Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Particulate form
Reexamination Certificate
2001-11-19
2003-04-08
Spear, James M. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Particulate form
C424S464000, C424S465000, C514S770000, C514S772300, C514S778000, C514S781000, C514S937000
Reexamination Certificate
active
06544558
ABSTRACT:
The present invention relates to pharmaceutical formulations for oral administration in the treatment of bacterial infections, and to processes for the manufacture of such formulations.
It is known to provide formulations for oral administration in the form of water-dispersible granules or tablets which may be swallowed or dispersed in water prior to swallowing.
In one known method of tablet manufacture, an intermediate granulate is prepared comprising an intragranular disintegrant and an active material such as an antibiotic. This granulate is then mixed with an intergranular disintegrant (and optional other additives including a lubricant) and compressed into tablets. Such a process, tablets and granulate are for example described in EP 0281200A, CA 1199871 and JP 3240023A.
It is desirable that such solid formulations should rapidly disperse on immersion in water, for example by rapid disintegration of tablets.
Novel formulations have now been discovered which assist in achieving some of the above-mentioned desirable features.
The invention therefore provides a tablet formulation having a structure comprising compacted granulates; the granulates comprising at least one compacted medicament optionally together with an intra-granular disintegrant; the granulates being compacted together into a tablet form together with an extra-granular disintegrant and optionally also together with an extra-granular lubricant, provided that if a lubricant is present the amount of lubricant is less than 0.5% by weight of the total tablet.
In the tablets of this invention the granulates may be in a crushed state resulting from the compaction of the tablet, and consequently may not have discrete boundaries, or may be sub-divided or broken up into smaller granulates. The invention is intended to include tablets having such a structure containing crushed granulates. Preferably the size of the granulates is in the range 100 &mgr;m to 2 mm, suitably around 1 mm±0.25 mm, maximum dimension.
The medicament is preferably one which is capable of oral absorption, in particular &bgr;-lactam antibiotics optionally in combination with a &bgr;-lactamase inhibitor. A preferred antibiotic is amoxycillin, for example present as a hydrate such as the trihydrate. Amoxycillin may be used alone, or may optionally be used in combination with other &bgr;-lactam antibiotics and/or &bgr;-lactamase inhibitors such as clavulanic acid or salts (especially the potassium salt) thereof, for example in a weight ratio equivalent to amoxycillin:clavulanic acid in the range 12:1 to 1:1 such as around 4:1 or 2:1. Preferably the proportion of the antibiotic in the tablet is 60-98% by weight of the total tablet, in the case of amoxycillin trihydrate calculated as the weight of the trihydrate. Preferably the particles of antibiotic in the granulates are in the size range 1 &mgr;m to 300 &mgr;m, especially 10 &mgr;m to 200 &mgr;m. A typical suitable size distribution of the antibiotic particles is: >200&mgr; 5% or less, 200-100&mgr; 5-15%, 100-50&mgr; 7.5-15%, <50&mgr; 70% or more.
Suitable intra-granular disintegrants are starches, such as maize starch and rice starch, cross-linked N-vinyl-2-pyrrolidone (“CLPVP”), sodium starch glycollate, croscarmellose sodium and formaldehyde—casein, or combinations thereof. A preferred intra-granular disintegrant is CLPVP, for example as marketed under the trade names Polyplasdone XL and Polyplasdone XL-10.
The granulate may consist entirely of antibiotic(s), optionally in the case of a &bgr;-lactam antibiotic combined with a &bgr;-lactamase inhibitor, and an intra-granular disintegrant. Alternatively, particularly when the granulate contains clavulanic acid or a salt thereof, the granulate may also contain a diluent such as silica gel (eg Syloid-Trade Mark). Suitable intra-granular disintegrants for use with antibiotics are CLPVP and sodium starch glycollate. Typically the proportion of intra-granular disintegrantin the granulate maybe 0.1-10 wt % of the granulate, suitably 1.0-8.0 wt %, such as 1.25-3.5 wt %. Typically the proportion of an antibiotic or antibiotic +&bgr;-lactamase inhibitor combination in the granulate may be 99.9-90 wt %, suitably 99-92 wt %, e.g. 99-95 wt %, such as 98.75-96.5 wt % of the weight of the granulate. When the granulate contains a diluent, this may comprise up to 30 wt % of the granulate, but is conveniently present in a 1:1 weight ratio with the amount of clavulanic acid or its salt in the granulate. When the granulate contains a diluent the granulate will contain a correspondingly lower proportion of antibiotic or antibiotic+&bgr;-lactamase inhibitor combination, for example 70-99.9 wt % of the granulate.
The intimate contact between the antibiotic and the intra-granular disintegrant in the granulate appears to assist in improved disintegration and dispersion of the granulate in contact with water to release antibiotic particles in the size range referred to above, and to provide finely dispersed suspensions. Problems are associated with preparation of granulates which include clavulanic acid or its salts, due to their hygroscopicity, and the granulate of the invention facilitates manufacture.
In the tablet formulation the granulate may suitably comprise 70% or more, e.g. 80% or more, 90% or more or 95% or more of the total tablet weight so that a high proportion of medicament is present.
The extra-granular disintegrant may be a conventional disintegrant for example starches such as maize-starch and rice starch, CLPVP, sodium starch glycollate, croscarmellose sodium, microcrystalline or microfine cellulose, low-substituted hydroxypropylcellulose (i.e. cellulose partially substituted with 2-hydroxypropyl groups, e.g. less than 25% substituted, preferably 7-16% substituted), cross-linked sodium carboxymethylcellulose, swellable ion exchange resins, formaldehyde-casein, or alginates. Preferred extra-granular disintegrants are CLPVP, sodium starch glycollate, microfine cellulose and croscarmellose sodium, and combinations thereof. An example of an extra-granular disintegrant combination is a combination of microcrystalline or microfine cellulose with sodium starch glycollate, croscarmellose sodium, or CLPVP, containing 80-90% by weight cellulose.
The proportion of extra-granular disintegrant to total tablet weight may vary between broad limits, for example 0.1-25 weight %. For example if CLPVP or sodium starch glycollate is used as extra-granular disintegrant it may suitably be used as such in a proportion 0.1-5.0 weight %, suitably 0.1-3.0 weight %, preferably 0.1-1.5 weight % of the total tablet weight. If cellulose or a combination containing cellulose is used, e.g. as described above containing around 80-90% by weight of cellulose, the extra-granular disintegrant may comprise 1-25 weight %, typically around 1-20 weight % of the total tablet.
Suitable lubricants are those conventional to the art, such as long-chain fatty acids, such as stearic acid, or salts thereof, in particular Group II metal salts, such as of magnesium or calcium.
A preferred lubricant is magnesium stearate. It is preferred to use a lubricant proportion as low as possible e.g. 0.35% by weight or preferably lower, e.g. 0.275% or less, e.g. 0.25% or less, preferably using no lubricant at all.
The granulate may also contain an intra-granular lubricant, which may be selected from the same materials as the extra-granular lubricant, such as magnesium stearate. However an advantage of the present tablet formulation is that the granulate and tablet need not contain any lubricant. This can lead to improved wettability and hence improved disintegration of the tablet. Further a reduced lubricant proportion can lead to a lower tablet weight for a given dose of antibiotic and in the case of dispersible formulations can avoid the “smeared” appearance associated with higher lubricant proportions.
The tablet may also include conventional excipients, typically present up to about 10% of the total tablet weight. These may include flavouring agents, for example flavourings such as menthol
Martin Luis Carvajal
Romero Juan Dedios
Dinner Dara L.
Kinzig Charles M.
Labratorios Beecham SA
Spear James M.
Venetianer Stephen
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