"MULTILAYER TABLET WITH DIFFERENTIATED RELEASE OF MELATONIN AND ACTIVE INGREDIENTS"

Technical Background

The International Classification of Sleep Disorders defines insomnia as the subjective perception of difficulty with sleep initiation, duration, consolidation, or quality that occurs despite adequate opportunity for sleep, and that results in some form of daytime impairment (e.g., fatigue, decreased energy, daytime sleepiness, and mood disorders).

Insomnia disorders can be primary or secondary. Primary insomnias may have both intrinsic and extrinsic factors involved in their etiology, but they are not considered secondary to another disorder. Secondary forms occur when insomnia is a symptom of a medical or psychiatric disease, another sleep disorder, or results from substance abuse.

The term primary insomnia (used in both the International Classification of Diseases (ICD-10) and the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV)) is a disorder identified as chronic when it persists for at least three months with a frequency of at least three times a week. When the disorder meets the symptom criteria but persists for less than three months, it is considered acute, short-term insomnia.

Different manifestations of insomnia can occur at different times during the sleep period.

By way of example:

• sleep onset insomnia (or initial insomnia) involves difficulty with sleep initiation before bedtime;

• sleep maintenance insomnia (or medium insomnia) involves frequent or prolonged awakenings during the night;

• late insomnia involves early morning awakening with an inability to return to sleep;

• nonrestorative sleep, a disorder of poor sleep quality that does not leave the individual refreshed upon awakening despite adequate duration, is a common sleep disorder that usually occurs in association with difficulty initiating or maintaining sleep; this disorder can also occur in association with other sleep disorders (e.g., breathing-related sleep disorder).

Impairment of cognitive performance may include difficulties in attention, concentration, and memory and even in performing simple manual activities. Associated mood disorders are generally described as irritability or mood lability and less commonly as depressive or anxious symptoms. Not all individuals with nighttime sleep disorders are anxious or have functional impairment. For example, sleep continuity is often disrupted in healthy elderly people who nevertheless identify themselves as good sleepers. A diagnosis of insomnia disorder should be reserved for those individuals with significant daytime discomfort or impairment related to their nighttime sleep difficulties.

An insomnia disorder is diagnosed if insomnia occurs as an independent condition or is in comorbidity with another mental disorder (e.g., major depressive disorder), a medical condition (e.g., pain) or another sleep disorder (e.g., a breathing-related sleep disorder).

Short-term insomnia affects from 30% to 50% of the population. The prevalence of chronic insomnia disorder in industrialized nations is estimated to be at least from 5% to 10%. Chronic insomnia is associated with numerous adverse effects on function, health, and quality of life. Increased rates of absenteeism from work, and occupational and motor vehicle accidents have also been widely reported. Persistent insomnia has been identified in numerous studies as a significant risk factor for the development of psychiatric disorders, particularly mood disorders. This condition is also associated with an increased risk of relapse for depression and alcoholism, as well as adverse effects in populations with chronic pain. More recent investigations suggest that chronic insomnia is associated with an increased risk of cardiovascular disease. In particular, insomnia with objectively short sleep times is a significant risk factor for the development of hypertension.

Melatonin is a hormone involved in the management of the circadian rhythm, melatonin levels in mammals being high at night and low during the day. Melatonin is for this reason used in the treatment of sleep disorders, in general, and insomnia in particular, and its administration is particularly indicated to induce sleep in individuals who experience severe difficulty with falling asleep. Compositions of melatonin having prolonged or rather delayed release to provide a longer-lasting effect during sleep and, consequently, better treatment of sleep disorders, are known.

However, because of the different types of sleep disorders highlighted above, it has become necessary to be able to provide pharmaceutical compositions containing melatonin and enhanced with additional active ingredients.

In this context, the Applicant has realized that while valerian is a very useful compound, even in combination with melatonin, valerian, even when present in extract form, has the major drawback of having an unpleasant color and taste that greatly reduce the compliance of the final product where they are included. Moreover, valerian is characterized by a degree of hygroscopicity that greatly affects the preparation of a formulation, for example, in tablet or even more in multilayer tablet.

Purposes of the invention

It is a first purpose of the invention to provide a composition in a solid form, preferably, in the form of a multilayer tablet, which comprises melatonin and/or other active ingredients and which provides a controlled release of melatonin and/or the other active ingredients.

It is another purpose of the invention to provide a process for preparing said composition of the invention.

It is another purpose of the invention to provide a pharmaceutical association comprising melatonin and/or other active ingredients and its use in a method of treatment of sleep disorders, particularly primary insomnia.

Advantageously, the multilayer tablet of the present invention containing melatonin, even in the presence of valerian, promotes falling asleep, contributes to peaceful sleep, and promotes uninterrupted sleep.

Drawings

Fig. 1 refers to the core after 3 hours

Fig. 2 refers to the core after 19 hours

Fig. 3 refers to the tablet filmed with Sepifilm 050 after 3 hours

Fig. 4 refers to the tablet filmed with Sepifilm 050 after 19 hours Fig. 5 refers to the tablet filmed with Sepifilm SN after 3 hours

Fig. 6 refers to the tablet filmed with Sepifilm SN after 19 hours

Fig. 7 refers to the tablet filmed with Aquapolish after 19 hours

Fig. 8 refers to the tablet filmed with Nutrafinish after 19 hours

Fig. 9 refers to comparative stress test result performed under open storage conditions in climatic chamber set at a temperature of 40°C and 75% relative humidity

Description of the invention

The Applicant, after intensive and prolonged research and development, has solved the problems discussed above and achieved the above-mentioned purposes by means of a composition comprising melatonin and/or other active ingredients according to the united claims, in particular to united claim 1. The composition allows prolonged release of at least part of the melatonin, which has been found to be particularly effective for the treatment of sleep disorders. The composition is advantageously in a tablet form, particularly as a multilayer tablet with stacked layers.

Thus, it is an object of the invention a tablet comprising three stacked layers having different formulations, wherein at least one layer comprises melatonin and at least one layer comprises an additional active ingredient selected from the group comprising or, alternatively, consisting of valerian, lemon balm, hawthorn, passion flower, vitamin B6 and/or mixtures thereof, the said tablet comprising a film coating.

Preferably, at least one layer comprises or, alternatively, consists of melatonin, vitamin B6, and valerian. Preferably, this layer represents the immediate-release layer.

Preferably, at least one layer comprises or, alternatively, consists of melatonin and passion flower. Preferably, this layer represents the slow-release layer.

Preferably, at least one layer comprises or, alternatively, consists of hawthorn and lemon balm. Preferably, this layer represents the intermediate-release layer.

All components of the tablet of the invention, including excipients and the tablet film coating are known in the art. Preferably, melatonin has a titer of 98% or higher, more preferably 99% or higher.

Preferably, vitamin B6 (pyridoxine hydrochloride) is selected, for example, with CAS No. 58 56-0 and molecular mass of about 205.64 g/mol.

Preferably, hawthorn is selected from, for example, the species Crataegus pinnatifida, Crataegus monogyna Jacg. and/or Crataegus laevigate (Poir.) DC, preferably in its leaf and flower components, as an extract (e.g., extraction with an extraction solvent comprising 80% ethanol and 20% water), preferably a dry extract. For example, 100 mg of extract is equivalent to about 400 mg of dry extract of hawthorn leaves and flowers. For example, a dry extract of hawthorn leaves and flowers contains about 1 %-5%, e.g., at least 1.5% of flavonoids (HPLC). Preferably, hawthorn is, for example, of the species Crataegus pinnatifida, is in the form of a dry extract titrated in vitexin (vitexin-2"-O-rhamnoside content), and has a titer ranging from 1% to 4%, preferably from 2% to 3%, by weight (HPLC). Preferably, valerian is, for example, of the species Valeriana Officinalis, in a dry extract form, preferably hydroalcoholic dry extract (CAS No. 8057-49-6). Preferably, the extract is a dry extract, titrated in valerenic acids, e.g., valerenic acid, hydroxyvalerenic acid, and acetoxyvalerenic acid measured by HPLC, and has a titer ranging from 0.5% to 2.5%, preferably from 0.8% to 1.5%, by weight (HPLC).

For example, extract is obtained from rhizome and roots with a water and ethanol solvent and a drug:extract ratio of about 3-4:1. The dry extract, such as powder or granules, has an average particle size of about 80-100 mesh (80 mesh = 180 micrometers) and a bulk density of about 0.70 g/ml.

Preferably, passion flower is, for example, of the species Passiflora Incarnata in a dry extract form, preferably hydroalcoholic dry extract (CAS No. 729668-47-9). Preferably, the extract is a dry extract, titrated in isovitexin, e.g., isovitexin, vitexin, iso-orientin and orientin, and has a titer ranging form 1.5% to 6%, preferably from 3% to 4%, by weight (HPLC).

For example, extract is obtained from flowers with a water and ethanol solvent and a drug:extract ratio of about 4:1. The dry extract, such as powder or granules, has an average particle size of about 80-100 mesh (80 mesh = 180 micrometers) and a bulk density of about 0.78 g/ml.

Preferably, lemon balm is, for example, of the species Melissa Officinalis in a dry extract form, preferably hydroalcoholic dry extract (CAS No. 84082-61-1). Preferably, the extract is a dry extract, titrated in hydroxycinnamic derivatives, e.g., expressed as rosmarinic acid, and has a titer ranging from 5% to 25%, preferably from 10% to 15%, by weight (HPLC).

For example, extract is obtained from leaves with a water and ethanol solvent and a drug:extract ratio of about 4:1. The dry extract, such as powder or granules, has an average particle size of about 75-300 mesh (75 mesh = 200 micrometers).

In an embodiment, the mass ratio (w/w) (calculated on the whole multilayer tablet) of melatonin/vitamin B6/valerian/hawthorn/passion flower/lemon balm may preferably be about 1/6.2/100/176/100/50.

Tablets of the invention may contain from 0.5 to 10 mg of melatonin, preferably from 1 to 5 mg of melatonin, e.g., 1 mg, 2 mg, 3 mg, 4 mg.

According to a preferred embodiment, the tablet has three layers, each layer having a different formulation. In an embodiment two layers contain melatonin, one layer being an immediate dissolution layer and one being a slow or delayed dissolution layer, preferably the immediate dissolution layer comprises melatonin and valerian, while the slow dissolution layer comprises melatonin and passion flower.

There are several known substances or compounds that can be used to coat a tablet.

The Applicant has found useful and advantageous to use a pharmaceutical or food-grade film selected from such films as polymeric films based on, for example, Polyvinyl alcohol (PVA) or based on Methyl hydroxypropyl cellulose or HPMC (hydroxypropyl methyl cellulose) as the tablet coating film.

Preferably, the process for preparing a multilayer tablet of the invention involves a preparation of an immediate- dissolution granulate (blue layer) containing melatonin and vitamin B6, a preparation of a blend containing said granulate and valerian to give the immediate-dissolution layer (blue layer), a preparation of a blend for the slow- dissolution layer (yellow layer) containing melatonin and passion flower, a preparation of an intermediate- dissolution granulate (red layer) containing hawthorn and lemon balm, and a preparation of an intermediatedissolution blend (red layer). Next, the pressing or compressing step takes place to give a three-layer (blue- yellow-red) tablet.

The multilayer (blue-yellow-red) tablet is then, advantageously, filmed using a pharmaceutical coating pan, a tool known to the skilled person in the art.

Preferably, a filming or coating of the trilayer tablet of the present invention can be made with a composition that comprises or, alternatively, consists of:

(I) water from 70% to 95%, preferably from 80% to 90%, more preferably from 82% to 88%, e.g., about 86% by weight; and

(ii) optionally, a flavoring agent such as a vanilla flavor from 0.5 to 1 .5%, preferably about 0.84% by weight; and

(iii) a compound from 5% to 30%, preferably from 10% to 20%, more preferably from 12% to 18%, e.g., about 13%, or 14%, or 15%, or 16%, or 17%, by weight; wherein:

- said compound (iii) comprises or, alternatively, consists of:

(iii. a) hydroxypropyl methyl cellulose from 40% to 80%, preferably from 50% to 70%, more preferably from 55% to 60%, by weight; and

(iii.b) microcrystalline cellulose from 2.5% to 25%, preferably from 5% to 20%, more preferably from 10% to 15%, by weight; and

(iii.c) a stearic acid from 5% to 50%, preferably from 10% to 40%, more preferably from 15% to 35%, even more preferably from 28% to 32%, by weight, and/or

(iii.d) acetylated mono- and diglycerides from 0.5% to 15%, preferably from 4% to 12%, more preferably from 6% to 10%, by weight.

Preferably, a filming of the trilayer tablet of the present invention can be made with a composition comprising or, alternatively, consisting of (I) + (optionally (II)) + (iii) wherein said (iii) is (iii. a) + (iii.b) and (iii.c), and/or (iii.d).

Preferably, a filming of the trilayer tablet of the present invention can be made with a composition comprising or, alternatively, consisting of (I) + (optionally (II)) + (iii) wherein said (iii) is (iii. a) + (iii.b) and (iii.d), and/or (iii.c).

Advantageously, with the use of said composition to coat or cover a tablet, for example, a trilayer tablet such as the one that is an object of the present invention, it is not necessary to apply sub-coating or pre-filming before the tablet is filmed because with said composition good isolation of the tablet core from the outside is achieved. The tablet core (3 coupled layers) contains hygroscopic ingredients (botanicals) which, in the absence of good protection or isolation, would absorb water with an inevitable swelling of the layers themselves and, subsequent, reduced stability and shelf-life of the tablet because the swollen layers would peel off (the phenomenon of delamination). By means of the filming composition of the present invention, a single step of filming or coating is sufficient to achieve a result that avoids pre-filming or sub-coating.

Preferably, hydroxypropyl methyl cellulose can also be identified with the name hypromellose, for example, E464. Preferably, microcrystalline cellulose can also be identified as, for example, E460. Preferably, stearic acid can be of plant origin and can also be identified as, for example, E570.

Preferably, acetylated mono- and diglycerides can also be identified as , for example, E472a.

Preferably, said composition and said compound may also be identified, for example, with the trade name SEPI FILM 050 or SEPI FILM LP030.

For example, a filming according to said composition comprising or, alternatively, consisting of (i) + (optionally (ii)) + (iii) wherein said (iii) is (iii.a) + (iii.b) and (iii.c) can be made, for example, with a composition comprising: water about 86% by weight, optionally a vanilla flavor about 0.8% by weight, and a compound about 13.2% by weight (e.g., a commercial product called Sepifilm 050). Said compound (iii) comprises hydroxypropyl methyl cellulose from 75% to 80%, microcrystalline cellulose from 10% to 15%, and acetylated mono- and diglycerides from 0.5% to 15% by weight.

For example, a filming according to said composition comprising or, alternatively, consisting of (i) + (optionally (ii)) + (iii) wherein said (iii) is (iii.a) + (iii.b) and (iii.d) can be made, for example, with a composition comprising: water about 86% by weight, optionally a vanilla flavor about 0.84% by weight, and a compound about 13.16% by weight (e.g., a commercial product called Sepifilm LP030). Said compound (iii) comprises hydroxypropyl methyl cellulose from 55% to 60%, microcrystalline cellulose from 10% to 15%, and stearic acid from 28% to 32%, by weight.

For example, a filming preparation according to said composition that comprises or, alternatively, consists of (i) + (optionally (ii)) + (iii) wherein said (iii) is (iii.a) + (iii.b) and (iii.d) can be performed as follows.

Preferably, water is added to the coating pan container and under stirring said compound is poured in. It is left under stirring for about 40-60 minutes until completely solubilized. Then, in the dissolver under stirring, a flavoring agent is added, such as vanilla flavor. This solution is applied by a spray process: the coating liquid, by an atomizer, is deposited on the core in the form of very fine droplets that first wet the surface of the core and, then, expand; upon evaporation of the solvent (almost instantaneous), a phenomenon of coalescence occurs, leading to the formation of the film on the surface of the tablet core. The process parameters applied in filming are as follows: IN air temperature: 50-55°C, core temperature: 35-37°C and coating pan rpm: 22-25 rpm.

The filming agent, represented by said composition comprising said compound (iii) was selected to provide a good release profile comparable and/or equal and/or better than that obtained with other filming agents, including those based on polyvinyl alcohol (see experimental part).

With the filming agent according to said composition and said compound (iii), greater core isolation and, therefore, greater stability of the filmed tablets, under stressful temperature and humidity conditions (40°C and 75% RH) is achieved. Said compound (iii) contains stearic acid. Preferably, the stearic acid used is of plant origin and does not contain alcohol. The presence of stearic acid, in combination with hydroxypropyl methyl cellulose and microcrystalline cellulose, gives the film-forming polymer greater lipophilicity and, therefore, greater core isolation and consequently greater stability of the film-coated tablets. Preferably, the filming agent according to said composition and said compound (iii) gives the tablet core greater isolation from the external environment and thus greater stability under stressful temperature and humidity conditions (40°C and 75% RH).

Preferably, the use of said composition (i) + optionally (ii) + (iii) containing said compound (iii) provides a higher level of safety than polyvinyl alcohol-containing filming agents (such as, for example, polyvinyl alcohol-Macrogol E1209) because the latter filming agents may contain traces of ethylene oxide, which is a carcinogenic and not permitted substance.

For example, a filming can be made with SEPI FILM 050: water about 86% by weight, vanilla flavor about 0.8% by weight and a compound having the trade name Sepifilm 050 about 13.2% by weight. Sepifilm 050 compound comprises: methyl hydroxypropyl cellulose from 75% to 80% by weight, microcrystalline cellulose from 10% to 15% by weight, and acetylated mono- and diglycerides from 0.5% to 15% by weight.

Preferably, a filming can be made with AQUAPOLISH F CLEAR BIOGRUND: water about 74.2% by weight, vanilla flavor about 0.8% by weight, and a compound having the trade name AquaPolish F Clear about 25% by weight. The AquaPolish compound comprises copolymers of polyvinyl alcohol-Macrogol E1209, talc E553b, stearic acid E570, polyvinyl alcohol E1203 and hydrated colloidal silica E551.

Preferably, water is added to the coating pan container and under stirring the AquaPolish compound is poured in. It is left under stirring for about 60 minutes until completely solubilized. Then vanilla flavor is added into the dissolver under stirring.

In this case the tablet comprises melatonin about 1 mg; vitamin B6 about 1.1 mg-2.1 mg.

The dissolution test for melatonin is after 5 minutes 5%; after 45 minutes 27%; after 2 hours 49%; after 4 hours 68%; and after 8 hours 85%.

Preferably, a filming can be made with NUTRAFINISH COLORCON: water about 91.2% by weight, vanilla flavor about 0.8% by weight, and a compound having the trade name Nutrafinish about 8% by weight. The Nutrafinish compound comprises copolymers of polyvinyl alcohol-macrogol E1209, talc E553b, mono- and diglycerides E471, and partially hydrolyzed polyvinyl alcohol E1203.

Preferably, water is added to the coating pan container and under stirring the Nutrafinish compound is poured in. It is left under stirring for about 60 minutes until completely solubilized. Then vanilla flavor is added into the dissolver under stirring.

In this case the tablet comprises melatonin about 1 mg; vitamin B6 about 1.1 mg-2.1 mg.

The dissolution test for melatonin is after 5 minutes 6%; after 45 minutes 28%; after 2 hours 50%; after 4 hours 70% and after 8 hours 95%.

Preferably, the film may contain at least one flavoring agent, preferably vanilla flavor. Suitable films are, for example, Sepifilm ® 050 (manufactured by Seppic), AquaPolish ® clear 699.08 from Biogrund and Nutrafinish ® from Colorcon. The film coating of the trilayer tablet, as described above, reduces the hygroscopicity of the core of the multilayer tablet and advantageously avoids delamination (layer separation) of the layers. This aspect was confirmed by placing the multilayer tablets in accelerated stability, under open storage conditions at 40°C, 75% relative humidity (RH). The tablets were then organoleptically evaluated after 3 hours (Figure 1) and after 19 hours (Figure 2).

The same test was conducted on the filmed tablets using different types of coatings based on different polymers such as Sepifilm 050 (based on HPMC) after 3 hours (Figure 3) and after 19 hours (Figure 4); Sepifilm SN (based on Shellac, animal origin) after 3 hours (Figure 5) and after 19 hours (Figure 6); Aquapolish (based on PVA) after 19 hours (Figure 7); and Nutrafinish (based on PVA) after 19 hours (Figure 8).

As can be seen from the attached photos (Figures 1-8) only the multilayer tablets filmed with PVA-based polymers such as, for example, Aquapolish and Nutrafinish do not show cracking and/or delamination after stress testing under open storage conditions at 40°C, 75%RH. Thus, this test confirms the hygroscopicity of the core and standard filming with HPMC. These data were further confirmed by stability studies conducted at 3 months at 30°C and 65% RH on the tablets filmed with the different compounds.

The filming process developed and the coating films used highlight the ability to isolate the core from the external environment, preventing the tablet from cracking or delaminating. The stabilization of the tablet with regard to the color of each individual layer is also evident. The isolation of the core, achieved by the application of these PVA- based coating films (Aquapolish and Nutrafinish) also makes it possible to avoid the release, diffusion, and consumer perception of the unpleasant odor of valerian extract present in the multilayer tablet.

According to another aspect, it is an object of the invention a process for preparing the composition of the invention according to claim 9 . It is also an object of the invention an association according to claim 11 .

"Multilayer tablet" here means that the tablet consists of layers, stacked on top of each other, comprising the different extracts listed above or mixtures thereof.

The term "immediate dissolution" means that the time required for the layer to start dissolving is 5 minutes or less.

The term "intermediate dissolution" is used here to indicate a starting dissolution time of about 40-60 minutes, for example, around 55 minutes.

The term "slow dissolution" is used here to indicate a starting dissolution time of about 6-8 hours, such as 8 hours.

"Starting dissolution time " refers to the time when the tablet begins to dissolve under the operating conditions known to the skilled person in the art.

Preferably, the melatonin dissolution profile is checked by "dissolution test" and can be of the type: 5 minutes 5%; 45 minutes 27%; 2 hours 49%; 4 hours 67% and 8 hours 85%.

The different dissolutions above will provide different release of active ingredients, namely melatonin, vitamin B6 and the extracts as defined here. The above compositions are preferably administered in the evening before bedtime or just before the rest period. The different releases described above result in appropriate sedation throughout the duration of rest, particularly at night. The choice and dosage of melatonin, vit. B6 and the officinal plants described above, and the different dissolution of the relevant layers of the tablet, result in proper sedation, in the absence of toxic effects and without leading to side effects upon waking or during the day.

Techniques for preparing controlled-release tablets are known, and to achieve the different dissolutions mentioned above, conventional excipients known in the art can be used.

In addition to those already mentioned, the types of pharmaceutical additives used in preparing the compositions of the invention, the contents ratios of additives with respect to active ingredients, and the methods of preparing the pharmaceutical composition may be appropriately chosen by the skilled person in the art.

For conventional vehicles and excipients, organic or inorganic substances, or solid or liquid substances can be used as excipients and vehicles, as long as they are edible, physiologically acceptable, and compatible with all other components of the composition. The skilled person in the art is fully capable of selecting the most suitable vehicles and excipients for the preparation of the composition.

As examples, organic or inorganic substances, or solid or liquid substances may be used as excipients and vehicles, provided they are edible and pharmaceutically acceptable. Examples of excipients used in the preparation of solid pharmaceutical compositions include, for example, lactose, sucrose, starch, talc, cellulose, dextrins, kaolin, calcium carbonate, stearic acid or magnesium stearate, lactose, polyethylene glycol PEG, mannitol, sorbitol, chelating agents, anti-caking agents, sweetening agents, preservative agents, and flavoring agents.

Sweeteners may be one or more natural sugars, optionally reduced, such as sucrose, dextrose, xylitol, mannitol, or sorbitol, or a synthetic product such as sodium saccharin, aspartame, acesulfame k, or sucralose. Acidifying agents may also be added.

Examples of the composition of the invention are provided in the Experimental Section below for illustrative purposes only.

The expression "sleep disorders" is intended here to include any sleep-related pathology, such as difficulty with falling asleep, duration, consolidation, or quality of sleep, and preferably the expression identifies primary insomnia.

The composition i.e., tablets of the invention are normally administered just before bedtime, e.g., 15-60 minutes before, preferably 30-40 minutes before. Normally a dose of one or two tablets, equivalent to the administration of 1 or 2 mg of melatonin, is sufficient to achieve the desired effect. However, these dosages may vary according to the age, sex and health status of the subject to be treated as well as the severity of the disorder. According to another of its aspects, it is an object of the invention the use of the composition, particularly in a tablet form, in the treatment of sleep disorders as defined above.

According to another of its aspects, it is an object of the invention a method of treatment of sleep disorders as defined above, which comprises administering an effective amount of the composition i.e. tablets of the invention to a subject in need. According to another of its aspects, it is also an object of the invention an association consisting of melatonin, vitamin B6, valerian, passion flower, hawthorn, and lemon balm.

According to another of its aspects, it is also an object of the invention an association consisting of melatonin, vitamin B6, valerian, passion flower, hawthorn, and lemon balm, for use in the treatment of sleep disorders as defined above.

According to another of its aspects, it is also an object of the invention an association consisting of melatonin, vitamin B6, valerian, passion flower, hawthorn, and lemon balm as the active ingredient of pharmaceutical compositions with differentiated release among the various active ingredients, useful in the treatment of sleep disorders as defined above.

The invention will now be described in more detail in the Experimental Section that follows, for illustrative purposes and in no way limiting.

Experimental Section

Preparation of a 1.02-gram multilayer tablet (blue layer 320 mg; yellow layer 340 mg; red layer 340 mg)

1. First layer

Granulate for the blue layer

Item name mg/unit%

Microcel 102 1 Endurance VE 090 130.26 mg 74.01

Dicalcium Phosphate Di-Cafos C92-14 30.00 mg 17.05

Colorant E 131 (blue) 0.24 mg 0.14

Explocel (sodium croscarmellose) 4.00 mg 2.27

Polyvinyl pyrrolidone PVP K30 5.00 mg 2.84

MELATONIN 0.30 mg 0.17

Vitamin B6 6.20 mg 3.52

Purified water 89.50 mg 50.85 Total weight 176.00 mg

The granulate, prepared by wet granulation, having a formulation as detailed above was used to prepare the following formulation "PP251-1C blue layer" formulated to have immediate release properties of melatonin and vitamin B6, equal to or less than 5 minutes.

PP251-1C Blue layer

Item name mg/unit%

Blue granulate 176.00 mg 55.00

VALERIAN DRY EXT. TIT 0.8% AC. VALERENIC 100.00 mg 31.25

VANILLA FLAVOR SYMRISE 655064 15.00 mg 4.69 AEROSIL 200 PHARMA 5.00 mg 1 .56

DISOLCEL GF (SODIUM CROSCARMELLOSE) 4.00 mg 1.25

MAGNESIUM STEARATE VEG. 765310 LIGA E470B 5.00 mg 1.56

POLYPLASDONE XL 15.00 mg 4.69

Total 320.00 mg

2. Second layer

The following formulation was then prepared for the second layer of the tablet (yellow layer) containing delayed- release melatonin and passion flower. The yellow layer begins to dissolve after about 6-8 hours.

PP251-3B Yellow layer

Item name mg/unit%

PASSIONFLOWER DRY EXT. 100.00 mg 29.41

MELATONIN 0.71 mg 0,21

METOLOSE 90 SH 4000 70.00 mg 20.59

MICROC. CELLULOSE 200 158.29 mg 46.56

AEROSIL 200 PHARMA 6.00 mg 1 .76

PYOXIDE YELLOW (E172) IRON OX. YELLOW 3.00 mg 0.88

MAGNESIUM STEARATE VEG. 765310 LIGA E470B 2.00 mg 0.59

Total 340.00 mg

3. Third layer.

Granulate for the red layer

Item name mg/unit%

HAWTHORN DRY EXT. 100.00 mg 33.33

LEMON BALM DRY EXT. 50.00 mg 16.67

Microcel 102 1 Endurance VE 090 115.74 mg 38.58

Dicalcium Phosphate Di-Cafos C92-14 20.26 mg 6.75 Explocel (sodium croscarmellose) 4.00 mg 1.33 Polyvinyl pyrrolidone PVP K30 10.00 mg 3.33 purified water 12.00 mg 4.00

Pure ethyl alcohol 96° (Kg) 12.00 mg 3.53

Total 300.00 mg

The granulate, prepared by wet granulation, having a formulation as detailed above was used to prepare the following formulation "PP251-1 A red layer" formulated to have melatonin release properties of 60 minutes or less. PP251-1Red layer

Item name mg/unit%

Granulate 300.00 mg 88,24

Microcel 1021 Endurance VE 090 25.60 mg 7.53

Plant magnesium stearate 4.00 mg 1.18

Explocel (sodium croscarmellose) 3.00 mg 0.88

Levilite 3.00 mg 0.88

Pyoxide Red (E172) 4.40 mg 1.29 Total 340.00 mg

The process involves preparation of blue layer granulate, preparation of blue layer blend, preparation of yellow layer blend, preparation of red layer granulate, and preparation of red layer blend. Next, the compression step takes place. The multilayer tablet (blue-yellow-red) is then subjected to filming using a pharmaceutical coating pan, a tool known to the skilled person in the art.

1) For example, a filming can be made with a composition (e.g., SEPIFILM 050): water about 86% by weight, vanilla flavor about 0.8% by weight, and a compound (e.g., a compound having the trade name Sepifilm 050) about 13.2% by weight.

Said compound (e.g., Sepifilm 050) comprises: methyl hydroxypropyl cellulose from 75% to 80% by weight, microcrystalline cellulose from 10% to 15% by weight, and acetylated mono- and diglycerides from 0.5% to 15% by weight.

Preferably, methyl hydroxypropyl cellulose can also be identified as, for example, E464.

Preferably, microcrystalline cellulose can also be identified as, for example, E460.

Preferably, acetylated mono- and diglycerides may also be identified as, for example, E472a.

2) For example, a filming can be made with a composition (e.g., SEPIFILM LP 030) that comprises or, alternatively, consists of: water from 70% to 95%, preferably from 80% to 90%, more preferably from 82% to 88%, e.g., about 86% by weight, (optionally a flavoring agent e.g., vanilla flavor from 0.5% to 1.5%, preferably about 0.84% by weight) and a compound (e.g., Sepifilm LP030) from 5% to 30%, preferably from 10% to 20%, more preferably from 12% to 18%, e.g., about 13%, or 14%, or 15%, or 16%, or 17%, by weight.

Said compound (e.g., Sepifilm LP 030) comprises or, alternatively, consists of: hydroxypropyl methyl cellulose from 40% to 80%, preferably from 50% to 70%, more preferably from 55% to 60%, microcrystalline cellulose from 2.5% to 25%, preferably from 5% to 20%, more preferably from 10% to 15%, and a stearic acid from 5% to 50%, preferably from 10% to 40%, more preferably from 15% to 35%, even more preferably from 28% to 32%, by weight. Preferably, hydroxypropyl methyl cellulose can also be identified with the name hypromellose, for example E464. Preferably, microcrystalline cellulose can also be identified as, for example, E460.

Preferably, stearic acid can be of plant origin and can also be identified as, for example, E570.

Preferably, said composition and said compound can also be identified, for example, with the trade name SEPI FILM LP030.

Preparation of a filming according to said paragraph 2) (Sepifilm LP030 from SEPPI C)

A filming can be made, for example, with a composition comprising: water about 86% by weight, optionally a vanilla flavor about 0.84% by weight, and a compound about 13.16% by weight (e.g., a commercial product named Sepifilm LP030). Said compound comprises hydroxypropyl methyl cellulose from 55% to 60%, microcrystalline cellulose from 10% to 15%, and stearic acid from 28% to 32%, by weight.

Water is added to the coating pan container and under stirring said compound is poured in. It is left under stirring for about 40-60 minutes until completely solubilized. Then, in the dissolver under stirring, a flavoring agent is added, such as vanilla flavor. This solution is applied by a spray process: the coating liquid, by an atomizer, is deposited on the core in the form of very fine droplets that first wet the surface of the core and, then, expand; upon evaporation of the solvent (almost instantaneous), a phenomenon of coalescence occurs, leading to the formation of the film on the surface of the tablet core. The process parameters applied in filming are as follows: IN air temperature: 50-55°C, core temperature: 35-37°C and coating pan rpm: 22-25 rpm.

COATING PAN PARAMETERS SETTIN

The filming agent, represented by said composition comprising said compound according to paragraph 2), has been selected to provide a release profile comparable and/or equal and/or better than that obtained with both the filming agent represented by said composition comprising said compound according to paragraph (1) (for example Sepifilm 050) and the filming agent according to paragraphs 3) and 4) (see below) where there is the presence of polyvinyl alcohol.

With the filming agent according to paragraph 2), greater core isolation is achieved and, therefore, greater stability of the filmed tablets, under stressful temperature and humidity conditions (40°C and 75% RH). The two filming agents, according to paragraphs (1) and (2), contain the same film-forming polymer i.e., hydroxypropyl methyl cellulose, but the one in paragraph 2) contains stearic acid, instead of acetylated mono- and diglycerides. Preferably, the stearic acid used is of plant origin and does not contain alcohol. The presence of stearic acid, in combination with hydroxypropyl methyl cellulose and microcrystalline cellulose, gives the filming agent greater lipophilicity and, therefore, greater core isolation and consequently greater stability of filmed tablets. Preferably, the filming agent according to paragraph 2) gives the tablet core greater isolation from the external environment and thus greater stability under stressful temperature and humidity conditions (40°C and 75% RH).

The result of the comparative stress test performed under open storage conditions (without packaging) in a climatic chamber set at a temperature of 40°C and 75% relative humidity is shown below, see Figure 9.

As shown in Figure 9, already after 2 hours, the tablet filmed with Sepifilm 050 shows cracked film while the tablet filmed with Sepifilm LP030 shows the film still intact. Therefore, the Sepifilm LP030 filming agent provides the same performance as the AQUAPOLISH F CLEAR BIOGRUND and NUTRAFINISH COLORCON filming agents (according to paragraphs 3) and 4) containing polyvinyl alcohol) in terms of stability but has a safer profile in terms of safety (Sepifilm LP030 does not contain polyvinyl alcohol-Macrogol E1209 which may contain ethylene oxide residues).

3) For example, a filming can be made with AQUAPOLISH F CLEAR BIOGRUND: water about 74.2% by weight, vanilla flavor about 0.8% by weight, and a compound with the trade name AquaPolish F Clear about 25% by weight. The AquaPolish compound comprises copolymers of polyvinyl alcohol-Macrogol E1209, talc E553b, stearic acid E570, polyvinyl alcohol E1203 and hydrated colloidal silica E551.

For example, water is added to the coating pan container and under stirring the AquaPolish compound is poured in. It is left under stirring for about 60 minutes until completely solubilized. Then vanilla flavor is added into the dissolver under stirring.

In this case the tablet comprises melatonin about 1 mg; vitamin B6 about 1.1 mg-2.1 mg.

The dissolution test for melatonin is after 5 minutes 5%; after 45 minutes 27%; after 2 hours 49%; after 4 hours 68%; and after 8 hours 85%.

4) For example, a filming can be made with NUTRAFINISH COLORCON: water about 91.2% by weight, vanilla flavor about 0.8% by weight, and a compound with the trade name Nutrafinish about 8% by weight. The Nutrafinish compound comprises copolymers of polyvinyl alcohol-macrogol E1209, talc E553b, mono- and diglycerides E471, and partially hydrolyzed polyvinyl alcohol E1203.

For example, water is added to the coating pan container and under stirring the Nutrafinish compound is poured in. It is left under stirring for about 60 minutes until completely solubilized. Then vanilla flavor is added into the dissolver under stirring. In this case the tablet comprises melatonin about 1 mg; vitamin B6 about 1.1 mg-2.1 mg.

The dissolution test for melatonin is after 5 minutes 6%; after 45 minutes 28%; after 2 hours 50%; after 4 hours 70% and after 8 hours 95%.