Falsified and substandard (SF) medications are a growing global public health threat, harming patients and promoting antimicrobial resistance 1 . There has been a recent deluge of SF medicines and medical products for management of COVID-19 infection, and this issue is likely to worsen 2 . Many portable technologies exist to protect the supply chain as medications are manufactured and transported for distribution 3 . However, surveillance and testing at the end of the supply chain remains difficult 1 . Accurate, scalable, easy to use, portable field-based screening technologies that can be used by clinicians, public health officials, pharmacists, and law enforcement agents are needed.
MedSnap (Indicator Sciences, LLC, Seattle, WA, USA) is a smartphone-based system that uses computer vision to evaluate the authenticity of solid oral medications. MedSnap is comprised of two smartphone applications: MedSnap VR and MedSnap DA. MedSnap DA is used to acquire images of trusted and authentic samples of tablets and capsules and is used only by MedSnap or project-specific designated technical personnel. Images are uploaded to cloud-based servers where statistical models of 25 visual features are built. MedSnap VR then uses those models to evaluate the precise appearance of tablets and capsules and returns results on whether or not the tested sample is visually consistent with known authentic products.
Both applications are secured by user credentials and securely transmit data when connected to cellular or Wi-Fi networks. MedSnap VR only requires network connectivity for periodic application updates and to send results to secure cloud servers. It does not require connectivity to test samples. MedSnap VR can be automatically disabled after extended off-network use and can be remotely disabled if inappropriate use is suspected.
The applications acquire images in reasonable diffuse lighting conditions (no direct sunlight or harsh shadows), and both automatically check ambient lighting before each snap to make sure lighting is within acceptable limits.
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For testing using MedSnap VR, the user selects a medication then holds the smartphone above a sample of up to 9 tablets or capsules arranged on a durable vinyl background called a Snap Surface. Once positioned, the application automatically takes an image with flash exposure. When 9 tablet images are collected for each side, the application computes 25 features of visual appearance per side, and compares them to statistical models of known authentic medications. The VR and DA applications measure sizes to within +/-0.1mm, construct detailed imprint composites, and differentiate 250,000+ shades of color.
We conducted a proof-of-principle laboratory and field-sample evaluation of MedSnap in Vientiane, Lao PDR (Laos) with the Medicine Quality Research Group at the Laos-Oxford-Mahosot-Wellcome Trust Research Unit (LOMWRU) of Mahosot Hospital.
Two MedSnap technicians visited the LOMWRU for three days. LOMWRU provided samples of azithromycin and ciprofloxacin directly obtained from trusted manufacturers and/or distributors in Laos, Cambodia, and Thailand. These trusted samples were assumed to be authentic for the purposes of this evaluation. LOMWRU also provided laboratory-tested samples of authentic and falsified artesunate and artemether-. CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)
The copyright holder for this preprint this version posted May 11, 2020. . https://doi.org/10.1101/2020.05.06.20093427 doi: medRxiv preprint lumefantrine (Coartem). Field-collected samples of ciprofloxacin and azithromycin were obtained in a convenience sample from local pharmacies in Vientiane City. All materials were organized and labeled by LOMWRU staff before being tested with the Medsnap technicians in a laboratory setting.
Trusted and authentic samples of all medicines were imaged with the MedSnap DA application and resulting data was securely transferred to cloud servers for model building by technicians in the United States. A statistical model was created for each sample. Monte Carlo simulation methods were used to remove redundant models that were statistically indistinguishable from those retained. Retained models were securely transmitted to the remote MedSnap VR applications.
With MedSnap VR and authentic models loaded, each sample of authentic, trusted, known falsified, and field-collected medicine was tested twice by the testing technician. In the case of a discrepancy between snap results, a third snap was performed and the majority result was counted.
Each VR snap was of a sample of one or more tablets, all with the same appearance. For brevity, we describe the process for tablet processing here. Capsule processing is similar with additional considerations for capsule caps, bodies, wrapped imprints, etc.
Tablets are placed on the Snap Surface, same-side-up according to the application prompt and imaged, then, if necessary, moved randomly and imaged again. Once enough images of the tablet-side are acquired (9 for MedSnap VR), the tablets are flipped and the same process is repeated.
With each snap, the applications first check for acceptable ambient lighting. Once the image is rectified and color-corrected, the application segments the image and extracts measurements of tablet features in five categories: shape, size, color, texture, and imprint. Each category is comprised of multiple features and in total, 25 features are computed per sample per tablet side. Each feature is averaged across the 9 images per tablet side and these average features are tested against their respective distributions in authentic models under the null hypothesis of no difference. If any test fails, the sample fails and is reported as not matching any authentic models. Multiple statistical tests are accommodated by the standard Holm-Bonferroni method 4 .
All samples of authentic and trusted medicines were tested with MedSnap VR. Twelve samples of known falsified artesunate of packaging types N°1,2,6,9,10,14 5 and 14 samples of known falsified Coartem were also tested. In addition, 13 samples of fieldcollected azithromycin and 8 samples of field-collected ciprofloxacin were also tested.
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One sample each of two visually distinct forms of authentic artesunate, 11 samples over 3 forms of trusted azithromycin, 8 samples over 7 forms of trusted ciprofloxacin, and 1 sample each of 2 forms of authentic artemether-lumefantrine (Coartem Ò Novartis Pharmaceuticals Corporation, Suffern, New York, USA) were imaged with MedSnap DA and modelled.
Of the 49 samples tested, first-snap sensitivity was 100%, and first-snap specificity was 96%. One sample of trusted azithromycin 250mg returned a discrepant result between the two VR snaps. It was tested a third time and passed the trusted model yielding 2/3 pass. This discrepancy-resolved result was correct. Overall, sensitivity was 100% and discrepancy-resolved specificity was 100% (Table 1) . In addition, all 21 field samples of azithromycin and ciprofloxacin purchased from local pharmacies in Vientiane passed trusted models.
Analysis of visual relationships between authentic medications showed that within doseform appearances, authentic samples were statistically indistinguishable.
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The copyright holder for this preprint this version posted May 11, 2020. Note that there is much less white in the overlay on the right, as the two composite imprints do not align. This can be due to materials used in manufacture, differences in dies, or how the tablet stamping machine was configured pre-production.
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MedSnap uses a consumer smartphone camera and durable vinyl Snap Surface to collect detailed, precise visual data for authentic reference model creation and to test solid oral medications for authenticity. With this approach "authentic" is defined by the precise combination of visual elements across 25 features which provide evidence of the ingredients and source of origin of the medication.
Modern medication manufacturing requires high volume production in order to keep individual unit costs low and maintain profit -this applies to the business models of both authentic and falsified manufacturers. Mass production techniques and equipment for both tablets and capsules produce product units which bear visual evidence of their common origin and ingredients. It is this evidence that MedSnap collects and uses to distinguish authentic and falsified for screening purposes.
In this study, MedSnap had a sensitivity of 100% and a specificity of 100%. One test of trusted authentic azithromycin yielded a discrepant result (fail then pass). A third snap correctly passed the sample making 2/3 tests for this sample correct. An investigation into this this result yielded the cause of the error which was related to image processing. This problem has since been corrected.
Within this 3-day project authentic and trusted reference models were created, deployed, and used to test the local supply of two key medications (azithromycin and ciprofloxacin) along with archived samples of artemether-lumefantrine and artesunate. This demonstrates that MedSnap can be quickly deployed to conduct falsified medicine surveillance.
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MedSnap uses high intensity visual light from the smartphone flash and obtains precise color, size, and position measurements calibrated by the background Snap Surface. For example, tablets and capsules are measured in several dimensions to within +/-0.1mm, over 250,000 shades of color can be captured, and highly detailed imprint composites are created and compared. Snap Surfaces can be cleaned with alcohol and are extremely durable.
Advantages of the MedSnap approach include handheld portability, ease of use for sample testing, high precision measurement of 25 aspects of visual appearance, and the ability to designate authentic or trusted using detailed visual evidence. In addition, central collection of detailed visual data on both authentic and falsified medications allow for prevalence analysis that benefits public health and law enforcement teams who must focus resources on areas of greatest need.
Authentic samples can be imaged centrally by MedSnap staff or remotely by trained partners or customer staff. Authentic models are maintained centrally by MedSnap team members. Authentic models collected for one project can also be included in another when necessary, so the library of authentic medications continues to grow.
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The copyright holder for this preprint this version posted May 11, 2020. . https://doi.org/10.1101/2020.05.06.20093427 doi: medRxiv preprint A typical project with a health system, regional healthcare provider, or government (sponsor) proceeds as follows: MedSnap can be used for ongoing screening surveillance and targeted investigations. Administrators of a MedSnap project can decide what is likely authentic or trusted, create authentic models on these samples, quickly conduct field testing, and definitive testing of chemical authenticity of the trusted medications can be completed at a future date if required -speeding the entire cycle of work.
The ease of use of the system makes it appropriate for use by clinic or pharmacy personnel when a patient is suspected of non-response to medications. In parts of the world with high prevalence of falsified medications, encouraging patients to bring their medications to clinic or to the pharmacy for authentication could become another vital sign to ensure their recovery and efficiency of care.
We assumed that samples of azithromycin and ciprofloxacin, acquired from trusted manufacturers and distributors, were authentic. Laboratory chemical testing was not performed on these samples. Laboratory testing was performed on curated authentic and falsified samples of artesunate and Coartem. Only four medicines, including five active pharmaceutical ingredients and only tablets were included. The falsified and authentic samples of artemether-lumefantrine and artesunate that were tested were well beyond expiry dates (at least 3 years past expiry) which may have altered the physical appearance of the tablets and distorted the results.
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MedSnap is an accurate, scalable application requiring only a handheld, widely available consumer smartphone and a durable, vinyl background for sample testing. It can be used in developing and developed markets to screen solid oral medications along the supply chain, including at the point of dispensing in the pharmacy or clinic. Use of MedSnap in combination with other chemical testing devices to evaluate API may increase confidence in the MedSnap authentic medication library. The ability for local or regional users to specify likely authentic medications as such and rapidly deploy models for surveillance is an advantage for the system.
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The copyright holder for this preprint this version posted May 11, 2020. CC-BY-NC-ND 4.0 International license It is made available under a is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review)
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The copyright holder for this preprint this version posted May 11, 2020. . https://doi.org/10.1101/2020.05.06.20093427 doi: medRxiv preprint