How GW Pharmaceuticals Grows Cannabis to Make Consistent Prescription Medicine

Producing pharmaceutical-grade cannabis medicine requires managing enormous natural variability in plant genetics, growing conditions, harvest timing, and processing methods.

Potter, David J·Drug testing and analysis·2014·Moderate EvidenceReview
RTHC-00850ReviewModerate Evidence2014RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Review
Evidence
Moderate Evidence
Sample
Not reported

What This Study Found

Cannabis is an extremely inhomogeneous raw material, with cannabinoid ratios affected by genetics, growing conditions, storage conditions, maturity at harvest, and processing methods. GW Pharmaceuticals had to develop comprehensive quality control systems across all these variables to produce Sativex, the first cannabis-based medicine approved in the UK.

The company developed specific cannabis chemotypes (chemical varieties) to produce consistent THC and CBD ratios. The botanical considerations are particularly challenging because cannabinoid content varies across different parts of the plant, changes with maturity, and is affected by environmental conditions during growth.

Sativex was approved for treating spasticity due to multiple sclerosis and contains both THC and CBD along with other plant constituents. The pharmaceutical standardization process described represents a significant departure from the variability inherent in recreational or even most medical cannabis products.

Key Numbers

Sativex contains both THC and CBD. It was the first cannabis-based medicine approved in the UK for MS spasticity. Cannabis contains over 100 cannabinoids whose ratios must be controlled.

How They Did This

This is a descriptive review authored by a GW Pharmaceuticals researcher, detailing the company's approach to cultivating and processing cannabis for pharmaceutical use. It covers botanical considerations, genetic selection, growing protocols, harvesting, and quality control processes.

Why This Research Matters

The gap between recreational/medical cannabis products and pharmaceutical-grade cannabis medicines is enormous in terms of consistency and quality control. Understanding the challenges of standardizing cannabis helps explain why pharmaceutical development is difficult and why product-to-product variability remains a concern in the broader cannabis market.

The Bigger Picture

As cannabis-based medicines move into mainstream pharmaceutical development, the challenges of standardizing a complex botanical product become apparent. The approach described here, controlling genetics, environment, and processing, represents the pharmaceutical industry's answer to cannabis variability, though it results in products very different from whole-plant cannabis.

What This Study Doesn't Tell Us

This review is written by a GW Pharmaceuticals employee and describes the company's proprietary methods. It is inherently promotional and does not compare their approach to alternative manufacturing methods. The focus is on process rather than clinical efficacy.

Questions This Raises

  • ?Can other companies replicate this level of consistency?
  • ?Does pharmaceutical standardization sacrifice beneficial components present in whole-plant cannabis?
  • ?Will synthetic cannabinoids eventually replace plant-derived medicines?

Trust & Context

Key Stat:
Sativex was the first cannabis-based medicine approved in the UK
Evidence Grade:
This is a descriptive industry review. It provides valuable process information but is not a clinical study.
Study Age:
Published in 2014. Since then, additional cannabis-based medicines (including Epidiolex) have received regulatory approval.
Original Title:
A review of the cultivation and processing of cannabis (Cannabis sativa L.) for production of prescription medicines in the UK.
Published In:
Drug testing and analysis, 6(1-2), 31-8 (2014)
Authors:
Potter, David J(2)
Database ID:
RTHC-00850

Evidence Hierarchy

Meta-Analysis / Systematic Review
Randomized Controlled Trial
Cohort / Case-Control
Cross-Sectional / ObservationalSnapshot without intervening
This study
Case Report / Animal Study

Summarizes existing research on a topic.

What do these levels mean? →

Frequently Asked Questions

Why is cannabis so hard to standardize?

Cannabis produces over 100 different cannabinoids whose ratios change based on plant genetics, growing conditions, light exposure, harvest timing, and storage. Unlike most pharmaceutical raw materials, each plant is slightly different, making batch-to-batch consistency extremely challenging.

How does pharmaceutical cannabis differ from dispensary products?

Pharmaceutical cannabis undergoes rigorous quality control to ensure every dose contains exactly the specified amount of active ingredients. Most dispensary products have wider variability in cannabinoid content and may not undergo the same level of testing.

Read More on RethinkTHC

Cite This Study

RTHC-00850·https://rethinkthc.com/research/RTHC-00850

APA

Potter, David J. (2014). A review of the cultivation and processing of cannabis (Cannabis sativa L.) for production of prescription medicines in the UK.. Drug testing and analysis, 6(1-2), 31-8. https://doi.org/10.1002/dta.1531

MLA

Potter, David J. "A review of the cultivation and processing of cannabis (Cannabis sativa L.) for production of prescription medicines in the UK.." Drug testing and analysis, 2014. https://doi.org/10.1002/dta.1531

RethinkTHC

RethinkTHC Research Database. "A review of the cultivation and processing of cannabis (Cann..." RTHC-00850. Retrieved from https://rethinkthc.com/research/potter-2014-a-review-of-the

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.