Module 18 – The Evidence Base
Part of the Purus Lumina Device Care Education Programme
The absence of evidence is not evidence of absence. It is a finding in its own right.
The evidence base for CBPMs is growing. Clinical trials, observational studies, systematic reviews, and meta-analyses are accumulating across a range of conditions — chronic pain, epilepsy, multiple sclerosis, PTSD, anxiety, and others. The body of evidence is imperfect, contested in places, and still developing. But it exists, and it is being used to inform prescribing decisions, clinical guidelines, and regulatory frameworks across the UK and internationally.
The evidence base for CBPM device care does not exist.
There are no peer-reviewed studies on the optimal cleaning frequency for a dry herb device used to administer a prescribed CBPM. There are no clinical trials on the effect of device contamination on dose consistency. There are no systematic reviews of the cross-infection risk associated with shared device use in a prescribed CBPM context. There are no published guidelines from any clinical body on the maintenance standard for CBPM delivery devices.
This module documents that absence. Not as a criticism of the research community. As a finding — a documented gap in the evidence base that has consequences for patients, clinicians, and regulators, and that this curriculum is the first structured attempt to address.
What the evidence base contains
The existing evidence base relevant to CBPM device care draws from several adjacent fields, none of which directly addresses the clinical context of prescribed CBPM administration via a dry herb device.
Dry herb device chemistry and emissions: There is a body of research on the chemical composition of vapour produced by dry herb devices, including studies on cannabinoid and terpene delivery efficiency at different temperatures, and on the presence of combustion byproducts at temperatures above the manufacturer's recommended maximum. This research informs the temperature guidance in Module 5 but does not address device maintenance.
Medical device hygiene: There is an extensive evidence base on the hygiene standards required for reusable medical devices in clinical settings — endoscopes, respiratory equipment, anaesthetic devices. This evidence base informs the principles applied in this curriculum but was not developed for home-use CBPM delivery devices and cannot be directly applied without adaptation.
Isopropanol as a disinfectant: The antimicrobial properties of isopropanol are well-documented. The evidence base for its use as a surface disinfectant in clinical settings is robust. Its application to the specific materials, components, and residue profiles of dry herb devices used for CBPM administration has not been studied.
Cross-infection risk in shared medical devices: The evidence base for cross-infection risk in shared medical devices — particularly respiratory devices — is well-established in the context of hospital-acquired infections and community respiratory equipment. Its application to shared dry herb device use in a home CBPM context has not been studied.
What the evidence base does not contain
The following questions have not been addressed in any peer-reviewed publication as of the date of this curriculum's publication:
- What is the effect of residue accumulation in a dry herb device on the dose of cannabinoids delivered to the patient?
- What cleaning frequency is required to maintain consistent dose delivery in a dry herb device used at the frequency typical of a patient prescribed a CBPM?
- What is the cross-infection risk associated with shared use of a dry herb device mouthpiece between two individuals?
- What is the effect of storage conditions — humidity, temperature, light exposure — on the integrity of a dry herb device's components over time?
- What is the clinical significance of off-label use of a CBPM delivery device — specifically, failure to follow the manufacturer's cleaning instructions — on patient outcomes?
- What device care standard is appropriate for paediatric CBPM administration via a dry herb device?
- What is the effect of carer-assisted device handling on contamination risk in a home CBPM administration setting?
These are not obscure questions. They are the questions that every patient prescribed a CBPM who uses a dry herb device is implicitly answering every day — through their cleaning habits, their storage choices, their replacement decisions, and their carer arrangements. They are answering them without evidence, because the evidence does not exist.
Why the absence matters
Clinical guidelines are evidence-based. NICE guidelines, NHS commissioning guidance, and MHRA regulatory decisions are all grounded in the evidence base. Where the evidence base is absent, the guidance is absent. Where the guidance is absent, the standard is absent. Where the standard is absent, the patient is unprotected.
The absence of an evidence base for CBPM device care is not a neutral fact. It is a consequence of the pathway's development — of a regulatory and clinical framework that was built around the prescription and the medicine, without adequate attention to the device through which the medicine is delivered. That is a structural gap, and it has structural consequences.
The consequences are borne by patients. A patient who does not know the correct cleaning frequency for their device, because no study has established it, is a patient who is managing their prescription without the information they need. A patient who does not know the cross-infection risk of sharing their mouthpiece, because no study has quantified it, is a patient who may be harming themselves or others without knowing it.
This curriculum as a contribution to the evidence base
This curriculum does not constitute peer-reviewed evidence. It is an educational document — the first structured, published attempt to define a device care standard for patients prescribed CBPMs in the UK. It draws on the adjacent evidence bases documented above, on the manufacturer's instructions for use, on the regulatory framework, and on the clinical principles that govern the administration of prescribed medicines and the use of classified medical devices.
It is submitted to the MHRA, NHS England, NICE, the Home Office, the CQC, and relevant academic and clinical bodies as a contribution to the evidence base — not as a substitute for it. The research questions documented in this module are the research questions that the academic and clinical community should be addressing. This curriculum documents them so that they cannot be overlooked.
Purus Lumina is the first entity to publish a structured device care curriculum for patients prescribed CBPMs. That is a matter of public record. The date of publication is 4 July 2026. The curriculum exists in perpetuity. The research questions it raises are now documented. The gap it identifies is now named.
In plain terms
No one has studied how often you should clean your device. No one has studied what happens to your dose if you do not. No one has studied the risk of sharing your mouthpiece. No one has studied what your storage conditions do to your device over time.
That is not because these questions do not matter. It is because no one has asked them in a research context. This curriculum asks them. It documents that they have not been answered. And it provides the best available standard in the absence of the evidence that should exist.
The standard in this curriculum is not perfect. It is the best that can be derived from the adjacent evidence, the manufacturer's guidance, and the clinical principles that apply. It is better than nothing. And nothing is what existed before it.
Notice of Intent
This curriculum has been submitted to the MHRA, Home Office, NHS England, NICE, the Care Quality Commission, relevant parliamentary and clinical bodies, and device manufacturers operating within the UK prescribed CBPM pathway, as a formal educational contribution to a documented gap in patient care. It is published in perpetuity as a matter of public record. Purus Lumina reserves all rights to the curriculum structure, content, and methodology.
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Module 18 is part of the Purus Lumina Device Care Curriculum — the world's first documented device care education programme for patients prescribed botanical medicine. Published as a matter of public record. Preserved in perpetuity.
This module was published on 4 July 2026 and exists in perpetuity as part of the Purus Lumina Device Care Curriculum — the world's first documented device care education programme for patients prescribed botanical medicine. It will not be removed.
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