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Cannabis Manufacturing Considerations: From Raw Materials to Finished Goods

By David Vaillencourt, Kathleen May
2 Comments

Facility layout and design are important components of overall operations, both in terms of maximizing the effectiveness and efficiency of the process(es) executed in a facility, and in meeting the needs of personnel. Prior to the purchase of an existing building or investing in new construction, the activities and processes that will be conducted in a facility must be mapped out and evaluated to determine the appropriate infrastructure and flow of processes and materials. In cannabis markets where vertical integration is the required business model, multiple product and process flows must be incorporated into the design and construction. Materials of construction and critical utilities are essential considerations if there is the desire to meet Good Manufacturing Practice (GMP) compliance or to process in an ISO certified cleanroom. Regardless of what type of facility is needed or desired, applicable local, federal and international regulations and standards must be reviewed to ensure proper design, construction and operation, as well as to guarantee safety of employees.

Materials of Construction

The materials of construction for interior work surfaces, walls, floors and ceilings should be fabricated of non-porous, smooth and corrosive resistant surfaces that are easily cleanable to prevent harboring of microorganisms and damage from chemical residues. Flooring should also provide wear resistance, stain and chemical resistance for high traffic applications. ISO 22196:2011, Measurement Of Antibacterial Activity On Plastics And Other Non-Porous Surfaces22 provides a method for evaluating the antibacterial activity of antibacterial-treated plastics, and other non-porous, surfaces of products (including intermediate products). Interior and exterior (including the roof) materials of construction should meet the requirements of ASTM E108 -11, Standard Test Methods for Fire Tests of Roof Covering7, UL 790, Standard for Standard Test Methods for Fire Tests of Roof Coverings 8, the International Building Code (IBC) 9, the National Fire Protection Association (NFPA) 11, Occupational Safety and Health Administration (OSHA) and other applicable building and safety standards, particularly when the use, storage, filling, and handling of hazardous materials occurs in the facility. 

Utilities

Critical and non-critical utilities need to be considered in the initial planning phase of a facility build out. Critical utilities are the utilities that when used have the potential to impact product quality. These utilities include water systems, heating, ventilation and air conditioning (HVAC), compressed air and pure steam. Non-critical utilities may not present a direct risk to product quality, but are necessary to support the successful, compliant and safe operations of a facility. These utilities include electrical infrastructure, lighting, fire detection and suppression systems, gas detection and sewage.

  1. Water
Microbial monitoring methods can include frequent/consistent testing

Water quality, both chemical and microbial, is a fundamental and often overlooked critical parameter in the design phase of cannabis operations. Water is used to irrigate plants, for personnel handwashing, potentially as a component in compounding/formulation of finished goods and for cleaning activities. The United States Pharmacopeia (USP) Chapter 1231, Water for Pharmaceutical Purposes 2, provides extensive guidance on the design, operation, and monitoring of water systems. Water quality should be tested and monitored to ensure compliance to microbiological and chemical specifications based on the chosen water type, the intended use of the water, and the environment in which the water is used. Microbial monitoring methods are described in USP Chapter 61, Testing: Microbial Enumeration Tests 3and Chapter 62, Testing: Tests for Specified Microorganisms 4, and chemical monitoring methods are described in USP Chapter 643, Total Organic Carbon 5, and Chapter 645, Water Conductivity 6.Overall water usage must be considered during the facility design phase. In addition to utilizing water for irrigation, cleaning, product processing, and personal hygiene, water is used for heating and cooling of the HVAC system, fogging in pest control procedures and in wastewater treatment procedures  A facility’s water system must be capable of managing the amount of water required for the entire operation. Water usage and drainage must meet environmental protection standards. State and local municipalities may have water usage limits, capture and reuse requirements and regulations regarding runoff and erosion control that must also be considered as part of the water system design.

  1. Lighting

Lighting considerations for a cultivation facility are a balance between energy efficiency and what is optimal for plant growth. The preferred lighting choice has typically been High Intensity Discharge (HID) lighting, which includes metal halide (MH) and high-pressure sodium (HPS) bulbs. However, as of late, light-emitting diodes (LED) systems are gaining popularity due to increased energy saving possibilities and innovative technologies. Adequate lighting is critical for ensuring employees can effectively and safely perform their job functions. Many tasks performed on the production floor or in the laboratory require great attention to detail. Therefore, proper lighting is a significant consideration when designing a facility.

  1. HVAC
urban-gro
Proper lighting is a significant consideration when designing a facility.

Environmental factors, such as temperature, relative humidity (RH), airflow and air quality play a significant role in maintaining and controlling cannabis operations. A facility’s HVAC system has a direct impact on cultivation and manufacturing environments, and HVAC performance may make or break the success of an operation. Sensible heat ratios (SHRs) may be impacted by lighting usage and RH levels may be impacted by the water usage/irrigation schedule in a cultivation facility. Dehumidification considerations as described in the National Cannabis Industry Association (NCIA) Committee Blog: An Introduction to HVACD for Indoor Plant Environments – Why We Should Include a “D” for Dehumidification 26 are critical to support plant growth and vitality, minimize microbial proliferation in the work environment and to sustain product shelf-life/stability. All of these factors must be evaluated when commissioning an HVAC system. HVAC systems with monitoring sensors (temperature, RH and pressure) should be considered. Proper placement of sensors allows for real-time monitoring and a proactive approach to addressing excursions that could negatively impact the work environment.

  1. Compressed Air

Compressed air is another, often overlooked, critical component in cannabis operations. Compressed air may be used for a number of applications, including blowing off and drying work surfaces and bottles/containers prior to filling operations, and providing air for pneumatically controlled valves and cylinders. Common contaminants in compressed air are nonviable particles, water, oil, and viable microorganisms. Contaminants should be controlled with the use appropriate in-line filtration. Compressed air application that could impact final product quality and safety requires routine monitoring and testing. ISO 8573:2010, Compressed Air Specifications 21, separates air quality levels into classes to help differentiate air requirements based on facility type.

  1. Electrical Infrastructure

Facilities should be designed to meet the electrical demands of equipment operation, lighting, and accurate functionality of HVAC systems. Processes and procedures should be designed according to the requirements outlined in the National Electrical Code (NEC) 12, Institute of Electrical and Electronics Engineers (IEEE) 13, National Electrical Safety Code (NESC) 14, International Building Code (IBC) 9, International Energy Conservation Code (IECC) 15 and any other relevant standards dictated by the Authority Having Jurisdiction (AHJ).

  1. Fire Detection and Suppression

“Facilities should be designed so that they can be easily expanded or adjusted to meet changing production and market needs.”Proper fire detection and suppression systems should be installed and maintained per the guidelines of the National Fire Protection Association (NFPA) 11, International Building Code (IBC) 9, International Fire Code (IFC) 10, and any other relevant standards dictated by the Authority Having Jurisdiction (AHJ). Facilities should provide standard symbols to communicate fire safety, emergency and associated hazards information as defined in NFPA 170, Standard for Fire Safety and Emergency Symbols 27.

  1. Gas detection

Processes that utilize flammable gasses and solvents should have a continuous gas detection system as required per the IBC, Chapter 39, Section 3905 9. The gas detection should not be greater than 25 percent of the lower explosive limit/lower flammability limit (LEL/LFL) of the materials. Gas detection systems should be listed and labeled in accordance with UL 864, Standard for Control Units and Accessories for Fire Alarm Systems 16 and/or UL 2017, Standard for General-Purpose Signaling Devices and Systems 17 and UL 2075, Standard for Gas and Vapor Detectors and Sensors 18.

Product and Process Flow

Product and process flow considerations include flow of materials as well as personnel. The classic product and process flow of a facility is unidirectional where raw materials enter on one end and finished goods exit at the other. This design minimizes the risk of commingling unapproved and approved raw materials, components and finished goods. Facility space utilization is optimized by providing a more streamlined, efficient and effective process from batch production to final product release with minimal risk of errors. Additionally, efficient flow reduces safety risks to employees and an overall financial risk to the organization as a result of costly injuries. A continuous flow of raw materials and components ensures that supplies are available when needed and they are assessable with no obstructions that could present a potential safety hazard to employees. Proper training and education of personnel on general safety principles, defined work practices, equipment and controls can help reduce workplace accidents involving the moving, handling, and storing of materials. 

Facilities Management

Facilities management includes the processes and procedures required for the overall maintenance and security of a cannabis operation. Facilities management considerations during the design phase include pest control, preventative maintenance of critical utilities, and security.

Damage from whiteflies, thrips and powdery mildew could be prevented with an appropriate PCP

A Pest Control Program (PCP) ensures that pest and vermin control is carried out to eliminate health risks from pests and vermin, and to maintain the standards of hygiene necessary for the operation. Shipping and receiving areas are common entryways for pests. The type of dock and dock lever used could be a welcome mat or a blockade for rodents, birds, insects, and other vermin. Standard Operating Procedures (SOPs) should define the procedure and responsibility for PCP planning, implementation and monitoring.

Routine preventative maintenance (PM) on critical utilities should be conducted to maintain optimal performance and prevent microbial and/or particulate ingress into the work environment. Scheduled PMs may include filter replacement, leak and velocity testing, cleaning and sanitization, adjustment of airflow, the inspection of the air intake, fans, bearings and belts and the calibration of monitoring sensors.

In most medical cannabis markets, an established Security Program is a requirement as part of the licensing process. ASTM International standards: D8205 Guide for Video Surveillance System 23, D8217 Guide for Access Control System[24], and D8218 Guide for Intrusion Detection System (IDS) 25 provide guidance on how to set up a suitable facility security system and program. Facilities should be equipped with security cameras. The number and location of the security cameras should be based on the size, design and layout of the facility. Additional cameras may be required for larger facilities to ensure all “blind spots” are addressed. The facility security system should be monitored by an alarm system with 24/7 tracking. Retention of surveillance data should be defined in an SOP per the AHJ. Motion detectors, if utilized, should be linked to the alarm system, automatic lighting, and automatic notification reporting. The roof area should be monitored by motion sensors to prevent cut-and-drop intrusion. Daily and annual checks should be conducted on the alarm system to ensure proper operation. Physical barriers such as fencing, locked gates, secure doors, window protection, automatic access systems should be used to prevent unauthorized access to the facility. Security barriers must comply with local security, fire safety and zoning regulations. High security locks should be installed on all doors and gates. Facility access should be controlled via Radio Frequency Identification (RFID) access cards, biometric entry systems, keys, locks or codes. All areas where cannabis raw material or cannabis-derived products are processed or stored should be controlled, locked and access restricted to authorized personnel. These areas should be properly designated “Restricted Area – Authorized Personnel Only”.

Future Expansion

The thought of expansion in the beginning stages of facility design is probably the last thing on the mind of the business owner(s) as they are trying to get the operation up and running, but it is likely the first thing on the mind of investors, if they happen to be involved in the business venture. Facilities should be designed so that they can be easily expanded or adjusted to meet changing production and market needs. Thought must be given to how critical systems and product and process flows may be impacted if future expansion is anticipated. The goal should be to minimize down time while maximizing space and production output. Therefore, proper up-front planning regarding future growth is imperative for the operation to be successful and maintain productivity while navigating through those changes.

References:

  1. United States Environmental Protection Agency (EPA) Safe Drinking Water Act (SDWA).
  2. United States Pharmacopeia (USP) Chapter <1231>, Water for Pharmaceutical Purposes.
  3. United States Pharmacopeia (USP) Chapter <61>, Testing: Microbial Enumeration Tests.
  4. United States Pharmacopeia (USP) Chapter <62>, Testing: Tests for Specified Microorganisms.
  5. United States Pharmacopeia (USP) Chapter <643>, Total Organic Carbon.
  6. United States Pharmacopeia (USP) Chapter <645>, Water Conductivity.
  7. ASTM E108 -11, Standard Test Methods for Fire Tests of Roof Coverings.
  8. UL 790, Standard for Standard Test Methods for Fire Tests of Roof Coverings.
  9. International Building Code (IBC).
  10. International Fire Code (IFC).
  11. National Fire Protection Association (NFPA).
  12. National Electrical Code (NEC).
  13. Institute of Electrical and Electronics Engineers (IEEE).
  14. National Electrical Safety Code (NESC).
  15. International Energy Conservation Code (IECC).
  16. UL 864, Standard for Control Units and Accessories for Fire Alarm Systems.
  17. UL 2017, Standard for General-Purpose Signaling Devices and Systems.
  18. UL 2075, Standard for Gas and Vapor Detectors and Sensors.
  19. International Society for Pharmaceutical Engineers (ISPE) Good Practice Guide.
  20. International Society for Pharmaceutical Engineers (ISPE) Guide Water and Steam Systems.
  21. ISO 8573:2010, Compressed Air Specifications.
  22. ISO 22196:2011, Measurement Of Antibacterial Activity On Plastics And Other Non-Porous Surfaces.
  23. D8205 Guide for Video Surveillance System.
  24. D8217 Guide for Access Control Syst
  25. D8218 Guide for Intrusion Detection System (IDS).
  26. National Cannabis Industry Association (NCIA): Committee Blog: An Introduction to HVACD for Indoor Plant Environments – Why We Should Include a “D” for Dehumidification.
  27. NFPA 170, Standard for Fire Safety and Emergency Symbols.

Pesticide Remediation by CPC

By Arpad Konczol, PhD
2 Comments

Like any other natural product, the biomass of legal cannabis can be contaminated by several toxic agents such as heavy metals, organic solvents, microbes and pesticides, which significantly influence the safety of the end products.

Let’s just consider the toxicological effects. Since cannabis products are not only administered in edible forms but also smoked and inhaled, unlike most agricultural products, pesticide residue poses an unpredictable risk to consumers. One example is the potential role of myclobutanil in the vape crisis.

Unfortunately, federal and state laws are still conflicted on cannabis-related pesticides. Currently, only ten pesticide products have been registered specifically for hemp by the U.S. Environmental Protection Agency. So, the question arises what has to be done with all pf the high-value, but also contaminated cannabis, keeping in mind that during the extraction processes, not only the phytocannabinoids get concentrated but the pesticides as well, reaching concentrations up to tens or hundreds of parts per million!

Currently, there are three different sets of rules in place in the regulatory areas of Oregon, California and Canada. These regulations detail which pesticides need to be monitored and remediated if a certain limit for each is reached. Because the most extensive and strict regulations are found in Canada, RotaChrom used its regulations as reference in their case study.

Centrifugal Partition Chromatographic (CPC) system

To illustrate that reality sometimes goes beyond our imagination, we evaluated the testing results of a THC distillate sample of one of our clients. This sample contained 9 (!) pesticides, of which six levels exceeded the corresponding action limits. The most frightening, however, regarding this sample, is that it contained a huge amount of carbofuran, a category I substance. It is better not to think of the potential toxicological hazard of this material…

The CPC-based purification of CBD is a well-known and straightforward methodology. As the elution profile on the CPC chromatogram of a distillate shows, major and minor cannabinoids can be easily separated from CBD. At RotaChrom, this method has been implemented at industrial-scale in a cost effective and high throughput fashion. In any case, the question arises: where are the pesticides on this chromatogram? To answer this, we set ourselves the goal to fully characterize the pesticide removing capability of our methodologies.

Our results on this topic received an award at the prestigious PREP Conference in 2019. The ease of pesticides removal depends on the desired Compound of Interest.

Here is a quick recap on key functionalities of the partition chromatography.

  • Separation occurs between two immiscible liquid phases.
  • The stationary phase is immobilized inside the rotor by a strong centrifugal force.
  • The mobile phase containing the sample to be purified is fed under pressure into the rotor and pumped through the stationary phase in the form of tiny droplets (percolation).
  • The chromatographic column in CPC is the rotor: cells interconnected in a series of ducts attached to a large rotor
  • Simple mechanism: difference in partition

Let’s get into the chemistry a bit:

The partition coefficient is the ratio of concentrations of a compound in a mixture of two immiscible solvents at equilibrium. This ratio is therefore a comparison of the solubilities of the solute in these two liquid phases.

The CPC chromatogram demonstrates the separation of Compounds of Interest based on their unique partition coefficients achieved through a centrifugal partition chromatography system.

CPC can be effectively used for pesticide removal. About 78% of the pesticides around CBD are very easy to remove, which you can see here:

In this illustration, pesticides are in ascending order of Kd from left to right. CBD, marked with blue, elutes in the middle of the chromatogram. The chart illustrates that most polar and most apolar pesticides were easily removed beside CBD. However, some compounds were in coelution with CBD (denoted as “problematic”), and some compounds showed irregular Kd-retention behavior (denoted as “outliers”).

If pesticides need to be removed as part of THC purification, then the pesticides that were problematic around CBD would be easier to remove and some of the easy ones would become problematic.

To simulate real-world production scenarios, an overloading study with CBD was performed, which you can see in the graph:

It is easy to see on the chromatogram that due to the increased concentration injected onto the rotor, the peak of CBD became fronting and the apparent retention shifted to the right. This means that pesticides with higher retention than CBD are more prone to coelution if extreme loading is applied.

To be able to eliminate problematic pesticides without changing the components of the solvent system, which is a typical industrial scenario, the so-called “sweet spot approach” was tested. The general rule of thumb for this approach is that the highest resolution of a given CPC system can be exploited if the Kd value of the target compounds fall in the range of 0.5-2.0. In our case, to get appropriate Kd values for problematic pesticides, the volume ratio of methanol and water was fine-tuned. Ascending mode was used instead of descending mode. For the polar subset of problematic pesticides, this simple modification resulted in an elution profile with significantly improved resolution, however, some coelution still remained.

In the case of apolar pesticides, the less polar solvent system with decreased water content in ascending mode provided satisfactory separation.

Moreover, if we focus on this subset in the three relevant regulatory areas, the outcome is even more favorable. For example, myclobutanil and bifenazate, dominant in all of the three regulatory regions, are fully removable in only one run of the CPC platform.

Based on these results, a generic strategy was created. The workflow starts with a reliable and precise pesticide contamination profile of the cannabis sample, then, if it does not appear to indicate problematic impurity, the material can be purified by the baseline method. However, if coeluting pesticides are present in the input sample, there are two options. First, adjusting the fraction collection of the critical pesticide can be eliminated, however the yield will be compromised in this case. Alternatively, by fine-tuning the solvent system, a second or even a third run of the CPC can solve the problem ultimately. Let me add here, that a third approach, i.e., switching to another solvent system to gain selectivity for problematic pesticides is also feasible in some cases.

In review, RotaChrom has conducted extensive research to analyze the list of pesticides according to the most stringent Canadian requirements. We have found that pesticides can be separated from CBD by utilizing our CPC platform. Most of these pesticides are relatively easy to remove, but RotaChrom has an efficient solution for the problematic pesticides. The methods used at RotaChrom can be easily extended to other input materials and target compounds (e.g., THC, CBG).

IR Spectrum of 2,4-Dichlorophenol in different physical states
From The Lab

Gas Chromatography/Infrared Spectroscopy: A Tool For the Analysis of Organic Compounds in Cannabis

By John F. Schneider
2 Comments
IR Spectrum of 2,4-Dichlorophenol in different physical states

Editor’s Note: The author will be teaching a 1/2 day short course on this topic at PITTCON in Philadelphia in March 2019.

The combination of gas chromatography and infrared spectroscopy (GC/IR) is a powerful tool for the characterization of compounds in complex mixtures. (1-5) Gas chromatography with mass spectroscopy detection (GC/MS) is a similar technique, but GC/MS is a destructive technique that tears apart the sample molecules during the ionization process and then these fragments are used to characterize the molecule. In GC/IR the molecules are not destroyed but the IR light produced by molecular vibrations are used to characterize the molecule. IR spectrum yields information about the whole molecule which allows the characterization of specific isomers and functional groups. GC/IR is complementary to GC/MS and the combination results in a powerful tool for the analytical chemist.

A good example of the utility of GC/IR vs GC/MS is the characterization of stereo isomers. Stereo isomers are mirror images such as a left hand and a right hand. In nature, stereo isomers are very important as one isomers will be more active then its mirror image. Stereo isomers are critical to medicinal application of cannabis and also a factor in the flavor components of cannabis.

GC/MS is good at identifying basic structure, where GC/IR can identify subtle differences in structure. GC/MS could identify a hand, GC/IR could tell you if it is a left hand or right hand. GC/MS can identify a general class of compounds, GC/IR can identify the specific isomer present.

Why GC/IR?

Gas chromatography interfaced with infrared detection (GC/IR), combines the separation ability of GC and the structural information from IR spectroscopy. GC/IR gives the analyst the ability to obtain information complementary to GC/MS. GC/IR gives the analyst the power to perform functional group detection and differentiate between similar molecular isomers that is difficult with GC/MS. Isomer specificity can be very important in flavor and medical applications.

IR Spectrum of 2,4-Dichlorophenol in different physical states

IR Spectrum of 2,4-Dichlorophenol in different physical states

Gas chromatography with mass spectrometry detection (GC/MS) is the state-of-the-art method for the identification of unknown compounds. GC/MS, however, is not infallible and many compounds are difficult to identify with 100 % certainty. The problem with GC/MS is that it is a destructive method that tears apart a molecule. In infrared spectrometry (IR), molecular identification is based upon the IR absorptions of the whole molecule. This technique allows differentiation among isomers and yields information about functional groups and the position of such groups in a molecule. GC/IR complements the information obtained by GC/MS.

Interfaces

Initial attempts to couple GC with IR were made using high capacity GC columns and stopped flow techniques. As GC columns and IR technology advanced, the GC/IR method became more applicable. The advent of fused silica capillary GC columns and the availability of Fourier transform infrared spectrometry made GC/IR available commercially in several forms. GC/IR using a flow cell to capture the IR spectrum in real time is known as the “Light Pipe”. This is the most common form of GC/IR and the easiest to use. GC/IR can also be done by capturing or “trapping” the analytes of interest eluting from a GC and then measuring the IR spectrum. This can be done by cryogenically trapping the analyte in the solid phase. A third possibility is to trap the analyte in a matrix of inert material causing “Matrix Isolation” of the analyte followed by measuring the IR spectrum.

Infrared Spectroscopy

The physical state of the sample has a large effect upon the IR spectrum produced. Molecular interactions (especially hydrogen bonding) broadens absorption peaks. Solid and liquid samples produce IR spectra with broadened peaks that loses much of the potential information obtained in the spectra. Surrounding the sample molecule with gas molecules or in an inert matrix greatly sharpens the peaks in the spectrum, revealing more of the information and producing a “cleaner” spectrum. These spectra lend themselves better to computer searches of spectral libraries similar to the computer searching done in mass spectroscopy. IR spectral computer searching requires the standard spectra in the library be of the same physical state as the sample. So, a spectrum taken in a gaseous state should be searched against a library of spectra of standards in the gaseous state.

IR of various phases:

  • Liquid Phase – Molecular interactions broaden absorption peaks.
  • Solid Phase – Molecular interactions broaden absorption peaks.
  • Gas Phase – Lack of molecular interactions sharpen absorption peaks.
  • Matrix Isolation – Lack of molecular interactions sharpen absorption peaks.

IR Chromatograms

GC/IR yields chromatograms of infrared absorbance over time. These can be total infrared absorbance which is similar to the total ion chromatogram (TIC) in GC/MS or the infrared absorbance over a narrow band or bands analogous to selected ion chromatogram. This is a very powerful ability, because it gives the user the ability to focus on selected functional groups in a mixture of compounds.

Conclusion

Gas chromatography with infrared detection is a powerful tool for the elucidation of the structure of organic compounds in a mixture. It is complementary to GC/MS and is used to identify specific isomers and congeners of organic compounds. This method is greatly needed in the Cannabis industry to monitor the compounds that determine the flavor and the medicinal value of its products.

References

  1. GC–MS and GC–IR Analyses of the Methoxy-1-n-pentyl-3-(1-naphthoyl)-Indoles: Regioisomeric Designer Cannabinoids, Amber Thaxton-Weissenfluh, Tarek S. Belal, Jack DeRuiter, Forrest Smith, Younis Abiedalla, Logan Neel, Karim M. Abdel-Hay, and C. Randall Clark, Journal of Chromatographic Science, 56: 779-788, 2018
  2. Simultaneous Orthogonal Drug Detection Using Fully Integrated Gas Chromatography with Fourier Transform Infrared Detection and Mass Spectrometric Detection , Adam Lanzarotta, Travis Falconer, Heather McCauley, Lisa Lorenz, Douglas Albright, John Crowe, and JaCinta Batson, Applied Spectroscopy Vol. 71, 5, pp. 1050-1059, 2017
  3. High Resolution Gas Chromatography/Matrix Isolation Infrared Spectrometry, Gerald T. Reedy, Deon G. Ettinger, John F. Schneider, and Sid Bourne, Analytical Chemistry, 57: 1602-1609, 1985
  4. GC/Matrix Isolation/FTIR Applications: Analysis of PCBs, John F. Schneider, Gerald T. Reedy, and Deon G. Ettinger, Journal of Chromatographic Science, 23: 49-53, 1985
  5. A Comparison of GC/IR Interfaces: The Light Pipe Vs. Matrix Isolation, John F. Schneider, Jack C. Demirgian, and Joseph C. Stickler, Journal of Chromatographic Science, 24: 330- 335, 1986
  6. Gas Chromatography/Infrared Spectroscopy, Jean ‐ Luc Le Qu é r é , Encyclopedia of Analytical Chemistry, John Wiley & Sons, 2006

Pennsylvania Medical Cannabis Program Blossoms

By Aaron G. Biros
1 Comment

Pennsylvania’s medical cannabis program may be young, but the industry in that state is off to a burgeoning start. Back in 2016, the state legalized medical cannabis. In 2017, the PA Department of Health began accepting applications for licenses and announced the first 12 winning applications. On February 15th, 2018, medical cannabis became available for more than 17,000 patients that registered in the program.

In March of this year, Governor Tom Wolf announced two more dispensaries were approved to operate as well as another grower/processor licensee. At that time, the press release indicated more than 21,000 patients have registered to participate in the medical cannabis program.

Then in April, Governor Wolf announced Phase Two of their medical cannabis program, allowing the industry to grow even more. That allowed for 13 new grower/processor permits and 23 new primary dispensary permits, according to a press release, which moved the total up to 25 grower/processors licensees and 50 dispensary licensees.

Just weeks later after that announcement, the PA Department of Health adjusted their program to allow patients access to whole plant, dried flower and opened up more qualifying conditions. The qualifying conditions added to the list now include cancer remission therapy as well as opioid-addiction therapy, which are two very notable additions. According to an April 6threport, 28,508 patients and 2495 caregivers registered with the program.

On May 15th, Governor Wolf approved eight universities to participate in a groundbreaking program, allowing Pennsylvania to take the first steps towards clinical research for medical cannabis. This research program would be the first of its kind in the country, allowing research institutions to explore the drug. The excitement was put on hold, however, when a Pennsylvania judge halted the program with an injunction. A handful of growers and dispensary owners in PA filed suit to stop the program on grounds that it violated the original intent of the law. State Representative Kathy Watson from Bucks County, the author of the research program, called the suit “pathetic because it’s all about the money.” We’ll follow closely with any new developments as they come.

Steve Schain, Esq. practicing at the Hoban law Group

Steven Schain, Esq., senior attorney at Hoban Law Group, a global cannabis law firm, represents multiple cannabis-related businesses in Pennsylvania. He says the program’s roll out has been fast with solid growth. “Within two years of the legislation’s enactment, Pennsylvania’s medical marijuana program has exceeded expectations with controlled, sustainable and quality growth,” says Schain. “The Pennsylvania Department of Health established ambitious goals, which they met timely and created a statewide program servicing over 10,000 patients in record time. Looming ahead is New Jersey’s adult use program, the anticipated robustness of which could undermine vigorous sales in southeastern Pennsylvania’s marijuana-related businesses.”

On May 30th, Philadelphia welcomed their first medical cannabis dispensary, with a location opening up their doors to patients in Fishtown. Now reports are coming in that say more than 37,000 patients have registered to date, with over 16,000 who have received their ID cards and medical cannabis at a dispensary.

Even though the research program might be on hold for now, Pennsylvania’s medical cannabis program is growing at a fast pace. The market there has blossomed in just a few short months to a whopping 37,000-registered patients, according to a press release form Governor Wolf’s office. Some say an additional 200,000 patients could qualify. With the second phase in sight, it seems Pennsylvania is on track to become a hotbed for business and research, developing into a massive medical cannabis marketplace soon. Stay tuned for more updates.

A More Effective and Efficient Approach to Purer Cannabidiol Production Using Centrifugal Partition Chromatography

By Lauren Pahnke
3 Comments

Many physicians today treat their patients with cannabidiol (CBD, Figure 1), a cannabinoid found in cannabis. CBD is more efficacious over traditional medications, and unlike delta-9 tetrahydrocannbinol (THC), the main psychoactive compound in cannabis, CBD has no psychoactive effects. Researchers have found CBD to be an effective treatment for conditions such as cancer pain, spasticity in multiple sclerosis, and Dravet Syndrome, a form of epilepsy.

CBD is still considered an unsafe drug under federal law, but to meet the medical demand, 17 states in the US recently passed laws allowing individuals to consume CBD for medical purposes. A recent survey found that half of medicinal CBD users rely on the substance by itself for treatment. As doctors start using CBD to treat more patients, the demand for CBD is only expected to rise, and meeting that demand can pose challenges for manufacturers who are not used to producing such high quantities of CBD. Furthermore, as CBD-based drugs become more popular, the US Food and Drug Administration (FDA) will likely require manufacturers to demonstrate they can produce pure, high-quality products.

cannabidiol
Figure 1. The structure of cannabidiol, one of 400 active compounds found in cannabis.

Most manufacturers use chromatography techniques such as high performance liquid chromatography (HPLC) or flash chromatography to isolate compounds from natural product extracts. While these methods are effective for other applications, they are not, however, ideal for CBD isolate production. Crude cannabis oil contains some 400 potentially active compounds and requires pre-treatment prior to traditional chromatography purification. Both HPLC and flash chromatography also require silica resin, an expensive consumable that must be replaced once it is contaminated due to irreversible absorption of compounds from the cannabis extract. All of these factors limit the production capacity for CBD manufacturers.

Additionally, these chromatography methods use large quantities of solvents to elute natural compounds, which negatively impacts the environment.

A Superior Chromatography Method

Centrifugal partition chromatography (CPC) is an alternative chromatography method that can help commercial CBD manufacturers produce greater quantities of pure CBD more quickly and cleanly, using fewer materials and generating less toxic waste. CPC is a highly scalable CBD production process that is environmentally and economically sustainable.

The mechanics of a CPC run are analogous to the mechanics of a standard elution using a traditional chromatography column. While HPLC, for instance, involves eluting cannabis oil through a resin-packed chromatography column, CPC instead elutes the oil through a series of cells embedded into a stack of rotating disks. These cells contain a liquid stationary phase composed of a commonly used fluid such as water, methanol, or heptane, which is held in place by a centrifugal force. A liquid mobile phase migrates from cell to cell as the stacked disks spin. Compounds with greater affinity to the mobile phase are not retained by the stationary phase and pass through the column faster, whereas compounds with a greater affinity to the stationary phase are retained and pass through the column slower, thereby distributing themselves in separate cells (Figure 2).

Figure 2- CPC
Figure 2. How CPC isolates compounds from complex, natural mixtures. As the column spins, the mobile phase (yellow) moves through each cell in series. The compounds in the mobile phase (A, B, and C) diffuse into the stationary phase (blue) at different rates according to their relative affinities for the two phases.

A chemist can choose a biphasic solvent system that will optimize the separation of a target compound such as CBD to extract relatively pure CBD from a cannabis extract in one step. In one small-scale study, researchers injected five grams of crude cannabis oil low in CBD content into a CPC system and obtained 205 milligrams of over 95% pure CBD in 10 minutes.

Using a liquid stationary phase instead of silica imbues CPC with several time and cost benefits. Because natural products such as raw cannabis extract adhere to silica, traditional chromatography columns must be replaced every few weeks. On the other hand, a chemist can simply rinse out the columns in CPC and reuse them. Also, unlike silica columns, liquid solvents such as heptane used in CPC methods can be distilled with a rotary evaporator and recycled, reducing costs.

Environmental Advantages of CPC

The solvents used in chromatography, such as methanol and acetonitrile, are toxic to both humans and the environment. Many environmentally-conscious companies have attempted to replace these toxic solvents with greener alternatives, but these may come with drawbacks. The standard, toxic solvents are so common because they are integral for optimizing purity. Replacing a solvent with an alternative could, therefore, diminish purity and yield. Consequently, a chemist may need to perform additional steps to achieve the same quality and quantity achievable with a toxic solvent. This produces more waste, offsetting the original intent of using the green solvent.

CPC uses the same solvents as traditional chromatography, but it uses them in smaller quantities. Furthermore, as previously mentioned, these solvents can be reused. Hence, the method is effective, more environmentally-friendly, andeconomically feasible.

CPC’s Value in CBD Production

As manufacturers seek to produce larger quantities of pure CBD to meet the demand of patients and physicians, they will need to integrate CPC into their purification workflows. Since CPC produces a relativelyduct on a larger scale, it is equipped to handle the high-volume needs of a large manufacturer. Additionally, because it extracts more CBD from a given volume of raw cannabis extract, and does not use costly silica or require multiple replacement columns, CPC also makes the process of industrial-scale CBD production economically sustainable. Since it also uses significantly less solvent than traditional chromatography, CPC makes it financially feasible to make the process of producing CBD more environmentally-friendly.

Suggested Reading:

CPC 250: Purification of Cannabidiol from Cannabis sativa

Introduction to Centrifugal Partition Chromatography

Terpene_KAS2
From The Lab

The Other Side of Cannabis: Terpenes

By Dr. Zacariah Hildenbrand, Allegra Leghissa, Dr. Kevin A. Schug
2 Comments
Terpene_KAS2

Have you ever wondered why all beers have that strong, characteristic smell? Or why you could tell the smell of cannabis apart from any other plant? The answer is simple – terpenes.

These 55,000 different molecules are responsible for a majority of the odors and fragrances around us, from a pine forest, to the air diffuser in your house 1–3. They all share the same precursor, isoprene, and because of that, they are all related and have similar molecular structures. Unfortunately, it is this uncanny similarity that makes their analysis so challenging; we still lack a complete list of which terpenes expected to be found in each given plant species 1,2.

Many different methods have been developed in an effort to provide a time-optimized and straightforward analysis. Gas chromatography (GC) is usually center stage due to the volatility of the terpenes. Therefore, there is significant concern with the type of GC detector used 2.

The flame ionization detector (FID) is a good quantitative detector for GC, but qualitatively it does not provide any information, except for retention time; the differentiation between terpene species is achieved solely by use of retention indices (RI), which are based on elution times from a particular GC stationary phase. The best part of the FID is its low cost, reliability, and relatively easy interface, which make it an effective tool for quality control (QC) but less so with respect to research and discovery 2.

The primary choice for a research setting is the mass spectrometer (MS) detector. It is more expensive and complicated than FID, but importantly, it provides both good quantitative capabilities, and it provides mass spectra for each species that elutes from the chromatograph. However, for terpene analysis, it may still not be the best detector choice. Since terpene class molecules share many structural and functional similarities, even their fragmentation and sub-sequential identification by MS may lead to inconsistent results, which need to be confirmed by use of RI. Still, MS is a better qualitative analysis tool than the FID, especially for distinguishing non-isobaric terpenes 2.

Recently, new technology based on vacuum ultraviolet spectroscopy (VUV) has been developed as a new GC detector. The VUV detector enables analysis of virtually all molecules; virtually all chemical compounds absorb light in the range in the 125-240 nm wavelength range probed by the detector, making it an essentially universal detector 4–11. Previously, spectroscopic absorption detectors for GC have lacked sufficient energy to measure absorption of most GC-amenable species. The VUV detector fills a niche, which is complementary to MS detection in terms of the qualitative information it provides.

Terpene_KAS2
Figure 1: A, Section of the chromatographic separation of a terpenes standard mix; B, highlight of the co-eluting terpenes, camphor and (-)-isopulegol; C, differences in the absorbance spectra of camphor and (-)-isopulegol.

With the VUV detector, each compound exhibits its own unique absorbance spectrum. Even isomers and isobars, which are prevalent in terpene mixtures and can be difficult to distinguish different species by their electron ionization mass spectra, can be well differentiated based on their VUV spectra 6,9,10.  Nevertheless, because analytes exhibit different spectra, it is not required to achieve a perfect chromatographic separation of the mixture components. Co-eluting peaks can be separated post-run through the use of library spectra and software inherent to the instrument 4,10. This ability is called “deconvolution”, and it is based on the fact that two co-eluting terpenes will give a peak with an absorbance spectrum equal to the sum of the two single absorbance spectra 4. Figure 1 shows the deconvolution process for two co-eluting terpenes, camphor and (-)-isopulegol. Due to their different absorbance spectra (Figure 1C), it is possible to fully separate the two peaks in post-run, obtaining sharp peaks for both analytes 6.

The deconvolution process has been shown to yield precise and accurate results. Thus, chromatographic resolution can be sacrificed in favor of spectroscopic resolution; this enables the development of methods with faster run times. With the ability to deconvolve unresolved peaks, a long temperature ramp to chromatographically separate all isomeric terpenes is not required 6. Additionally, the presence of coeluting components, which might normally go undetected with some GC detectors, can be easily judged based on comparison of the measured spectra with pure reference spectra contained in the VUV spectral library.

The other issue in terpenes analysis is the extraction process. Terpenes can be extracted with the use of solvents (e.g., methanol, ethanol, hexane, and cyclohexane, among others), but the process is usually time-consuming, costly and not so environmentally-friendly 2. The plant needs to be manually crushed and then aliquots of solvent are used to extract components from the plant, ideally at least 3 times and combined to achieve acceptable results. The problem is that some terpenes may respond better to a certain solvent, making their extraction easier and more optimized than for others 2. The choice of solvent can cause discrimination against the extraction some terpenes, which limits the comprehensiveness of analysis.

Headspace is another technique that can be used for the sample preparation of terpenes. Headspace sampling is based on heating the solid or liquid sample inside a sealed vial, and then analyzing the air above it after sufficient equilibration. In this way, only volatile analytes are extracted from the solid/liquid sample into the gas phase; this allows relatively interference-free sampling 12–14.

How do we know whether our extraction analysis methods are correct and comprehensive for a certain plant sample? Unfortunately, there is not a complete list of available molecules for each plant species, and even if two specimens may smell really similar to our nose, their terpenes profiles may be notably different. When working with a new plant material, it is difficult to predict the extraction efficiency for the vast array of terpenes that may be present. We can only perform it with different extraction and detection methods, and compare the results.

The route for a comprehensive and fast analysis of terpenes is therefore still long; however, their intoxicating aromas and inherent medicinal value has provided a growing impetus for researchers around the world. Considering the evolving importance of Cannabis and the growing body of evidence on the synergistic effects between terpenes and cannabinoids, it is likely that newly improved extraction and analysis methods will be developed, paving the way for a more complete list of terpene species that can be found in different cultivars. The use of new analytical technologies, such as the VUV detector for GC, should aid considerably in this endeavor.

References:

[1]          Breitmaier E., Terpenes: Flavors, Fragrances, Pharmaca, Pheromones. John Wiley & Sons 2006.

[2]          Leghissa A., Hildenbrand Z. L., Schug K. A., A Review of Methods for the Chemical Characterization of Cannabis Natural Products. J. Sep. Sci.2018, 41, 398–415 .

[3]          Benvenuto E., Misra B. B., Stehle F., Andre C. M., Hausman J.-F., Guerriero G., Cannabis sativa: The Plant of the Thousand and One Molecules. Front. Plant Sci2016, 719, DOI: 10.3389/fpls.2016.00019.

[4]          Schug K. A., Sawicki I., Carlton D. D., Fan H.,Mcnair H. M.,Nimmo J. P., Kroll P.,Smuts J.,Walsh P., Harrison D., Vacuum Ultraviolet Detector for Gas Chromatography. Anal. Chem.2014, 86, 8329–8335 .

[5]          Fan H.,Smuts J., Walsh P.,Harrison D., Schug K. A., Gas chromatography-vacuum ultraviolet spectroscopy for multiclass pesticide identification. J. Chromatogr. A2015, DOI: 10.1016/j.chroma.2015.02.035.

[6]          Qiu C.,Smuts J., Schug K. A., Analysis of terpenes and turpentines using gas chromatography with vacuum ultraviolet detection. J. Sep. Sci.2017, 40, 869–877 .

[7]          Leghissa A., Smuts J., Qiu C., Hildenbrand Z. L., Schug K. A., Detection of cannabinoids and cannabinoid metabolites using gas chromatography-vacuum ultraviolet spectroscopy. Sep. Sci. Plus2018, 1.

[8]          Bai L.,Smuts J., Walsh P., Fan H., Hildenbrand Z., Wong D., Wetz D., Schug K. A., Permanent gas analysis using gas chromatography with vacuum ultraviolet detection. J. Chromatogr. A2015,1388, 244–250 .

[9]          Skultety L., Frycak P., Qiu C.,Smuts J., Shear-Laude L., Lemr K., Mao J. X., Kroll P., Schug K. A., Szewczak A., Vaught C., Lurie I., Havlicek V., Resolution of isomeric new designer stimulants using gas chromatography – Vacuum ultraviolet spectroscopy and theoretical computations. Anal. Chim. Acta2017, 971, 55–67 .

[10]       Bai L., Smuts J., Walsh P., Qiu C., McNair H. M., Schug K. ., Pseudo-absolute quantitative analysis using gas chromatography–vacuum ultraviolet spectroscopy–a tutorial. Anal. Chim. Acta2017, 953, 10–22 .

[11]       Schenk J., Nagy G., Pohl N. L. B., Leghissa A., Smuts J., Schug K. A., Identification and deconvolution of carbohydrates with gas chromatography-vacuum ultraviolet spectroscopy. J. Chromatogr. A2017, 1513, 210–221 .

[12]       Van Opstaele F., De Causmaecker B., Aerts G., De Cooman L., Characterization of novel varietal floral hop aromas by headspace solid phase microextraction and gas chromatography-mass spectrometry/olfactometry. J. Agric. Food Chem.2012, 60, 12270−12281 .

[13]       Hamm S., Bleton J., Connan J., Tchapla A., A chemical investigation by headspace SPME and GC-MS of volatile and semi-volatile terpenes in various olibanum samples. Phytochemistry2005,66, 1499–1514 .

[14]       Aberl A., Coelhan M., Determination of volatile compounds in different hop Varieties by headspace-trap GC/MS-in comparison with conventional hop essential oil analysis. J. Agric. Food Chem.2012, 60, 2785−2792 .