COMBUSTION-FREE CIGARETTE

Description

The invention relates to a combustion-free cigarette consisting of a sleeve, to the inner casing of which a nicotine solution is applied, according to the preamble of claim 1.

Conventional cigarettes are based on the combustion of a nicotine-containing tobacco that is held in a paper sleeve. The combustion process releases nicotine, which is inhaled by the smoker by sucking in a so-called mainstream smoke. Between puffs, the combustion process continues, with nicotine escaping into the environment in a so-called sidestream smoke without being absorbed by the smoker. The effect desired by the smoker is based on the nicotine absorbed, which has activating effects on cells of the autonomic nervous system. Conventional cigarettes contain around 10 mg of nicotine, but due to the combustion and the sidestream, only around 1-2 mg of nicotine is inhaled by the smoker when consuming the entire cigarette. This shows that with conventional cigarettes, the majority of the nicotine in the tobacco is not inhaled, but burns or escapes. Instead, a large number of other ingredients and combustion products of tobacco are inhaled, which have been proven to have carcinogenic effects, in particular tar substances or benzene, lead and cadmium. Nicotine itself, however, is not carcinogenic. Although nicotine is considered an addictive substance and can cause addiction, the addictive effect is proven to be greatly increased by the substances contained in tobacco smoke, for example by the monoamine oxidase inhibitors contained in tobacco smoke. If the combustion process of tobacco could be avoided, the addictive potential of nicotine would also be significantly reduced.

Attempts have therefore been made to provide combustion-free cigarettes in which nicotine is applied to carrier bodies of various designs and made available for inhalation without other ingredients of natural tobacco.

For example, U.S. Pat. No. 4,800,903 describes a porous carrier body made from polyethylene, polypropylene or similar plastics. As an alternative to the porous carrier bodies, carrier bodies made from a solid (non-porous) material have also been described.

U.S. Pat. No. 4,284,089 describes a porous carrier body that is designed in the shape of a cylinder and is funnel-shaped at both ends. The two funnel-shaped structures are connected by a channel through which the nicotine mixture can pass. The carrier body, which is designed with funnels on both sides, is arranged inside a sleeve.

U.S. Pat. No. 4,813,437 shows a cigarette-shaped nicotine delivery device in which several sections and several types of cylinder-shaped porous carrier bodies are arranged. These carrier bodies are made of plastic and cellulose fibers. Manufacturing with several zones and several porous carrier bodies requires several work steps, which results in high manufacturing costs.

U.S. Pat. No. 6,089,632 describes a cylinder-shaped and porous carrier body that is designed as a nicotine reservoir. This porous carrier body is soaked in a nicotine solution in a mixing vessel and then dried, thus loading it with nicotine and inserted into a sleeve. To use it, the sleeve with the carrier body must be inserted into a pipe-shaped inhalation device.

However, it has been shown that open-pored carrier bodies have pores of different sizes, so that the porous carrier body does not have a precisely defined pore surface, which is disadvantageous when the porous carrier body is impregnated with a nicotine solution, since different amounts of nicotine are always deposited in an open-pored carrier body. In a combustion-free cigarette, however, the amount of nicotine deposited must be precisely adjustable, since otherwise the consumer could ingest excessive amounts of nicotine that exceed the amount stated on the packaging.

The aforementioned solutions have also not been successful on the market because their nicotine release does not satisfactorily reproduce the properties of a conventional cigarette. It is not sufficient for market acceptance to store a nicotine solution in the required quantities in a sleeve; the nicotine must also be absorbed in sufficient quantities by the air flow that occurs inside the sleeve during the usual suction process and be available for inhalation. Experimental studies on typical smoking behavior show that when consuming a conventional cigarette, at least 10-20 puffs are typically taken, with typical puffs having a volume of around 40-80 ml. There are typically 10-40 seconds between puffs on a conventional cigarette. The total consumption time is around 10-15 minutes. With such typical smoking behavior, the nicotine must be released in the usual quantities, i.e. in an amount of around 1 mg, using a combustion-free cigarette and made available for inhalation. Under standard conditions, however, nicotine is present as an oily liquid that is difficult to evaporate (boiling point 246° C., vapor pressure 0.058 hPa at 20° C., 0.13 hPa at 30° C. and 0.58 hPa at 50° C.). In conventional cigarettes without a combustion process, it is not possible to bring the nicotine from its attachment to solid surfaces of carrier bodies and the like into the intake stream quickly enough. However, if it is not possible to release the nicotine in the usual quantities using a combustion-free cigarette and make it available for inhalation in typical smoking behavior, the effect desired by the smoker is missing and the acceptance of such a product suffers despite the health benefits due to the absence of carcinogenic substances.

The aim of the invention is therefore to provide a combustion-free cigarette in which the nicotine can be brought from its attachment to solid surfaces into the intake stream quickly enough so that the effect intended by the smoker of the nicotine intake of conventional cigarettes by inhalation can be reproduced in a suitable manner.

This aim is achieved by the features of claim 1. Claim 1 relates to a combustion-free cigarette consisting of a sleeve, to the inner casing of which a nicotine solution is applied, wherein according to the invention it is proposed that the sleeve is closed at one of its two ends by a partially air-tight draw-in brake and the nicotine solution consists of an amount of 0.8-1.2 mg of nicotine dissolved in 75-105 μl of ethanol, the nicotine solution being applied as an at least partial wetting of the inner casing. The cigarette according to the invention corresponds in its dimensions to conventional cigarettes, as will be explained in more detail, and in its structure with the draw-in brake arranged at one end also imitates that of a conventional cigarette. In contrast to the filter of conventional cigarettes, the draw-in brake does not serve to filter the air flow that is sucked in, but to generate a flow resistance within the otherwise empty sleeve, which is intended to imitate the suction resistance of a conventional cigarette, and to prevent axial air flows during storage. Of course, the draw-in brake can also be made from a conventional cigarette filter, which does not filter nicotine itself.

According to the invention, the nicotine is applied to the inner casing of the tube as a nicotine solution of an amount of 0.8-1.2 mg nicotine dissolved in 75-105 μl ethanol, preferably as a nicotine solution of an amount of 1 mg nicotine dissolved in 100 μl ethanol. Nicotine is highly soluble in ethanol. However, the decisive factor for the applicability of such a solution for combustion-free cigarettes is the evaporation behavior of the solution of nicotine in ethanol, which in turn depends on the relative quantity distribution. As will be explained in more detail below, the applicants were able to show that a solution according to the invention, when applying periodic air flows by suction, as corresponds to typical smoking behavior, ensures that the nicotine is released from the adhesion to the inner casing into the air flow in accumulated amounts of 250-800 μg within the times of 10-20 minutes that correspond to typical smoking behavior. The ethanol enables co-evaporation of nicotine with ethanol, in that ethanol mobilizes the otherwise difficult-to-evaporate nicotine into the gas phase.

The surface properties of the inner casing have also proven to be crucial for this, which, according to the invention, must ensure at least partial wetting of the inner casing by the nicotine solution. The wettability of a surface by a liquid is characterized by the contact angle (also referred to as the “wetting angle”), which describes the angle that a drop of liquid forms on the surface of the solid. The shape that the liquid droplet takes on a surface depends on the surface tension of the liquid and the nature of the surface. At the boundary between the liquid droplet and the gaseous environment, the surface tension causes a curved contour. At the edge of the liquid droplet, where the contour merges into the solid surface, the contact angle is formed between the liquid/solid interface and the tangent to the liquid/gas interface. If the liquid flows evenly over the solid surface, complete wetting with a contact angle of 0° is present. If the contact angle is between 0° and 90°, the surface is partially wettable. An angle between 90° and 180° means that the surface is not wettable. The inner casing of the cigarette according to the invention must be partially wettable, i.e. have a contact angle with the wetting liquid of less than 90°. The nicotine solution is preferably applied as an at least partial wetting of the inner casing with a maximum contact angle of 75°.

One possibility for this is to make the sleeve from bagasse. Bagasse is the name given to fibrous residues that arise primarily during the processing of sugar cane and have recently been used as a plastic substitute in the food industry because they can be processed into grease and water-impermeable packaging. Within the scope of the invention, sleeves can be made by mixing bagasse with water to form a paste, which is then formed into sleeves and dried. After drying, the sleeves are coated on their outer shell with melamine resins or biodegradable PLA (polylactic acid) to make them waterproof. On the inner shell, the sleeves have the wettability required by the invention. In addition, the sleeves made in this way are biodegradable and can therefore be easily disposed of.

Another possibility is to make the sleeve from glass, with the inner shell being roughened to ensure a contact angle of a maximum of 90°. Glass can be reused for the same application, for example by collecting it through a deposit system, cleaning it and sterilizing it, or it can be reused for another application, for example by disposing of it in glass collection containers.

Another cost-effective manufacturing option for the sleeve is to make the sleeve from a plastic that can be applied using FFF (Fused Filament Fabrication) manufacturing processes. FFF processes (also known as Fused Deposition Modeling) are additive manufacturing processes (“3D printing”) in which a plastic in molten form is applied layer by layer to a construction platform. The plastics used for this are mainly PLA and ABS (acrylonitrile butadiene styrene copolymer) as well as PETG. PETG is a glycol-modified polyethylene terephthalate (PET) that is characterized by its particularly high transparency and low viscosity. These plastics are drawn into a heated nozzle as a plastic wire (“filament”) and melted. To produce a sleeve according to the invention, the melted plastic material is applied and cured layer by layer in accordance with the sleeve geometry in an automated manner. The polymer sleeves produced in this way have the wettability required by the invention on the inner jacket.

With regard to the sleeve geometry, it is proposed that the inner jacket, which is at least partially wetted by the nicotine solution, has a surface area of 500-2000 mm², preferably a surface area of 1000 mm². The amount of 75-105 μl of ethanol proposed by the invention is applied to the inner jacket on this surface, as will be explained in more detail below. With regard to the dimensions of the sleeve, it is proposed that the sleeve is cylindrical and has a length of 50-100 mm and an inner diameter of 3-6 mm. The wall thickness of the sleeve is 1.5 mm to 2.5 mm, preferably 1.5 mm, so that there is sufficient strength to prevent the chemicals from diffusing through the wall.

It is also proposed that flavorings be added to the nicotine solution. In the amounts used here, nicotine is an almost tasteless and odorless substance. The flavorings serve to make the inhaled nicotine solution sensorially perceptible, on the one hand to increase the consumption pleasure and on the other hand to indicate to the consumer that the nicotine solution of a cigarette has been completely consumed. In contrast to conventional cigarettes, which burn out quickly, the cigarette according to the invention remains physically intact apart from the consumption of the applied nicotine solution. In addition, the cigarette according to the invention is suitable for nicotine release over a longer period of time than with a conventional cigarette, as will be explained in more detail below, namely for around 100 puffs, which, assuming a break of 10 seconds between the individual puffs, corresponds to a total consumption time of around 15 minutes. During these approximately 100 puffs, the entire amount of nicotine solution applied to the inner casing evaporates, and thus also the flavorings. The decisive factor here is that the presence of the flavorings does not interfere with the co-evaporation of nicotine with ethanol, which the applicants were able to demonstrate for a number of flavorings, as will be explained in more detail below.

It is also proposed that the nicotine used for the nicotine solution has a pH value in the alkaline range. The pH value of cigarette smoke from conventional cigarette tobacco is in the range of 6.3-5.6, i.e. in the acidic range. The nicotine of the nicotine solution with a pH value in the alkaline range, which is preferably proposed within the scope of the invention, corresponds more to cigar or pipe tobacco, which is obtained from leaves that are harvested in an unripe state. The pH value of cigar smoke from conventional cigar tobacco is in the range of 8.0-8.6, i.e. in the alkaline range. Free nicotine from such alkaline smoke is easily absorbed via mucous membranes. By using nicotine with a pH value in the alkaline range, this effect is exploited and the effect of cigar or pipe tobacco is imitated.

The invention is explained in more detail below using exemplary embodiments with the help of the accompanying figures. Here, the

FIG. 1 shows a schematic view of an embodiment of a cigarette according to the invention,

FIG. 2 shows experimental results on the cumulative amount of nicotine in μg absorbed by an air stream within a sleeve over the number of simulated puffs, whereby the sleeve is made of a PETG that can be applied using an FFF (Fused Filament Fabrication) manufacturing process,

FIG. 3 shows experimental results on the cumulative amount of ethanol (uncalibrated) absorbed by an air stream within a sleeve according to FIG. 2 over the number of simulated puffs, and

FIG. 4 shows experimental results on the cumulative amount of nicotine in μg absorbed by an air stream within a sleeve over the number of simulated puffs, whereby the sleeve is made of glass, the inner casing of which is roughened to ensure a contact angle of a maximum of 90°.

First, reference is made to FIG. 1, which shows a schematic view of an embodiment of a cigarette according to the invention. The cigarette according to the invention is similar in its dimensions to a conventional tobacco cigarette and has a cylindrical sleeve 1 with a length of 50-100 mm and an inner diameter of 3-6 mm. The inner casing 1a of the sleeve 1 has a surface area of 500-2000 mm², preferably a surface area of 1000 mm². The outer casing 1b of the sleeve 1 can be colored with food-safe color to give the sleeve 1 a white color, for example. The wall thickness of the sleeve 1 is 1.5 mm to 2.5 mm, preferably 1.5 mm, so that there is sufficient strength to prevent the chemicals from diffusing through the wall.

At its first end, the sleeve 1 is closed with a partially airtight draw-in brake 2, which is designed, for example, as a conventional cigarette filter. The draw-in brake 2 represents an intake resistance that reduces the air flow speed within the sleeve 1, so that the contact time between the air flow and the inner casing 1a is increased. In addition, the smoker is offered the usual intake resistance. The air sucked in enters the interior of the sleeve 1 via the opening at the opposite, second end of the sleeve 1, passes in an axial direction through the interior of the sleeve 1 in the direction of the draw-in brake 2 and through the draw-in brake 2 until it leaves the cigarette according to the invention at the free end of the draw-in brake. Alternatively, the draw-in brake 2 can also be designed as a solid, cylindrical intake plug with a conical channel made of biodegradable plastic, which has a conical air channel inside that tapers towards the intake opening and is open at both ends.

The open, second end of the cigarette according to the invention can be closed with a sealing film to prevent the nicotine solution from escaping during storage. Such a sealing film would have to be removed before use. The applicants, however, have determined that the closure of the second, open end of the cigarette can also be omitted because the escape of evaporated nicotine solution is negligible under the given geometric conditions, especially when cigarettes according to the invention are stored sealed in an airtight package. The air exchange between the sleeve 1, which is sealed on one side, and the environment is obviously sufficiently low so that saturation of evaporated nicotine solution quickly occurs within the sleeve 1, which prevents further evaporation of the nicotine solution.

A quantity of 75-105 μl of ethanol, which is mixed with a quantity of 0.8-1.2 mg of nicotine, is applied to the surface of the inner casing la. The nicotine solution can be applied to the inner casing 1a using a dosing and spray needle, which has a large number of holes or nozzles along its axial length. With such a dosing and spray needle, it is possible to wet the entire inner casing 1a of the sleeve 1 with the nicotine solution with one spray.

The following investigations have shown that the applied nicotine is sufficiently mobilized and carried away by a periodic air stream, as corresponds to typical smoking behavior.

Experimental Evidence

First, the co-evaporation of nicotine and ethanol was demonstrated and quantified using a nicotine solution of 1 mg nicotine in 100 μl ethanol. The evaporation should take place in a process that corresponds to typical smoking behavior. To do this, a smoker was asked to suck on a sleeve that was connected to a measuring cylinder, just as he would suck on a cigarette. This experiment was repeated with a female smoker. Both people repeated the process at least five times. It was shown that typical puffs taken by these people had volumes of around 40-80 ml. Questioning the people showed that they had around 10-40 seconds between puffs on a normal cigarette.

In order to be able to reproduce this smoking behavior in a reproducible manner for laboratory tests, a measurement setup was developed in which air was cyclically sucked through a tube whose dimensions corresponded to a cigarette according to the invention and whose inner casing 1a was wetted with a 100 μl ethanol-nicotine mixture with 1 mg/100 μl nicotine, whereby the “exhalation” did not take place through the tube. These tubes, which are filled with a nicotine-ethanol mixture, are referred to below as evaporator tubes. In a first experiment, the evaporator tubes were made from PETG using an FFF (Fused Filament Fabrication) manufacturing process. These evaporator tubes were manufactured using a commercially available “Ultimaker 2+” 3D printer with a needle tip of 0.25 mm. The layer thickness of the applied plastic layers was between 60-150 μm.

The measurement setup also allowed a variable time period between puffs to be programmed as a break using a microcontroller that controlled the setup. Suction was carried out using two 50 ml syringes connected in parallel, which were driven by a linear motor. A switching valve allowed air to be sucked out of the evaporator tube through an adsorber tube (Tenax tube) and an alcohol sensor as well as a UV sensor. The switching valve switched off the path through the tubes and allowed the syringes to be emptied into the ambient air,

The adsorber tubes were filled with Tenax. Tenax is the brand name of poly(2, 6-diphenyl-p-phenylene oxide), a polymer adsorber resin that is used as a column packing material for gas chromatography, since substances such as nicotine adsorb almost completely to the resin when the amount of substance is significantly below the binding capacity. The substances can then be desorbed by heating and fed to a mass spectrometer in the gas phase for further analysis. The Tenax tubes (17.8 cm) were analyzed using a “Gerstel TDS 3” with a “TDS A2” autosampler, typically using a split of 20:1 or 5:1. The molecules to be analyzed are transferred to the gas phase (desorption) and ionized by heating in an inert gas atmosphere at negative pressure. The ions are then accelerated by an electric field and fed to an analyzer, which separates them according to their mass-to-charge ratio m/z. The molecules can be fragmented in the process, which can lead to different peaks in the spectrogram,

The resulting chromatograms showed clear nicotine peaks, which were quantified by the nicotine-typical m/z ratio at 133 and 162. No influences from methanol or traces of other organic compounds were found in the corresponding m/z ranges. A total of 30 suction processes were carried out and the air sucked in from puffs 1-3, 3-5, 5-10, 10-20 and 20-30 was analyzed chromatographically.

Since a measure of the amount of the substance is the integral area under the curve of a peak, the peaks were integrated for further analysis and the areas were determined in this way. For calibration, glass tubes were filled with known amounts of nicotine and these were also measured in thermal desorption. The real, actual amount of substance could be estimated from the ratios of the areas of the peaks of the calibration measurements to the areas of the actual tests.

The tests showed that around 20 μg of nicotine was released after 30 puffs. It can be seen over time that the curve of the cumulative nicotine quantity is still increasing after 30 puffs. Therefore, further tests were carried out with a larger number of puffs. In addition, the course of the amount of alcohol that evaporated was quantified using the integrated alcohol sensor, although no absolute measurement was made. However, since a known amount of 100 μl was used, exact quantification can be omitted. FIG. 2 shows the measured course of the cumulative nicotine quantity, and FIG. 3 shows the measured course of the cumulative alcohol quantity, whereby the alcohol quantity was only given in arbitrary units (a.u.), since, as mentioned, no exact calibration was carried out here.

In the measurements described, a pause time of 10 s between the individual puffs was programmed, so that 60 puffs were taken in 10 minutes.

As can be seen from FIG. 2, nicotine was released over 150 puffs, with the release appearing to follow a biphasic (sigmoid) curve. As can be seen from FIG. 3, alcohol was also released sigmoidally, but much faster. Nicotine release is obviously concentration-dependent. The total amount of nicotine released during this time is approximately 75% of the amount used.

As mentioned, these measurements were carried out using 3D-printed polymer tubes as evaporator tubes, which had a relatively porous wall structure. Since it can be assumed that the porous wall structure delayed evaporation due to the capillary effects and the resulting reduced exposed surface, the tests were repeated with roughened glass tubes. For this purpose, commercially available Pasteur pipettes were cut to length using a glass cutter and ground using a grinding attachment on a Dremel. This roughness led to a reduction in the contact angle below 90° and thus to a spreading of the nicotine-ethanol mixture in the glass tube. This had the effect that after just 80 puffs, i.e. about 14 minutes, all ethanol and nicotine were released, as can be seen in FIG. 4.

The results presented here fit well with previous studies by the applicants in which the residual amounts of nicotine were determined in tubes in which an alcohol-nicotine solution was vaporized. It was found that only very small residual amounts were detectable.

Finally, the influence of flavorings on the co-evaporation of nicotine with ethanol was investigated. For this purpose, the following flavorings were added to the nicotine-ethanol mixture in different test series: “Smoke flavor” (product no.: 01400238), “Chocolate flavor” (product no.: 01602888), “Tea flavor” (product no.: 628/19A), “Coffee flavor” (product no.: 01602932) and “Akrastevia XI” (product no.: 86600108). An amount of 10 μl of each of these solutions was taken and this mixture was diluted with ethanol until only a weak (tolerable) sensory impression could be subjectively detected. 100 μl of this mixture was put into an evaporator tube together with 100 μl of the nicotine-ethanol solution, taking care that these solutions did not mix. Then 150 puffs were taken with the apparatus and the adsorber tubes were then eluted with methanol. As a control, the experiment was also carried out without flavorings. The methanol eluates were then applied to an Alox-RP18 thin layer chromatography plate (Alugram-RP18). After drying, a capillary force-driven run was carried out with methanol as the mobile phase. The nicotine bands visible under UV illumination did not differ visibly between the samples with flavorings and those without. This procedure was chosen because the flavorings were not precisely specified and quantified and contamination of the thermal desorption system was to be avoided.

Nicotine-ethanol evaporation measurements were repeated at least 3 times with the 3D-printed evaporator tubes and showed consistent results. The measurements with reduced evaporation time due to roughened glass surfaces and those with flavorings were each carried out twice and also showed consistent results.

These experimental studies show that by intermittent, bursty aeration of a tube in which a nicotine-ethanol solution of 1 mg/100 μl is spread, significant amounts of nicotine can be transferred into the gas phase and transported away, Using a 3D-printed porous plastic tube as a carrier, around 750 μg of nicotine (1 mg was applied) could be released over 30 minutes. This co-evaporation of ethanol and nicotine was also not noticeably influenced by flavorings. By choosing the appropriate surface of the evaporator tube, the speed of evaporation can be influenced to a certain extent. In the present case, with a roughened glass tube, nicotine could be released over a period of about 15 minutes with an inhalation frequency of one “puff” per 10 seconds, whereby here, too, about 70% of the originally applied nicotine could be detected in the gas phase.

The applicants were thus able to show that a solution according to the invention, when applying periodic air flows by suction, as corresponds to typical smoking behavior, ensures a release of the nicotine from the adhesion to the inner casing 1a into the air flow in accumulated amounts of 250-800 μg within the times of 10-20 minutes corresponding to typical smoking behavior. The cigarette according to the invention thus reproduces the properties of a conventional cigarette in its nicotine release in that the nicotine is absorbed in sufficient quantities by the air flow that occurs inside the sleeve 1 during the usual suction process and is available for inhalation. The ethanol enables a co-evaporation of nicotine with ethanol, as ethanol mobilizes the otherwise difficult-to-evaporate nicotine into the gas phase. The cigarette according to the invention can also be consumed without restrictions, for example in cafes, bars or restaurants, but also in train stations or airplanes, and is compliant with non-smoking laws, as neither harmful tobacco combustion smoke nor any form of smoldering as with tobacco heaters or steam as with e-cigarettes or e-shishas is emitted.