LIQUID NICOTINE FORMULATION

Abstract

A liquid nicotine formulation for use in an aerosol generating system, the liquid nicotine formulation comprising water and one or more water-miscible solvents, wherein the liquid nicotine formulation has a water content greater than or equal to approximately 30 percent by weight and a water-miscible solvent content greater than or equal to approximately 10 percent by weight, and wherein the ratio of the weight percent of water content to the weight percent of water-miscible solvent content of the liquid nicotine formulation is greater than or equal to approximately 1, and wherein the liquid nicotine formulation has at least one of the following: a water content greater than or equal to approximately 45 percent by weight; and a combined water and water-miscible solvent content greater than or equal to approximately 70 percent by weight.A cartridge for use in an aerosol generating system, the cartridge containing the liquid nicotine formulation. An aerosol generating system comprising the liquid nicotine formulation and an atomizer configured to generate an aerosol from the liquid nicotine formulation.

Description

LIQUID NICOTINE FORMULATION Field of invention The invention relates to a liquid nicotine formulation for use in an aerosol generating system. In particular, the invention relates to a liquid nicotine formulation for use in an aerosol generating system comprising a non-thermal atomizer. The invention further relates to a cartridge for an aerosol generating system comprising the liquid nicotine formulation and an aerosol generating system comprising the liquid nicotine formulation and an atomizer configured to generate an aerosol from the liquid nicotine formulation. Background of the invention Aerosol generating systems for delivering nicotine to a user are known to comprise an atomizer configured to generate an inhalable aerosol from a liquid nicotine formulation. Some known aerosol generating systems comprise a thermal atomizer, such as an electric heater, configured to heat and vaporize the liquid nicotine formulation to generate an aerosol. Other known aerosol generating systems comprise a non-thermal atomizer configured to generate an aerosol from the liquid nicotine formulation using, for example, impact jet, ultrasonic mesh, or vibratory technologies. In these aerosol-generating systems, the pulmonary delivery of the inhalable aerosol generated from the liquid nicotine formulation is believed to be important for palatability and user satisfaction. Nicotine adsorption through the pulmonary alveoli is rapid and efficient. In contrast, nicotine adsorption in the upper respiratory tract is slower and less efficient. A user may also perceive the adsorption of nicotine in the upper respiratory tract as having a harsh sensory experience, and such adsorption can induce irritation in the mouth and throat. The pulmonary deposition characteristics, and therefore the efficacy of the inhalable aerosol generated from the liquid nicotine formulation, depend on the aerosol particle or droplet size. Typically, a small particle or droplet size is desired to maximize nicotine delivery and retention in the lungs. In particular, a particle or droplet size of approximately 5 micrometers in diameter or less is believed to be suitable for maximizing pulmonary delivery. frZQ / nn / Lznz / E / Yi To improve nicotine delivery and retention in the lungs, it would be advantageous to provide a liquid nicotine formulation for use in an aerosol generating system that facilitates the generation of an aerosol with a small droplet size. For example, it would be advantageous to provide a liquid nicotine formulation for use in an aerosol generating system that facilitates the generation of an aerosol with a particle or droplet size less than or equal to approximately 5 micrometers in diameter. Description of the invention According to the invention, a liquid nicotine formulation is provided for use in an aerosol generating system, the liquid nicotine formulation comprising water and one or more water-miscible solvents, wherein the liquid nicotine formulation has a water content of at least approximately 30 percent by weight and wherein the ratio of the weight percent of the water content to the weight percent of the water-miscible solvent content of the liquid nicotine formulation is greater than or equal to approximately 1. In accordance with the invention, a cartridge for use in an aerosol generating system is also provided, the cartridge containing a liquid nicotine formulation comprising water and one or more water-miscible solvents, wherein the liquid nicotine formulation has a water content of at least approximately 30 percent by weight and wherein the ratio of the weight percent of the water content to the weight percent of the water-miscible solvent content of the liquid nicotine formulation is greater than or equal to approximately 1. According to the invention, an aerosol generating system is further provided comprising: a liquid nicotine formulation comprising water and one or more water-miscible solvents, wherein the liquid nicotine formulation has a water content of at least approximately 30 percent by weight and wherein the ratio of the weight percent of the water content to the weight percent of the water-miscible solvent content of the liquid nicotine formulation is greater than or equal to approximately 1; and an atomizer configured to generate an aerosol from the liquid nicotine formulation. As used herein with reference to the invention, the expression “liquid nicotine formulation” describes a liquid formulation comprising nicotine. As used herein with reference to the invention, the term “nicotine” refers to nicotine, nicotine base, or a nicotine salt. In embodiments where the liquid nicotine formulation comprises a nicotine base or a nicotine salt, the amounts of nicotine mentioned herein are the amount of free nicotine base or the amount of protonated nicotine, respectively. As used herein with reference to the invention, the expression “water miscible solvent” describes a compound that is neither water nor an organic acid that is liquid at 20 °C and mixes with water in all proportions to form a homogeneous solution. Unless otherwise stated, the weight percentages of the liquid nicotine formulation components quoted in this description are based on the total weight of the liquid nicotine formulation. In combination, a water content of at least approximately 30 percent by weight and a water content weight percentage greater than or equal to the water-miscible solvent weight percentage facilitates the generation of an inhalable aerosol with a small particle or droplet size when the liquid nicotine formulation according to the invention is used in an aerosol generating system. This can advantageously improve nicotine delivery and retention in the lungs. The use of the liquid nicotine formulation according to the invention in an aerosol generating system comprising a non-thermal atomizer is particularly advantageous. In combination, water and one or more water-miscible solvents in the liquid nicotine formulation according to the invention can advantageously help to dissolve and stabilize polar components and ionic components of the liquid nicotine formulation. Liquid nicotine formulations may comprise natural nicotine or synthetic nicotine. Liquid nicotine formulations may have a nicotine content greater than or equal to approximately 0.5 percent by weight. Preferably, the liquid nicotine formulation has a nicotine content greater than or equal to approximately 1 percent by weight. More preferably, the liquid nicotine formulation has a nicotine content greater than or equal to approximately 1.5 percent by weight. The liquid nicotine formulation may have a nicotine content less than or equal to approximately 10 percent by weight. The liquid nicotine formulation may have a nicotine content less than or equal to approximately 8 percent by weight. Preferably, the liquid nicotine formulation has a nicotine content of approximately 5 percent by weight or less. More preferably, the liquid nicotine formulation has a nicotine content of approximately 3 percent by weight or less. frZQ / nn / Lznz / E / Yi Liquid nicotine formulations can have a nicotine content of between approximately 0.5 percent by weight and approximately 10 percent by weight. For example, liquid nicotine formulations can have a nicotine content of between approximately 0.5 percent by weight and approximately 8 percent by weight, between approximately 0.5 percent by weight and approximately 5 percent by weight, or between approximately 0.5 percent by weight and approximately 3 percent by weight. Preferably, the liquid nicotine formulation has a nicotine content of between approximately 1 percent by weight and approximately 10 percent by weight. For example, the liquid nicotine formulation may have a nicotine content of between approximately 1 percent by weight and approximately 8 percent by weight, between approximately 1 percent by weight and approximately 5 percent by weight, or between approximately 1 percent by weight and approximately 3 percent by weight. Ideally, liquid nicotine formulations have a nicotine content of between approximately 1.5 percent and approximately 10 percent by weight. For example, a liquid nicotine formulation might have a nicotine content of between approximately 1.5 percent and approximately 8 percent by weight, between approximately 1.5 percent and approximately 5 percent by weight, or between approximately 1.5 percent and approximately 3 percent by weight. The liquid nicotine formulation comprises water and has a water content greater than or equal to approximately 30 percent by weight. Liquid nicotine formulations may have a water content greater than or equal to approximately 35 percent by weight. For example, liquid nicotine formulations may have a water content greater than or equal to approximately 40 percent by weight or greater than or equal to approximately 45 percent by weight. Preferably, the liquid nicotine formulation has a water content of approximately 90 percent by weight or less. More preferably, the liquid nicotine formulation has a water content of approximately 85 percent by weight or less. For example, the liquid nicotine formulation may have a water content of approximately 80 percent by weight or less, approximately 75 percent by weight or less, approximately 70 percent by weight or less, or approximately 65 percent by weight or less. Preferably, the liquid nicotine formulation has a water content of between approximately 30 percent by weight and approximately 90 percent by weight. For example, the liquid nicotine formulation may have a water content of between approximately frZQ / nn / Lznz / E / Yi percent by weight and approximately 85 percent by weight, between approximately 30 percent by weight and approximately 80 percent by weight, between approximately 30 percent by weight and approximately 75 percent by weight, between approximately 30 percent by weight and approximately 70 percent by weight, or between approximately 30 percent by weight and approximately 65 percent by weight. Liquid nicotine formulations can have a water content of between approximately 35 percent and approximately 90 percent by weight. For example, liquid nicotine formulations can have a water content of between approximately 35 percent and approximately 85 percent by weight, between approximately 35 percent and approximately 80 percent by weight, between approximately 35 percent and approximately 75 percent by weight, between approximately 35 percent and approximately 70 percent by weight, or between approximately 35 percent and approximately 65 percent by weight. Liquid nicotine formulations can have a water content of between approximately 40 percent by weight and approximately 90 percent by weight. For example, liquid nicotine formulations can have a water content of between approximately 40 percent by weight and approximately 85 percent by weight, between approximately 40 percent by weight and approximately 80 percent by weight, between approximately 40 percent by weight and approximately 75 percent by weight, between approximately 40 percent by weight and approximately 70 percent by weight, or between approximately 40 percent by weight and approximately 65 percent by weight. Liquid nicotine formulations can have a water content of between approximately 45 percent and approximately 90 percent by weight. For example, liquid nicotine formulations can have a water content of between approximately 45 percent and approximately 85 percent by weight, between approximately 45 percent and approximately 80 percent by weight, between approximately 45 percent and approximately 75 percent by weight, between approximately 45 percent and approximately 70 percent by weight, or between approximately 45 percent and approximately 65 percent by weight. The ratio of the weight percent of water content to the weight percent of water-miscible solvent content of the liquid nicotine formulation is greater than or equal to approximately 1. That is, the weight percent of water content of the liquid nicotine formulation is greater than or equal to the weight percent of water-miscible solvent content of the nicotine formulation. frZQ / nn / Lznz / E / Yi Preferably, the ratio of the weight percent of water content to the weight percent of water-miscible solvent content of the liquid nicotine formulation is greater than or equal to approximately 1.5. That is, preferably, the weight percentage of the water content of the liquid nicotine formulation is at least approximately 1.5 times the weight percentage of the water-miscible solvent content of the liquid nicotine formulation. The ratio of the weight percent of water content to the weight percent of water-miscible solvent content of the liquid nicotine formulation may be greater than or equal to approximately 2, greater than or equal to approximately 3, greater than or equal to approximately 4, or greater than or equal to approximately 5. That is, the weight percentage of the water content of the liquid nicotine formulation may be at least approximately 2 times the weight percentage of the water-miscible solvent content of the liquid nicotine formulation, at least approximately 3 times the weight percentage of the water-miscible solvent content of the liquid nicotine formulation, at least approximately 4 times the weight percentage of the water-miscible solvent content of the liquid nicotine formulation, or at least approximately 5 times the weight percentage of the water-miscible solvent content of the liquid nicotine formulation. Preferably, the ratio of the weight percent of water content to the weight percent of water-miscible solvent content of the liquid nicotine formulation is less than or equal to approximately 9, with more preferably less than or equal to approximately 8. That is, preferably the weight percentage of water content in the liquid nicotine formulation is less than or equal to approximately 9 times the weight percentage of water-miscible solvent content in the liquid nicotine formulation. More preferably, the weight percentage of water content in the liquid nicotine formulation is less than or equal to approximately 8 times the weight percentage of water-miscible solvent content in the liquid nicotine formulation. The ratio of the weight percent of water content to the weight percent of water-miscible solvent content of the liquid nicotine formulation may be less than or equal to approximately 7. In other words, the weight percentage of water content in the liquid nicotine formulation may be less than or equal to approximately 7 times the weight percentage of water-miscible solvent content in the liquid nicotine formulation. frZQ / nn / Lznz / E / Yi Preferably, the ratio of the weight percent of water content to the weight percent of water-miscible solvent content of the liquid nicotine formulation is between approximately 1 and approximately 9. For example, the ratio of the weight percent of water content to the weight percent of water-miscible solvent content of the liquid nicotine formulation may be between approximately 1 and approximately 8 or between approximately 1 and approximately 7. Preferably, the ratio of the weight percent of water content to the weight percent of water-miscible solvent content of the liquid nicotine formulation is between approximately 1.5 and approximately 9. For example, the ratio of the weight percent of water content to the weight percent of water-miscible solvent content of the liquid nicotine formulation may be between approximately 1.5 and approximately 8 or between approximately 1.5 and approximately 7. The ratio of the weight percent of water content to the weight percent of water-miscible solvent content of the liquid nicotine formulation can be between approximately 2 and approximately 9. For example, the ratio of the weight percent of water content to the weight percent of water-miscible solvent content of the liquid nicotine formulation can be between approximately 2 and approximately 8 or between approximately 2 and approximately 7. The ratio of the weight percent of water content to the weight percent of water-miscible solvent content of the liquid nicotine formulation can be between approximately 3 and approximately 9. For example, the ratio of the weight percent of water content to the weight percent of water-miscible solvent content of the liquid nicotine formulation can be between approximately 3 and approximately 8 or between approximately 3 and approximately 7. The ratio of the weight percent of water content to the weight percent of water-miscible solvent content of the liquid nicotine formulation can be between approximately 4 and approximately 9. For example, the ratio of the weight percent of water content to the weight percent of water-miscible solvent content of the liquid nicotine formulation can be between approximately 4 and approximately 8 or between approximately 4 and approximately 7. The ratio of the weight percent of water content to the weight percent of water-miscible solvent content of the liquid nicotine formulation can be between approximately 5 and approximately 9. For example, the ratio of the weight percent of water content to the weight percent of water-miscible solvent content of the liquid nicotine formulation can be between approximately 5 and approximately 8 or between approximately 5 and approximately 7. Preferably, the liquid nicotine formulation has a water-miscible solvent content greater than or equal to approximately 5 percent by weight. More preferably, the liquid nicotine formulation has a water-miscible solvent content greater than or equal to approximately 10 percent by weight. For example, the liquid nicotine formulation may have a water-miscible solvent content greater than or equal to approximately 15 percent by weight, greater than or equal to approximately 20 percent by weight, or greater than or equal to approximately 25 percent by weight. Liquid nicotine formulations may have a water-miscible solvent content less than or equal to approximately 50 percent by weight. Preferably, the liquid nicotine formulation has a water-miscible solvent content of approximately 45 percent by weight or less. More preferably, the liquid nicotine formulation has a water-miscible solvent content of approximately 40 percent by weight or less. For example, the liquid nicotine formulation may have a water-miscible solvent content of approximately 35 percent by weight or less. Liquid nicotine formulations may have a water-miscible solvent content of between approximately 5 percent by weight and approximately 50 percent by weight. Preferably, the liquid nicotine formulation has a water-miscible solvent content of between approximately 5 percent by weight and approximately 45 percent by weight. For example, the liquid nicotine formulation may have a water-miscible solvent content of between approximately 5 percent by weight and approximately 40 percent by weight or between approximately 5 percent by weight and approximately 35 percent by weight. Liquid nicotine formulations may have a water-miscible solvent content of between approximately 10 percent by weight and approximately 50 percent by weight. Preferably, the liquid nicotine formulation has a water-miscible solvent content of between approximately 10 percent by weight and approximately 45 percent by weight. For example, the liquid nicotine formulation may have a water-miscible solvent content of between approximately 10 percent by weight and approximately 40 percent by weight or between approximately 10 percent by weight and approximately 35 percent by weight. frZQ / nn / Lznz / E / Yi The liquid nicotine formulation may have a water-miscible solvent content of between approximately 15 percent by weight and approximately 50 percent by weight, between approximately 15 percent by weight and approximately 45 percent by weight, between approximately 15 percent by weight and approximately 40 percent by weight, or between approximately 15 percent by weight and approximately 30 percent by weight. The liquid nicotine formulation may have a water-miscible solvent content of between approximately 20 percent by weight and approximately 50 percent by weight, between approximately 20 percent by weight and approximately 45 percent by weight, between approximately 20 percent by weight and approximately 40 percent by weight, or between approximately 20 percent by weight and approximately 35 percent by weight. The liquid nicotine formulation may have a water-miscible solvent content of between approximately 25 percent by weight and approximately 50 percent by weight, between approximately 25 percent by weight and approximately 45 percent by weight, between approximately 25 percent by weight and approximately 40 percent by weight, or between approximately 25 percent by weight and approximately 35 percent by weight. The liquid nicotine formulation may have a combined content of water and water-miscible solvent greater than or equal to approximately 50 percent by weight or greater than or equal to approximately 55 percent by weight. Preferably, the liquid nicotine formulation has a combined water and water-miscible solvent content greater than or equal to approximately 60 percent by weight. For example, the liquid nicotine formulation may have a combined water and water-miscible solvent content greater than or equal to approximately 65 percent by weight. Most preferably, the liquid nicotine formulation has a combined water and water-miscible solvent content greater than or equal to approximately 70 percent by weight. Most preferably, the liquid nicotine formulation has a combined water and water-miscible solvent content greater than or equal to approximately 75 percent by weight. The liquid nicotine formulation may have a combined content of water and water-miscible solvent greater than or equal to approximately 80 percent by weight or greater than or equal to approximately 85 percent by weight. Preferably, the liquid nicotine formulation has at least one of the following: a water content greater than or equal to approximately 45 percent by weight and a combined water and water-miscible solvent content greater than or equal to approximately 70 percent by weight. That is, preferably the liquid nicotine has a water content greater than or equal to approximately 45 percent by weight, or a combined water and water-miscible solvent content greater than or equal to approximately 70 percent by weight, or a water content greater than or equal to approximately 45 percent by weight and a combined water and water-miscible solvent content greater than or equal to approximately 70 percent by weight. Preferably, the one or more water-miscible solvents are one or more water-miscible polyhydric alcohols. As used herein with reference to the invention, the expression “water miscible polyhydric alcohol” describes a polyhydric alcohol that is liquid at 20 °C and mixes with water in all proportions to form a homogeneous solution. According to a preferred embodiment of the invention, a liquid nicotine formulation is provided for use in an aerosol generating system, the liquid nicotine formulation comprising water and one or more water-miscible polyhydric alcohols, wherein the liquid nicotine formulation has a water content of at least approximately 30 percent by weight and wherein the ratio of the weight percent water content to the weight percent water-miscible polyhydric alcohol content of the liquid nicotine formulation is greater than or equal to approximately 1. According to a preferred embodiment of the invention, a cartridge for use in an aerosol generating system is further provided, the cartridge containing a liquid nicotine formulation comprising water and one or more water-miscible polyhydric alcohols, wherein the liquid nicotine formulation has a water content of at least approximately 30 percent by weight and wherein the ratio of the weight percent of the water content to the weight percent of the water-miscible polyhydric alcohol content of the liquid nicotine formulation is greater than or equal to approximately 1. According to a preferred embodiment of the invention, an aerosol generating system is further provided comprising: a liquid nicotine formulation comprising water and one or more water-miscible polyhydric alcohols, wherein the liquid nicotine formulation has a water content of at least approximately 30 percent by weight and wherein the ratio of the weight percent of the water content to the weight percent of the water-miscible polyhydric alcohol content of the liquid nicotine formulation is greater than or equal to approximately 1; and an atomizer configured to generate an aerosol from the liquid nicotine formulation. As used herein with reference to the invention, the expression “water miscible polyhydric alcohol” describes a polyhydric alcohol that is liquid at 20 °C and mixes with water in all proportions to form a homogeneous solution. frZQ / nn / Lznz / E / Yi Preferably, the liquid nicotine formulation has a water-miscible polyhydric alcohol content greater than or equal to approximately 5 percent by weight. More preferably, the liquid nicotine formulation has a water-miscible polyhydric alcohol content greater than or equal to approximately 10 percent by weight. For example, the liquid nicotine formulation may have a water-miscible polyhydric alcohol content greater than or equal to approximately 15 percent by weight, greater than or equal to approximately 20 percent by weight, or greater than or equal to approximately 25 percent by weight. The liquid nicotine formulation may have a water-miscible polyhydric alcohol content less than or equal to approximately 50 percent by weight. Preferably, the liquid nicotine formulation has a water-miscible polyhydric alcohol content of approximately 45 percent by weight or less. More preferably, the liquid nicotine formulation has a water-miscible polyhydric alcohol content of approximately 40 percent by weight or less. For example, the liquid nicotine formulation may have a water-miscible polyhydric alcohol content of approximately 35 percent by weight or less. Liquid nicotine formulations may have a water-miscible polyhydric alcohol content of between approximately 5 percent by weight and approximately 50 percent by weight. Preferably, the liquid nicotine formulation has a water-miscible polyhydric alcohol content of between approximately 5 percent by weight and approximately 45 percent by weight. For example, the liquid nicotine formulation may have a water-miscible polyhydric alcohol content of between approximately 5 percent by weight and approximately 40 percent by weight or between approximately 5 percent by weight and approximately 35 percent by weight. Liquid nicotine formulations may have a water-miscible polyhydric alcohol content of between approximately 10 percent by weight and approximately 50 percent by weight. Preferably, the liquid nicotine formulation has a water-miscible polyhydric alcohol content of between approximately 10 percent by weight and approximately 45 percent by weight. For example, the liquid nicotine formulation may have a water-miscible polyhydric alcohol content of between approximately 10 percent by weight and approximately 40 percent by weight or between approximately 10 percent by weight and approximately 35 percent by weight. frZQ / nn / Lznz / E / Yi The liquid nicotine formulation may have a water-miscible polyhydric alcohol content of between approximately 15 percent by weight and approximately 50 percent by weight, between approximately 15 percent by weight and approximately 45 percent by weight, between approximately 15 percent by weight and approximately 40 percent by weight, or between approximately 15 percent by weight and approximately 30 percent by weight. The liquid nicotine formulation may have a water-miscible polyhydric alcohol content of between approximately 20 percent by weight and approximately 50 percent by weight, between approximately 20 percent by weight and approximately 45 percent by weight, between approximately 20 percent by weight and approximately 40 percent by weight, or between approximately 20 percent by weight and approximately 35 percent by weight. The liquid nicotine formulation may have a water-miscible polyhydric alcohol content of between approximately 25 percent by weight and approximately 50 percent by weight, between approximately 25 percent by weight and approximately 45 percent by weight, between approximately 25 percent by weight and approximately 40 percent by weight, or between approximately 25 percent by weight and approximately 35 percent by weight. The liquid nicotine formulation may have a combined content of water and water-miscible polyhydric alcohol greater than or equal to approximately 50 percent by weight. Preferably, the liquid nicotine formulation has a combined water and water-miscible polyhydric alcohol content greater than or equal to approximately 60 percent by weight. For example, the liquid nicotine formulation may have a combined water and water-miscible polyhydric alcohol content greater than or equal to approximately 65 percent by weight. More preferably, the liquid nicotine formulation has a combined water and water-miscible polyhydric alcohol content greater than or equal to approximately 70 percent by weight. Superlatively, the liquid nicotine formulation has a combined water and water-miscible polyhydric alcohol content greater than or equal to approximately 75 percent by weight. The liquid nicotine formulation may have a combined content of water and water-miscible polyhydric alcohol greater than or equal to approximately 80 percent by weight or greater than or equal to approximately 85 percent by weight. Preferably, the ratio of the weight percent of water content to the weight percent of water-miscible polyhydric alcohol content of the liquid nicotine formulation is greater than or equal to approximately 1.5. frza / nn / Lznz / E / Yii That is, preferably, the weight percentage of the water content of the liquid nicotine formulation is at least approximately 1.5 times the weight percentage of the water-miscible polyhydric alcohol content of the liquid nicotine formulation. The ratio of the weight percent of water content to the weight percent of water-miscible polyhydric alcohol content of the liquid nicotine formulation may be greater than or equal to approximately 2, greater than or equal to approximately 3, greater than or equal to approximately 4, or greater than or equal to approximately 5. That is, the weight percentage of the water content of the liquid nicotine formulation may be at least approximately 2 times the weight percentage of the water miscible polyhydric alcohol content of the liquid nicotine formulation, at least approximately 3 times the weight percentage of the water miscible polyhydric alcohol content of the liquid nicotine formulation, at least approximately 4 times the weight percentage of the water miscible polyhydric alcohol content of the liquid nicotine formulation, or at least approximately 5 times the weight percentage of the water miscible polyhydric alcohol content of the liquid nicotine formulation. Preferably, the ratio of the weight percent of water content to the weight percent of water-miscible polyhydric alcohol content of the liquid nicotine formulation is less than or equal to approximately 9, with more preferably less than or equal to approximately 8. That is, preferably, the weight percentage of water content in the liquid nicotine formulation is less than or equal to approximately 9 times the weight percentage of water-miscible polyhydric alcohol content in the liquid nicotine formulation. More preferably, the weight percentage of water content in the liquid nicotine formulation is less than or equal to approximately 8 times the weight percentage of water-miscible polyhydric alcohol content in the liquid nicotine formulation. The ratio of the weight percent of water content to the weight percent of water-miscible polyhydric alcohol content of the liquid nicotine formulation may be less than or equal to approximately 7. In other words, the weight percentage of water content in the liquid nicotine formulation may be less than or equal to approximately 7 times the weight percentage of water-miscible polyhydric alcohol content in the liquid nicotine formulation. Preferably, the ratio of the weight percent of water content to the weight percent of water-miscible polyhydric alcohol content of the liquid nicotine formulation is between approximately 1 and approximately 9. For example, the ratio frZQ / nn / Lznz / E / Yi of the weight percent of water content to the weight percent of water-miscible polyhydric alcohol content of the liquid nicotine formulation may be between approximately 1 and approximately 8 or between approximately 1 and approximately 7. Preferably, the ratio of the weight percent of water content to the weight percent of water-miscible polyhydric alcohol content of the liquid nicotine formulation is between approximately 1.5 and approximately 9. For example, the ratio of the weight percent of water content to the weight percent of water-miscible polyhydric alcohol content of the liquid nicotine formulation may be between approximately 1.5 and approximately 8 or between approximately 1.5 and approximately 7. The ratio of the weight percent of water content to the weight percent of water-miscible polyhydric alcohol content of the liquid nicotine formulation can be between approximately 2 and approximately 9. For example, the ratio of the weight percent of water content to the weight percent of water-miscible polyhydric alcohol content of the liquid nicotine formulation can be between approximately 2 and approximately 8 or between approximately 2 and approximately 7. The ratio of the weight percent of water content to the weight percent of water-miscible polyhydric alcohol content of the liquid nicotine formulation can be between approximately 3 and approximately 9. For example, the ratio of the weight percent of water content to the weight percent of water-miscible polyhydric alcohol content of the liquid nicotine formulation can be between approximately 3 and approximately 8 or between approximately 3 and approximately 7. The ratio of the weight percent of water content to the weight percent of water-miscible polyhydric alcohol content of the liquid nicotine formulation can be between approximately 4 and approximately 9. For example, the ratio of the weight percent of water content to the weight percent of water-miscible polyhydric alcohol content of the liquid nicotine formulation can be between approximately 4 and approximately 8 or between approximately 4 and approximately 7. The ratio of the weight percent of water content to the weight percent of water-miscible polyhydric alcohol content of the liquid nicotine formulation can be between approximately 5 and approximately 9. For example, the ratio of the weight percent of water content to the weight percent of water-miscible polyhydric alcohol content of the liquid nicotine formulation can be between approximately 5 and approximately 8 or between approximately 5 and approximately 7. frZQ / nn / Lznz / E / Yi Preferably, the one or more water-miscible polyhydric alcohols are selected from the group consisting of 1,3-butanediol, glycerin, propylene glycol, and triethylene glycol. Most preferably, the one or more water-miscible polyhydric alcohols are selected from the group consisting of glycerin and propylene glycol. With superlative preference, the one or more water-miscible polyhydric alcohols are selected from the group consisting of vegetable glycerin and propylene glycol. According to a preferred embodiment of the invention, a liquid nicotine formulation is provided for use in an aerosol generating system. The liquid nicotine formulation comprises water and one or more water-miscible polyhydric alcohols selected from the group consisting of glycerin and propylene glycol, wherein the liquid nicotine formulation has a water content of at least approximately 30 percent by weight and wherein the ratio of the weight percent of the water content to the weight percent of the water-miscible polyhydric alcohol content of the liquid nicotine formulation is greater than or equal to approximately 1. According to a preferred embodiment of the invention, a cartridge for use in an aerosol generating system is further provided. The cartridge contains a liquid nicotine formulation comprising water and one or more water-miscible polyhydric alcohols selected from the group consisting of glycerin and propylene glycol, wherein the liquid nicotine formulation has a water content of at least approximately 30 percent by weight and wherein the ratio of the weight percent of the water content to the weight percent of the water-miscible polyhydric alcohol content of the liquid nicotine formulation is greater than or equal to approximately 1. According to a preferred embodiment of the invention, an aerosol generating system is further provided comprising: a liquid nicotine formulation comprising water and one or more water-miscible polyhydric alcohols selected from the group consisting of glycerin and propylene glycol, wherein the liquid nicotine formulation has a water content of at least approximately 30 percent by weight and wherein the ratio of the weight percent of the water content to the weight percent of the water-miscible polyhydric alcohol content of the liquid nicotine formulation is greater than or equal to approximately 1; and an atomizer configured to generate an aerosol from the liquid nicotine formulation. Preferably, the liquid nicotine formulation has a combined glycerin and propylene glycol content greater than or equal to approximately 5 percent by weight. More preferably, the liquid nicotine formulation has a combined glycerin and propylene glycol content greater than or equal to approximately 10 percent by weight. For example, the liquid nicotine formulation may have a combined glycerin and propylene glycol content greater than or equal to approximately 15 percent by weight, greater than or equal to approximately 20 percent by weight, or greater than or equal to approximately 25 percent by weight. The liquid nicotine formulation may have a combined glycerin and propylene glycol content less than or equal to approximately 50 percent by weight. Preferably, the liquid nicotine formulation has a combined glycerin and propylene glycol content of approximately 45 percent by weight or less. More preferably, the liquid nicotine formulation has a combined glycerin and propylene glycol content of approximately 40 percent by weight or less. For example, the liquid nicotine formulation may have a combined glycerin and propylene glycol content of approximately 35 percent by weight or less. Liquid nicotine formulations may have a combined glycerin and propylene glycol content of between approximately 5 percent by weight and approximately 50 percent by weight. Preferably, the liquid nicotine formulation has a combined glycerin and propylene glycol content of between approximately 5 percent and approximately 45 percent by weight. For example, the liquid nicotine formulation may have a combined glycerin and propylene glycol content of between approximately 5 percent and approximately 40 percent by weight or between approximately 5 percent and approximately 35 percent by weight. The liquid nicotine formulation may have a combined glycerin and propylene glycol content of between approximately 10 percent by weight and approximately 50 percent by weight. Preferably, the liquid nicotine formulation has a combined glycerin and propylene glycol content of between approximately 10 percent and approximately 45 percent by weight. For example, the liquid nicotine formulation may have a combined glycerin and propylene glycol content of between approximately 10 percent and approximately 40 percent by weight or between approximately 10 percent and approximately 35 percent by weight. The liquid nicotine formulation may have a combined glycerin and propylene glycol content of between approximately 15 percent by weight and approximately 50 percent by weight, between approximately 15 percent by weight and approximately 45 percent by weight, between approximately 15 percent by weight and approximately 40 percent by weight, or between approximately 15 percent by weight and approximately 30 percent by weight. The liquid nicotine formulation may have a combined glycerin and propylene glycol content of between approximately 20 percent by weight and approximately 50 percent by weight, between approximately 20 percent by weight and approximately 45 percent by weight, between approximately 20 percent by weight and approximately 40 percent by weight, or between approximately 20 percent by weight and approximately 35 percent by weight. The liquid nicotine formulation may have a combined glycerin and propylene glycol content of between approximately 25 percent by weight and approximately 50 percent by weight, between approximately 25 percent by weight and approximately 45 percent by weight, between approximately 25 percent by weight and approximately 40 percent by weight, or between approximately 25 percent by weight and approximately 35 percent by weight. The liquid nicotine formulation may have a combined content of water, glycerin, and propylene glycol greater than or equal to approximately 50 percent by weight or greater than or equal to approximately 55 percent by weight. Preferably, the liquid nicotine formulation has a combined content of water, glycerin, and propylene glycol greater than or equal to approximately 60 percent by weight. For example, the liquid nicotine formulation may have a combined content of water, glycerin, and propylene glycol greater than or equal to approximately 65 percent by weight. More preferably, the liquid nicotine formulation has a combined content of water, glycerin, and propylene glycol greater than or equal to approximately 70 percent by weight. Superlatively, the liquid nicotine formulation has a combined content of water, glycerin, and propylene glycol greater than or equal to approximately 75 percent by weight. The liquid nicotine formulation may have a combined content of water, glycerin, and propylene glycol greater than or equal to approximately 80 percent by weight or greater than or equal to approximately 85 percent by weight. Preferably, the ratio of the weight percent of water content to the combined weight percent of glycerin and propylene glycol content of the liquid nicotine formulation is greater than or equal to approximately 1.5. That is, preferably, the weight percentage of the water content of the liquid nicotine formulation is at least approximately 1.5 times the combined weight percentage of the glycerin and propylene glycol content of the liquid nicotine formulation. The ratio of the weight percent of water content to the combined weight percent of glycerin and propylene glycol content of the liquid nicotine formulation frZQ / nn / Lznz / E / Yi may be greater than or equal to approximately 2, greater than or equal to approximately 3, greater than or equal to approximately 4, or greater than or equal to approximately 5. That is, the weight percentage of water content in the liquid nicotine formulation may be at least approximately 2 times the combined weight percentage of glycerin and propylene glycol content in the liquid nicotine formulation, at least approximately 3 times the combined weight percentage of glycerin and propylene glycol content in the liquid nicotine formulation, at least approximately 4 times the combined weight percentage of glycerin and propylene glycol content in the liquid nicotine formulation, or at least approximately 5 times the combined weight percentage of glycerin and propylene glycol content in the liquid nicotine formulation. Preferably, the ratio of the weight percent of water content to the combined weight percent of glycerin and propylene glycol content of the liquid nicotine formulation is less than or equal to approximately 9, with more preferably less than or equal to approximately 8. That is, preferably, the weight percentage of water content in the liquid nicotine formulation is less than or equal to approximately 9 times the combined weight percentage of glycerin and propylene glycol content in the liquid nicotine formulation. More preferably, the weight percentage of water content in the liquid nicotine formulation is less than or equal to approximately 8 times the combined weight percentage of glycerin and propylene glycol content in the liquid nicotine formulation. The ratio of the weight percent of water content to the combined weight percent of glycerin and propylene glycol content of the liquid nicotine formulation may be less than or equal to approximately 7. In other words, the weight percentage of water content in the liquid nicotine formulation may be less than or equal to approximately 7 times the combined weight percentage of glycerin and propylene glycol content in the liquid nicotine formulation. Preferably, the ratio of the weight percent of water content to the combined weight percent of glycerin and propylene glycol content of the liquid nicotine formulation is between approximately 1 and approximately 9. For example, the ratio of the weight percent of water content to the combined weight percent of glycerin and propylene glycol content of the liquid nicotine formulation may be between approximately 1 and approximately 8 or between approximately 1 and approximately 7. Preferably, the ratio of the weight percent of water content to the combined weight percent of glycerin and propylene glycol content of the liquid nicotine formulation is between approximately 1.5 and approximately 9. For example, the ratio of the weight percent of water content to the combined weight percent of glycerin and propylene glycol content of the liquid nicotine formulation may be between approximately 1.5 and approximately 8 or between approximately 1.5 and approximately 7. The ratio of the weight percent of water content to the combined weight percent of glycerin and propylene glycol content in the liquid nicotine formulation can be between approximately 2 and approximately 9. For example, the ratio of the weight percent of water content to the combined weight percent of glycerin and propylene glycol content in the liquid nicotine formulation can be between approximately 2 and approximately 8 or between approximately 2 and approximately 7. The ratio of the weight percent of water content to the combined weight percent of glycerin and propylene glycol content in the liquid nicotine formulation can be between approximately 3 and approximately 9. For example, the ratio of the weight percent of water content to the combined weight percent of glycerin and propylene glycol content in the liquid nicotine formulation can be between approximately 3 and approximately 8 or between approximately 3 and approximately 7. The ratio of the weight percent of water content to the combined weight percent of glycerin and propylene glycol content in the liquid nicotine formulation can be between approximately 4 and approximately 9. For example, the ratio of the weight percent of water content to the combined weight percent of glycerin and propylene glycol content in the liquid nicotine formulation can be between approximately 4 and approximately 8 or between approximately 4 and approximately 7. The ratio of the weight percent of water content to the combined weight percent of glycerin and propylene glycol content in the liquid nicotine formulation can be between approximately 5 and approximately 9. For example, the ratio of the weight percent of water content to the combined weight percent of glycerin and propylene glycol content in the liquid nicotine formulation can be between approximately 5 and approximately 8 or between approximately 5 and approximately 7. Preferably, the liquid nicotine formulation has a glycerin content greater than or equal to approximately 5 percent by weight. Preferably, the liquid nicotine formulation has a glycerin content greater than or equal to approximately 6 percent by weight. For example, the liquid nicotine formulation frZQ / nn / Lznz / E / Yi may have a glycerin content greater than or equal to approximately 7 percent by weight or greater than or equal to approximately 8 percent by weight. Liquid nicotine formulations may have a glycerin content less than or equal to approximately 50 percent by weight. Preferably, the liquid nicotine formulation has a glycerin content of approximately 45 percent by weight or less. More preferably, the liquid nicotine formulation has a glycerin content of approximately 40 percent by weight or less. For example, the liquid nicotine formulation may have a glycerin content of approximately 35 percent by weight or less. Liquid nicotine formulations may have a glycerin content of between approximately 5 percent by weight and approximately 50 percent by weight. Preferably, the liquid nicotine formulation has a glycerin content of between approximately 5 percent by weight and approximately 50 percent by weight. For example, the liquid nicotine formulation may have a glycerin content of between approximately 5 percent by weight and approximately 45 percent by weight, between approximately 5 percent by weight and approximately 40 percent by weight, or between approximately 5 percent by weight and approximately 35 percent by weight. Preferably, the liquid nicotine formulation has a glycerin content of between approximately 6 percent by weight and approximately 50 percent by weight. For example, the liquid nicotine formulation may have a glycerin content of between approximately 6 percent by weight and approximately 45 percent by weight, between approximately 6 percent by weight and approximately 40 percent by weight, or between approximately 6 percent by weight and approximately 35 percent by weight. The liquid nicotine formulation may have a glycerin content of between approximately 7 percent by weight and approximately 50 percent by weight, between approximately 7 percent by weight and approximately 45 percent by weight, between approximately 7 percent by weight and approximately 40 percent by weight, or between approximately 7 percent by weight and approximately 35 percent by weight. The liquid nicotine formulation may have a glycerin content of between approximately 8 percent by weight and approximately 50 percent by weight, between approximately 8 percent by weight and approximately 45 percent by weight, between approximately 8 percent by weight and approximately 40 percent by weight, or between approximately 8 percent by weight and approximately 35 percent by weight. frZQ / nn / Lznz / E / Yi Preferably, the liquid nicotine formulation comprises one or more water-immiscible solvents. As used herein with reference to the invention, the expression “water-immiscible solvent” describes a compound that is liquid at 20 °C and has a solubility in water at 20 °C less than or equal to approximately 100 mg / mL. Unless otherwise stated, the water solubility values ​​mentioned herein are the water solubility measured based on the OECD Preliminary Test (1995), Test No. 105: Water Solubility, OECD Guidelines for the Testing of Chemicals, Section 1, OECD Publishing, Paris, https: / / doi.org / 10.1787 / 9789264069589-en. In a stepwise procedure, increasing volumes of distilled water at 20 °C are added to 0.1 g of the sample (solid substances must be pulverized) in a 10 mL glass-stoppered measuring cylinder. However, when the substance is an acid, the sample is added to the distilled water in the first step. After each addition of water, the mixture is stirred for 10 minutes and visually checked for any undissolved portion of the sample.If, after the addition of 10 mL of water, the sample or parts thereof remain undissolved, the experiment is continued in a 100 mL measuring cylinder. The approximate solubility is provided in Table 1 below the volume of water in which complete dissolution of the sample occurs. When solubility is low, a long time may be required to dissolve a substance, and at least 24 hours should be allowed to elapse. If, after 24 hours, the substance is still not dissolved, the measuring cylinder is placed in an ultrasonic bath at 40 °C for 15 minutes and then allowed to remain for another 24 hours (up to a maximum of 96 hours). If the substance is still not dissolved, the solubility is considered to be below the limit value or the substance is considered insoluble. frZQ / nn / Lznz / E / Yi mL of water in which 0.1 g of sample can be dissolved 0.1 0.5 1 2 10 100 >100 Approximate solubility (mg / mL) >1000 from 1000 to 200 from 200 to 100 from 100 to 50 from 50 to 10 from 10 to 1 <1 Table 1 One or more water-immiscible solvents can advantageously help to dissolve and stabilize non-polar components of the liquid nicotine formulation. One or more water-immiscible solvents can reduce the hygroscopicity of an aerosol generated from a liquid nicotine formulation when used in an aerosol generating system. This can advantageously reduce or prevent increases in aerosol particle or droplet size when inhaled by a user as a result of water adsorption in the airways. Preferably, the liquid nicotine formulation comprises water, one or more water-miscible polyhydric alcohols, and one or more water-immiscible solvents. Most preferably, the liquid nicotine formulation comprises water, one or more water-miscible polyhydric alcohols selected from the group consisting of glycerin and propylene glycol, and one or more water-immiscible solvents. When used in an aerosol-generating system, the liquid nicotine formulation produces an aerosol comprising two-phase droplets or particles: a water-miscible phase and a water-immiscible phase. This can advantageously reduce nicotine adsorption in the upper respiratory tract and improve nicotine delivery and retention in the lungs. While not wishing to remain purely theoretical, it is believed that the improvement in nicotine delivery and retention in the lungs is due to the coating or enveloping of the water-miscible phase by the water-immiscible phase. This is thought to reduce nicotine evaporation and adsorption in the upper respiratory tract. Preferably, the liquid nicotine formulation has a water-immiscible solvent content greater than or equal to approximately 1 percent by weight. More preferably, the liquid nicotine formulation has a water-immiscible solvent content greater than or equal to approximately 2 percent by weight. For example, the liquid nicotine formulation may have a water-immiscible solvent content greater than or equal to approximately 4 percent by weight, greater than or equal to approximately 6 percent by weight, or greater than or equal to approximately 8 percent by weight. The liquid nicotine formulation may have a water-immiscible solvent content less than or equal to approximately 40 percent by weight. Preferably, the liquid nicotine formulation has a water-immiscible solvent content of approximately 35 percent by weight or less. More preferably, the liquid nicotine formulation has a water-immiscible solvent content of approximately 30 percent by weight or less. For example, the liquid nicotine formulation may have a water-immiscible solvent content of approximately 25 percent by weight or less, approximately 20 percent by weight or less, or approximately 15 percent by weight or less. frZQ / nn / Lznz / E / Yi Liquid nicotine formulations may have a water-immiscible solvent content of between approximately 1 percent by weight and approximately 40 percent by weight. Preferably, the liquid nicotine formulation has a water-immiscible solvent content of between approximately 1 percent by weight and approximately 35 percent by weight. For example, the liquid nicotine formulation may have a water-immiscible solvent content of between approximately 1 percent by weight and approximately 30 percent by weight, between approximately 1 percent by weight and approximately 25 percent by weight, between approximately 1 percent by weight and approximately 20 percent by weight, or between approximately 1 percent by weight and approximately 15 percent by weight. Liquid nicotine formulations may have a water-immiscible solvent content of between approximately 2 percent by weight and approximately 40 percent by weight. Preferably, the liquid nicotine formulation has a water-immiscible solvent content of between approximately 2 percent by weight and approximately 35 percent by weight. For example, the liquid nicotine formulation may have a water-immiscible solvent content of between approximately 2 percent by weight and approximately 30 percent by weight, between approximately 2 percent by weight and approximately 25 percent by weight, between approximately 2 percent by weight and approximately 20 percent by weight, or between approximately 2 percent by weight and approximately 15 percent by weight. Liquid nicotine formulations may have a water-immiscible solvent content of between approximately 4 percent by weight and approximately 40 percent by weight, or between approximately 4 percent by weight and approximately 35 percent by weight. For example, liquid nicotine formulations may have a water-immiscible solvent content of between approximately 4 percent by weight and approximately 30 percent by weight, between approximately 4 percent by weight and approximately 25 percent by weight, between approximately 4 percent by weight and approximately 20 percent by weight, or between approximately 4 percent by weight and approximately 15 percent by weight. Liquid nicotine formulations may have a water-immiscible solvent content of between approximately 6 percent by weight and approximately 40 percent by weight, or between approximately 6 percent by weight and approximately 35 percent by weight. For example, liquid nicotine formulations may have a water-immiscible solvent content of between approximately 6 percent by weight and approximately 30 percent by weight, between approximately 6 percent by weight and approximately 25 percent by weight, between approximately 6 percent by weight and approximately 20 percent by weight, or between approximately 6 percent by weight and approximately 15 percent by weight. Liquid nicotine formulations may have a water-immiscible solvent content of between approximately 8 percent by weight and approximately 40 percent by weight, or between approximately 8 percent by weight and approximately 35 percent by weight. For example, liquid nicotine formulations may have a water-immiscible solvent content of between approximately 8 percent by weight and approximately 30 percent by weight, between approximately 8 percent by weight and approximately 25 percent by weight, between approximately 8 percent by weight and approximately 20 percent by weight, or between approximately 8 percent by weight and approximately 15 percent by weight. Preferably, the one or more water-immiscible solvents comprise one or more solvents that are partially soluble in water. As used herein with reference to the invention, the expression “partially water-soluble solvent” describes a compound that is liquid at 20 °C and has a solubility in water at 20 °C of between approximately 20 mg / mL and approximately 100 mg / mL. One or more partially water-soluble solvents may have a maximum carbon chain length less than or equal to 12. For example, one or more partially water-soluble solvents may have a maximum carbon chain length less than or equal to 10. Suitable partially water-soluble solvents include, but are not limited to, polysorbate 80, triacetin, and triethyl citrate. Preferably, the one or more water-immiscible solvents comprise one or more water-insoluble solvents. As used herein with reference to the invention, the expression “water-insoluble solvent” describes a compound that is liquid at 20 °C and has a solubility in water at 20 °C less than or equal to approximately 5 mg / mL. The one or more water-insoluble solvents may have a maximum carbon chain length less than or equal to 30. For example, the one or more water-insoluble solvents may have a maximum carbon chain length less than or equal to 20, less than or equal to 18, less than or equal to 16, less than or equal to 14, or less than or equal to 12. Suitable water-insoluble solvents include, but are not limited to, oleic acid and MIGLYOL® (mixture of decanoyl and octanoyl glycerides). frZQ / nn / Lznz / E / Yi Preferably, the one or more water-immiscible solvents comprise one or more partially water-soluble solvents and one or more water-insoluble solvents. Preferably, the liquid nicotine formulation comprises one or more water-soluble organic acids. As used herein with reference to the invention, the expression “water-soluble organic acid” describes an organic acid having a solubility in water at 20 °C greater than or equal to approximately 500 mg / mL. One or more water-soluble organic acids can be advantageously bonded to nicotine in the liquid nicotine formulation through the formation of one or more nicotine salts. One or more nicotine salts can be advantageously dissolved and stabilized in water and one or more water-miscible solvents. In formulations where the liquid nicotine comprises water, one or more water-miscible solvents, and one or more water-immiscible solvents, this can advantageously reduce nicotine adsorption in the upper respiratory tract and improve nicotine delivery and retention in the lungs, as described above. Most preferably, the liquid nicotine formulation comprises one or more water-soluble carboxylic acids. Suitable water-soluble carboxylic acids include, but are not limited to, acetic acid, citric acid, lactic acid, levulinic acid, malic acid, malonic acid, and pyruvic acid. With superlative preference, the liquid nicotine formulation comprises lactic acid. Preferably, the liquid nicotine formulation has a water-soluble organic acid content greater than or equal to approximately 2 percent by weight. More preferably, the liquid nicotine formulation has a water-soluble organic acid content greater than or equal to approximately 3 percent by weight. Preferably, the liquid nicotine formulation has a water-soluble organic acid content of approximately 8 percent by weight or less. More preferably, the liquid nicotine formulation has a water-soluble organic acid content of approximately 6 percent by weight or less. Preferably, the liquid nicotine formulation has a water-soluble organic acid content of between approximately 2 percent by weight and approximately 8 percent by weight. For example, the liquid nicotine formulation may have a water-soluble organic acid content of between approximately 2 percent by weight and approximately 6 percent by weight. frZQ / nn / Lznz / E / Yi Ideally, liquid nicotine formulations have a water-soluble organic acid content of between approximately 3 percent and approximately 8 percent by weight. For example, liquid nicotine formulations may have a water-soluble organic acid content of between approximately 2 percent and approximately 6 percent by weight. The liquid nicotine formulation can be a liquid nicotine formulation that is substantially caffeine-free. As used herein with reference to the invention, the term “substantially caffeine-free liquid nicotine formulation” describes a liquid nicotine formulation having a caffeine content of less than 0.5 percent by weight. For example, the liquid nicotine formulation may have a caffeine content of less than approximately 0.4 percent by weight, less than approximately 0.3 percent by weight, or less than approximately 0.2 percent by weight. The liquid nicotine formulation can be a liquid nicotine formulation that is substantially caffeine-free. As used herein with reference to the invention, the expression “substantially caffeine-free liquid nicotine formulation” describes a liquid nicotine formulation having a caffeine content of less than approximately 0.1 percent by weight. The liquid nicotine formulation can be a caffeine-free liquid nicotine formulation. As used herein with reference to the invention, the expression “caffeine-free liquid nicotine formulation” describes a liquid nicotine formulation having a caffeine content of 0 percent by weight. As used herein with reference to the invention, the term “caffeine” describes caffeine or a caffeine salt. When referring to a caffeine salt, the amounts of caffeine mentioned herein are the amount of caffeine cation. Liquid nicotine formulations may include one or more flavorings. Suitable flavorings include, but are not limited to, menthol. Preferably, the liquid nicotine formulation has a flavoring content of approximately 4 percent by weight or less. More preferably, the liquid nicotine formulation has a flavoring content of approximately 3 percent by weight or less. frZQ / nn / Lznz / E / Yi In accordance with the invention, a cartridge for use in an aerosol generating system is also provided; the cartridge contains a liquid nicotine formulation in accordance with the invention. The cartridge may comprise an atomizer configured to generate an aerosol from the liquid nicotine formulation. A cartridge containing the liquid nicotine formulation and an atomizer configured to generate an aerosol from the liquid nicotine formulation can be referred to as a “cartomizer”. The atomizer can be a thermal atomizer. As used herein with reference to the invention, the term “thermal atomizer” describes an atomizer configured to heat the liquid nicotine formulation to generate an aerosol. The cartridge can comprise any suitable type of thermal atomizer. The thermal atomizer may comprise a heater and a liquid transport element configured to transport the liquid nicotine formulation to the heater. The liquid transport element may comprise a capillary wick. The heater may comprise a heater coil. The thermal atomizer may include an electric heater. For example, the thermal atomizer may include an electric heater comprising a resistive heating element or an inductive heating element. Preferably, the atomizer is a non-thermal atomizer. As used herein with reference to the invention, the expression “non-thermal atomizer” describes an atomizer configured to generate an aerosol from the liquid nicotine formulation by means other than heating. The cartridge can comprise any suitable type of non-thermal atomizer. For example, a non-thermal atomizer can be an impact jet atomizer, an ultrasonic atomizer, or a vibrating mesh atomizer. In accordance with the invention, an aerosol generating system is further provided comprising a liquid nicotine formulation according to the invention and an atomizer configured to generate an aerosol from the liquid nicotine formulation. The atomizer can be a thermal atomizer. The aerosol generating system may comprise any suitable type of thermal atomizer. frza / nn / Lznz / E / Yii The thermal atomizer may comprise a heater and a liquid transport element configured to transport the liquid nicotine formulation to the heater. The liquid transport element may comprise a capillary wick. The heater may comprise a heater coil. The thermal atomizer may include an electric heater. For example, the thermal atomizer may include an electric heater comprising a resistive heating element or an inductive heating element. Preferably, the atomizer is a non-thermal atomizer. The aerosol generating system may comprise any suitable type of non-thermal atomizer. For example, a non-thermal atomizer can be an impact jet atomizer, an ultrasonic atomizer, or a vibrating mesh atomizer. The aerosol generating system may comprise: a cartridge according to the invention containing the liquid nicotine formulation; and an aerosol generating device comprising a housing that defines a device cavity configured to receive at least a portion of the cartridge. The aerosol generating system may comprise: a consumable cartridge according to the invention containing the liquid nicotine formulation; and a reusable aerosol generating device comprising a housing that defines a device cavity configured to receive at least a portion of the cartridge. The aerosol generating device may comprise a battery and electronic control components. The aerosol generating system may comprise: a cartridge according to the invention containing the liquid nicotine formulation and the atomizer; and an aerosol generating device comprising a housing that defines a device cavity configured to receive at least a portion of the cartridge. The aerosol generating system may comprise: a cartridge according to the invention containing the liquid nicotine formulation; and an aerosol generating device comprising a housing that defines a device cavity configured to receive at least a portion of the cartridge and atomizer. To avoid any doubt, the features described above with respect to one aspect of the invention may also apply to other aspects of the invention. In particular, the features described above with respect to the liquid nicotine formulation of the invention may also, where appropriate, refer to the cartridge of the invention and the aerosol generating system frza / nn / Lznz / E / Yii of the invention. Similarly, the features described above with respect to the cartridge of the invention may also relate, where appropriate, to the aerosol generating system of the invention, and vice versa. The embodiments of the invention will now be described, by way of example only, with reference to the following examples and accompanying drawings, in which: Figures 1A and 1B show the aerodynamic character size distribution of aerosols generated from a liquid nicotine composition according to the invention by using four aerosol generating systems comprising non-thermal atomizers. frZQ / nn / Lznz / E / Yi Examples Four liquid nicotine formulations were prepared in accordance with the invention (Examples A, B, C and D) having the compositions shown in Table 2. Example ABCD Nicotine (% by weight) 2.7 2.7 2.7 2 Water (% by weight) 80 60 60 31 Vegetable glycerin (% by weight) water-miscible polyhydric alcohol 8.7 25 25 31 Propylene glycol (% by weight) 1.5 4.2 4.2 0 (Water): (glycerin and polypropylene glycol) 92:10 12:5 12:5 1:1 Triacetin (% by weight) partially water-soluble solvent 0.9 2 2 0 Triethyl citrate (% by weight) 2 2 10 30 Polysorbate 80 (% by weight) 0 0 0 1 Lactic acid (% by weight) water-soluble organic acid 4.3 4.3 4.3 3 Flavorings (% by weight) 0 0 0 2 Table 2 Aerosols were generated from the liquid nicotine composition according to the invention of Example A using the four aerosol generating systems comprising non-thermal atomizers shown in Table 3. The aerodynamic particle size distributions of the aerosols were measured using a TSI Incorporated Model 3321 Aerodynamic Particle Sizer® (APS™) spectrometer. The results are shown in Figures 1A and 1B. frZQ / nn / Lznz / E / Yi Example Non-thermal aerosol generating system Example A1 Impact jet nebulizer (nozzle opening: 10 micrometers; drive force: 51 N) Example A2 OMRON Healthcare MicroAIR U100 passive mesh nebulizer (driven by 50 Vpp at 177 kHz with 2 Hz modulation; mesh hole diameter: approximately 4 micrometers; distance between mesh holes approximately 60 micrometers) Example A3 Air Wick® Essential Mist Diffuser active mesh nebulizer (120 - 180 kHz; mesh hole diameter: 4-8 micrometers) Example A4 Surface acoustic wave (SAW) device (dual motor operation with each side driven by 600 mVpp at 42.122 MHz with 500 Hz modulation) Table 3 Figure 1A shows the differential mass concentration (dM) with respect to the aerodynamic diameter (APS diameter) of the aerosols and Figure 1B shows the differential number of particles concentration (dN) with respect to the aerodynamic diameter (APS diameter) of the aerosols. As shown in Figures 1A and 1B, the use of the liquid nicotine composition according to the invention of Example A in the four aerosol generating systems 15 advantageously generates aerosols exhibiting a small droplet size.

Claims

1. A liquid nicotine formulation for use in an aerosol generating system, the liquid nicotine formulation comprising water and one or more water-miscible solvents, wherein the liquid nicotine formulation has a water content greater than or equal to approximately 30 percent by weight and a water-miscible solvent content greater than or equal to approximately 10 percent by weight, wherein the ratio of the weight percent of water content to the weight percent of water-miscible solvent content of the liquid nicotine formulation is greater than or equal to approximately 1, wherein the liquid nicotine formulation has a glycerin content greater than or equal to approximately 6 percent by weight, and wherein the liquid nicotine formulation has at least one of the following: a water content greater than or equal to approximately 45 percent by weight;and a combined content of water and water-miscible solvent greater than or equal to approximately 70 percent by weight.; 2. A liquid nicotine formulation according to claim 1 wherein the weight percent ratio of water content to weight percent of water-miscible solvent content of the liquid nicotine formulation is less than or equal to approximately 8.

3. A liquid nicotine formulation according to claim 1 or 2 wherein the weight percent ratio of water content to weight percent of water-miscible solvent content of the liquid nicotine formulation is greater than or equal to approximately 1.

5.

4. A liquid nicotine formulation according to any of claims 1 to 3 having a water-miscible solvent content less than or equal to approximately 40 percent by weight.

5. A liquid nicotine formulation according to any of claims 1 to 4 having a combined water and water-miscible solvent content of at least approximately 75 percent by weight.

6. A liquid nicotine formulation according to any of claims 1 to 5, wherein the one or more water-miscible solvents are one or more water-miscible polyhydric alcohols.

7. A liquid nicotine formulation according to any of claims 1 to 6, comprising one or more water-immiscible solvents having a solubility in water at 20 °C less than or equal to approximately 100 mg / mL, wherein the liquid nicotine formulation has a water-immiscible solvent content less than or equal to approximately 2 percent by weight.

8. A liquid nicotine formulation according to claim 7 wherein the one or more water-immiscible solvents comprise one or more partially water-soluble solvents having a water solubility at 20 °C of between approximately 20 mg / mL and approximately 100 mg / mL and one or more water-insoluble solvents having a water solubility at 20 °C less than or equal to approximately 5 mg / mL.

9. A liquid nicotine formulation according to any of claims 1 to 8 comprising one or more water-soluble organic acids, wherein the liquid nicotine formulation has a water-soluble organic acid content of at least approximately 2 percent by weight.

10. A cartridge for use in an aerosol generating system, the cartridge containing the liquid nicotine formulation in accordance with any of claims 1 to 9.

11. A cartridge according to claim 10 comprising an atomizer configured to generate an aerosol from the liquid nicotine formulation.

12. An aerosol generating system comprising: a liquid nicotine formulation according to any of claims 1 to 9; and an atomizer configured to generate an aerosol from the liquid nicotine formulation.

13. A cartridge according to claim 11 or an aerosol generating system according to claim 12, wherein the atomizer is a non-thermal atomizer.

14. A cartridge according to claim 11 or an aerosol generating system according to claim 12 wherein the atomizer is a thermal atomizer comprising a heater and a liquid transport element configured to transport the liquid nicotine formulation to the heater.