Modern pharmaceutical technology still seeks new excipients and investigates the further use in already known ones. An example is magnesium aluminometasilicate Neusilin^® US2 (NEU), a commonly used inert filler with unique properties that are usable in various pharmaceutical fields of interest. We aimed to explore its application in hypromellose matrix systems (HPMC content 10–30%) compared to the traditionally used microcrystalline cellulose (MCC) PH 102. The properties of powder mixtures and directly compressed tablets containing individual fillers NEU or MCC, or their blend with ratios of 1.5:1, 1:1, and 0.5:1 were investigated. Besides the routine pharmaceutical testing, we have enriched the matrices’ evaluation with a biorelevant dynamic dissolution study and advanced statistical analysis. Under the USP apparatus 2 dissolution test, NEU, individually, did not provide advantages compared to MCC. The primary limitations were the burst effect increase followed by faster drug release at the 10–20% HPMC concentrations. However, the biorelevant dynamic dissolution study did not confirm these findings and showed similarities in dissolution profiles. It indicates the limitations of pharmacopoeial methods in matrix tablet development. Surprisingly, the NEU/MCC blend matrices at the same HPMC concentration showed technologically advantageous properties. Besides improved flowability, tablet hardness, and a positive impact on the in vitro drug dissolution profile toward zero-order kinetics, the USP 2 dissolution data of the samples N75M50 and N50M50 showed a similarity to those obtained from the dynamic biorelevant apparatus with multi-compartment structure. This finding demonstrates the more predictable in vivo behaviour of the developed matrix systems in human organisms.

The growing need for processing natural lipophilic and often volatile substances such as thymol, a promising candidate for topical treatment of intestinal mucosa, led us to the utilization of solid-state nuclear magnetic resonance (ss-NMR) spectroscopy for the rational design of enteric pellets with a thymol self-emulsifying system (SES). The SES (triacylglycerol, Labrasol^®, and propylene glycol) provided a stable o/w emulsion with particle size between 1 and 7 µm. The ex vivo experiment confirmed the SES mucosal permeation and thymol delivery to enterocytes. Pellets W90 (MCC, Neusilin^®US2, chitosan) were prepared using distilled water (90 g) by the M1–M3 extrusion/spheronisation methods varying in steps number and/or cumulative time. The pellets (705–740 µm) showed mostly comparable properties—zero friability, low intraparticular porosity (0–0.71%), and relatively high density (1.43–1.45%). They exhibited similar thymol release for 6 h (burst effect in 15th min ca. 60%), but its content increased (30–39.6 mg/g) with a shorter process time. The M3-W90 fluid-bed coated pellets (Eudragit^®L) prevented undesirable thymol release in stomach conditions (<10% for 3 h). A detailed, ss-NMR investigation revealed structural differences across samples prepared by M1–M3 methods concerning system stability and internal interactions. The suggested formulation and methodology are promising for other lipophilic volatiles in treating intestinal diseases.

Antimicrobial agent abuse poses a serious threat for future pharmacotherapy, including vaginal administration. The solution can be found in simple polymeric systems with inherent antimicrobial properties without the need to incorporate drugs, for instance alginate beads cross-linked by bivalent ions. The main goal of the presented study was to provide improvement on the well-documented cytotoxicity of Cu²⁺ cross-linked alginate. Alginate beads were prepared by external ionotropic gelation by cross-linking with Cu²⁺, Ca²⁺ and Zn²⁺ ions, separately and in mixtures. Morphological properties, swelling capacity, ion release and efficacy against the most common vaginal pathogens (C. albicans, E. coli, E. faecalis and virus strain—human herpesvirus type 1) were evaluated. The prepared particles (particle size 1455.68 ± 18.71–1756.31 ± 16.58 µm) had very good sphericity (0.86 ± 0.04–0.97 ± 0.06). In mixture samples, Cu²⁺ hampered second ion loading, and was also released incompletely (18.75–44.8%) compared to the single ion Cu²⁺ sample (71.4%). Efficacy against the selected pathogens was confirmed in almost all samples. Although anticipating otherwise, ion mixture samples did not show betterment over a Cu²⁺ cross-linked sample in cytotoxicity–pathogen efficacy relation. However, the desired improvement was found in a single ion Zn²⁺ sample whose minimal inhibition concentrations against the pathogens (0.6–6.12 mM) were close to, or in the same mathematical order as, its toxic concentration of 50 (1.891 mM). In summary, these findings combined with alginate’s biocompatibility and biodegradability give the combination solid potential in antimicrobial use.

Self-microemulsifying drug delivery systems (SMEDDS) containing volatile phytotherapeutics such as thymol (T), carvacrol (C), and eugenol (E) present significant formulation challenges, even when solidified. Their instability and interactions with coatings often hinder intestinal delivery. To address these limitations, we developed solid SMEDDS consisting of pellets (microcrystalline cellulose/magnesium aluminometasilicate/chitosan) and enteric capsules (CEC) for enhanced intestinal delivery. Based on solubility and pseudo-ternary phase diagrams, SMEDDS formulations (SES1-3) differing in component ratios (glycerol monooleate/caprylocaproyl macrogol-8 glycerides/diethylene glycol monoethyl ether) with 5% w/w of each drug were identified, demonstrating nano-scale droplet sizes (PDI 85% drug release within 120 min after a pH change to 6.8 during a one-year stability study (25 °C; 60% RH). FTIR-ATR analysis of the CEC internal surface confirmed the temperature-dependent restructuring of hypromellose and E sorption, a phenomenon not observed with C or T, which is likely attributable to physicochemical distinctions. Oral administration of CEC with T-SES1-pellets (0.5 mg/kg) in piglets demonstrated a delayed peak plasma concentration (C_max 11.67 ng/mL at 9 h) and sustained systemic exposure (AUC 119.8 ng·h/mL). These in-vivo findings substantiate the gastro-protective effect and enhanced intestinal absorption, positioning the pellet/CEC system as a promising strategy for the application of volatile phytotherapeutics in current pharmacotherapy.