from these tablets are shown in Fig. 6. The release curves were linear (r=0.99) and the release rate appeared to decrease with increasing coating amounts. On the basis of the linear inverse relation found between the drug release rate and the coat (Fig. 7), the release rate can be varied with predictable effects by varying the coating amount. In particular the KET-R 15 tablet showed a lower rate of drug release than the 2/3 CAP coated tablet (0.96%/h
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:
Page 20 and 21:
Page 22:
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 35 and 36: 34 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 72 and 73: 6 Controlled release matrix tablets
Page 74 and 75: 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 88: CH. 7] A NEW IBUPROFEN PULSED RELEA
Page 91 and 92: 90 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 117 and 118: 116
Page 119 and 120: 118 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:
Page 137 and 138:
Page 139 and 140:
Page 141 and 142:
140
Page 143 and 144:
142 CH. 13] A COMPARISON OF DISSOLU
Page 145 and 146:
Page 147 and 148:
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
152
Page 155 and 156:
154
Page 157 and 158:
156 OPHTHALMIC FORMULATION [CH. 14
Page 159 and 160:
Page 161 and 162:
Page 163 and 164:
162 CH. 15] A SUSTAINED RELEASE OPH
Page 165 and 166:
Page 167 and 168:
Page 169 and 170:
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:
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
192
Page 195 and 196:
194 INDEX dry granulation, 43 elect
show all

Pharmaceutical Technology: Controlled Drug Release, Volume 2

Create successful ePaper yourself

Delete template?

Save as template?