This study concerned the quality of mini-tablets’ coating uniformity obtained by either the bottom spray chamber with a classical Wurster distributor (CW) or a swirl distributor (SW). Mini-tablets with a diameter of 2.0, 2.5, and 3.0 mm were coated with hypromellose using two different inlet air distributors as well as inlet airflow rates (130 and 156 m³/h). Tartrazine was used as a colorant in the coating layer and the coating uniformity was assessed by spectrophotometric analysis of solutions obtained after disintegration of the mini-tablets (n = 100). Higher uniformity of coating material distribution among the mini-tablets was observed in the case of SW distributor, even for the biggest mini-tablets (d = 3.0 mm), with an RSD no larger than 5.0%. Additionally, coating thickness was evaluated by colorimetric analysis (n = 1000), using a scanner method, and expressed as a hue value. A high correlation (R = 0.993) between inter-tablet variability of hue and UV-Vis results was obtained. Mini-tablets were successfully coated in a fluid bed system using both a classical Wurster distributor as well as a swirl generator. However, regardless of the mini-tablets’ diameter, better film uniformity was achieved in the case of a distributor with a swirl generator.

According to the Quality by Design (QbD) concept, Design of Experiment (DoE) was used to indicate critical process parameters and optimize the fluid bed coating of minitablets in a laboratory size batch. Full factorial design was employed to increase knowledge of the process for three kinds of minitablet (MT) cores using two commercial gastro-resistant coating mixtures. The statistical analysis showed that different critical process parameters were indicated for the tested minitablets: X3: the coating mixture flow rate for MTs with pantoprazole sodium and Eudragit L; X2: the product temperature; X3 and X4: the spraying pressure for MTs with pantoprazole sodium and Acryl Eze II; and X1 and X2: MTs with diclofenac sodium. Such differences were the result of features, such as the sub-coat, size, and mass of the cores and the core and coating mixture composition. No optimal parameters were found for any of the tested MT types. Therefore, DoE should be considered as a statistical tool to individually optimize the process for the product, equipment, and tested parameters. However, optimization of the fluid bed coating allowed us to predict the values of the process parameters necessary to obtain good-quality products. Therefore, fluid bed coating may be successfully used to obtain modified-release MTs of high quality after applying the statistical tool DoE.

Background and Objectives: Bladder neck stenosis (BNS) and vesicourethral anastomotic stenosis (VUAS) are challenging complications following prostate surgery and radiation therapy, with recurrence rates reaching 30–60% after conventional endoscopic management. The Optilume^® paclitaxel drug-coated balloon (DCB) has emerged as a novel minimally invasive treatment combining mechanical dilation with local anti-fibrotic drug delivery. This narrative review synthesizes current evidence on Optilume DCB specifically for BNS and VUAS. Materials and Methods: A comprehensive literature search identified eight relevant publications (2024–2026), including randomized controlled trials, prospective and retrospective cohort studies, and case series addressing Optilume DCB for posterior urethral stenoses. Results: Across the reviewed studies, freedom from reintervention for BNS ranged from 77.5% to 100% at 12 months, while VUAS outcomes were more variable (40–81%). A comparative study of 141 patients demonstrated significantly improved recurrence-free survival with DCB versus standard endoscopic treatment (HR 0.40, p = 0.021). Radiation-induced posterior urethral stenosis showed 81.1% freedom from repeat intervention. Complications were predominantly minor (Clavien-Dindo grade I), with no de novo incontinence attributable to the device. Conclusions: Optilume DCB represents a promising minimally invasive option for BNS and VUAS, particularly in patients with recurrent disease or those unsuitable for reconstructive surgery. BNS appears to respond more favorably than VUAS, likely reflecting distinct pathophysiological mechanisms. Prior radiation therapy remains a negative prognostic factor. Prospective randomized trials with longer follow-up are needed to define the role of DCB in posterior urethral stenosis management.

Gastro-resistant oral dosage forms remain essential for protecting acid-labile active pharmaceutical ingredients, reducing gastric irritation, and enabling site-specific intestinal or colonic drug delivery. Although conventional enteric coatings are well established, their in vivo performance remains affected by gastric pH variability, food intake, alcohol exposure, gastric residence time, coating integrity, and interindividual differences in gastrointestinal transit. Advanced platforms, including ready-to-fill enteric capsules, hot-melt technologies, three-dimensional printing, electrospinning, micro- and nanocarriers, and pH-responsive hydrogels, have been proposed to overcome these limitations, but many remain at an experimental or early translational stage. This narrative review critically evaluates gastro-resistant oral formulations from technological, physiological, and regulatory perspectives. It compares established and emerging technologies with respect to release mechanisms, material requirements, processing constraints, acid-resistance performance, translational maturity, scalability, regulatory acceptability, and commercial feasibility. Recent advances, including rapid-release double-coating concepts and dual pH- and microbiota-triggered colonic delivery systems, are also discussed. Overall, the field is moving from simple gastric protection toward more predictive and functionally complex oral drug delivery platforms. Future progress will depend on biorelevant dissolution testing, stronger in vitro – in vivo correlations, quality-by-design approaches, process analytical technologies, greener manufacturing, and regulatory pathways capable of accommodating innovative materials and personalized oral therapeutics.

The development of age-appropriate pediatric dosage forms remains an important challenge, particularly for acid-labile drugs requiring gastro-resistant protection. Pantoprazole, a proton pump inhibitor, must be protected from gastric acid until intestinal absorption; however, conventional enteric-coated tablets may be difficult to use in younger children, while manipulation of dosage forms or mixing with food can compromise dose accuracy and drug release performance. Multiparticulate systems, such as minitablets, pellets, or granules, offer flexible dosing but may still require a suitable vehicle to improve acceptability, handling, and ease of swallowing. In this study, enteric-coated pantoprazole minitablets were developed and evaluated after dispersion in selected hydrogel vehicles intended to serve as standardized alternatives to food-based carriers. Hydrogels based on hypromellose (HPMC), carbomer (CAR), and sodium alginate (SA) were characterized in terms of pH, rheological properties, firmness, acid penetration, and their effect on pantoprazole release. Dissolution performance was assessed using both conventional pharmacopoeial testing and dynamic non-pharmacopoeial conditions. Low-concentration gels prepared from high-viscosity HPMC grades showed the most favorable performance, combining suitable spoonable consistency with limited impact on drug release. Among them, 5% HPMC 65SH4000 was particularly promising, as it did not markedly delay pantoprazole release in either pharmacopoeial or dynamic dissolution testing. CAR gels provided advantageous rheological properties, including high viscosity at rest and shear-thinning behavior, and allowed efficient pantoprazole release after transition to buffer conditions; however, their interaction with enteric-coated minitablets should be further optimized with respect to gel amount, concentration, and neutralization strategy. SA gel showed strong structural persistence and delayed release under pharmacopoeial conditions, although this effect was less pronounced in the dynamic model. Overall, the findings indicate that appropriately selected hydrogels may improve the practical use of pediatric multiparticulate formulations, but their composition, pH, rheology, and interaction with enteric coatings must be carefully evaluated.