Compositions: coating or plastic – Coating or plastic compositions – Carbohydrate or derivative containing
Reexamination Certificate
2001-11-26
2004-03-02
Brunsman, David (Department: 1755)
Compositions: coating or plastic
Coating or plastic compositions
Carbohydrate or derivative containing
C106S162800, C106S205600, C106S205900, C424S479000
Reexamination Certificate
active
06699315
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to edible, hardenable prompt release coating compositions comprising a film forming amount of low viscosity propylene glycol alginate that serves as the principle, primary or sole film former of the coating composition. The coatings of the present invention can be applied to pharmaceutical, including neutraceutical, and veterinary solid dosage forms, such solid substrates such as seeds, animal feed, fertilizers, pesticide tablets and granules, and also to confectionery and foods. They are readily dispersed in aqueous media, and, when applied as a coating, provide high lustre coatings which do not retard or extend release of active ingredient from a coated substrate.
BACKGROUND OF THE INVENTION
It is a common practice to coat pharmaceutical and veterinary tablets to obtain several advantages. Among these are to improve the surface characteristics of tablets to make them easier to swallow, to reduce the absorption of water or moisture which can potentially degrade the active ingredient or promote some other undesirable change in the tablet structure, and simply to make a more elegant appearing tablet.
Another very important function of a pharmaceutical or veterinary tablet coating is to improve the integrity of the tablet itself. Uncoated tablets are often subject to being abraded or chipped, causing a loss of active ingredient in the process. More dramatically, they may break into two or more pieces. One measure of a useful coating is its ability to prevent any of these physical degradations of tablet structure. The effectiveness of a coating material to prevent abrading, chipping, or breakage of the tablet is determined by friability testing.
Confectionery and foods may be coated with a formulation to preserve the confection or food from deteriorating by contact with the oxygen and the moisture in the atmosphere. Coatings also can provide improved appearance and desirable organoleptic properties to the food as well as preventing loss of flavor.
Seeds may be coated to preserve the viability of the seeds by protecting against moisture. They may also be coated as a means for increasing particle size to facilitate mechanical planting. A dye can be included in the coating formulation to identify the seeds as to quality, type, or some other designation. Frequently, a pesticide, e.g., a fungicide, is incorporated into the coating formulation to protect both the seed itself and the seedling that results from germination of the seed. In all cases, this coating must not decrease the viability of the seeds or interfere with germination when the seeds are planted in the soil.
Animal feed may be coated to improve its flowability, appearance and its resistance to powdering or dusting. In such applications, the coating may be formulated to include vitamins, hormones, antibiotics, or the like, to benefit the livestock which will consume the feed.
Fertilizers, in either granular or tableted forms, may be coated to retain the integrity of the form and, especially, to protect the fertilizer from moisture which can cause agglomeration during storage, which could make rapid, even application to the soil difficult or inconvenient.
Coating of tableted pesticide formulations serves to maintain the integrity of the tablets or granules until they are placed in water where they rapidly disintegrate, forming a solution or slurry to be applied to the soil or plants. A second, and equally important, function of the coatings on tablets containing pesticides is to prevent human contact with the pesticide, thereby increasing safety for those handling and applying the pesticide.
In the preparation of a coating formulation to be sprayed, the film former is usually dissolved or dispersed in a solvent, for example, water, along with the other ingredients of the formulation. In aqueous systems, since many polymers require significant time to become fully hydrated, the coating formulation must frequently be prepared in advance of the time it is to be applied to the tablets. A common procedure is to prepare these coating formulations the day preceding the coating operation in order to assure adequate hydration of the polymers used in them.
A particular disadvantage of coatings based primarily on HPMC is that the coating may harden over time and therefore increase tablet disintegration times. An increase in disintegration time delays the bioavailability of the active ingredient at least in proportion to the increase in disintegration time. Many other agents commonly used in coating compositions are also known to delay release of pharmaceutical agents, such as enteric coatings which use polymeric film forming materials which are insoluble in water, or gastric fluid, some of these being specifically selected to by-pass both the stomach and small intestine and provide colonic release.
The coatings of this invention meet U.S. Pharmacopoeia standards for rapid or immediate dissolution (U.S.P. monograph 23) of active ingredients from tablets or other solid dosage forms coated with them. They provide prompt release or dissolution consistent with the release rates which is normally obtained with the uncoated tablets or other substrates. Thus, they do not adversely impact or retard release of active ingredients from a substrate coated with them. Further, the coatings of this invention are readily dispersed and rapidly hydrated in aqueous media for application to a coating substrate, and provide elegant coatings which have all the benefits of coatings now in commercial use without the drawbacks that are common to them.
SUMMARY OF THE INVENTION
It has been found that these and other advantages may be achieved in accordance with the present invention by a coating composition which comprises a low viscosity propylene glycol alginate as the principle or only film-forming component of the coating composition in combination with a surface active agent. The coating composition of the present invention utilizes as the primary film former a low viscosity propylene glycol alginate (PGA), a 1% aqueous solution of which has a viscosity in the range of about 1 to 500 mPa·s at 25° C. The PGA is used in combination a surface active agent, and optionally such additional ingredients as a filler, a coloring agent, or combination of these, and may also contain a small amount of a secondary film former and/or a strengthening polymer as an additional ingredient. More specifically, the present invention provides a prompt release, edible, hardenable PGA coating composition, as well as dry coatings and aqueous dispersions thereof and solid dosage forms coated therewith.
DETAILED DESCRIPTION OF THE INVENTION
For purposes of this application, the term “edible” is intended to mean food or pharmaceutical grade materials which are approved by regulatory authorities for use in pharmaceutical or food applications. The term “hardenable,” used to describe the coating compositions of this invention, is intended to include only those coating compositions that are capable of being dried from an aqueous solution or dispersion thereof into a solid coating which resists abrasive forces, i.e. a hardened coating, as distinguished from those “enrobing” coatings on confections which set up into a soft coating that can be handled and packaged but which do not resist abrasive forces significantly. The terms “immediate,” “rapid,” or “prompt,” as applied to dissolution rates or times for the coating compositions of this invention or tablets coated with the compositions of this invention, mean that the coatings of this invention meet U.S. Pharmacopoeia standards (U.S.P. monograph 23) for rapid or immediate dissolution of active ingredients from tablets or other solid dosage forms coated with them. Thus, they provide prompt release or dissolution consistent with the release rates which is normally obtained with the uncoated tablets or other substrate. They do not, when placed in water or ingested, adversely impact or retard release or dissolution of tablets or other dosage forms coated with them. Coatings made in accordance with
Augello Michael
Bliefernich Eric
Brunsman David
FMC Corporation
Woodcock Wasburn LLP
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