PORTABLE LOOSE-LEAF MATERIAL VAPORIZER
20220401665 · 2022-12-22
Assignee
Inventors
- Cortney Smith (Las Vegas, NV, US)
- Josh Wang (Las Vegas, NV, US)
- Markus Haller (Bad Neuenahr-Ahrweiler, DE)
- Alexander Wegener (Bad Neuenahr-Ahrweiler, DE)
- Christan HAUPTMANN (Bad Neuenahr-Ahrweiler, DE)
Cpc classification
International classification
A61M11/04
HUMAN NECESSITIES
Abstract
A portable loose-leaf material vaporizer 1 comprises a heating chamber 20 for housing loose leaf material and vaporizing one or more active agents from the loose-leaf material, a mouthpiece 3 for withdrawal of the one or more active agents vaporized from the loose-leaf material, and a processing unit. The processing unit is configured to control temperature of the heating chamber 20 and to estimate a dosage of the one or more active agents withdrawn from the vaporizer 1 based on a mathematical model. The mathematical model relates vapor generating time and loose-leaf material properties, and optionally temperature of the heating chamber 20, to the dosage of the one or more active agents withdrawn or to be withdrawn from the vaporizer 1.
Claims
1.-15. (canceled)
16. Portable loose-leaf material vaporizer comprising: a heating chamber for housing loose leaf material and vaporizing one or more active agents from the loose-leaf material, a mouthpiece for withdrawal of the one or more active agents vaporized from the loose-leaf material, and a processing unit, wherein the processing unit is configured to control temperature of the heating chamber and to estimate a dosage of the one or more active agents withdrawn from the vaporizer based on a mathematical model, wherein the mathematical model relates vapor generating time and loose-leaf material properties to the dosage of the one or more active agents withdrawn or to be withdrawn from the vaporizer.
17. The portable loose-leaf material vaporizer of claim 1, wherein the estimation is performed continuously.
18. The portable loose-leaf material vaporizer of claim 1, wherein the processing unit is configured to determine, based on the mathematical model, one or more of the following: (i) the vapor generating time until a predetermined dosage is available for withdrawal from the vaporizer and/or (ii) the temperature or temperature profile of the heating chamber so that a predetermined dosage is available within a predetermined vapor generating time for withdrawal from the vaporizer and/or (iii) the number of draws until a predetermined dosage is withdrawn from the vaporizer.
19. The portable loose-leaf material vaporizer of claim 1, wherein the processing unit is configured to stop heating of the heating chamber and/or start cooling of the heating chamber when the processing unit determines that the predetermined dosage is available for withdrawal from the vaporizer.
20. The portable loose-leaf material vaporizer of claim 1, wherein the processing unit is configured to indicate to the user when a predetermined dosage is available for withdrawal from the vaporizer.
21. The portable loose-leaf material vaporizer of claim 1, wherein the mathematical model further relates temperature of the heating chamber to the dosage of the one or more active agents withdrawn or to be withdrawn from the vaporizer.
22. A portable loose-leaf material vaporizer, comprising: a heating chamber for housing loose leaf material and vaporizing one or more active agents from the loose-leaf material, a mouthpiece for withdrawal of the one or more active agents vaporized from the looseleaf material, a processing unit, and a flow detector for detecting flow through the vaporizer, wherein the processing unit is configured to control temperature of the heating chamber, and estimate a dosage of the one or more active agents withdrawn from the vaporizer based on a mathematical model, and wherein the mathematical model relates vapor generating time and looseleaf material properties to the dosage of the one or more active agents withdrawn or to be withdrawn from the vaporizer.
23. The portable loose-leaf material vaporizer of claim 22, wherein the flow detector is arranged outside a flow path connecting the heating chamber and the mouthpiece, wherein the flow detector is preferably arranged in a dead-end branch branching from the flow path connecting the chamber and the mouthpiece.
24. The portable loose-leaf material vaporizer of claim 22, wherein the flow detector is selected from the group consisting of differential pressure sensors, capacitive air flow sensors, spinning fans/turbines, moving flap-type sensors, temperature sensors and thermal flow sensors.
25. The portable loose-leaf material vaporizer of claim 22, wherein the mathematical model further relates temperature of the heating chamber to the dosage of the one or more active agents withdrawn or to be withdrawn from the vaporizer.
26. A portable loose-leaf material vaporizer, comprising: a heating chamber for housing loose leaf material and vaporizing one or more active agents from the loose-leaf material, a mouthpiece for withdrawal of the one or more active agents vaporized from the looseleaf material, a processing unit, and a flow regulating element configured to exert one among a plurality of resistances against flow through the vaporizer, and optionally a flow detector for detecting flow through the vaporizer, wherein the processing unit is configured to, control temperature of the heating chamber, and estimate a dosage of the one or more active agents withdrawn from the vaporizer based on a mathematical model, and wherein the mathematical model preferably relates vapor generating time and looseleaf material properties and the one resistance exerted by the flow regulating element against the flow through the vaporizer, to the dosage of the one or more active agents withdrawn or to be withdrawn from the vaporizer.
27. Portable loose-leaf material vaporizer of claim 26, wherein the flow regulating element comprises a rotatable disk having at least a first section, which when rotated into a flow path of the vaporizer defines a first effective cross sectional flow area, and a second section, which when rotated into the flow path of the vaporizer defines a second effective cross sectional flow area different from the first cross sectional flow area.
28. The portable loose-leaf material vaporizer of claim 26, wherein the processing unit is further configured to control the resistance exerted by the flow regulating element against the flow through the vaporizer.
29. The portable loose-leaf material vaporizer of claim 26, further comprising: a sensor for determining the resistance exerted by the flow regulating element against the flow through the vaporizer.
30. The portable loose-leaf material vaporizer of claim 26, further comprising: one or more temperature sensors, wherein the one or more temperature sensors are preferably located adjacent to the heating chamber and/or adjacent to the mouthpiece.
31. The portable loose-leaf material vaporizer of claim 26, wherein the vaporizer further comprises: an interface for receiving sensor data and/or user input data, wherein the interface for receiving user input data is optionally a user interface.
32. The portable loose-leaf material vaporizer of claim 26, wherein the mathematical model further relates temperature of the heating chamber to the dosage of the one or more active agents withdrawn or to be withdrawn from the vaporizer.
33. The portable loose-leaf material vaporizer of claim 26, wherein the sensor data and/or user input data include one or more of the following: (i) a predetermined dosage of the one or more active agents to be withdrawn from the vaporizer; and/or (ii) a number of draws to be taken from the vaporizer; and/or (iii) the loose-leaf material properties; and/or (iv) resistance exerted by a flow regulating element against the flow through the vaporizer; and/or (v) a temperature of the heating chamber.
Description
[0083]
[0084]
[0085]
[0086]
[0087] The vaporizer comprises a housing 2, a mouthpiece 3 and a bottom cap 4 opposite of the mouthpiece 3. The mouthpiece has a shape that conforms to the lips so that users purse their lips against the mouthpiece 3, rather than placing any part of the device 1 into their mouths. This reduces the amount of saliva that is left on the mouthpiece 3 and thus transferred when in a group-sharing setting. A group of LEDs 5 is arranged in an ordered pattern on the housing 2 visibly to the users. The LEDs 5 allow to display information and are also referred to as display LEDs 5. Three buttons 6 are placed on a side of the housing 2 in order to switch the vaporizer 1 on and off, enter and navigate through the menu. In the menu, users may select different modes and input data, as disclosed herein.
[0088] The following illustrates by means of a specific example how user input data can be entered in a user interface comprised of buttons 6. When users turn on the vaporizer 1, they have two minutes to enter a so-called “Dosage Control Mode” or DCM. This mode enables the user to input the THC and CBD percentage strength, the size of their bowl, and the status of that bowl—a fresh bowl with fresh herb, a bowl that had been previously heated once, and a bowl that had been previously heated twice. Exiting DCM into regular Smart Path or Precision Temperature modes enables the device to begin calculating and displaying dose via display LEDs 5. Within the two minute window, users are able to access or re-access DCM which also informs them of the inputted values via display LEDs 5. After the 2 minutes window, DCM is no longer accessible. During each inhalation, the button LEDs will light up reacting to the inhalation while the display LEDs 5 will progressively shine more rows of lights over time. After each inhalation, the THC and CBD consumed is shown on the display 5. At the end of the session upon an 8 minute timeout or when the device 1 is turned off before then, the total consumed THC and CBD is displayed.
[0089] The vaporizer 1 further comprises an air dial 10 at the bottom cap 4 of the vaporizer 1, which is best seen in
[0090] Filling the vaporizer 1 with loose-leaf material is continued to be explained with reference to
[0091] When inhaling, ambient air flows through the slot 13 of the air dial 10 and through the inlet 7. The air then flows between the annular gap 23 formed between the pearl 22 and the inner surface of the heating chamber 20 into the heating chamber 20, where it mixes with vapor of the loose-leaf material. The mixture of air and vapor exits the heating chamber 20 through heating chamber exit 25, flows then through the flow path 30 to the outlet 35, where the mixture can be withdrawn by pressing the lips on the mouthpiece 3 and inhaling. The flow path 30 directly connects the heating chamber 20 and the mouthpiece 3.
[0092] The mouthpiece 3 can be pivoted around a pivot axis 9 away from the housing 2. Thereby, the flow path 30 can be accessed and filed with flavor material. The flow path 30 is therefore also referred to as flavor chamber 30.
[0093] A branching 40 branches from the flow path 30 so that the branching 40 is outside of the flow path 30. The branching 40 is a dead-end branch. Thereby the mixture of vapor and air does not flow through the branching 40. A flow detector 50 is arranged in the branching 40. The flow detector 50 is capable to detect whether flow through the flow path 30 occurs.
[0094] Elements that stand in contact with vapor and heat, including the heating chamber 20, are preferably made of zirconia ceramic or coated in glass—two materials that are inert and resistant to corrosion and high temperatures. High temperature silicone is preferably used to seal the flow path against leaks.
[0095] The vaporizer 1 further comprises a receptacle 60 for receiving a power source (not shown) to power the heating chamber 20 and a processing unit (not shown) as disclosed herein. The processing unit is configured to control temperature of the heating chamber 20.
[0096] Attempts to deliver accurate, real-time data regarding THC/CBD dosage are dependent on the ability for the sensors to detect THC/CBD and real-time feedback is dependent on delivery that data during an inhalation. The first issue was found in a lack of available sensors that can directly detect THC/CBD, are very small, simple, and cost-effective. Such sensors have yet to be found. As a result, a direct measurement is unobtainable. This leads to the next best option: an indirect measurement using an air sensor 50. Air sensors are reliable and economical, measuring user inhalation up to 12 seconds. Other required data points, like temperature, time, and cannabis strain data could be acquired through either the device or user input.
[0097] Accordingly, the processing unit is configured to estimate a dosage of one or more active agents withdrawn from the vaporizer 1 based on a mathematical model. The mathematical model relates vapor generating time and loose-leaf material properties, and optionally temperature of the heating chamber 20, to the dosage of the one or more active agents withdrawn or to be withdrawn from the vaporizer 1.
[0098] The development of the mathematical model for dosage estimation using an empirical approach and a mechanistic approach is described next.
[0099] A. Developing an Empirical Mathematical Model for Dosage Estimation
[0100] 1. Method Development
[0101] The consumption process of THC and CBD begins with grinding and homogenizing 0.2-0.5 g of flower into pieces typically 1.2 mm or smaller, then loading that loose-leaf material into the bowl of their device, and finally compacted using a finger or tool. The device is turned on and the bowl heats, beginning decarboxylation or the conversion of THCA and CBDA into THC and CBD respectively. As described herein, temperature and time are assumed to be the primary driving element for decarboxylation and vaporization. The form of THCA and CBDA decarboxylation is taken to be an exponential decay with lower temperatures leading to slower decay and higher temperatures leading to faster decay. Ideal decarboxylation efficiencies of 99.9% and 99.8% for THC and CBD, respectively, is expected within 4 minutes at 410° F., although realistic results will vary due to cooling from inhalations.
[0102] As the temperature of the loose-leaf material rises, cannabinoids vaporize into the voids between the loose-leaf particulate. If the user does not inhale, then vapor pressure equilibrium is reached. If the user inhales, then the vaporized cannabinoids are evacuated from the bowl and the heated plant matter is cooled by the in-flowing air. Decarboxylation and vaporization do not stop as a result of this cooling, but their rates do drop considerably the longer the inhalation. Temperature and time are therefore assumed to be the primary driving element for these processes, within reasonable normal use. The form of THCA and CBDA decarboxylation is taken to be an exponential decay with lower temperatures leading to slower decay and higher temperatures leading to faster.
[0103] Implementing a dosage algorithm to capture this decarboxylation and vaporization begins in hardware selection. As a starting point, if THC and CBD are present in vapor, then the vapor should be the measurement target. However, direct measurement of vapor is highly improbable given the size and cost constraints of the project. An indirect measurement is therefore the next best option, but that carries its own challenges. Related values such as vapor temperature, flow rate, pressure, and so on are unobtainable as the appropriate sensors are too fragile or too large. One value that is regularly known is the composition of the input material via user input. Another value is the timing as well as duration of each inhalation via a draw or flow sensor. With these two values, a mathematical model can be created to relate input loose-leaf material properties and operating conditions to an output dosage.
[0104] Two key assumptions are made: first that all THC and CBD vaporized within the device leaves the device and second that an average loose-leaf cannabis and an average user can be used to create the model. While no cannabis strain nor user adheres perfectly to the average, both assumptions are made to reduce the complexity of the model, while at the same time allowing a good estimate on the dosage. Environmental factors such as air temperature and so on are assumed to be negligible for the average use case.
[0105] As the model is based on indirect measurement, a critical component of that model is a reference table created from empirical testing and data. That table would be based on a production rate of THC and CBD. The model would therefore output the THC and CBD produced at a certain time, at a certain temperature, under specific operating conditions. Any amount of THC and CBD produced therefore would also be the amount of THC and CBD consumed. Measuring how much THC and CBD is produced can be conducted by measuring the amount of THC and CBD lost within heated loose-leaf material. An additional benefit of measuring heated material is that the effects from decarboxylation are inherently included within the data.
[0106] Other considerations such as the decarboxylation efficiency, distribution of THC and CBD in vapor vs. residue, and effects due to an airflow control valve (air dial) built into the device would also be explored, though ultimately decided to be negligible.
[0107] The Initial Algorithm Follows:
[A]×[B]×[C]×[D]×[E]=[THCand CBD produced] (1)
[0108] where [A] is the mass of the loose-leaf material, [B] is the percentage concentration of THC and CBD present, [C] is the reference table production rate and based on temperature and time conditions, [D] is the inhalation duration, [E] represents any other effects that might be discovered during testing.
[0109] Additionally, only [C] is a reference-based value whereas all other variables are either fixed or measured by sensors.
[0110] 2. Hypothesis
[0111] There were 3 Hypotheses Tested:
[0112] #1: The amount of THC and CBD lost within heated loose-leaf material is affected by temperature, time, and inhalation duration. Changing those variables will change the lost amount, thus the produced amount, thus the consumed amount.
[0113] #2: The amount of THC and CBD lost within heated loose-leaf material is affected by the time it spends being heated, but not inhaled. Changing that variable will change the amount available for consumption.
[0114] #3: The amount of THC and CBD lost within heated loose-leaf material is affected by flow rate and pressure caused by the ‘air dial’ feature. Changing the air dial setting will change the flow rate and pressure, thus changing the list amount.
[0115] These hypotheses would be tested in 3 phases: a preliminary phase using averaged human parameters to explore hypothesis #3 and provide initial data for hypothesis #1 and #2, a primary phase using averaged human parameters to explore hypothesis #1 and #2, and a final phase using real human subjects to adjust the reference table.
[0116] 3. Testing and Data Analysis
[0117] 3.1 Procedures
[0118] For Phase 1 and Phase 2, the procedures focused on preparing samples of heated loose-leaf material for the lab to test. Phase 3 focused on surveying users and then adjusting numerical values to better reflect user feedback.
[0119] 3.2 Materials
[0120] The materials used for testing can be categorized as cannabis, equipment, and sample containment. In each phase of testing, one batch of cannabis flower (sativa, 20-30% THC, 0-1% CBD) was purchased at local dispensaries and used for testing. Equipment consisted of a grinder, pump, tubing, and other hardware needed to expedite sample preparation during Phase 1 and Phase 2. Sample containment consisted or containers used to house the cannabis flower as well as transport heated loose-leaf material to the testing lab.
[0121] 3.3 Testing Phase 1: Preliminary
[0122] The goals of preliminary testing were to determine the parameters of an average user, troubleshoot the procedures, test hypothesis #3, and obtain initial data for hypothesis #1 and #2 with the intent of condensing the scope of the primary testing phase. Early forecasts placed test quantities of 150-200 samples in the primary testing phase alone, which would be a significant cost for the project. Each of these goals were fulfilled, though many opportunities for improvement are present—See Discussion section.
[0123] The average user was determined through an informal, internal survey. 6 test subjects were surveyed where each would be given an IQ device, cannabis flower, and then asked to “vape” as they would normally across a light, medium, and heavy inhalation. The inhalations and delay between inhalations were observed and timed. Additionally, each test subject self-rated their THC tolerance. The IQ device was chosen. The results of this survey are listed below in Table 1.
TABLE-US-00001 TABLE 1 Internal Survey on the Determination of Standard User Parameters Inhalation Parameters Light Average Delay Flower Toler- (sec- (sec- (sec- User Used (g) ance onds) Medium Heavy onds) onds) LT 0.3 Light 2.17 2.05 2.82 2.23 18.96 RM 0.4 Medium 7.74 6.93 10.01 8.23 5.69 HM 0.3 Medium 2.62 2.09 5.44 3.38 10.43 MB 0.4 Heavy 2.23 3.93 8.74 4.97 8.66 PM 0.3 Heavy 3.72 7.45 16.19 9.12 N/A JB 0.4 Heavy 6.21 6.19 8.84 7.08 25.88 Average 5.85 13.92
[0124] From Table 1, the average inhalation time was rounded from 5.85 seconds to 6 seconds and the average delay between inhalations was rounded from 13.92 seconds to 14 seconds to result in a draw frequency of 3 draws per minute. Using this data, 5 samples were prepared and submitted to the lab. The condition as well as the lab result for each of the samples are listed below in Table 2.
TABLE-US-00002 TABLE 2 Comparison of THC and CBD Loss between Air Dial Settings and Runtimes - Preliminary Test Results Obtained via LCMS Testing Sample 25% Air 100% Air 25% Air 100% Air Dial Dial Dial Dial 8 min 8 min 16 min 16 min Cannabinoid* Control runtime runtime runtime runtime Total 19.620 17.249 16.714 14.282 15.910 THC (%) THCA** 21.066 8.266 6.634 4.872 5.749 Δ9-THC 1.145 10.000 10.896 10.009 10.868 CBDA** 1.635 1.635 <LOQ <LOQ <LOQ CBD <LOQ <LOQ <LOQ <LOQ <LOQ *Other cannabinoids such as Δ8-THC, CBN, and so on are omitted as they are not of interest for this report and also tested below the Limit of Quantitation (<LOQ). **THCA and CBDA both mostly convert into Δ9-THC and CBD, respectively.
[0125] Due to the bare CBD data, only the THC data was usable. By determining the Total THC loss over time and across Air Dial settings, the effect of the Air Dial can be determined. Since the difference between settings was about +0.4%/−0.5% and there being such a small sample size (sample size=5), this result was determined to be unreliable. However, it was decided to be negligible and thus removed from consideration for further testing since the little data present showed a nearly insignificant difference between settings. This decision disproved hypothesis #3.
[0126] By visualizing the Total THC loss overtime, as well as the Total THC produced, the beginnings of the mathematical model are created—the model originates from THC loss in the heated loose-leaf material, equates to the THC gain in the vapor, and ultimately the slope of that gain is found to determine production rate.
[0127] 3.4 Testing Phase 2: Primary
[0128] The goals of primary testing are to test hypothesis #1 and #2, thereby creating the reference table and explore the difference between inhalation frequencies. Following the preliminary testing, the test quantity required for the primary phase was reduced from an estimated 150-200 samples down to 66 samples for the reference table. However, only 43 of the 66 samples could be tested as the remainder was reallocated to exploring other considerations. The empty data points between the test samples were interpolated. The goals of this section can also be considered fulfilled, but one step was made that requires further exploration—See Discussion section.
[0129] A total of 59 samples were submitted to the testing lab. These samples were prepared across the range of temperatures allowed by the IQ device—from a room temperature of 70° F. up to a maximum of 430° F.—and across the range of times most commonly used—up to 24 minutes of continuous use. Temperature and usage time are inversely related where the hotter a user vapes, the less time they will vape for as vapor flavor will rapidly begin to deteriorate. The data points relevant to the reference table are listed below in Table 3.
TABLE-US-00003 TABLE 3 THC Loss Over Time at a Range of Temperatures Temperature 70 Time (° F.) 310 350 370 390 410 430 0 0.2094 Same as control** (sec- onds) 60 Same as 0.22414 0.23383 0.23065 0.23357 0.23266 0.22180 120 control * * * 0.21442 0.23846 0.23583 240 0.20373 0.22124 0.22701 0.20137 0.19082 0.19059 360 * * * 0.18504 0.18337 0.17198 480 0.21378 0.18400 0.20764 0.18675 0.16611 0.16050 600 * * * 0.16460 0.16913 0.15810 720 * * * 0.17318 * * 840 0.22513 0.17915 0.19567 0.16993 0.18206 0.15920 960 * * * 0.17888 * * 1200 * * * 0.16349 * * 1400 0.20492 0.17749 0.17398 0.17326 0.14072 0.15525 *Data points marked with (*) were omitted from testing due to tack of available budget. These points were chosen based on which temperatures users most commonly used and disused. **“Same as control” indicates the data point for 0 seconds/70° F.
[0130] In order to process the values into usable data, some adjustments are required to account for variations in sample size and then generalizations and smoothing. The result represents the THC Loss, in percentage, for any input cannabis loose-leaf material if the initial conditions are close to that of the average user. Outlier conditions may exist, but this model provides a starting point for modifications to the model in later design iterations. Inverting the data converts the values from THC loss in heated loose-leaf material to THC gain in vapor. The results represent the THC gain of vapor, in percentage, for any input cannabis loose-leaf material if the initial conditions are close to that of the average users and their flower. An assumption is made here in that THC gain will be the same for any amount of THC present and available in flower whether 0.5% or 30%.
[0131] Two additions were made that revised the size of the reference table's data ranges, namely: [0132] (i) 11 time ranges increased to 12 time ranges to give greater clarity to the first minute of heating. [0133] (ii) 6 temperature ranges increased to 7 temperature ranges to give greater clarity to the 350-430° F. temperature ranges where most users would be most active.
[0134] The blank values where interpolated, and the slope found. An arbitrary coefficient of 30 was multiplied as well to allow to scale the entire table up or down based on user feedback later. The adjusted values are listed below in Table 4. The unit of this table can be expressed as either % THC per second or second{circumflex over ( )}−1.
TABLE-US-00004 TABLE 4 THC Production Rate Temperature Range Floor 250 290 310 350 370 390 410 Ceiling Time Range 289 309 349 369 389 409 430 0 29 0.00050 0.00071 0.00420 0.00556 0.00733 0.00779 0.00864 30 59 0.00070 0.00222 0.00720 0.01111 0.01476 0.01557 0.01727 60 119 0.00222 0.00385 0.00702 0.00966 0.01112 0.01200 0.01300 120 239 0.00235 0.00354 0.00599 0.00771 0.00811 0.00852 0.00900 240 359 0.00221 0.00279 0.00435 0.00501 0.00522 0.00622 0.00700 360 479 0.00118 0.00245 0.00350 0.00391 0.00420 0.00437 0.00500 480 599 0.00111 0.00235 0.00332 0.00301 0.00388 0.00333 0.00388 600 719 0.00105 0.00210 0.00249 0.00255 0.00266 0.00298 0.00288 720 839 0.00090 0.00151 0.00179 0.00205 0.00225 0.00267 0.00211 840 959 0.00083 0.00137 0.00166 0.00176 0.00201 0.00232 0.00205 960 1199 0.00063 0.00113 0.00126 0.00112 0.00137 0.00157 0.00198 1200 1440 0.00053 0.00101 0.00075 0.00085 0.00095 0.00101 0.00155
[0135] CBD production rate can be found with the same process and tested for concurrently with THC. Both flower strains purchased at the dispensary for Phase 1 and Phase 2 testing listed 0.30-0.50% CBD which would have been detectable even after heating, except the control samples tested at 0.00% CBD. As a temporary measure, the CBD production rate table was decided to be adapted from the THC production rate table and then retested for later.
[0136] The adaptation from THC to CBD production rate consisted of shifting columns by 5.8%: for the temperature ranges below the boiling point of CBD, they would be shifted down by 5.8% which those ranges above would be shifted up by 5.8%. This assumes that CBD production rate is less active at cooler temperatures and more active at higher temperatures on either side of its boiling points. The result of adapting THC to CBD production rates is listed below in Table 5.
TABLE-US-00005 TABLE 5 CBD Production Rate Temperature Range Floor 250 290 310 350 370 390 410 Ceiling Time Range 289 309 349 369 389 409 430 0 29 0.00047 0.00067 0.00396 0.00588 0.00781 0.00824 0.00913 30 59 0.00066 0.00209 0.00678 0.01175 0.01561 0.01647 0.01827 60 119 0.00209 0.00363 0.00661 0.01022 0.01176 0.01269 0.01375 120 239 0.00221 0.00334 0.00564 0.00616 0.00858 0.00901 0.00952 240 359 0.00208 0.00263 0.00410 0.00530 0.00552 0.00658 0.00741 360 479 0.00111 0.00231 0.00330 0.00413 0.00444 0.00463 0.00529 480 599 0.00105 0.00221 0.00313 0.00318 0.00410 0.00352 0.00410 600 719 0.00099 0.00198 0.00235 0.00270 0.00281 0.00315 0.00305 720 839 0.00085 0.00142 0.00169 0.00217 0.00238 0.00282 0.00223 840 959 0.00078 0.00129 0.00156 0.00186 0.00213 0.00245 0.00217 960 1199 0.00059 0.00106 0.00119 0.00118 0.00145 0.00166 0.00209 1200 1440 0.00050 0.00095 0.00071 0.00090 0.00100 0.00107 0.00164
[0137] Two additional variables were investigated: “Draw Capture” and “Resting Loss”. Draw capture is an application of hypothesis #1 to the inhalation itself, where the production rate will change at each second of the inhalation. Resting loss represents the effect of hypothesis #2, in which prolonged heating can cause THC to either escape the device or decompose into other compounds. Resting loss is only significant to a degree in longer duration use sessions as a majority of the initial few minutes of every session is spent decarboxylating THCA into THC. Each of these variables were investigated in the same way as THC production rate, but the samples were prepared differently.
[0138] For draw capture, the timing of the inhalations used during sample preparation was changed from a 6-second inhalation every 20 seconds to 5/10/17-second inhalations every 30 seconds. These samples were tested at 390° F. The loss was compared between time and then interpolated out to its own reference table. This draw capture loss rate is listed below in Table 6.
TABLE-US-00006 TABLE 6 Draw Capture Rate Time Range Floor Ceiling Modifier 0 0.9 1.00000 1 1.9 1.00000 2 2.9 0.94393 3 3.9 0.88785 4 4.9 0.83178 5 5.9 0.77571 6 6.9 0.71963 7 7.9 0.66356 8 8.9 0.60748 9 9.9 0.55141 10 16.9 0.49534 17 99*.sup. 0.10282
[0139] For resting loss, loose-leaf material was loaded into the IQ device and baked for an amount of time. These samples were tested at 390° F. The results were evaluated and when the loss rate was used where the rate change reached closer to steady state. This resting loss rate is listed below in Table 7.
TABLE-US-00007 TABLE 7 Resting Loss Time Range Floor Ceiling Modifier 0 14 1.00000 15 29 0.99286 30 44 0.98572 45 59 0.97858 60 119 0.97144 120 239 0.94287 240 480 0.88575 481 960 0.77150 961 1440 0.54300
[0140] The results in Table 4 through Table 7 conclude Phase 2 testing and modifications are made to Equation 1 such that the modified algorithm follows:
[A]×[B]×[C]×[D]×[E]×[F]×[G]=[THCand CBD produced per sec.] (2)
[0141] Where [A] is the mass of the loose-leaf material, [B] is the percentage concentration of THC and CBD present. [C] is the reference table production rate and based on temperature and time conditions, [D] is the inhalation duration of 1 second, [E] is the reference table draw capture modifier, [F] is the reference resting loss modifier, [G] is a reference “depletion state” modifier.
[0142] The depletion state modifier is a failsafe measure to prevent the THC and CBD produced per session from exceeding the theoretical maximum THC and CBD producible, which is simple and easy to calculate. For example, a user has 0.2 g of cannabis flower at 20% THC, yielding 40 mg of THC. If the session THC is 50 mg when only 40 mg is available, then end users will cast doubt onto the validity of the mathematical model. This modifier is rarely used for loose-leaf material—it is more prevalent with concentrates. When the calculated session dose is less than the theoretical maximum dose, this value is set equal to 1. When the dose exceeds maximum, this value is set equal to 0.01.
[0143] The firmware and/or mobile application would handle how additional values are calculated and displayed such as THC and CBD produced per inhalation. THC and CBD produced per session, and other historical data points.
[0144] 3.5 Testing Phase 3: Final
[0145] The goal of final testing is to adjust the reference tables using real human test subjects.
[0146] A total of 5 subjects were used in this testing phase. Each subject was asked to “vape” at regular intervals (5 second inhalations every 30 seconds). The dose per inhalation from Equation 2 is recorded and then compared to both user expectation and vapor density expelled after each inhalation. While not entirely scientifically reasonable, the market holds the perception that denser vapor and larger vapor clouds equates to a higher high.
[0147] As a result of the adjustment, Table 4 through Table 6 are revised to Table 7 through Table 10 below.
TABLE-US-00008 TABLE 7 THC Production Rate Temperature Range Floor 250 290 310 350 370 390 410 Ceiling Time Range 289 309 349 369 389 409 430 0 29 0.00008 0.00012 0.00073 0.00111 0.00253 0.00350 0.00475 30 59 0.00023 0.00078 0.00288 0.00556 0.00959 0.01246 0.01468 60 119 0.00100 0.00183 0.00351 0.00676 0.00873 0.01020 0.01170 120 239 0.00118 0.00195 0.00359 0.00694 0.00750 0.00809 0.00378 240 359 0.00166 0.00223 0.00370 0.00501 0.00522 0.00622 0.00700 360 479 0.00104 0.00221 0.00333 0.00391 0.00420 0.00437 0.00500 480 599 0.00105 0.00229 0.00332 0.00301 0.00388 0.00333 0.00388 600 719 0.00105 0.00210 0.00249 0.00255 0.00266 0.00298 0.00288 720 839 0.00090 0.00151 0.00188 0.00205 0.00225 0.00267 0.00211 840 959 0.00083 0.00140 0.00174 0.00176 0.00201 0.00232 0.00205 960 1199 0.00064 0.00119 0.00139 0.00112 0.00137 0.00157 0.00198 1200 1440 0.00056 0.00107 0.00075 0.00085 0.00095 0.00101 0.00155
TABLE-US-00009 TABLE 8 CBD Production Rate Temperature Range Floor 250 290 310 350 370 390 410 Ceiling Time Range 289 309 349 369 389 409 430 0 29 0.00007 0.00012 0.00073 0.00118 0.00273 0.00371 0.00502 30 59 0.00022 0.00073 0.00271 0.00588 0.01015 0.01318 0.01553 60 119 0.00094 0.00172 0.00331 0.00715 0.00923 0.01079 0.01238 120 239 0.00111 0.00183 0.00339 0.00734 0.00794 0.00856 0.00928 240 359 0.00156 0.00210 0.00348 0.00530 0.00552 0.00658 0.00741 360 479 0.00098 0.00208 0.00313 0.00413 0.00444 0.00463 0.00529 480 599 0.00099 0.00216 0.00313 0.00313 0.00410 0.00352 0.00410 600 719 0.00099 0.00198 0.00235 0.00270 0.00281 0.00315 0.00305 720 839 0.00085 0.00142 0.00177 0.00217 0.00238 0.00282 0.00223 840 959 0.00078 0.00132 0.00164 0.00186 0.00213 0.00245 0.00217 960 1199 0.00061 0.00112 0.00131 0.00113 0.00145 0.00166 0.00209 1200 1440 0.00052 0.00100 0.00071 0.00090 0.00100 0.00107 0.00164
TABLE-US-00010 TABLE 3 Draw Capture Rate Time Range Floor Ceiling Modifier 0 0.9* 1.00000 1 1.9 1.00000 2 2.9 0.94393 3 3.9 0.88785 4 4.9 0.83178 5 5.9 0.77571 6 6.9 0.71963 7 7.9 0.66356 8 8.9 0.60748 9 9.9 0.55141 10 16.9* 0.49534 17 99*.sup. 0.10282 *Part of these time ranges are invalid due to the 12-second limitation of the air sensor. They have no impact on the result
TABLE-US-00011 TABLE 10 Resting Loss Time Range Floor Ceiling Modifier 0 14 1.00000 15 29 0.99286 30 44 0.98572 45 59 0.97858 60 119 0.97144 120 239 0.94287 240 480 0.88575 481 960 0.77150 961 1440 0.54300
[0148] 3.6 Mathematical Model
[0149] Phase 3 testing did not influence the structure of the mathematical model, only the numerical values in the reference tables. As a result, Equation (2) stands as the most current algorithm, where [A] is the mass of the loose-leaf material, [B] is the percentage concentration of THC and CBD present, [C] is the reference table production rate and based on temperature and time conditions (See Table 7 for THC and Table 8 for CBD), [D] is the inhalation duration of 1 second, [E] is the reference table draw capture modifier (See Table 9), [F] is the reference resting loss modifier (See Table 10), [G] is a reference depletion state modifier.
[0150] 4. Conclusion and Discussion
[0151] This report represents an approach into the determination of precision dosing for loose-leaf cannabis. Other devices that claim to dose use pre-measured containers of cannabis oil, limiting their heating mechanisms by an approximation of mass loss and thus cannabinoid consumption. By departing from that dosing method, the mathematical model gives a framework to build from that is flexible for a variety of use cases and economical in the hardware it uses. The behavior of THC and CBD confirmed expectations. Cooler temperatures led to both slower decarboxylation and vaporization while hotter temperatures led to faster activity.
[0152] The results of Phase 1 and Phase 2 testing were particularly revealing, in that about 40-50% of THC was removed from the loose-leaf material across a 24-minute time range. Later surveys and observations during Phase 3 indicated that an inhalation frequency of 3 inhalations per minute was much higher than normal for the average use case, and high even for a shared setting. As the temperature of the loose-leaf material reached steady-state equilibrium with the consistent inhalations, the decarboxylation of THCA slowed significantly with about 4% THCA remaining unconverted and about 12.5% THC available, but unvaporized due to the constant cooling. A variation of the testing would look like repeating the tests for a single user and a group of users and changing the inhalation frequency to be more reasonable. Overall, the model follows behavior set by previous studies.
[0153] B. Developing a Mechanistic Mathematical Model for Dosage Estimation
[0154] 1. Decarboxylation of Medical Cannabis
[0155] THCA is found in abundance in growing and harvested cannabis and is a biosynthetic precursor of THC. THCA is converted into THC when heat is added (known as decarboxylation or activation). The conversion is a naturally occurring chemical reaction, the rate of which is greatly increased at higher temperatures. The released carboxylic acid group is converted to CO2 gas during the process.
[0156] THC activation is a mathematical calculation to determine what percentage of the combined THCA & THC molecules is in the activated THC form. To do this, we use the following equation:
THC Activation=THC value/(THC value+THCA value)*100% (3)
[0157] Decarboxylation of THCA into THC starts at 90° C. At 100° C. it takes 3 hours to convert THCA fully into THC. At 160° C. it takes 10 Minutes to convert THCA fully into THC. At 200° C. it takes seconds to convert THCA fully into THC.
[0158] Starting from 157° C. THC evaporates. The point of CBD is 180° C. Because of the small quantities of THC and CBD that evaporate, it can be assumed, that the already decarboxylated amounts of THC and CBD immediately evaporate and that any newly produced THC and CBD also immediately are available in the gaseous phase. Evaporation stops immediately, once the temperature is reduced to values below the boiling points.
[0159] The volume of evaporated THC and CBD needs to be defined. If 1 gram of herbal cannabis type bediol with 6.3% total THC and 8% total CBD is decarboxylated and evaporated, 63 mg THC and 80 mg CBD are produced. The molar mass is 314.469 g/mol for THC and 314.464 g/mol for CBD, therefore, if can be assumed that both components have the same molar mass of 314.5 g/mol.
[0160] The total of 0.143 g of THC and CBD correspond to 0.000455 mol of active components. If we assume that the vaporized THC and CBD can be treated as ideal gas, one mol would be a volume of 22,4 litres. Therefore, the THC and CBD contained in 1 gram of BEDIOL corresponds to 10.2 cm.sup.2.
[0161] During decarboxylation and vaporization typically only 25% of active components are vaporized for one draw (four draws per charge). If the total volume of the vapor path is larger than 2.5 cm.sup.2 it could be assumed that no active components leaves the vapor path.
[0162] Some articles report, that only 67% THCA was converted to THC, because of side reactions (THCA and THC to CBNA and CBN). It is also reported, that the total mass of THCA/THC or CBDA/CBD is reduced after decarboxylation. Degradation of THC to CBN starts at 85° C. E.g. optimal conversion of THCA to THC was observed for a temperature of 150° C. For higher temperatures side products like CBN (Cannabinol) result and conversion rate is lowered. According to a further report, during smoking a joint, most THC is destroyed and the consumer can take up only about 30% of the active substance.
[0163] The total mass of the products (e.g. THCA & THC or CBDA & CBD) after such a decarboxylation reaction is reduced compared to the initial mass. The reduction was reported to be 7.94% for THCA/THC and 18.05% and 13.75% for CBDA/CBD and extracts and pure standard material, respectively.
[0164] The relationship between the rate of the decarboxylation reaction d[C]/dt concentration of acidic cannabinoids [C] can be expressed by Eq. 3 or the alternative Eq. 4:
D[C]/dt=−k*[C]
In([C].sub.0/[C].sub.t)=k*t (4)
[0165] where k presents the rate constant, and [C].sub.0 and [C].sub.t are the concentrations of reactants at time 0 and t min. respectively.
[0166] The activation energy, E.sub.A, which indicates the minimum energy for the reaction to occur, can be determined from the temperature dependence of the rate constant by the so-called Arrhenius equation, Eq. 5:
In k=In k.sub.0−E.sub.A/(R*T)
[0167] where k.sub.0 is the frequency factor and R is the gas constant.
[0168] For THCA, the following values have been published:
[0169] E.sub.A=84.8 kJ/mol with k.sub.0=3.7*10.sup.8 sec.sup.−1. Experiments were reproduced by others resulting in the values E.sub.A=88 kJ/mol with k.sub.0=8.7*10.sup.8 sec.sup.−1. E
[0170] For CBDA corresponding experimental values for the rate constant can be found. This allows calculating the amount of acidic cannabinoids that was already decarboxylated.
TABLE-US-00012 TABLE 11 Rate constants k (times 10.sup.3) [sec.sup.−1] Activation Energy Reactant 80° C. 95° C. 110° C. E.sub.A [kJ/mol] THCA 0.18 0.66 1.83 88 CBDA 0.05 0.27 0.83 112
[0171] The rate constant of CBDA is nearly always approximately 50% of the rate constant of THCA. Using Arrhenius' law, the following values for the activation energy results E.sub.A=98.51 kJ/mol and k.sub.0=2.24*10.sup.10 sec.sup.−1.
[0172] These derived values of E.sub.A and k.sub.0 can be used to calculate the k-values for higher temperatures, which allows to calculate the conversion of THCA to THC and CBDA to CBD at higher temperatures as typically used in vaporizers.
TABLE-US-00013 TABLE 12 Rate constants k (times 10.sup.3) [sec.sup.−1] Reactant 80° C. 95° C. 110° C. 130° C. 150° C. 170° C. 190° C. 210° C. 230° C. THCA 0.18 0.66 1.83 5.55 18.78 56.90 156.63 396.50 932.31 CBDA 0.05 0.27 0.83 3.83 15.35 54.34 172.44 497.34 1318.58
[0173] A value of k=693 sec.sup.−1 means that 50% of the acidic cannabinoids is decarboxylated within one second, which is the case for temperatures around 210° C. A value of k=10 sec.sup.−1 means that only 1% of the acidic cannabinoids is decarboxylated within one second.
[0174] To result in a decarboxylation of 25% of the acidic cannabinoids (e.g. to release the amount of active components for one draw) it would be sufficient to heat the herbal cannabis up to 170° C. where k-values of approx. 55 results. With such a k-value it takes only 5 seconds to convert 25% of the acidic components. Since the temperature is above the boiling point of THC and CBD it could be assumed, that after 5 seconds the 25% of contained active components are ready to be delivered to the patient and the herbal cannabis needs to be cooled down immediately.
[0175] If the same temperature would be used prior to the next draws, the time when the next 25% of active components are ready for the next draw increases, since the initial amount of acidic components is already reduced (to 75, 50, 25%). The time prior to the second draw increases to 7.5 seconds, for the third draw to 12.5 seconds and for the fourth draw to >40 seconds.
TABLE-US-00014 TABLE 13 Calculated time for delivery of approx. equal amounts of active components for each draw at a constant temperature. Constant temperature Temperature [° C.] Time to be ready [sec] Draw 1 170 5 Draw 2 170 7.5 Draw 3 170 12.5 Draw 4 170 >40
[0176] Alternatively, the temperature used prior to the second, third and fourth draw can be increased to result in the same time to be ready. The following k-values would be needed to convert 25% or active components within 5 seconds, 55, 80, 140 and 1000, which corresponds to the following temperatures: 170° C., 176.5° C. 187.7° C. and 230° C.
TABLE-US-00015 TABLE 14 Target temperatures for a temperature profile delivering approx. equal amounts of active components for each draw. Constant time to be ready k-value [sec.sup.−1] Temperature [° C.] Draw 1 55 170 Draw 2 80 176.5 Draw 3 140 187.7 Draw 4 1000 230
[0177] Such temperatures would be the starting points for the temperature profiles resulting in the delivery of equal amounts of active components for each draw.
[0178] The calculated k-values were used to calculate the THCA/CBDA and THC/CBD content resulting from an initial, not optimized temperature profile. The temperature was increased from 170° C., 176° C. 186° C. and 230° C. for the four drawing cycles. The raise time (heating up) was assumed to be 1° C. per 0.1 seconds, the cooling caused by the fresh air going through the heating chamber (turned off) was assumed to be 5° C. per 0.1 seconds. The resulting k-values for the decarboxylation of THCA and CBDA was calculated. The THCA and CBDA content was reduced by approx. 25% for each draw cycle. The produced THC and CBD was calculated and was increasing by approx. 25% prior to each draw. When the temperature was increased above the boiling point of THC (157° C.) and CBD (180° C.) the produced THC and CBD was released into the air and can be consumed by the patient via a draw.
[0179] Since the boiling point of CBD is above the maximal temperatures of the first two draws, all CBD is still bound within the herbal cannabis. During the heating phase of the third draw (up to 186° C.) the boiling point of CBD is reached and all bound CBD is released. Therefore, the amount of CBD in the four draws is different: the CBD content in the first two draws is close to zero, while the third draw contains nearly 75% of the available CBD and the fourth draw contains 25% of CBD. All four draws contain approx. 25% of THC.
[0180] Several assumptions and simplifications were made, which need to be validated and tested for a specific vaporizer. E.g. the temperature raise time needs to be adapted to the configuration of the heating chamber and the temperature drop caused by a draw needs to be evaluated by a corresponding experiment. Further, the calculated and used k-values need to be validated by appropriate experiments.
[0181] 2. Mathematical Model
[0182] In a next step, a simulation model using these rate constants k is built, which enables to calculate the total amount of THC and CBD after a certain time at a given temperature. Such a model ideally considers the following points: [0183] (i) Because of continuous temperature increase (e.g. from room temperature to target temperature) the integral over time of the heat mediated decarboxylation should be evaluated, for each temperature the calculated k-value needs to be used (see above). [0184] (ii) Because of the inhomogeneous temperature profile within the heated herbal cannabis, also an integration over space could be evaluated. [0185] (iii) Degradation of THC and CBD within the herbal cannabis needs to be considered by limiting the total amount of converted THC to 70% [0186] (iv) The actual vaporization of THC/CBD starts at 157° C./180° C. and makes the active components immediately available to be inhaled.
[0187] Such a model with its various assumptions (immediate vaporization, extrapolated k-values etc.) is then validated and, if necessary, adjusted by real measurements.