Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Tablets – lozenges – or pills
Reexamination Certificate
1998-10-26
2001-02-20
Page, Thurman K. (Department: 1615)
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Tablets, lozenges, or pills
C424S469000, C424S476000, C424S195110
Reexamination Certificate
active
06190697
ABSTRACT:
The invention relates to an effervescent formulation according to the preamble of claim
1
. Plant extracts have long been a popular dosage form for prophylaxis and therapy; they are becoming more important, not least owing to the increasing elucidation of the action mechanism and of the structure of the active ingredients. Where higher doses are necessary, instant tea has to date been the most important dosage form but has some disadvantages, namely on the one hand the inexact dosage as a result of dissolving a teaspoon or tablespoon of the instant tea in water, It being scarcely possible exactly to maintain the fill-weight; on the other hand, the instant teas containing plant extracts and usually present in powder or granular form are very hygroscopic and agglomerate in a container after the latter has been opened a few times.
In order to avoid these disadvantages and to provide an attractive dosage form, the administration of the plant extracts in the form of an effervescent tablet was developed. However, it has been found that in particular the very water-soluble plant extracts, which are generally present in a finely pulverulent form spray-dried from aqueous and/or alcoholic solution, slow down the dissolution of the effervescent tablet to an extreme extent. These include, inter alia, ivy and sabale dry extracts, solidago, plantago, nettle root, nettle leaf, birch leaf, cynara and thyme extracts, extracts of hypericum, harpagophytum, gingko and ruscus (Extractum Rusci aculeati). The dissolution is slowed down because, on admission of water, these very soluble plant extracts very rapidly form highly concentrated, tacky, slimy solutions which prevent the further admission of water to the interior of the tablet, thus hindering rapid dissolution. Moreover, effervescent particles which are intended to promote disintegration and dissolution of the tablet are also coated with the solution and their reaction with the water is thus suppressed. In addition, most plant extracts contain saponin and consequently exhibit extreme foaming behavior in the effervescent tablet. The dissolution is thus further slowed down because frothy, highly concentrated solutions form between the effervescent particles.
Thus, for example when a dose of 400 mg of solidago extract is added to effervescent granules which are then compressed to form tablets, dissolution times of 15 to 20 minutes result on dissolution in water. Even smaller amounts, for example 65 mg of an ivy dry extract in an effervescent tablet, exhibit dissolution times of 5 to 7 minutes or more on dissolution in water at 17° C. This no longer meets the requirements of pharmacopoeias, according to which the dissolution time of effervescent tablets in water at 20° C. should be less than 5 minutes.
By means of conventional measures, such as, for example, by the addition of antifoams, such as, for example, simethicone or dimethicone, or by the application of the antifoam to the dry plant extract itself it was possible to achieve only a slight improvement by reducing the foaming and—associated with this—also only a slight reduction in the dissolution time of the effervescent tablet.
Granulation of the plant extracts with the object of increasing the size of the particles and reducing their number within the effervescent tablet in order thus to prevent the formation of a concentrated solution around the plant extract particles and effervescent particles during dissolution of the tablet in water also did not achieve the object since precisely these granulated particles then agglomerated to an extreme extent and exhibited undesired and by no means rapid dissolution properties.
Binding to a slightly soluble substance also did not lead to a short dissolution time since the extracts at the surface of the slightly soluble substance likewise formed highly concentrated solutions and thus rendered this measure ineffective.
Although granulation with slightly soluble substances once again resulted in the effervescent tablet with plant extracts dissolving somewhat more rapidly, the granulated particles could not dissolve completely and formed a residue.
The object of the invention was therefore to provide a galenical formulation for freely soluble plant extracts in the form of an effervescent tablet, which formulation has a dissolution time of less than 4 minutes and significantly reduced foam formation.
Surprisingly, the achievement of this object and the overcoming of the above-mentioned problems were possible for the first time by the measures described in the defining clause of claim
1
. Particular embodiments and further developments of the concept of the invention are described in the defining clauses of the dependent claims.
The invention comprises treating the plant extract with at least one fatty, oily or waxy substance, in particular producing a thin coating film of this substance or these substances on the plant extract particles, preferably emulsifiers also being added to this hydrophobic extract phase with fatty, oily or waxy substances. The fatty, oily or waxy substances can be applied to the plant extract particles either in the molten state or in solution in a solvent in which the emulsifiers too are soluble. The plant extracts treated in this manner can then—optionally with further addition of the emulsifier—be mixed with effervescent granules and the mixture compressed to give tablets. Effervescent tablets containing plant extracts which dissolve in water at 17° C. within 1½ to 4 minutes are obtained.
As a result of the treatment with the above-mentioned substances, the plant extracts become sufficiently hydrophobic to prevent conversion of the effervescent tablet into a paste on dissolution of water, so that the effectiveness of the effervescent particles on admission of water is displayed as desired and rapid dissolution of the tablet is thus permitted. As a result of the contact with water, the effervescent particles display their effervescent activity and the plant extract particles are ejected from the tablet owing to the hydrophobic structure and because of the effervescent effect and dissolve only thereafter. It has proven advantageous to add suitable emulsifiers to the phase containing the fatty, oily or waxy substances, in order to achieve appropriate suspension properties for these substances on dissolution of the effervescent tablet in water.
In particular, the following substances can be used as fatty, oily or waxy substances which are suitable for the surface treatment of the plant extract particles: esters of medium-chain, vegetable fatty acids, such as, for example, caprylic and capric acid, with glycerol and propylene glycol, preferably Miglyol® neutral oils.
Furthermore, all edible, animal and vegetable fats may be used as fat components. These are in particular triglycerides which essentially consist of mixtures of glyceryl esters of higher fatty acids, in particular of vegetable or animal origin, having a chain length of about 10 to 22 C atoms. These include, for example, microcrystalline triglycerides and glyceryl esters of saturated, linear and unbranched fatty acids, e.g. glyceryl trimyristate, glyceryl tripalmitate, trimyristin, etc. Further suitable fat components are, for example, coconut oil, hydrogenated coconut oil, hydrogenated castor oils, tocopheryl acetate, esters of higher fatty acids, such as, for example, isopropyl palmitate, polyethylene glycol, such as, for example, Carbowax®, it being possible to use Carbowax® 400 or Carbowax® 6000, depending on the plant extract.
The fat, oily or waxy substances are used in an amount of 0.5 to 25 parts by weight, preferably 0.8-19 parts by weight, based on 100 parts by weight of the freely soluble plant extract, these substances being at least partly contained in the plant extract phase but possibly also additionally being added as a separate fat phase to the effervescent granules. The emulsifiers are on the one hand applied together with the fatty, oily or waxy substances directly to the plant extract and optionally on the other hand added in the form of a
Gergely Gerhard
Gergely Irmgard
Gergely Stefan
Gergely Thomas
Gergely Gerhard
Ghali Isis
Page Thurman K.
Rothwell Figg Ernst & Manbeck
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