Authenticatable coatings for pharmaceutical tablets and ingestible materials

Abstract

An authenticable and machine readable coating for pills, tablets and other ingestible materials is provided. The disclosure also relates to methods of authenticating the same. The coatings are formed from a lattice of particles stacked to cause selective diffraction such that each pill or tablet has an optical signature. The signature associated with each coating can be read and authenticated. In one embodiment, the particles are substantially spherical and self-organized. In one embodiment, generally recognized as safe (GRAS) materials are used to form the particles.

Claims

1. A coating for an ingestible material comprising: a substrate; a first coating applied onto said substrate said coating having a first plurality of substantially spherical particles suspended therein, the particles having a first dimension that equals a fraction of a wavelength that will satisfy a Bragg scattering condition, wherein the particles self-arrange during application to define a plurality of lattices that selectively diffract electromagnetic radiation and wherein each of the plurality of particles comprise a generally recognized as safe material.

2. The coating of claim 1 wherein the first coating is opalescent or pearlescent.

3. The coating of claim 1 wherein the first dimension ranges from about 100 nm to about 2000 nm.

4. The coating of claim 1 wherein the substrate is a pill or tablet.

5. The coating of claim 1 wherein the first coating has a unique optical signature that is machine readable and authenticable using a detector.

6. The coating of claim 1 wherein the first plurality of particles is self-organized and defines one or more surfaces that selectively diffracts light.

7. The coating of claim 1 further comprising: a second coating disposed adjacent to the first coating, the second coating comprising a second plurality of particles, the particles having a second dimension, wherein the particles are stacked to define a plurality of lattices that selectively diffract electromagnetic radiation and wherein each of the second plurality of particles comprise a generally recognized as safe material.

8. The coating of claim 1 wherein the generally recognized as safe material is selected from the group consisting of cellulose and a cross-linked polylactic acid.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings which illustrate the best mode presently contemplated for carrying out the present invention:

(2) FIG. 1 is an image of tablets with the coating of the present invention thereon;

(3) FIGS. 2A-B are magnified views of exemplary coatings firmed using a plurality of particles;

(4) FIG. 3 is an exemplary coating formed from two layers of spherical particles;

(5) FIG. 4 is an illustration of multiple diffraction peaks resulting from a plurality of coatings; and

(6) FIG. 5 is a depiction of a system for testing and authenticating coated materials in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(7) Now referring to the drawings, there is disclosed a coating for pills, tablets and other ingestible materials that is authenticable and serves to identify the underlying material onto which the coating has been deposited as being genuine material. As a result, the invention also relates to methods and devices for authenticating the coating and thus the material on which it is disposed.

(8) The coatings disclosed herein are machine readable and can encode unique information that can be read to indicate the source, dosage, and drug type. The coatings are formed from a lattice of particles stacked to cause selective diffraction of light. Thus, each coating has an optical signature that can be read and authenticated. As can be seen at FIG. 1, this coating, results in both a distinct appearance to the user as well as a specific optical signature which can be controlled. The tablet or pill having a coating formed thereon as described below exhibits an opalescence or a pearlescent sheen which is distinct, visually appealing to a viewer and very difficult to replicate. In one embodiment, the coating causes a tablet or pill to look like a synthetic opal or pearl. The unique appearance is visually striking and different from conventional pill or tablet coatings.

(9) The coatings can be formed by various nano-scale and micron scale materials. In one embodiment, the coating is formed from a layer or multiple layers of nano-particles. In one embodiment, the particles are self-organizing. For example, the particles can be spherical or substantially spherical in one embodiment. Further, as discussed below the particles can all be substantially the same size or have a common dimension, such as a diameter or layers of different sized particles can be used. Two images showing exemplary coatings formed from a plurality of particles are shown in FIGS. 2A and 2B.

(10) In particular, FIGS. 2A and 2B are electron microscopy images of an exemplary coating. The coating is authenticable and machine readable. FIG. 2B shows a magnified view of a region of the image of FIG. 2A. From both figures, a lattice or periodic structure that operates as a diffraction grating results from the close packing of the individual particles. The coatings are formed as a result of a self-organization and assembly process. The size and properties of the lattice pattern can be controlled and adjusted using this process. When illuminated with electromagnetic radiation, diffraction of light at specific wavelengths occurs at the coating. The spectral position of this diffraction is controlled through a built in periodicity on the scale of a fraction of the wavelength of visible light. Similar structures can be created with near infrared signatures using micron scale particles. Self-organization of the particles into a lattice occurs through evaporation of solvent and close-packing drives ordered states.

(11) In one embodiment, the coatings include surface functionalized polystyrene nanospheres which are not generally recognized as safe (GRAS) materials. However, when producing these coatings to pills or other ingestible materials, GRAS nano-materials are used. In one embodiment, the GRAS materials can include, without limitation cross-linked polylactic acid and similar biopolymers. Other GRAS materials, can include, shellac, com protein, cellulose derivatives, and others. The coatings can be made using various materials and include multiple layers or only one layer of particles.

(12) An example of a coating for a pill tablet or other ingestible material that is formed from two layers of spherical particles is shown in FIG. 3. As shown, the coating includes a top layer that includes two layers of particles having a common dimension d1 and bottom layer that includes a single layer of particles having a common dimension d2 that is smaller than d1. In one embodiment, the stacking geometry of the spheres can be adjusted to tune the optical signature reflected from the coating. Different sized particles can also be mixed together so long as a lattice results that diffracts light in a desirable manner for coating authentication.

(13) In one embodiment, the particles forming the coating can vary slightly in size, but are fabricated to remain within a particular size distribution. In one embodiment, the center to center particle distance or the particle diameter is the lattice spacing of a diffraction grating. Thus, the particle arrangement and size allows the lattice geometry to be tuned to selectively backscatter light. Thus, one dimension of the lattice is typically selected to be a fraction of a wavelength that will satisfy a Bragg scattering condition. In one embodiment, the coatings comprise a plurality of spherical particles having diameters which approximate a lattice spacing sized relative to a wavelength of light such that a Bragg scattering condition is satisfied. When electric magnetic radiation impinges on the coating, a reflective signal is propagated in the opposite direction that can be received processed by detector. In part, one embodiment of the invention is selectively tuning a lattice of spacing by changing the diameter or another dimension of the particles used to form the coating. This allows the optical signature for different coatings to be changed for different applications.

(14) For example, a drug having three different dosages, can use three different coatings that incorporate particles sized to generate a different signal that is correlated with the three dosages. Multiple or nested coatings can be used to further modify the optical signature for the overall coating. Thus, a coating can include two layers of stacked particles with the particles in each layer having different sizes. In one embodiment, when light is shined on a double layer coating, two reflectivity spikes are detected. This allows various types of codes to be created by adjusting the peak and valley profile of the optical signature that is detected for a given coating when it is illuminated.

(15) By controlling the lattice spacing as well as the orientation of the Face Centered Cubic (FCC) crystal planes relative to the pill surface, a narrow band spectral diffraction peak can be covertly created. Accordingly, various geometric parameters can be adjusted to created different arrangements of diffraction peaks. White light illumination can be used when detecting an optical signature from a given coating in some embodiments. By using individual signatures as shown in FIG. 4 for the three different coatings shown, or by making combinations of different coatings, covert machine readable codes can be created. These unique codes can be stored in a database and associated with any number of parameters of interest. For example, the codes can be used to assure both authenticity of the product as well as the dosage of specific variants of the same compounds.

(16) FIG. 5 depicts a system 100 suitable for use at a hospital, pharmacy, or manufacturing facility in which an ingestible material such as a pill 105 having a coating embodiment as described herein disposed thereon can be tested or authenticated. The pills 105 are be sorted using a sorter 107 such as a funnel or other pill 105 delivery device and deposited in a container 110 such as a prescription container. When each pill 105 is exposed to a source 115, which may be regular white light, a reader or detector 120 reads the optical signature that is scattered by the coating. These readers 120 are able to verify that the machine readable coating is authentic and also verify other information associated with the optical signature of the coating applied to each pill. Thus, before each prescription or load of pills 105 is stored in a container 110 the type of drug, its source, its dosage, expiration date, and other information can be verified. Further, given the optical nature of the signature and the detector, the process of scanning and verifying can happen very quickly such as on a real time basis.

(17) It can therefore be seen that the present invention provides a coating material that is reliably authenticable yet difficult to copy or counterfeit. Further, the present invention provides a coating that has a particular optical signature that can be authenticable for verification of genuine pharmaceutical materials while being machine readable to provide encoded information relating to the source, dosage and drug type.

(18) While there is shown and described herein certain specific structure embodying the invention, it will be manifest to those skilled in the art that various modifications and rearrangements of the parts may be made without departing from the spirit and scope of the underlying inventive concept and that the same is not limited to the particular forms herein shown and described except insofar as indicated by the scope of the appended claims.