In Situ Imaging of Subcutaneous Drug Delivery Systems Using Microspatially Offset Low-Frequency Raman Spectroscopy.

The noninvasive in situ monitoring of the status of drug retention and implant integrity of subcutaneous implants would allow optimization of therapy and avoid periods of subtherapeutic delivery kinetics. A proof-of principle study was conducted to determine the use of microspatially offset low-frequency Raman spectroscopy (micro-SOLFRS) for nonintrusive in situ analysis of subcutaneous drug delivery systems. Caffeine was used as the model drug, and it was embedded in a circular-shape Soluplus matrix via vacuum compression molding. For the exploratory analysis, prototype implants were positioned underneath skin tissue samples, and various caffeine concentrations (1-50% w/w) and micro-SOLFRS displacement settings (Δz = 0-8 mm) were tested from the pseudo three-dimensional (3D)-imaging perspective. This format allowed the optimization of real-time micro-SOLFRS analysis of implants through skin tissue that was embedded in an agarose hydrogel. Notably, this analytical approach allowed the temporal and spatial erosion of the implant and solid-state transformations of caffeine to be distinguished. The spectrometric results correlated with complementary high-performance liquid chromatography (HPLC) determination of changes in drug concentration, illustrating drug dissipation/diffusion characteristics. The discovered capability of micro-SOLFRS for in situ measurements of drugs and implants makes it attractive for biomedical diagnostics that, ultimately, could result in development of a new point-of-care technology.

In Operando Analysis of Milk-Based Oral Formulations during Digestion Using Synchrotron Small-Angle X-ray Scattering Coupled to Low-Frequency Raman Spectroscopy.

A low-frequency Raman (LFR) probe was coupled to an in-line small-angle X-ray scattering (SAXS) beamline to test the capabilities of a combinatory approach for the determination of lipid and drug behavior during the enzymatic lipolysis of milk-based oral formulations. Cinnarizine was used as the model drug, and its solubilization dynamics as well as its potential impact on the supramolecular structures formed by the digestion products of bovine milk were evaluated from the perspective of both techniques. The SAXS data were superior in distinguishing various liquid crystalline assemblies formed during the digestion process, with LFR providing complementary information regarding the formation of calcium soaps. On the other hand, studying changes in the LFR domain allowed the differentiation of drug solubilization and precipitation; processes that were less clear from the X-ray scattering data. Given the relative simplicity of the combined experimental setup, these results highlight the advantages that the combination of the two techniques can provide for understanding and developing new lipid-based formulations and will help to translate the results obtained at synchrotron facilities to routine analysis procedures in laboratory/industry-based environments.

Montmorillonite restricts free fatty acid liberation and alters self-assembled structures formed during in vitro lipid digestion.

The global rise in obesity necessitates innovative weight loss strategies. Naturally occurring smectite clays, such as montmorillonite (MMT), offer promise due to their unique properties that interfere with free fatty acid (FFA) liberation, reducing systemic uptake. However, the mechanisms of MMT-FFA interactions and their implications for weight management are undefined. This study investigates these interactions by adding MMT (10 % w/w) to in vitro lipolysis media containing medium chain triglycerides (MCTs), and monitoring FFA liberation using pH-stat titration. Nanoparticle tracking analysis (NTA) and synchrotron-based small-angle X-ray scattering (sSAXS) observed time-dependent structural changes, while electron microscopy examined clay morphology during digestion. A 35 % reduction in FFA liberation occurred after 25 min of digestion with MCT + MMT, with digestion kinetics following a biphasic model driven by calcium soap formation. NTA revealed a 17-fold decrease in vesicular structures with MCT + MMT, and sSAXS highlighted a rapid lamellar phase evolution linked to calcium soap formation. This acceleration is attributed to MMT's adsorption to unionized FFAs via hydrogen bonding, supported by TEM images showing a decrease in d-spacing, indicating FFA intercalation is not the main adsorption mechanism. These findings highlight MMT's potential as a novel intervention for reducing dietary lipid absorption in obesity and metabolic diseases.

Compartmentalised enzyme-induced phase transformations in self-assembling lipid systems.

HYPOTHESIS: Understanding the digestion of lipid-based pharmaceutical formulations and food systems is necessary for optimising drug and nutrient delivery and has been extensively studied in bulk emulsion systems using the pH-stat method [1]. However, this approach is not suitable for investigation of individual lipid droplets, in particular the interface where the lipase acts. Microfluidic approaches to study digestion at lipid-water interfaces using droplet trapping have been proposed, however the aqueous phase in that case washes over the interface presenting uncertainty over the stoichiometry of interactions [2]. The internal interface of a Janus-like droplet, containing distinct aqueous and lipid compartments, mimics the interface of a lipid droplet in aqueous solution with controlled stoichiometry [3]. Hence, it was hypothesised that the internal interface of Janus droplets can offer a precise way to study the enzymatic digestion of lipids formulations. EXPERIMENTS: Using microfluidic methods, Janus-like droplets were formed by coalescing emulsion droplets containing lipid formulation and pancreatic lipase. Polarised light microscopy (PLM) and in-situ small-angle X-ray scattering (SAXS) were used to investigate the droplets. FINDINGS: PLM revealed the growth of an aligned inverse hexagonal phase (H2), and with SAXS showed that this phase transformation and alignment resulted from enzymatic digestion. A subsequent partial transformation from H2 to inverse bicontinuous cubic phase occurred when simulated intestinal fluid was used instead of Tris buffer. Suggesting that phospholipids and bile salts could diffuse across the internal interface to locally affect their surroundings.

Infant formula as a solid lipid dose form for enhancement of the oral bioavailability of cannabidiol for paediatric patients.

Cannabinoids can save paediatric patients from harmful psychological conditions caused by epilepsy. However, the limited aqueous solubility of the drug presents a limitation to oral absorption and bioavailability. Previous studies have shown the enhancement of oral bioavailability for poorly water-soluble drugs using milk or milk-based products like infant formula as a novel lipid-based formulation, due to digestion of the lipids to enhance drug solubility that is particularly well suited to infants and in low economy settings. Therefore, this study has investigated the in vitro solubilisation enhancement of cannabidiol (CBD) in milk-based products during digestion using synchrotron small angle X-ray scattering, followed by pharmacokinetic studies to determine the relative oral bioavailability. The in vitro results, coupled with in vivo data, demonstrate a two-fold increase in the oral bioavailability of CBD in bovine milk as well as infant formula. The results of this study indicate the potential for infant formula to be considered as a novel formulation approach for CBD. Further study is encouraged for more drugs with infant formula to strengthen the correlation between the solubilisation of drug and their oral bioavailability.

Enhanced clearance of C. muridarum infection using azithromycin-loaded liposomes.

Chlamydia trachomatis is an intracellular bacterium which infects around 129 million people annually. Despite similar infection rates between sexes, most research investigating the effects of chlamydial infection on fertility has focused on females. There is now emerging evidence of a potential link between Chlamydia and impaired male fertility. The only treatments for chlamydial infection are antibiotics, with azithromycin (AZI) being one of the commonly used drugs. However, recent studies have suggested that optimizing the treatment regime is necessary, as higher concentrations of AZI may be required to effectively clear the infection in certain cell types, particularly testicular macrophages. To address this challenge, we have prepared liposomes consisting of 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) and D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS) loaded with AZI for clearing Chlamydia. These liposomes exhibited stability over time and were readily taken up by both macrophages and epithelial cells. Moreover, they demonstrated significant enhancement of chlamydial clearance in both cell types. In a mouse model, the drug-loaded liposomes cleared Chlamydia within the penile urethra more efficiently than the same dose of unencapsulated drug. Furthermore, the liposome-drug treatment showed significant protective effects on sperm motility and morphology, suggesting potential benefits in reducing sperm damage caused by the infection.