H. Lundbeck A/s

Rikke E Humble

Hans Petersen

Robert Dancer

Troels Volsgaard Christensen

Michael Harold Rock

Andrea Castellin

Ole Nielsen

Ken Liljegren

Federico Sbrogiò

Poul Dahlberg Nielsen

Steen Sogaard

Jacobo Zanon

Kim Bojstrup Jensen

Brian Christiansen

Thomas Pittelkow

Methods for manufacture of 5-alkoxycarbonylphthtalides are disclosed. The 5-alkoxycarbonylphthtalides are useful in syntheses of the well-known antidepresssants citalopram and escitalopram.

Intermediates for the preparation of citalopram and escitalopram

The present invention discloses crystalline particles of escitalopram oxalate which either have a broad particle size distribution or comprise at least 0.01% (w/w) of Z-4-(4-dimethylamino-1-(4-fluorophenyl)-but-1-enyl)-3-hydroxymethyl-benzonitrile, said particles being suitable for use in direct compression. Furthermore, the invention discloses a novel pharmaceutical unit dosage form containing such crystalline particles of escitalopram oxalate as well as methods for manufacture of such crystalline particles of escitalopram oxalate Finally, the invention provides a method for reduction of the amount of hydroxyl containing impurities in a solution of citalopram or escitalopram.

Crystalline composition containing escitalopram

In the following, citalopram diol means 4-(4-(dimethylamino)-1-(4-fluorophenyl)-1-hydroxybutyl)-3-(hydroxymethyl)-benzonitrile, as free base and/or acid addition salt. The invention relates to a process for the preparation of racemic citalopram diol and/or R- or S-citalopram diol, comprising the separation of a non-racemic mixture of R- and S-citalopram diol with more than 50% of one of the enantiomers into a fraction being enriched with S- or R-citalopram diol and a fraction comprising RS-citalopram diol wherein the ratio of R-citalopram diol:S-citalopram diol is equal to 1:1 or closer to 1:1 than in the initial mixture. The method is characterized in that (i) RS-citalopram diol is precipitated from a solution of the initial non-racemic mixture, or R- or S-citalopram diol is dissolved into a solvent from the initial non-racemic mixture, leaving a residue of RS-citalopram diol, and in that (ii) the residue/precipitate formed is separated from the final solution phase, followed by optional steps of repetition, recrystallisation, purification, isolation and conversion between free base and salts. The invention also relates to a process for the preparation of RS-citalopram, S-citalopram or R-citalopram (all as free base and/or acid addition salt) comprising the method described above followed by ring closure.

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The invention relates to a process for the preparation of racemic citalopram free base or an acid addition salt thereof and/or R- or S-citalopram as the free base or an acid addition salt thereof by separation of a mixture of R- and S-citalopram with more than 50% of one of the enantiomers into a fraction consisting of racemic citalopram and/or a fraction of S-citalopram or R-citalopram characterized in that i) citalopram is precipitated from a solvent as the free base or as an acid addition salt thereof; ii) the precipitate formed is separated from the mother liquor; iia) if the precipitate is crystalline it is optionally recrystallised one or more times to form racemic citalopram, and then optionally converted into an acid addition salt thereof; iib) if the precipitate is not crystalline, steps i) and ii) are optionally repeated until a crystalline precipitate is obtained and the crystalline precipitate is recrystallised one or more times to form racemic citalopram, and then optionally converted into an acid addition salt thereof; iii) the mother liquor is optionally subjected to further purification and S-citalopram or R-citalopram is isolated from the mother liquor and optionally converted into an addition salt thereof.

Process for the preparation of racemic citalopram and/or S-or R-citalopram by separation of a mixture of R-and S-citalopram

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Copenhagen, Denmark

Rikke E Humble