United States Patent:  6,099,863

Assignee:  Janssen Pharmaceutica N.V. (Beerse, BE)

Filed:  December 9, 1998

The present invention is concerned with a fast-dissolving tablet for oral administration comprising as an active ingredient a therapeutically effective amount of galanthamine hydrobromide (1:1) and a pharmaceutically acceptable carrier, characterized in that said carrier comprises a spray-dried mixture of lactose monohydrate and microcrystalline cellulose (75:25) as a diluent, and a disintegrant; and with a direct compression process of preparing such fast-dissolving tablets.

Summary of the Invention

Thus the present invention relates to a tablet comprising as an active ingredient a therapeutically effective amount of galanthamine hydrobromide (1:1) and a pharmaceutically acceptable carrier, characterized in that said carrier comprises a spray-dried mixture of lactose monohydrate and microcrystalline cellulose (75:25) as a diluent, and a disintegrant. Said tablets have a dissolution of at least 80% after 30 minutes (Q=80% after 30') (USP 23,<711> Dissolution, pp 1791-1793, Apparatus 2 (paddle, 50 rpm)).

Initial experiments started out using either lactose anhydrous or lactose monohydrate as diluent, and either powdered cellulose or microcrystalline cellulose as disintegrant (see tablet formulations F1 and F2 in the Experimental Part). A particular problem which occurred during feeding the dry blend into the tablet press for direct compression, was segregation of the tablet excipients, thus causing the tablets to have a variable composition. In addition, the tablets formulations F1 and F2 did not comply at Stage 1 with the dissolution specification of Q=80% after 30'. In order to solve the percieved problems, the diluent was substituted for a spray-dried mixture of lactose monohydrate and microcrystalline cellulose (75:25), commercially available as Microcelac.TM.. In addition to having a reduced tendency to segregate during feeding into the tablet press, the dry blend comprising the above diluent was further found to have excellent rheological properties (flowability), as well as to be easily miscible with the active ingredient and other tablet excipients. The dissolution specification was not met, however, unless a disintegrant having a large coefficient of expansion was employed, more in particular, if an insoluble or poorly soluble cross-linked polymer such as, for example, crospolyvidone or croscarmellose was employed. The amount of said disintegrants in the fast-dissolving tablets according to the present invention conveniently ranges from about 3 to about 8% (w/w), preferably about 5% (w/w).

In order to make the blending and the direct compression processes easier to perform, the carrier further comprises a glidant and a lubricant. Preferably, the glidant is colloidal anhydrous silica and the lubricant is magnesium stearate. In the initial experiments (see F1 and F2), talc was used as a glidant and sodium lauryl sulphate as a wetting agent/lubricant. The former was found to affect the dissolution properties of the tablets adversely (retarding the dissolution of the active ingredient) and the latter was found to be entirely superfluous and easy to omit from the tablet formulation.

Fast-dissolving tablets according to the present invention comprise by weight based on the total weight of the tablet core:

(a) from 2 to 10% galanthamine hydrobromide (1:1);

(b) from 83 to 93% spray-dried mixture of lactose monohydrate and microcrystalline cellulose (75:25);

(c) from 0.1 to 0.4% glidant;

(d) from 3 to 8% insoluble crosslinked polymeric disintegrant; and

(e) from 0.2 to 1% lubricant.

In particular, the tablets comprise

(a) about 2 to 10% galanthamine hydrobromide (1:1);

(b) about 83 to 93% spray-dried mixture of lactose monohydrate and microcrystalline cellulose (75:25);

(c) about 0.2% colloidal anhydrous silica;

(d) about 5% crospolyvidone; and

(e) about 0.5% magnesium stearate.

The fast-dissolving galanthamine hydrobromide (1:1) tablets according to the present invention may in addition include other optional excipients such as, for example, flavors, sweeteners and colors.

Tablets of galanthamine hydrobromide (1:1) are conveniently film-coated following art-known coating procedures. Film-coated tablets are easier to swallow than uncoated tablet cores, are usually easier to distinguish from other tablets - in particular when the film-coat contains a dye or a pigment -, and may furthermore have an improved stability (shelf-life). In the instant case, a mixture comprising a film-forming polymer and a plasticizer, in particular hydroxypropyl methylcellulose and a polyethylene glycol, e.g. macrogol 6000, may be employed for film-coating tablet cores as described hereinbefore. Of particular importance in the case of fast-dissolving tablets, is the requirement that the film-coat should not adversely affect the disintegration and dissolution of the active ingredient from the tablet. Therefore, the weight of the film-coat conveniently is in the range of 3 to 8%, particularly 4 to 7.5%, of the uncoated tablet core. As illustrated in the experimental part both the uncoated tablet cores and the film-coated tablets according to the present invention (F5, F6, F7) both comply with the dissolution requirement of Q=80% after 30' (USP).

The tablets according to the present invention are suitable as unit dose forms for oral administration to patients in need of galanthamine therapy. The tablets conveniently comprise from 2 to 20 mg galanthamine (2.563 to 25.63 mg galanthamine hydrobromide (1:1)), in particular from 4 to 16 mg galanthamine (5.026 to 20.506 mg galanthamine hydrobromide (1:1)). They are best administered three times daily (t.i.d), approximately every eight hours, or two times daily (b.i.d), approximately every 12 hours, as these dosage regimens give therapeutic plasma levels of the active ingredient throughout the day.

The present invention is also concerned with a process of preparing fast-dissolving galanthamine hydrobromide (1:1) tablets, comprising the steps of:

(i) dry blending the active ingredient, the disintegrant and the optional glidant with the diluent;

(ii) optionally mixing the lubricant with the mixture obtained in step (i);

(iii) compressing the mixture obtained in step (i) or in step (ii) in the dry state into a tablet; and

(iv) optionally film-coating the tablet obtained in step (iii).

The dry blending can conveniently be performed in a planetary mixer; the direct compression on a tablet press; and the film-coating in a coating pan.

Claim 1 of 10 Claims

1. A tablet comprising as an active ingredient a therapeutically effective amount of galanthamine hydrobromide (1:1) and a pharmaceutically acceptable carrier, wherein said carrier comprises a spray-dried mixture of lactose monohydrate and microcrystalline cellulose (75:25) as a diluent, and an insoluble or poorly soluble cross-linked polymer disintegrant

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