WO2003097013A1

WO2003097013A1 - Mono-coating for powdered pharmaceuticals

Info

Publication number: WO2003097013A1
Application number: PCT/US2002/015648
Authority: WO
Inventors: Julio Cesar Rodriquez; Ferrando Jordi Verite
Original assignee: Tecnofarma Corp.
Priority date: 2002-05-16
Filing date: 2002-05-16
Publication date: 2003-11-27
Also published as: AU2002309911A1

Abstract

A particulate composition for suspension in an aqueous solution prior to administration to a patient and a method for obtaining the composition, wherein the composition comprises a particulate active pharmaceutical principle with the particles having a size of between 10 microns to 90 microns and the particles are coated with a lipidic coating comprising between 10% w/w to 70% w/w of the total composition weight.

Description

MONO-COATING FOR POWDERED PHARMACEUTICALS

BACKGROUND OF THE INVENTION 1. Field of the Invention.

The present invention relates to a coated particulate composition that can be used to obtain a suspension in aqueous media for treating diseases or for administration during diagnostic method, as well as to methods for obtaining the composition. More particularly, the inventive composition comprises a particulate or powdered active principle or ingredient, wherein the particles have about 10 microns to 90 microns and wherein the particles are coated with a lipid derivative coating comprising about 10% w/w to 70% w/w relative to the total weight of the composition.

2. Description of the Prior Art.

The coating of particulate active principles comprising small particles or fine powders is a matter under continuous development. When these coatings are related to active ingredients or pharmaceutical products that are suspended in aqueous solutions for their administration, the coating thereof is a concern. This is more particularly remarkable when the product is rejected by the patients due to their unpleasant taste or the products are aggressive to the gastric mucosa.

There are several pharmaceuticals like the laxatives, for example comprising unpleasant taste. Monosodic sodium phosphates and disodic sodium phosphates are laxatives commercialized in water solution for administration. These laxatives are employed for clinical constipation, for bowel clearance before radiological examination, for endoscopy or for surgery, and they have always been found to be rejected by the patients because they produce nausea. With the purpose of masking the unpleasant taste, some attempts have been made to coat the powdered products with several flavors and the like.

U.S. Patent No. 5,997,906 to Wood et al . discloses a coated sodium phosphate bowel cleansing composition which has been improved by a coating comprising at least one edible grade film forming polymer such as hydroxypropyl-methyl cellulose (HMPC) or polyethylene glycol .

The example to illustrate the improved coating, as provided in the above mentioned US Patent, calls for phosphate powders consisting of monobasic sodium phosphate powder and dibasic sodium phosphate powder. The monobasic sodium phosphate powder is heated to a temperature of 55-65°C and hydroxypropylmethyl cellulose (HPMC) , is applied to the powder to obtain a coated powder. Then, the coated phosphate powder is dried and melted paraffin is sprayed on the coated phosphate powder until a ratio of between 1-10% w/w is obtained. During the spraying of the paraffin, the atomization air is heated to 95-105°C and the final product is classified through a 10 mesh Sweco screen to remove the oversized particles. The dibasic phosphate powder is heated to 55- 65°C and a HPMC solution is applied through atomized air without applying paraffin.

While US Patent No. 5,997,906 claims for particulate monobasic phosphate and particulate dibasic phosphate coated with "at least one edible film forming polymer", only a two-layer coating, namely an inner HPMC coating and an outer paraffin coating, is exemplified in the specification. The only one-layer coating employed for coating the dibasic sodium phosphate is a HPMC layer. The aim of coating the particulate phosphate primarily with HPMC is to have pores small enough to prevent the migration of ions through the coating. However care must be taken to have the particles coated with a coating amount not adversely affecting the desired pharmacological effect of the pharmaceutical powder. The HMPC coating must have a controlled porosity to guarantee the desired controllable releasing of the pharmaceutical product and the additional paraffin coating is disclosed for resisting the prolonged contact with water in a suspension prior to the administration of the product to a patient. Otherwise, the HMPC, that is water soluble, would form a colloidal suspension in water and release the encapsulated product . This seems to be the reason of employing paraffin as a second coating to encapsulate the HMPC-coated powder. US Patent No. 5,997,906 also discloses and claims for a method for obtaining a coated phosphate powder comprising the step of applying a first coating solution to the phosphate powder and a further step of applying a second coating consisting of melted paraffin on said coated phosphate powder. The combination of these two coatings seems to be related to a complex structure to obtain a desired controllable releasing of the active ingredient. However, this combination involves a number of complex and unnecessary steps for obtaining the final product, such as the combined temperatures for applying the first coating and the second coating, with the risk of affecting the pharmaceutical characteristics of the product . In addition, the final product not always are obtained with the desired controlled releasing features.

As stated above, while US Patent No. 5,997,906 discloses the use of at least one coating, not clear and enough examples are given for any person skilled in the art to obtain a powdered product, particularly a sodium phosphate powder, with only one coating capable of resisting the prolonged contact with the water during the suspension and of providing the controlled releasing properties of the pharmaceutical product. If a low amount of only one coating is applied the same may be not enough to keep the covered mixture of phosphates impervious during the suspension and, on the contrary, if a large amount of a coating material is applied the excessive impermeability may affect the releasing of the pharmaceutical product. In addition, if the density of the coating is low, the coated powder may result excessively light and will float in the water instead of being suspended therein. On the contrary, the if the density of coating material is too high, it may result in the coated product falling down and remaining in the bottom of the water container during the suspension prior to the administration.

It would be therefore convenient to have a simple coated composition as well as a process for obtaining the desired coated product, wherein the coated composition would provide a stable and controlled releasing of the active ingredient contained in the composition. The inventor has now discovered that only one coating may be effectively employed for masking the taste of the powdered pharmaceutical product, for keeping impermeability during the suspension and for controllably releasing the pharmaceutical product into the digestive tract of the patient. The inventor has obtained a coated powder with the powder and coating material employed in the proper combination, sizes and proportions to obtain a desired suspension. In addition, the coating is biodegradable and metabolizable to allow the absorption of mixed phosphates in the gastrointestinal tract .

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a new composition comprising particulate active principles for suspending in an aqueous solution, wherein the particles are coated with a lipidic coating or lipid derivative coating for masking the taste of the pharmaceutical and/or protecting the gastric mucose when ingested by the patient, wherein the coating is only one coating and, based in an appropriate relationship between the sizes and weights of the coating layer and the pharmaceutical product, the density of the coated particles are controlled in order to afford a suspension with an homogeneous distribution of the particles in the aqueous medium.

It is still another object of the present invention to provide a particulate composition for suspension in an aqueous solution prior to administration to a patient who needs it; the composition comprising a pharmaceutical product in particles having a size of about 10 microns to 90 microns, the particles being coated with a lipidic coating comprising about 10% w/w to 70% w/w of the total composition weight. It is another object of the present invention to provide a particulate composition for suspension in an aqueous solution prior to administration, the composition comprising a particulate pharmaceutical product such as phosphates, biphosphonates, analgesics, non-steroid anti- inflamatories, and corticoids, and a lipidic coating comprising a lipid having a melting point of about 38°C to 75°C, wherein the lipidic coating is preferably glyceryl esters, synthetic glyceryl ester derivatives, C10-C2₅ alcohol, tertiary alcohols, fatty acids with linear or branched_> chain, and solid poly-alcohol with a molecular weight higher than 1000, with a melting point between 45°C and 65°C, Cιo-C₂₅.

It is a further object of the present invention to provide a particulate composition for suspension in an aqueous solution prior to administration, wherein the composition comprises a pharmaceutical product in small particles and a lipidic coating, with the composition having a dissolution index, in aqueous media, higher than 75%, and a dissolution time of between 30 and 45 minutes, employing the method disclosed in USP XXIV, and wherein the composition has a bulk density of between 0,520 g/ml and 0,600 g/ml.

It is a further object of the present invention to provide a pharmaceutical composition comprising a pharmaceutical product in particles having a size of about 10 microns to 90 microns, the particles being coated with a lipidic coating comprising about 10% w/w to 70% w/w of the total composition weight, and pharmaceutically acceptable stabilizers and excipients selected from the group comprising essences, flavor, sweeteners, dyes, sugars, antioxidants and surfactants. It is even another object of the present invention to provide a method for obtaining a particulate composition for suspension in an aqueous solution prior to administration to a patient who needs this composition; the composition comprising a pharmaceutical product in particles having a size of about 10 microns to 90 microns, the particles being coated with a lipidic coating comprising about 10% w/w to 70% w/w of the total composition weight, wherein the method comprises: i. drying and milling the pharmaceutical product to obtain particle size of between 10 and 90 microns; ii. suspending the particulate pharmaceutical product into a solution of a lipidic coating material; into a solution of the lipidic material or into a melted lipidic material; iii. introducing the suspension obtained in step ii) into a drying spray ejected by a gas stream at a temperature between 0°C and 55 °C; and iv. Sifting, if necessary, the coated particles to obtain the particles having a desired uniform size. It is still another object of the present invention to provide a method for obtaining a particulate composition for suspension in an aqueous solution prior to administration to a patient who needs the composition; the composition comprising a pharmaceutical product in particles having a size of about 10 microns to 90 microns, the particles being coated with a lipidic coating comprising about 10% w/w to 70% w/w of the total composition weight, wherein the method comprises: i. drying and milling the pharmaceutical product to be coated in order to obtain a particle size of 10 to 90 microns; ii. mixing the particulate pharmaceutical product with a melted lipidic coating material under agitation, for at least 30 minutes, gradually reducing the temperature in a gas stream at a temperature of between 10°C and 20°C; and iii. sifting the coated particles, if necessary, to obtain the particles having a desired uniform size.

It is a further object of the present invention to provide a method for obtaining a particulate composition for suspension in an aqueous solution prior to administration to a patient who needs this composition; the composition comprising a pharmaceutical product or active principle in particles having a size of about 10 microns to 90 microns, the particles being coated with a lipidic coating comprising about 10% w/w to 70% w/w of the total composition weight, wherein the method comprises : i . dissolving a lipidic coating material in an organic solvent selected from the group consisting of linear, branched C₂-C₈ alcohols and chlorinated hydrocarbons ; ii. drying and milling the pharmaceutical product to obtain particle sizes of between 10 and 90 microns; iii. suspending the particulate pharmaceutical product into the suspension containing the lipidic coating material; iv. drying the suspension obtained in step iii) in a spray equipment under a temperature between 20°C and 70 °C ; and v. sifting the dry coated particles, if necessary, to obtain the particles having a desired uniform size. It is still another object of the present invention to provide a method as above disclosed wherein the lipidic coating material is selected from the group comprising glyceryl esters, synthetic glyceryl ester derivatives, Cιo-C₂₅ alcohol, tertiary alcohols, Cι₀-C₂s fatty acids with linear or branched chain, and solid poly-alcohol with a molecular weight higher than 1000, with a melting point between 45°C and 65°C.

The above and other objects, features and advantages of this invention will be better understood upon reading of the following non limitative description.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The composition of the present invention comprises at least an active principle in particles of between 10 and 90 microns of size, where each one of these particles is totally covered by a layer of lipidic coating or lipid derivative coating.

Any expert in the art will understand that the active principle of the composition of the invention can be any active principle in particles which are resistant and stable to temperatures of 80 °C and lower. Preferred examples of active principles are the group of chemical compounds having an aggressive action on the gastric mucosa such as analgesics, non-steroid and corticoid anti-inflammatories . The analgesic and non-steroid anti- inflammatory compounds can be, for example, paracetamol, aspirin, diclofenac and their salts, indometacine, piroxicam, meloxicam, ketorolac and their salts. The corticoids can be, for example, prednisone, prednisolone, deflazacort and dexametasone . The active principle can also be a compound of the biphosphonates group such as, for example, alendronate, risendronate and pamidronate .

Examples of active principles also are those having an unpleasant flavour, for example, the active principle of the composition of the invention is a mixture of sodium phosphates with laxative activity, particularly a mixture of monosodic and disodic phosphate . The composition of the invention comprises between about 10% and about 70% p/p regarding the total weight of the composition of a layer of lipidic coating, where these lipids have a melting point between about 38°C and about 75°C, preferably the melting point of the lipids is between about 45°C and about 68°C.

It is evident for an expert in the art that the layer of the lipidic coating can comprise any natural or synthetic lipid such as monoglycerid, diglycerid or triglycerid with the following chemical structure.

CH20 - Rl

CH20 R2

CH20 - R3

where Rl, R2 and R3 can be Hydrogen atoms or alkyl radicals from C3 to C20. They can be saturated or with one or more double bonds, of lineal or branched chain, whenever their melting point is comprised between about 45° C and about 68° C. The molecule should have an alkyl radical at least, being able to have also two or three of these radicals.

For obtaining the desired results it is preferred to work with synthetic lipids because the same have some competitive advantages over the natural ones, for example: they allow to obtain a lipid with an appropriate melting point; it is achieved a lipid with a particular density, in such a way that when coating an active principle of more density than water, the coated product does not deposit, but it rather forms a homogeneous suspension. These synthetic products are easy to obtain and an excellent state of purity is achieved at low cost. Also derivatives of semi synthetic glycerids can be used, such as the fatty acids of C12 to C25, of lineal or branched chain, which can have from one to three double bonds. Saturated or unsaturated fatty alcohols can also be used with one to three double bonds, conjugated or not, of CIO to C25. These alcohols can be primary, secondary or tertiary, whose melting point is comprised within the previously mentioned range.

According to a preferred embodiment a composition is provided that consists of a mixture of sodium phosphates coated with a lipidic substance that can be a derivative substance from a natural fat or a substance derived from a synthetic process, whereby such fat is of synthetic origin. Such coating substance can be a triglyceride, a diglyceride or a monoglyceride derived from chemical entities . The melting point of same should be comprised between about 38 °C and about 75 °C, preferably between about 45 °C and about 68 °C. For example, they can be used as coating lipids, glyceril esters, synthetics derived from glyceryl and/or substances obtained by hydrolysis of these ones like a superior alcohol or acid from C4 to C25 and/or solid polyalcohol of molecular weight higher than 1000. The synthetic derivates from glyceride esters can be, for example, glyceril monoestearate or diestearate, glyceril monopalmitate or dipalmitate glycerol monomiristate or dimiristate, glyceril monoesters or diesters of eicosanoic acid.

The coating herein described is metabolised and it does not modify the laxatives properties of the product, which is absorbed in the gastrointestinal tract.

The weight relationship between the active principle and the lipids of the coating can be variable, in general the lipids comprise between about 10% and about 70%, preferably between about 35% and about 60% in weight regarding the total weight of the composition. This relationship provides to the composition of the invention a certain density, which density is smaller than the density of the active principles in all the cases. This allows the composition of the invention to stay homogeneously and evenly distributed in an aqueous suspension.

The composition of the invention is preferably employed in compositions that are marketed in the form of dry powders to be re- suspended in aqueous solutions at the moment they are to be orally administrated to the patient, wherein the homogeneous distribution of the particles of the composition is important to guarantee the incorporation of the entire composition. Alternatively a tensoactive substance as polysorbate 80 (tween 80) or an anionic detergent, cationic or not ionic, can be incorporated in a small proportion into the composition of the invention to facilitate their absorption in the intestinal tract. It is also possible to incorporate into the composition of the invention any excipient such as for example, essences, flavourings, sweeteners, colouring, sugars; edible tensoactive substances such as Sorbitan esters (Span) and etoxilated Sorbitan esters (Tween 80) , sulfonated as DOSSNa and sodium laurylsulfate; lecithin; and antioxidants as ascorbic acid, BHT and BHA tocopherols.

When the composition of the invention contains as active principle a mixture of sodium phosphate monobasic, monohydrate (P0₄H₂Na. H₂0) and sodium phosphate dibasic, heptahydrate (P0H Na₂. 7H₂0) , in a proportion of, for example, 96g/36g respectively, this composition completely lacks the characteristic unpleasant flavour of the known formulations.

As an option and if desired to differentiate the formulation for children to that one for adults, it is possible to incorporate small quantities of sweeteners and/or flavourings for some particular taste.

The lipidic coating allows the via oral administration of the mixture of phosphates at the high concentrations required to achieve the necessary laxative effect for the pursued diagnostic and/or therapeutic purposes, without the unpleasant effects caused by the original flavour thereof. Therefore, the inventive composition is completely tolerable, without causing nausea and/or emetic effects. For example, for the laxative mixture of phosphates, the inventive coating method is based on the treatment of the previously prepared mixture of phosphates, dried and milled, to fine powder, preferably between 60 and 200 mesh, equivalent to 250-50 microns, with the glyceride fused in a mixer, with an endless screw type system of agitation, or Ribbon type mixer. The mixture should be made in the predetermined weight proportions, by smoothly cooling under agitation until obtaining the particles granulate completely coated by a layer of the employed coating agent, a glyceride for example . This procedure can also be carried out by loading the mixture of suspended dry and milled salts into the active principle, in solution or in melting condition, in the correct weight proportion, in the form of dew impelled by a gas current such as methane, ethane, propane, butane or nitrogen. Air can also be used enriched with nitrogen. When the used glyceride contains some proportion of unsaturated fatty acids, the oxygen presence should be avoided in the impelling gas current, in order not to generate peroxides, which can give the characteristic rancid flavour. The temperature of the gaseous current should be between about 0°C and about +65°C, preferably between 5°C and 45°C.

The coating process can also be made on each of the phosphates forming the laxative mixture, dry and milled as it was indicated above, in separate form, by mixing, in an efficient form, each one of the coated salts in the indicated proportion until achieving a uniform preparation.

The size of the phosphate particles will be comprised preferably between about 50 and about 150 microns. The particles, once coated, can be sifted in order to achieve a uniform distribution of the size without alteration of the achieved properties such as their low density and, mainly, the absence of the flavour of the sodium phosphates of the original salts.

The methods of the present invention allow to prepare any active principle in the form of particles coated by a lipidic layer, for example glyceryl monoestearate or of stearic acid, in a way that the composition obtained as coated particles may be homogeneously re- suspended in an aqueous environment. The procedure includes, while not limited to this, sprayed coating, that is drying by spray or fluid bed or spraying with the agent in solution or melting in a cauldron, or by immersion, either in the melted agent or in a solution, with a subsequent drying step. Previously to the administration to the patient, the composition of the invention can be re-suspended in water or in an aqueous solution, wherein the proportion weight-volume of the composition, regarding the aqueous solution, depends on the employed active principle. This invention is better illustrated according to the following examples, which should not be interpreted as a limitation imposed to its scope. On the contrary, it should be clearly understood that it can be resorted to other embodiments, modifications and equivalents to this invention, which can be suggested to those experts in the art after reading this description, without falling out of the spirit of the present invention and/or the scope appended claims.

EXAMPLE 1 : Preparation of the mixture of phosphate laxatives with a lipidic coating. 960 grams of P0H₂Na.H₂0 and 360 grams of P0₄HNa₂.7H₂0 are mixed evenly and the mixture is dried in a stove at 80°C-90°C, preferably under vacuum. The mixture is dried and milled until achieving a distribution of particles comprised between 60 and 100 microns .

Half of fine granulated weight obtained after the milling it is placed in a type Ribbon mixer together with 10 grams of Polisorbate 80 (Tween 80) and 594 grams of melted glyceril monoestearate is added in form of spray, impelled by a cold nitrogen current (2°C to 8°C) and under a line pressure of 4Kg, under soft agitation. After concluding the aggregate, the agitation must be continued until obtaining a coated powder to room temperature. No saline flavour is detected in the obtained composition.

EXAMPLE 2 :

Preparation of a mixture of laxative phosphates with a lipidic coating and sweeteners to be used, for example, in pediatrics.

A composition according to Example 1 is prepared and a mixture of 500 mg of saccharin and sodium cyclamate is added to the mixture.

EXAMPLE 3 :

660 grams of the mixture of phosphates prepared as it was described in the Example 1 are weighed and suspended in a solution of 694 grams of Glyceryl monoestearate and 10 grams of polysorbate 80 in 1.5 litres of ethanol . The suspension so prepared is loaded in a spray drying equipment at 40 °C under a Nitrogen stream. The dry product is picked up and sifted. The absence of the original flavour of the coated salts is verified.

EXAMPLE 4 :

Evaluation of the dissolution value.

The dissolution test of the prepared composition was performed in an aqueous medium according to Examples 1 and 2, in accordance with the method described in the USA Pharmacopoeia (XXIV USP) .

The result of the essay showed in all the cases and under the working conditions specified in the aforementioned USP XXIV, that the active principles are released, in the first half hour, between 80 and 100% of the coated phosphates .

In this way the absorption of the phosphates in the gastrointestinal tract is assured.

EXAMPLE 5:

A mixture of phosphates (990 grams) prepared as it was described in Example 1 is suspended in 1041 grams of melting stearic acid containing 14 grams of polisorbate 80. This suspension is loaded in a spray drying equipment, impelled by a nitrogen stream at 45°C - 55 °C.

The obtained solid product is used directly in the pharmaceutical formulations.

EXAMPLE 6:

It is proceeded as in Example 5 by processing 480 grams of P0₄H₂Na.H₂0 with 5 grams of polysorbate 80 and separated form.

The obtained products are mixed in the given proportions and are dosed into the final pharmaceutical product .

EXAMPLE 7:

Preparation of sodium diclofenac coated according to the method of the invention. The method was carried out in agreement with

Example 1, wherein the particle size for the ground sodium diclofenac was comprised between 50 and 75 microns .

The weight proportion between the sodium diclofenac and the glyceryl monoestearate was of 1:1. The percentage of Tween 80 was ca. 1:100 (weight/weight) regarding the total of solids.

While preferred embodiments of the present invention have been illustrated and described, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the invention as defined in the appended claims.

Claims

WE CLAIM :

1. A particulate composition for suspension in an aqueous solution prior to administration to a patient who needs the composition, the composition comprising a pharmaceutical product in particles having a size of about 10 microns to 90 microns, the particles being coated with a lipidic coating comprising about 10% w/w to 70% w/w of the total composition weight.

2. The particulate composition of claim 1, wherein the pharmaceutical product is selected from the group consisting of phosphates, biphosphonates, analgesics, non-steroid anti-inflamatories, and corticoids.

3. The particulate composition of claim 1, wherein the lipidic coating is a lipid having a melting point of about 38°C to 75°C.

4. The particulate composition of claim 1, wherein the lipidic coating is selected from the group consisting of glyceryl esters, synthetic glyceryl ester derivatives, C₁₀-C₂₅ alcohol, tertiary alcohols, Cι₀-C₂₅ fatty acids with linear or branched chain, and solid poly-alcohol with a molecular weight higher than 1000, with a melting point between about 45 °C and about 65 °C.

5. The particulate composition of claim 1, wherein the composition has a dissolution index, in aqueous media, higher than 75%, and a dissolution time between 30 and 180 minutes, employing the method disclosed in USP XXIV.

6. The particulate composition of claim 1, wherein the composition has a density of between about 0,520 g/ml and about 0,600 g/ml.

7. A pharmaceutical composition comprising: a pharmaceutical product in particles having a size of about 10 microns to 90 microns, the particles being coated with a lipidic coating comprising about 10% w/w to 70% w/w of the total composition weight, and pharmaceutically acceptable excipients and stabilizers.

8. The composition of claim 7, wherein the pharmaceutically acceptable excipients are selected from the group consisting of essences, flavor, sweeteners, dyes, sugars, antioxidants and surfactants.

9. The composition of claim 7, wherein the lipidic coating is selected from the group consisting of glyceryl esters, synthetic glyceryl ester derivatives, Cι₀-C₂₅ alcohol, tertiary alcohols, Cι₀-C₂₅ fatty acids with linear or branched chain, and solid poly-alcohol with a molecular weight higher than 1000, with a melting point between about 45 °C and about 65 °C.

10. A method for obtaining a particulate composition for suspension in an aqueous solution prior to administration to a patient who needs the composition, the composition comprising a pharmaceutical product in particles having a size of about 10 microns to 90 microns, the particles being coated with a lipidic coating comprising about 10% w/w to 70% w/w of the total composition weight, wherein the method comprises: i. drying and milling the pharmaceutical product to obtain particle sizes of between 10 and 90 microns; ii. suspending the particulate active principle into a lipidic coating material; iii. introducing the suspension obtained in step ii) into a drying spray ejected by a gas stream at a temperature between 0°C and 55 °C; and iv. sifting the coated particles to obtain the particles having a desired uniform size.

11. The method of claim 10, wherein the step of suspending the particulate pharmaceutical product into a lipidic coating material is carried out into a solution of the lipidic material.

12. The method of claim 10, wherein the step of suspending the particulate pharmaceutical product into a lipidic coating material is carried out into a melted lipidic material.

13. The method of claim 10, wherein the lipidic coating material is selected from the group consisting of glyceryl esters, synthetic glyceryl ester derivatives, Cιo-C₂₅ alcohol, tertiary alcohols, Cι₀-C₂₅ fatty acids with linear or branched chain, and solid poly-alcohol with a molecular weight higher than 1000, with a melting point between about 45°C and about 65°C.

14. A method for obtaining a particulate composition for suspension in an aqueous solution prior to administration to a patient who needs the composition, the composition comprising a pharmaceutical product in particles having a size of about 10 microns to 90 microns, the particles being coated with a lipidic coating comprising about 10% w/w to 70% w/w of the total composition weight, wherein the method comprises: i. drying and milling the active principle to obtain particle sizes of between 10 and 90 microns; ii. mixing the particulate active principle with a melted lipidic coating material under agitation, for at least 30 minutes, gradually reducing the temperature in a gas stream at a temperature of between 10 °C and 20°C; and iii. sifting the coated particles for obtaining the particles having a desired uniform size.

15. The method of claim 14, wherein the lipidic coating material is selected from the group consisting of glyceryl esters, synthetic glyceryl ester derivatives, C10-C25 alcohol, tertiary alcohols, C₁₀-C₂s fatty acids with linear or branched chain, and solid poly-alcohol with a molecular weight higher than 1000 with a melting point between about 45 °C and about 65 °C.

16. A method for obtaining a particulate composition for suspension in an aqueous solution prior to administration to a patient who needs the composition, the composition comprising an active principle in particles having a size of about 10 microns to 90 microns, the particles being coated with a lipidic coating comprising about 10% w/w to 70% w/w of the total composition weight, wherein the method comprises: i . dissolving a lipidic coating material in an organic solvent; ii . drying and milling the active principle to obtain particle sizes of between 10 and 90 microns; iii. suspending the particulate active principle into the suspension containing the lipidic coating material ; iv. drying the suspension obtained in step iii) in a spray equipment at a temperature between 20°C and 70 °C;

v. sifting the dry coated particles for obtaining the particles having a desired uniform size.

17. The method of claim 16, wherein the organic solvent is selected from the group consisting of linear or branched C₂-C₈ alcohols and low boiling point chlorinated hydrocarbons.

18. The method of 16, wherein the lipidic coating material is selected from the group consisting of glyceryl esters, synthetic glyceryl ester derivatives, C10-C25 alcohol, tertiary alcohols, Cι₀-C₂₅ fatty acids with linear or branched chain, and solid poly-alcohol with a molecular weight higher than 1000, with a melting point between about 45°C and about 65°C.