Drug – bio-affecting and body treating compositions – Preparations characterized by special physical form – Particulate form
Patent
1988-05-02
1992-09-22
Page, Thurman K.
Drug, bio-affecting and body treating compositions
Preparations characterized by special physical form
Particulate form
424451, 424470, 424497, 424498, A61K 958, A61K 962, A61K 922, A61K 948
Patent
active
051495422
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a coating membrane for pharmaceutical and industrial purposes and to compositions prepared therefrom. More particularly it relates to a coating membrane for the controlled release of an active ingredient which may be of pharmaceutical, veterinary, synthetic or extractive type, and to compositions containing said coated active ingredient.
In the pharmaceutical field, the production of sustained release microgranules is known (see for example EP 123,470 and 122,077).
The preparation involves the application of the active ingredient on a spherical nucleus having a diameter of from 0.2 to 2 mm by means of a particular binding agent, or a spherical nucleus of active ingredient with or without binding agent may be prepared. Then a semipermeable membrane is applied, which allows the diffusion of the drug over a controlled period of time or it disgregates over a well-established period of time releasing the drug.
The membrane normally used and described in several patents consists of: shellac, methacrylic acid copolymers, ethylcellulose, ethylcellulose phtalate, hydroxypropyl methylcellulose, cellulose acetophtalate, etc. The abovementioned and currently used membranes are also of natural source, such as shellac, and thus of indefinite composition. As a consequence, the amounts used to obtain identical coating notably change from time to time and give, therefore, stability problems. The productions from batch to batch are thus difficult, and often it is not possible to obtain the same release pattern.
Moreover, it is very difficult to reach a zero order release or a release over a controlled period of time according to the drug needs.
In the pharmaceutical field, the purpose of the sustained release formulations is to obtain a 12 hours therapeutically active hematic level with consequent posology of two daily administrations, or else a 24 hours hematic level with administration of a sole capsule a day. In order to achieve said results, the drug release has to be more or less delayed according to the characteristics half-life of each drug.
It has now been found that, modifying the amount of the applied membrane or the ratios between two components, it is possible to obtain sustained releases from 4-6 hours up to 18-22 hours and higher, as shown in FIG. 1 for ketoprofen (ethylcellulose/stearic acid membrane) and in FIG. 2 for diltiazem hydrochloride (paraffin/methacrylic acid copolymers membrane).
This technological flexibility allows to choose the most suitable in vitro release for obtaining the in vivo blood level which provides the pharmaceutical effect over a desired period of time.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 and 2 are graphs of the rate of release versus time for Ketoprofen and Diltazem.
Several tests have shown a very good reproducibility from PG,4 batch to batch and good stability. Membranes from synthetic products with a well-definite molecular composition, and often reported in International Pharmacopeias, provide an improved purity, as shown by the analytical tests.
These new membranes, like paraffin, have for their own nature a very low chemical affinity for the products which have to be coated. In this way, a very good compatibility does exist between membrane and product to be coated, and a good time stability may be achieved.
Accordingly, the present invention relates to the use, as semipermeable or breakable membranes, of lipophilic compounds alone or in admixture with a suitable hardening agent. More particularly the present invention relates to a coating membrane for pharmaceutical, cosmetic, veterinary, synthetic and extractive substances and to the compositions prepared therefrom.
In a further embodiment, the invention provides also a method for preparing said compositions, which comprises coating inert material pellets with a first layer of a therapeutically active compound and applying then thereon a second layer consisting of a lipophilic substance, alone or in admixture with a hardening agent.
In the compositions of the present invention, the inert p
REFERENCES:
patent: 2828206 (1958-03-01), Rosenberg
patent: 3078216 (1963-02-01), Greif
patent: 3080294 (1963-03-01), Shepard
patent: 3432593 (1969-03-01), Shepard
patent: 3492397 (1976-01-01), Peters et al.
patent: 3922339 (1975-11-01), Shear
patent: 4341759 (1982-07-01), Bogentoft et al.
patent: 4572833 (1986-02-01), Pedersen et al.
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