Telithromycin is an already known antibacterial active described in EP 680,967.

Unfortunately it has an unpleasant taste and therefore it cannot be formulated in a simple oral composition, mainly for paediatric use, and so far it has not be found how to overcome the problem of preparing a composition that could be acceptable.

The international application WO 01/14393 describes spherical agglomerates of telithromycin which are obtained by direct transformation of cristal into spherical forms. These agglomerates have a size of between 30 and 400um and preferentially 80 to 150um. The described agglomerates are used to prepare micro-capsules for the preparation of oral suspensions, with using a coacervation process. Unfortunately when using the general methods of micro-encapsulation and coacervation it is impossible to obtain a composition with sufficient properties of taste masking.

It has now be found that using specific components it is possible to prepare a composition of telithromycin which taste is enough masked to be acceptable on an organoleptic point of view and where the suspension after reconstitution has good stability properties and acceptable bioavailability.

According to the invention the composition comprise microcapsules having a 2 layers coating. A first coating comprising ethylcellulose and a second coating comprising a layer of an acrylic polymer. This provides thus improved pharmaceutical formulations where the umpleasant taste is masked and that can give an immediate delivery on the stomach. Advantageously the composition can be administered in the form of a suspension for oral administration.

According to the invention the composition comprises spherical agglomerates of telithromycin ethylcellulose, 'acrylic polymer anti-agglomeration agent In a prefered embodiment, the composition comprises :

spherical agglomerates of telithromycin 'the) ethylcellulose, acrylic polymer, anti-agglomeration agent, D (-) N-methylglucamine aluminium and magnesium silicate and optionally agents chosen from suspending agents, aromatization agents, sweetening agents and/or antimicrobial preservation agents.

According to the invention the acrylic polymer can be chosen for instance among Eudragit0 E.

For example, the anti-agglomeration agent can be talc.

Among the suspending agents, xanthan gum can be cited for instance, the aromatization agents can be chosen from sugars and for instance maltitol, the antimicrobial preservation agent can be chosen from parabens and the sweetening agent can be chosen for instance from sodium saccharinate.

In a more prefered embodiment the composition comprises : spherical agglomerates of telithromycin : 40 to 65% ethylcellulose : 8 to 18%, acrylic polymer 18 to 35%, talc 4. 5 to 10%, D (-) N-methylglucamine : 0.8 to 1.8% aluminium and magnesium silicate: 4 to 9% and optionally xanthan gum: 0.3 to 0.7% maltitol : 40 to 90% 'sodium saccharinate: 0.6 to 1.4% flavouring agent: 0.6 to 1.4% More preferably the composition comprises from 45 to 63% of telithromycin agglomerates; from 9 to 15% of ethylcellulose ; from 18 to 33% of the acrylic polymer ; from 5 to 8% of talc, D (-) N-methylglucamine from 0.8 to 1. 8%, aluminium and magnesium silicate from 4 to 9% and optionally the above mentioned additives.

Also, according to a prefered embodiment of the invention the ratio acrylic polymer/ anti-agglomeration agent is advantageously chosen around 2 to 4, preferably 4.

According to the invention the mean size of the telithromycin agglomerates used as starting material is comprised between 30 and 500, um. In a prefered embodiment the mean size is comprised between 60 and 250, um (light scattering analysis).

According to the invention the composition is prepared from telithromycin in the form of spherical agglomerates (as described in WO 01/14393) using 2 main steps of encapsulation: 'first step: microencapsulation with ethylcellulose, * second step: fluid bed coating of the microcapsules with the acrylic polymer.

In the prefered embodiment where the composition comprises D (-) N-methylglucamine, aluminium and magnesium silicate and optionally suspending agents, aromatization agents, sweetening agents and/or antimicrobial preservation agents these additives are added in a third step of the process after the 2 encapsulation steps. In the more prefered embodiment where the composition comprises D (-) N-methylglucamine, aluminium and magnesium silicate and optionally xanthane gum, maltitol, sodium saccharinate and flavouring agent, these additives are also added in a third step of the process after the 2 encapsulation steps.

The 2 main steps of encapsulation can be advantageously conducted as follows : microencapsulation in ethylcellulose can be made by coacervation according to the method described in US 6,139, 865 and EP 38585 (incorporated here as a references), with ethylcellulose in cyclohexane and polyethylen wax, followed by separation of the microcapsules from the liquid phase and drying on a fluid bed. the encapsulation in an acrylic polymer can be made using fluid bed coating technics, in the presence of an anti-agglomeration agent. The process is carried out in a hydro alcoholic medium (for example in hydro-ethanolic medium).

According to the invention for instance the polyethylen wax can be Polen0 ; for instance, the acrylic polymer can be chosen among Eudragit E (EudragitS) E100) ; the anti-agglomeration agent is preferably talc and more preferably a micronized talc or talc of less than 75um.

The amount of the primary coating with ethylcellulose is defined such as to get a optimal particule size distribution, residual solvents complying with the regulator acceptance and such as the microcapsules are suitable to be coated using a fluid bed technic. Usually an amount between 15 and 30% of coating level is suitable; preferably a coating level between 18 and 25% is advantageously chosen, and more prefered is 18%. The microcapsules prepared with the primary coating comprise 50 to 95 % of telithromycin agglomerates and 5 to 50% of ethylcellulose. After the first coating the mean particule size is acceptable and is for example less than 250um for more than 90% of the resulting microcapsules.

The secondary coating, made of acrylic polymer in the presence of an anti- agglomeration agent is made in an amount that allows a narrow particule size distribution, together with the properties of satisfactory taste-masking and fast dissolution rate for the preparation of the suspension. Usually an amount between 20 and 45% of coating level is suitable; preferably a coating level between 25 and 40% is advantageously chosen. After the second coating the mean particule size is less than 300um for more than 90% of the resulting microcapsules.

According to the invention, it is possible to prepare from the microcapsules, suspensions comprising from 5 to 250 mg/ml and more preferably 100 mg/mi.

The prepared microcapsules have the capability of forming a sufficiently stable suspension, and have a fast dissolution rate: equal or superior to 80% over 2 to 10 minutes and in some preferential aspects of the invention: 90% within 2 mn.

It has been shown that they provide a satisfactory taste masking up to five days after suspension reconstitution.

The following examples illustrate the invention.

Example 1 The first step of coating was carried out using a 5 liter reactor with a pneumatic stirring, introducing spherical agglomerates of telithromycin with ethylcellulose in cyclohexane and Epolene0, with agitation at a temperature of 80°C, according to the coacervation method described in US 6,139, 865.

The resulting microcapsules are sieved

After carrying out the first step, the second coating was performed over 75mn, with using a Glatt GPCG1 fluid bed equipped with Wurster insert (4"), bottom plate « A » type, filter « T165P » type, 1mm spraying nozzle and adding to 456 g of the first coated microcapsules, Eudragit0 E100 10%, talc <75, um 5.0%, ethanol 51%, purified water 34%. The coating layer was applied at a spraying rate of 2.5 to 5.5 g/mn. The temperature of the air was 45 to 52°C and the air speed 1.0 to 1.5 m/s. The atomisation pressure was 1.8 bars. The temperature of the product during the coating was between 30 and 33°C. The coating is performed with an amount of membrane of 25%. After drying on the fluid bed and sieving the corresponding 2 coatings microcapsules are obtained. The resulting composition comprises telithromycin agglomerates 58.5%, ethylcellulose 6.5%, Eudragit0 E 23.3%, talc 11.7%. The coated samples were easily dispersible in aqueous medium without any agglomeration or segregation phenomena.

Example 2 After carrying out a first step according to the example 1, the second coating was performed over 92mn, with using a Glatt GPCG1 fluid bed equipped with Wurster insert (4"), bottom plate « A » type, filter « T165P » type, 1mm spraying nozzle and adding to 456 g of the first coated microcapsules, Eudragit0 E100 10%, talc <75, um 5.0%, ethanol 51 %, purified water 34%. The coating layer was applied at a spraying rate of 2.0 to 5.0 g/mn. The temperature of the air was 54 to 55°C and the air speed 1.0 to 1.5 m/s. The atomisation pressure was 1.8 bars. The temperature of the product during the coating was between 30 and 33°C. The coating is performed with an amount of membrane of 35%. After drying on the fluid bed and sieving the corresponding 2 coatings microcapsules are obtained. The resulting composition comprises telithromycin agglomerates 67.5%, ethylcellulose 7.5%, EudragitQ E 16.7%, talc 8.3%. The coated samples were easily dispersible in aqueous medium without any agglomeration or segregation phenomena.

Example 3 After carrying out a first step according to the example 1 with 3 kg cyclohexane and a coating level of ethylcellulose of 9.5%, the second coating was performed over 92mn, with using a Glatt GPCG1 fluid bed equipped with Wurster insert (4"), bottom plate « A » type, filter « T165P » type, 1mm spraying nozzle and adding to 456 gof the first coated microcapsules, Eudragit (E) E100 10%, micronized talc 2.5%, ethanol

52.5%, purified water 35%. In order to avoid any damage to the ethylcellulose coating, the first part of the coating layer was applied at a lower spraying rate: 2.0 to 3.0 g/mn. Then at a spraying rate of 4.8 to 5.8 g/mn. The temperature of the air was 55 to 60°C and the air speed 1.0 to 1.8 m/s. The atomisation pressure was 1.8 bars.

The temperature of the product during the first part of the coating was between 33 and 38°C. The temperature of the product during the second part of the coating was between 30 and 32°C. The coating is performed with an amount of membrane of 20.9%. After drying on the fluid bed and sieving the corresponding 2 coatings microcapsules are obtained. The resulting composition comprises telithromycin agglomerates 71.6%, ethylcellulose 7.5%, Eudragit0 E 16.7%, talc 4. 2%. The coated samples were easily dispersible in aqueous medium without any agglomeration or segregation phenomena. The release is 97 + 1 after 2 mn.