The present invention relates to the denaturing or destruction of controlled drugs and to the deactivation of the active ingredients in drug formulations prior to their disposal. In particular the present invention relates to a kit and method for controlled drug destruction.

There are a number of commercially available controlled drug denaturing/destruction kits available on the market. These kits are supposed to destroy the controlled drugs so that they can be safely disposed of in the general waste. However the commercially available kits do not actually destroy the active drugs but simply denature the dosage form (tablet/capsule) and encapsulate the active drug in a gel matrix. The danger to this is that current guidelines require controlled drugs destruction kits to be securely stored for only 48 hours after introduction of a controlled drug to the destruction medium, after which time they can be disposed of as normal waste. If the drug is still in its active form this leaves the drugs open to potential abuse. If addicts are able to remove the used destruction kits from a pharmacy's general waste they will have access to a cocktail of controlled drugs in a convenient easy to use semi-solid dosage form. Anyone determined to get controlled drugs could simply swallow the gel from the kits, or in search of quicker drug absorption, rub the gel into any mucosal membrane including the linings of the buccal, nasal or rectal cavities.

The aim of the present invention is to provide a controlled drug destruction kits that actually destroy most, or all, of the active ingredient within the medication. A further alternative aim is to develop a method of deactivating/destroying a controlled drug formulation.

The terms destroy, destruction and the like as used herein refer to a process that includes the change, by for example denaturing or deactivation, of the active ingredients within a medication formulation to a form that is suitable for disposal.

According to the present invention there is provided a drug destruction kit comprising:

a. a water soluble gelling agent comprising starch; and

b. an oxidising agent comprising a peroxide-releasing compound; whereby drugs are introduced to the gelling agent and oxidising agent which are combined with water to form a gelled mixture for denaturing an active ingredient of the drug.

The gelling agent predominantly or totally comprises starch. Preferably the starch is an organic starch, such as that extracted from plants. Most preferably the starch is potato starch.

The peroxide-releasing compound is preferably selected from sodium perborate, sodium percarbonate, sodium persulfate, tetrasodium pyrophosphate. Most preferably the peroxide-releasing compound is sodium perborate.

Sodium perborate is a white, odorless, water-soluble chemical compound with the chemical composition NaB03. It crystallizes as the monohydrate, NaB03 H ₂ 0, trihydrate, NaB03 3H ₂ 0 and tetrahydrate, NaB03-4H ₂ 0. The tetrahydrate is particularly preferred for use in the present invention. The elementary structural unit of sodium perborates is a dimer anion B ₂ O ₄ (OH) ₄ ^2_ , in which two boron atoms are joined by two peroxo bridges in a chair-shaped 6-membered ring. In a kit according to the present invention the gelling agent and oxidising agent are provided in a suitable form. A kit may have quantities of gelling agent and oxidising agent suitable to make one or several batches of gelled mixture. Quantities may be packaged in such a way to facilitate the preparation of batches of gelled mixture. For example measured quantities for each component may be in separate containers for single use.

The gelling agent and/or oxidising agent may usually be provided in a solid form (e.g. powdered). One or both component may also be supplied in a dissolved form, either ready for mixing or in a concentrate stock solution ready for dilution at use.

Powdered components may be supplied premixed in the correct ratio ready to be dissolved in water for use. The drug would be added prior to forming of a gelled mixture with water because of the difficulty of mixing drugs into a gel.

In a gelled mixture that is combined with water and ready to use (but excluding the weight of any added drug that may have been added prior to addition of water) the gelling agent is preferably provided in an amount of 5 to 10% w/v and the oxidising agent in a range of 1 to 10%w/v, more preferably 5% w/v. According to the present invention there is also provided a method of denaturing the active ingredient in a waste drug formulation, comprising:

a introducing the waste drug formulation into a mixture of gelling agent comprising starch and an oxidising agent comprising a peroxide-releasing compound;

b dissolving the water soluble gelling agent and oxidising agent in sufficient water to form a gelled mixture;

c allowing reaction between the components in the gelled mixture to denature the active ingredient in a waste drug formulation; and

d disposing of the combination of gelled mixture and drug formulation.

In this method it is also preferable that the starch is potato starch and the oxidising agent is sodium perborate.

To ensure suitable rapid reaction it is preferred that the drug formulation to be destroyed is ground, milled or otherwise crushed prior to introduction into the gelled mixture in step a. However drugs can be added in an original un-altered form. Ampoules may require crushing or splitting prior to addition to the mixture and Patches may also need to be cut into pieces before addition to the mixture.

Ideally step c is carried out for a period of 12-72 hours. More preferably the drug formulation is held in the gelled mixture for a period of at least 48 hours prior to disposal in step d.

The gelling agent and peroxide-releasing compound may be provided in a solid form premixed in the correct ratio prior to step a. EXAMPLES

In order that it may be better understood, the present invention will now be described in more details with reference to the accompanying examples. For the following examples in order to test the efficacy of the present invention and prior art systems, morphine was used as a representative test drug. A HPLC method for morphine was used and the short term stability of morphine in aqueous solution was determined and it was found to be stable in solution for at least 3 days.

Example 1

Five commercially available controlled drug destruction kits were tested and the ability of these kits to degrade morphine was determined. A known quantity of morphine was added to the kits and the drug content assayed immediately and the assay repeated after 48 hours to determine the extent of drug destruction.

In order to assess the ability of the kits to destroy a controlled drug placed within them morphine was used as a model drug. A sample of each of the following kits was prepared.

Each of these was prepared in separate glass vials to which morphine was also added. Water was then added (w/w) in the proportion indicated on the kit instructions.

Table 1 : Amount of water (g) added per gram of material for each kit tested

These were immediately mixed using a spatula for 2 min and then left to stand for 2h. All mixtures were prepared in triplicate. After 2h a 1 g sample was taken from the kit by weighing directly into a 100ml_ volumetric flask and made up to volume using deionised water. A magnetic flea was then added and the volumetric flask placed on a magnetic stirrer and left for approximately 2h until all gel had visibly dissolved. A sample was then taken from the volumetric flask for analysis by HPLC and use as a T=0 sample.

After 48h each kit was re-sampled and diluted 1 : 100 before analysis by HPLC. Samples were analysed at Oh and 48h and the amount of drug present at 48h calculated as a percentage of the drug present at Oh (Table 2).

Table 2: Degradation of morphine in drug destruction kits tested. Morphine content at 48h expressed as a percentage of morphine content at Oh (n=3,

It is apparent from this that the prior art drug denaturing/destruction kits tested did not cause chemical degradation of morphine, with between 78- 1 1 1 % of the initial drug concentration still present after 48h.

In conclusion all previous drug denaturing kits do not destroy controlled drugs but simply encapsulate them in gel. This means the active form of the drug is still present and could potentially be recovered and abused by addicts who would simply have to spread the gel on to any mucosal membrane to receive a quick acting hit of the drug.

Example 2

The ability of the kit according to the present invention to degrade morphine in solution was determined using a similar methodology to that described in Example 1. A drug destruction kit according to the present invention was prepared containing sufficient amounts of sodium perborate such that when the kit was hydrated the final concentration of sodium perborate would be either 1 % or 5%. Morphine (10mg) was added to the kits and then the kits hydrated with sufficient water to make the final weight up to 10g, placebos (containing no morphine) kits were also prepared. The kits were initially mixed by hand using a spatula for 2 min then dispensed into 10ml disposable syringes.

Samples of each kit (including placebos) were analysed immediately at T=0. To do this, 1 g aliquots of each kit were dispensed into 100ml volumetric flasks and made up to volume using water. They were then stirred for 3h until all visible gel had dissolved. Samples were then analysed by HPLC. This process was repeated for further samples at T=24h and 48h. The morphine content at T=24 and 48h was calculated as a percentage of the content at T=0h and is shown in Table 3.

Table 3 shows the degradation of morphine caused by a drug denaturing kit of the present invention with either 1 % or 5% concentration of sodium perborate. Morphine content is expressed as a percentage of morphine content at Oh (n = 1 ).

Table 3

When a drug destruction kit containing 1 % sodium perborate and starch was tested 59.12% of the morphine was degraded within 48h. When the drug destruction kit containing 5% sodium perborate was used 78.38% of the morphine was degraded within 48h. This is a very satisfactory result as at this point UK law permits disposal (48 hours) the amount of active ingredient has been significantly removed. The amount will continue to drop over time even after disposal of the mixture of drug and gelled mixture.

From the examples it is clear that prior art drug denaturing kits do not destroy the active ingredient of controlled drugs but appear simply to encapsulate them in gel. This means the parent form of the drug is still present and could potentially be recovered and abused by addicts who would simply have to spread the gel on to any mucosal membrane to receive a quick acting hit of the drug. By comparison the drug destruction kit of the present invention chemically destroys drugs such that the active ingredient is removed or its amount greatly reduced so that the disposed product no longer prone to abuse.