Seok Chan Park

Nicotine pouches are a growing category in the smoke-free market, serving as an alternative to traditional tobacco products due to their noncombustible nature. Liquid and gas chromatography techniques coupled to various detectors were proven to be effective for determining nicotine content in tobacco products, including nicotine pouches. However, they require multiple steps and labor-intensive procedures for analysis. In this study, we developed a novel Raman spectroscopic method for accurately determining nicotine content in nicotine pouch products using a wide-area illumination scheme providing a 6 mm laser illumination diameter and a long focal length. Using chemometric tools, we analyzed 15 nicotine pouch products from a single commercially available brand (on! nicotine pouches), encompassing five flavor variantsOriginal, Mint, Wintergreen, Citrus, and Berryacross three nicotine levels (2, 4, and 8 mg). Partial least-squares regression was used to determine the nicotine content. The method accuracy was found to be 99.0–102.3% for all 4 and 8 mg nicotine pouch products, including all five flavor variants. For 2 mg nicotine pouches, method accuracy was calculated to be 93.1–108.8%, except for the Berry flavor due to the more significant fluorescence interference in lower nicotine content. Furthermore, the Raman spectra were analyzed using the k-nearest neighbor, allowing the classification of nicotine pouches into five groups based on their flavor variants. The results underscore the use of Raman spectroscopy as a rapid, direct, and noninvasive technique for product characterization, enabling accurate determination of nicotine content in nicotine pouches and facilitating their classification into distinct flavor-based groups.

In this study, we conducted a comprehensive analysis of seven commercially available nicotine pouch products, including on! , Zyn , Velo , Dryft , Rogue , Volt , and Loop nicotine pouches. Analyses include nicotine content, nicotine dissolution release, particle size, imaging (bulk filler and outer pouch material), bulk density (tapped and untapped), true density, crystallinity, solubility, oven volatiles (OV as measured by percent moisture content, % MC), pH of aqueous extracts, water activity, and extract viscosity. The nicotine dissolution profiles showed a faster release for on! , Zyn , and Rogue when compared to Velo , Dryft , Volt , and Loop nicotine pouches. When all nicotine pouches release profiles were compared to on! , only Zyn and Rogue were found equivalent. Particle size analysis revealed Gaussian-like distributions for on! , Rogue , and Zyn nicotine pouches. The remaining products displayed bimodal particle size distributions. Tapped and untapped bulk densities were measured to assess the flowability of the filler in all seven nicotine pouches. Rogue and Loop nicotine pouches exhibited the highest and lowest flowabilities, respectively. Solubility data indicated that Zyn nicotine pouches had the highest percentage of soluble components, whereas Rogue nicotine pouches had the lowest. Rheology results from the nicotine pouch extracts in artificial saliva showed the highest viscosity for Loop and lowest viscosity for Volt and Rogue nicotine pouches. All products were found to have crystalline structures with both high and low temperature melting points. Our results indicate that nicotine pouch products exhibit differences and similarities in their physicochemical properties, providing valuable insights into understanding their formulation and development.

As nicotine pouches have emerged as a potentially reduced-risk alternative to smoking cigarettes, accurate determination of nicotine concentration in these pouches is vital for ensuring regulatory compliance and product consistency. Although chromatographic methods such as liquid chromatography with tandem mass spectrometry (LC-MS/MS), gas chromatography with mass spectrometry (GC-MS), and gas chromatography with flame ionization detection (GC-FID) have proven effective for determining nicotine content in nicotine pouches, they involve multiple steps and time-consuming procedures. In this study, we developed and validated a simple ultraviolet (UV) spectrophotometry method for nicotine analysis in nicotine pouches. The UV spectrophotometry method simplifies the process of nicotine quantitation by reducing reagent preparation, extraction steps, and analysis time, offering ease of implementation and making it suitable for routine testing. The method was validated using 12 nicotine pouches of four flavor variants (original, citrus, mint, and wintergreen) and three nicotine levels (2, 4, and 8 mg per pouch). The method demonstrated an accuracy ranging from 95.2% to 107.7% recovery, repeatability with less than 8.02% relative standard deviation (RSD), and intermediate precision with less than 8.44% RSD. Robustness tests showed a less than 2% change for varying extraction times and devices. We demonstrated the applicability and accuracy of this UV method by comparing the nicotine quantitation results to results obtained from a standardized chromatographic Cooperation Centre for Scientific Research Relative to Tobacco (CORESTA) Recommended Method (CRM). We believe this method is a valuable tool for nicotine analysis in nicotine pouches, supporting product development, quality control, and regulatory reporting.

Mineral oil hydrocarbons (MOH) are widely used in the food industry for applications such as printing inks, additives, adhesives, and processing aids for food additives. Recently, the migration of MOH from food contact paper and board into foods has raised public health concerns. In this study, a total of 110 food contact paper and board samples, including baking and cooking paper (23), baking cups (28), food packaging bags (22), lunch boxes (8), party plates (26), and straws (3) were evaluated to quantify the content and short-term migration levels of MOH. The MOH were separated into mineral oil saturated hydrocarbons (MOSH)/polyolefin oligomeric saturated hydrocarbons (POSH) and mineral oil aromatic hydrocarbons (MOAH) via a validated on-line liquid chromatography−gas chromatography−flame ionisation detection (LC–GC–FID) technique. The coating materials of the sample products comprised polyethylene, polypropylene, polyethylene terephthalate, and silicone. The effects of the coating materials on the content and migration of MOH/POSH were evaluated. Quantitative analysis of the MOH in the samples showed that the MOSH/POSH and MOAH content varied widely, ranging from 16 to 5626 mg kg⁻¹ for MOH, regardless of the coating materials. Short-term migration of MOSH/POSH was observed only in samples with polyolefinic coatings, such as polyethylene and polypropylene, in experiments conducted at 25 °C for 10 min, although the extent of MOAH migration for all samples was at the trace level. The migration of MOSH/POSH was detected within the range of 0.93 to 62.3 μg L⁻¹ in 22 samples, and the migration of MOAH was detected within the range of 0.80 to 2.6 μg L⁻¹ in only 4 samples. These results demonstrate that although the short-term migration potential of MOH is generally negligible, the migration of MOSH/POSH into wet fatty foods can be accelerated by polyolefinic coatings, even within a very short time.

Aberrant splicing and protein interaction of Ras binding domain (RBD) is associated with melanoma drug resistance. Here cobalt or nickel doped zinc oxide (ZnO) physiometacomposite (PMC) materials bind to RNA and peptide shown by Ninhydrin staining, UV/Vis, FT-IR and CD spectroscopy. PMC deliver splice switching oligomer (SSO) into melanoma cells or 3-D tumor spheroids shown by flow cytometry, fluorescence microscopy and bioluminescence. Stability in serum, liver or tumor homogenate up to 48 hours and B16F10 melanoma inhibition >98-99% is shown. These data suggest pre-clinical potential of PMC for delivery of SSO, RBD or other nucleic acid therapeutic and anticancer peptides.

In this study we present polymeric microneedles composed of multiple layers to control drug release kinetics. Layered microneedles were fabricated by spraying poly(lactic-co-glycolic acid) (PLGA) and polyvinylpyrrolidone (PVP) in sequence, and were characterized by mechanical testing and ex vivo skin insertion tests. The compression test demonstrated that no noticeable layer separation occurred, indicating good adhesion between PLGA and PVP layers. Histological examination confirmed that the microneedles were successfully inserted into the skin and indicated biphasic release of dyes incorporated within microneedle matrices. Structural changes of a model protein drug, bovine serum albumin (BSA), in PLGA and PVP matrices were examined by circular dichroism (CD) and fluorescence spectroscopy. The results showed that the tertiary structure of BSA was well maintained in both PLGA and PVP layers while the secondary structures were slightly changed during microneedle fabrication. In vitro release studies showed that over 60% of BSA in the PLGA layer was released within 1 h, followed by continuous slow release over the course of the experiments (7 days), while BSA in the PVP layer was completely released within 0.5 h. The initial burst of BSA from PLGA was further controlled by depositing a blank PLGA layer prior to forming the PLGA layer containing BSA. The blank PLGA layer acted as a diffusion barrier, resulting in a reduced initial burst. The formation of the PLGA diffusion barrier was visualized using confocal microscopy. Our results suggest that the spray-formed multilayer microneedles could be an attractive transdermal drug delivery system that is capable of modulating a drug release profile.

Developing a facile means of controlling drug release is of utmost interest in drug delivery systems. In this study, core–shell structured nanofibers containing a water-soluble porogen were fabricated via solution blow spinning, to be used as drug-loaded bioactive tissue scaffolds. Hydrophilic polyvinylpyrrolidone (PVP) and hydrophobic poly(ε-caprolactone) (PCL) were chosen to produce the core and the shell compartments of the fiber, respectively. In the core, a hydrophilic sulforhodamine B (SRB) dye was loaded as a model drug. In the PCL shell, two kinds of PVP with different molecular weights (40 kDa and 1300 kDa) were added, and the influence of PVP leaching on the SRB release and cell growth was investigated. The monolithic PCL-shelled fibers displayed a sustained SRB release with a weak burst effect. The addition of PVP in the shell induced a phase separation, forming microscale PVP domains. The PVP domain, acting as a porogen, was leached out in the medium and, as a result, the burst release of SRB was promoted. This burst effect was more prominent with the lower molecular weight PVP. The biocompatibility of the core–shell fibers was evaluated with human epidermal keratinocytes (HEK) by a cell viability assay and microscopic observation of cell proliferation. The HEK cells on fibers with a PVP/PCL composite shell formed self-assembled spherical clusters, displaying higher cell viability and proliferation than those on the monolithic PCL-shelled fibers that induced HEK cell growth in two-dimensional monolayers. The results demonstrate that the presence of hydrophilic porogens on tissue scaffolds can accelerate drug release and enhance cell proliferation by increasing surface wettability, roughness and porosity. The findings of this study provide a basic insight into the construction of bioactive three-dimensional tissue scaffolds.

In this study we present the fabrication of multilayer microneedles with circular obelisk and beveled-circular obelisk geometries, which have potential applications in implantable drug delivery devices. Micro-milling was adopted as an environmental-friendly and cost-effective way to fabricate primary metal microneedle masters. Polylactic acid (PLA) microneedles with sharp tips were then obtained by micromolding followed by oxygen plasma etching and used for preparing polydimethylsiloxane (PDMS) microneedle molds. A spray deposition process was employed for microneedle fabrication to facilitate the formation of multilayer microneedles while helping in maintenance of drug stability. Multilayer microneedles were successfully formed by sequential spraying of poly(lactic-co-glycolic acid) (PLGA) and polyvinylpyrrolidone (PVP) solutions into the mold. The fabricated PLGA-PVP multilayer microneedles penetrated the pig cadaver skin without breakage and released dyes in the skin at different rates, which reveals the potential for implantable microneedles enabling controlled release. Mechanical testing demonstrated that the obelisk-shaped microneedles were mechanically stronger than a pyramid-shaped microneedle and suggested that strong adhesion between PLGA and PVP layers was achieved as well. Structural stability and functionality of a model drug, horseradish peroxidase (HRP), upon spray deposition was examined using circular dichroism (CD) spectroscopy and enzyme activity assay. HRP retained its secondary structure and activity in PVP, whereas HRP in PLGA showed structural changes and reduced activity. Combination of micro-milling and spray deposition would be an attractive way of fabricating drug-containing polymer microneedles with various geometries while reducing prototyping time and process-induced drug instability.