Cross-linked high amylose starch for use in controlled-release pharmaceutical formulations and processes for its manufacture
DCFirst Claim
1. A process for manufacturing, in an aqueous medium, a controlled release excipient consisting primarily of cross-linked high amylose starch, for use in preparation of tablets, said process comprising(a) cross-linking high amylose starch thereby forming a reaction medium containing a reaction product consisting of a cross-linked high amylose starch slurry;
- (b) subjecting said cross-linked high amylose starch slurry from step (a) to chemical modification at a temperature of about 10 to about 90°
C. for about 1 to about 72 hours;
(c) neutralizing said reaction medium obtained in step (b) with an acid, washing the slurry formed and optionally dewatering or to form a starch cake or a dry powder;
(d) diluting said slurry or re-slurrifying said starch cake or said dry powder from step (c) with water to form a slurry at a concentration of about 2% to about 40% w/w, adjusting pH to a desired value between about 3 and about 12, and gelatinizing said slurry at a temperature of about 80 to 180°
C. for about 1 second to about 120 minutes; and
(e) drying the thermally treated product obtained in step (d) to obtain said controlled release excipient consisting mainly of chemically modified and cross-linked high amylose starch in form of a powder.
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Abstract
The present invention relates to a novel form of cross-linked high amylose starch and processes for its manufacture. Such cross-linked high amylose starch is useful as an excipient in a controlled-release pharmaceutical formulation when compressed with pharmaceutical agent(s) in a tablet. Such cross-linked high amylose starch is prepared by (a) cross-linking and chemical modification of high amylose starch, (b) gelatinization, and (c) drying to obtain a powder of said controlled release excipient. In a preferred embodiment, such cross-linked high amylose starch is prepared in the following steps: (1) granular cross-linking and additional chemical modification (e.g., hydroxypropylation) of high-amylose starch; (2) thermal gelatinization of the starch from step (1); and (3) drying the starch from step (2) to yield a powder capable of being used as a controlled release excipient.
104 Citations
43 Claims
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1. A process for manufacturing, in an aqueous medium, a controlled release excipient consisting primarily of cross-linked high amylose starch, for use in preparation of tablets, said process comprising
(a) cross-linking high amylose starch thereby forming a reaction medium containing a reaction product consisting of a cross-linked high amylose starch slurry; -
(b) subjecting said cross-linked high amylose starch slurry from step (a) to chemical modification at a temperature of about 10 to about 90°
C. for about 1 to about 72 hours;
(c) neutralizing said reaction medium obtained in step (b) with an acid, washing the slurry formed and optionally dewatering or to form a starch cake or a dry powder;
(d) diluting said slurry or re-slurrifying said starch cake or said dry powder from step (c) with water to form a slurry at a concentration of about 2% to about 40% w/w, adjusting pH to a desired value between about 3 and about 12, and gelatinizing said slurry at a temperature of about 80 to 180°
C. for about 1 second to about 120 minutes; and
(e) drying the thermally treated product obtained in step (d) to obtain said controlled release excipient consisting mainly of chemically modified and cross-linked high amylose starch in form of a powder. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
(a) cross-linking high amylose starch containing at least 70% w/w of amylose with about 0.005 g to about 0.3 g cross-linking reagent per 100 g of dry-based high amylose starch in an aqueous medium at a temperature of about 10 to about 90° - C. thereby forming a reaction medium containing a reaction product consisting of a cross-linked high amylose starch slurry;
(b) subjecting said cross-linked high amylose starch slurry from step (a) to hydroxypropylation with propylene oxide at a temperature of about 10 to about 90°
C. for about 1 to about 72 hours to yield a reaction medium containing a hydroxypropylated cross-linked high amylose starch slurry;
(c) neutralizing said reaction medium obtained in step (b) with a dilute aqueous acid, washing slurry formed and optionally dewatering to obtain a starch cake or a dry powder;
(d) diluting said slurry, or re-slurrifying starch cake or dry powder from step (c) with water to form a slurry at a concentration of about 2% to about 40% w/w, adjusting pH to about 4.0 to about 9.0, and gelatinizing said slurry formed in current step at a temperature of about 80 to about 180°
C. for about 1 second to about 120 minutes; and
(e) drying said thermally treated product obtained in step (d) to obtain said controlled release excipient consisting mainly of hydroxypropylated and cross-linked high amylose starch in form of a powder.
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4. The process of claim 3, wherein, in step (a), said cross-linking reagent is phosphorous oxychloride in an amount of between about 0.01 and about 0.2 g per 100 g starch dry basis or sodium trimetaphosphate in an amount of between about 0.05 and about 0.3 g per 100 g starch dry basis.
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5. The process of claim 3 wherein step (a) is performed in an aqueous alkaline medium.
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6. The process of claim 4, wherein, in step (a), said cross-linking is carried out at a pH of about 10 to about 14 and at a temperature of about 15 to about 90°
- C. for about 0.2 to about 40 hours.
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7. The process of claim 3, wherein, in step (b), said hydroxypropylation is carried out with up to 10% propylene oxide at a temperature of about 40 to about 80°
- C. for about 10 to about 72 hours.
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8. The process of claim 3, wherein, in step (c), said neutralization of said reaction medium is carried out with dilute sulfuric acid or hydrochloric acid.
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9. The process of claim 3, wherein, in step (d), said gelatinization is carried out by direct steam injection into an aqueous suspension of said cross-linked high amylose starch.
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10. The process of claim 3, wherein, in step (d), said pH is adjusted to about 6.0 and said temperature is kept at about 80 to about 180°
- C. for about 2 to about 10 minutes.
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11. The process of claim 3, wherein, in step (e), said drying is carried out by spray-drying.
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12. The process of claim 11, wherein, in step (e), inlet temperature is from about 60 to about 350°
- C., and outlet temperature is set from about 40 to about 210°
C.
- C., and outlet temperature is set from about 40 to about 210°
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13. A process for manufacturing, in an aqueous medium, a controlled release excipient consisting primarily of cross-linked high amylose starch, for use in preparation of tablets, said process comprising
(a) subjecting high amylose starch to chemical modification at a temperature of about 10 to about 90° - C. for about 1 to about 72 hours thereby forming a reaction medium containing a chemically modified high amylose slurry;
(b) cross-linking said chemically modified high amylose starch in said slurry obtained in step (a);
(c) neutralizing said slurry obtained in step (b) with an acid, washing the slurry formed and optionally dewatering to form a starch cake or drying to form dry powder;
(d) diluting said slurry, or re-slurrifying said starch cake or said dry powder from step (c) with water to form a slurry at a concentration of about 2% to about 40% w/w, adjusting pH to a desired value between about 3 and about 12, and gelatinizing said slurry at a temperature of about 80 to 180°
C. for about 1 second to about 120 minutes; and
(e) drying the thermally treated product obtained in step (d) to obtain said controlled release excipient consisting mainly of chemically modified and cross-linked high amylose starch in form of a powder. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
(a) subjecting high amylose starch containing at least 70% w/w of amylose to hydroxypropylation With propylene oxide at a temperature of about 10 to about 90° - C. for about 1 to about 72 hours to yield a reaction medium containing a reaction product of consisting primarily of a hydroxypropylated high amylose starch slurry;
(b) cross-linking said hydroxypropylated high amylose starch slurry with about 0.005g to about 0.3 g cross-linking reagent per 100 g of dry-based high amylose starch in an aqueous medium at a temperature of about 10 to about 90°
C. to yield a reaction medium containing a cross-linked hydroxypropylated high amylose starch slurry;
(c) neutralizing said reaction medium obtained in step (b) with a dilute aqueous acid, washing slurry formed and optionally dewatering to obtain a starch cake or a dry powder;
(d) diluting said slurry, or re-slurrifying said starch cake or said dry powder from step (c) with water to form a slurry at a concentration of about 2% to about 40% w/w, adjusting pH to about 4.0 to about 9.0, and gelatinizing said slurry formed in current step at a temperature of about 80 to about 180°
C. for about 1 second to about 120 minutes; and
(e) drying said thermally treated product obtained in step (d) to obtain said controlled release excipient consisting mainly of hydroxypropylated and cross-linked high amylose starch in form of a powder.
- C. for about 1 to about 72 hours thereby forming a reaction medium containing a chemically modified high amylose slurry;
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16. All The process of claim 15, wherein, in step (a), said cross-linking reagent is phosphorous oxychloride in an amount of between about 0.01 and about 0.2 g per 100 g starch dry basis or sodium trimetaphosphate in an amount of between about 0.05 and about 0.3 g per 100 g starch dry basis.
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17. The process of claim 15 wherein step (b) is performed in an aqueous alkaline medium.
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18. The process of claim 16, wherein, in step (b), said cross-linking is carried out at a pH of about 10 to about 14 and at a temperature of about 15 to about 90°
- C. for about 0.2 to about 40 hours.
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19. The process of claim 15, wherein, in step (a), said hydroxypropylation is carried out with up to 10% propylene oxide at a temperature of about 40 to about 80°
- C. for about 10 to about 72 hours.
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20. The process of claim 15, wherein, in step (c), said neutralization of said reaction medium is carried put with dilute sulfuric acid or hydrochloric acid.
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21. The process of claim 15, where, in step (d), said gelatinization is carried out by direct steam injection into an aqueous suspension of said cross-linked high amylose starch.
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22. The process of claim 15, wherein, in step (d), said pH is adjusted to about 6.0 and said temperature is kept at about 80 to about 180°
- C. for about 2 to about 10 minutes.
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23. The process of claim 15, wherein, in step (e), said drying is carried out by spray-drying.
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24. The process of claim 23, wherein, in step (e), inlet temperature is from about 60 to about 350°
- C., and outlet temperature is set from about 40 to about 210°
C.
- C., and outlet temperature is set from about 40 to about 210°
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25. A controlled release tablet comprising a compressed blend of at least two dry powders, including a powder of at least one pharmaceutical agent and a powder of a controlled release excipient;
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wherein said controlled release excipient comprises a chemically-modified, cross-linked high amylose starch prepared by a method comprising;
(a) cross-linking high amylose starch, followed by (b) chemically modifying the cross-linked high amylose starch, followed by (c) gelatinization, and (d) drying to obtain a powder of said controlled release excipient;
wherein said cross-linked high amylose starch is characterized in that upon solubilization in 90% DMSO at 80°
C. for about three days and gel permeation chromatography, the height of the peak corresponding to amylose in said cross-linked high amylose starch is at least 90% of that of the peak corresponding to amylose in said high amylose starch prior to (a).- View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39)
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26. A controlled release tablet comprising a compressed blend of at least two dry powders, including a powder of at least one pharmaceutical agent and a powder of a controlled release excipient;
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wherein said controlled release excipient comprises a chemically-modified, cross-linked high amylose starch prepared by a method comprising;
(a) cross-linking high amylose starch, followed by (b) chemically modifying the cross-linked high amylose starch, followed by (c) gelatinization, and (d) drying to obtain a powder of said controlled release excipient;
wherein said cross-linked high amylose starch is characterized in that less than about 20% of the amylose present in said high amylose starch prior to (a) is chemically cross-linked to amylopectin.
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27. A controlled release tablet comprising a compressed blend of at least two dry powders, including a powder of at least one pharmaceutical agent and a powder of a controlled release excipient;
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wherein said controlled release excipient comprises a chemically-modified, cross-linked high amylose starch prepared by a method comprising;
(a) cross-linking high amylose starch, followed by (b) chemically modifying the cross-linked high amylose starch, followed by (c) gelatinization, and (d) drying to obtain a powder of said controlled release excipient;
wherein said cross-linked high amylose starch is characterized in that upon solubilization in 90% DMSO at 80°
C. for about three days and gel permeation chromatography, less than about 20% of the amylose present prior to (a) is chemically cross-linked to and eluted with amylopectin.
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28. A controlled release tablet comprising a compressed blend of at least two dry powders, including a powder of at least one pharmaceutical agent and a powder of a controlled release excipient;
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wherein said controlled release excipient comprises a chemically-modified, cross-linked high amylose starch prepared by a method comprising;
(a) cross-linking high amylose starch, followed by (b) chemically modifying the cross-linked high amylose starch, followed by (c) gelatinization, and (d) drying to obtain a powder of said controlled release excipient;
wherein said cross-linked high amylose starch is characterized in that upon solubilization in 90% DMSO at 80°
C. for about three days and gel permeation chromatography, the height of the peak corresponding to amylose is higher than that of the peak corresponding to amylopectin-containing entities.
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40. A chemically-modified, cross-linked high amylose starch prepared by a method comprising:
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(a) cross-linking high amylose starch, followed by (b) chemically modifying the cross-linked high amylose starch, followed by (c) gelatinization, and (d) drying to obtain a powder of said controlled release excipient;
wherein said cross-linked high amylose starch is characterized in that upon solubilization in 90% DMSO at 80°
C. for about three days and gel permeation chromatography, the height of the peak corresponding to amylose in said cross-linked high amylose starch is at least 90% of that of the peak corresponding to amylose in said high amylose starch prior to (a).
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41. A chemically-modified, cross-linked high amylose starch prepared by a method comprising:
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(a) cross-linking high amylose starch, followed by (b) chemically modifying the cross-linked high amylose starch, followed by (c) gelatinization, and (d) drying to obtain a powder of said controlled release excipient;
wherein said cross-linked high amylose starch is characterized in that less than about 20% of the amylose present in said high amylose starch prior to (a) is chemically cross-linked to amylopectin.
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42. A chemically-modified, cross-linked high amylose starch prepared by a method comprising:
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(a) cross-linking high amylose starch, followed by (b) chemically modifying the cross-linked high amylose starch, followed by (c) gelatinization, and (d) drying to obtain a powder of said controlled release excipient;
wherein said cross-linked high amylose starch is characterized in that upon solubilization in 90% DMSO at 80°
C. for about three days and gel permeation chromatography, less than about 20% of the amylose present prior to (a) is chemically cross-linked to and eluted with amylopectin.
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43. A chemically-modified, cross-linked high amylose starch prepared by a method comprising:
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(a) cross-linking high amylose starch, followed by (b) chemically modifying the cross-linked high amylose starch, followed by (c) gelatinization, and (d) drying to obtain a powder of said controlled release excipient;
wherein said cross-linked high amylose starch is characterized in that upon solubilization in 90% DMSO at 80°
C. for about three days and gel permeation chromatography, the height of the peak corresponding to amylose is higher than that of the peak corresponding to amylopectin-containing entities.
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Specification