A drug dissolution profile is one of the most critical dosage form characteristics with immediate and controlled drug release. Comparing the dissolution profiles of different pharmaceutical products plays a key role before starting the bioequivalence or stability studies. General recommendations for dissolution profile comparison are mentioned by the EMA and FDA guidelines. However, neither the EMA nor the FDA provides unambiguous instructions for comparing the dissolution curves, except for calculating the similarity factor f₂. In agreement with the EMA and FDA strategy for comparing the dissolution profiles, this manuscript provides an overview of suitable statistical methods (CI derivation for f₂ based on bootstrap, CI derivation for the difference between reference and test samples, Mahalanobis distance, model-dependent approach and maximum deviation method), their procedures and limitations. However, usage of statistical approaches for the above-described methods can be met with difficulties, especially when combined with the requirement of practice for robust and straightforward techniques for data evaluation. Therefore, the bootstrap to derive the CI for f₂ or CI derivation for the difference between reference and test samples was selected as the method of choice.

The present study focused on the more detailed characterization of chitosan–carrageenan-based matrix tablets with respect to their potential utilization for drug targeting in the intestine. The study systematically dealt with the particular stages of the dissolution process, as well as with different views of the physico-chemical processes involved in these stages. The initial swelling of the tablets in the acidic medium based on the combined microscopy–calorimetry point of view, the pH-induced differences in the erosion and swelling of the tested tablets, and the morphological characterization of the tablets are discussed. The dissolution kinetics correlated with the rheological properties and mucoadhesive behavior of the tablets are also reported, and, correspondingly, the formulations with suitable properties were identified. It was confirmed that the formation of the chitosan–carrageenan polyelectrolyte complex may be an elegant and beneficial alternative solution for the drug targeting to the intestine by the matrix tablet.

Tablets used for extended drug release commonly contain large amounts of drugs. The corresponding drug release mechanism thus has to be well-known and invariable under numerous conditions in order to prevent any uncontrolled drug release. Particularly important is the stability and invariability of the release mechanism in the presence of alcohol due to the possible occurrence of the dose dumping effect. The effect of 3D printing (3DP) coating on the drug release mechanism and the drug release rate was studied as a possible tool for the prevention of the alcohol-induced dose dumping effect. Three types of matrix tablets (hydrophilic, lipophilic, and hydrophilic-lipophilic) were prepared by the direct compression method and coated using 3DP. The commercial filament of polyvinyl alcohol (PVA) and the filament prepared from hypromellose by hot melt extrusion (HME) were used as coating materials. Both coating materials were characterized by SEM, DSC, Raman spectroscopy, and PXRD during particular stages of the processing/coating procedure. The dissolution behavior of the uncoated and coated tablets was studied in the strongly acidic (pH 1.2) and alcoholic (40% of ethanol) dissolution media. The dissolution tests in the alcoholic medium showed that the Affinisol coating was effective in preventing the dose dumping incidence. The dissolution tests in the acidic dissolution media showed that the Affinisol coating can also be useful for the delayed release of active substances.

Materials based on the hydroxypropyl methylcellulose mixed with different biopolymers (BioP; 5 w% of chitosan, sodium alginate, apple pectin, or citrus pectin) were processed by hot-melt extrusion and 3D printing to produce capsules intended for controlled drug release. Microscopic analyses confirmed significant impact of BioP on the processing temperatures and quality of the 3D printing. The capsules’ chemical composition had a more significant impact on the dissolution profiles in acidic and neutral media, which are a robust function of the intermolecular bonds and swelling characteristics of the particular BioP (as indicated by the combined results of Raman spectroscopy, differential scanning calorimetry [DSC], and thermogravimetry). The capsules of all tested compositions retained the model drug for 120 min in pH 1.2, i.e., fulfilled the condition of targeting the small intestine. The presence of the particular BioP was found to be particularly beneficial in the development of personalized capsules for oral administration. The addition of both pectins led to a relatively fast pH-independent release of the model drug and has the potential applications in the targeting of the duodenum or jejunum. The capsules containing alginate and chitosan exhibited later initial release in pH 1.2, guaranteeing an unaltered passage through the stomach environment.

This study introduces a novel approach to prepare an intestine‐targeting transport system with a controlled drug release profile, combining two 3D printing techniques: selective laser sintering (SLS) and fused deposition modeling (FDM). Material evaluations indicate that a mixture of Kollidon^® VA64 with 20% of Kollicoat^® IR and 0.2% of Aeroperl^® has the best flow behavior and exhibits optimal printability at a laser speed of 90 mm s⁻¹. The formulation is subsequently drug‐loaded and the printed cores are coated using the FDM technique. The core serves as a drug carrier and the FDM coating shell, consisting of 95% HPMC and 5% pectin, provides modified drug release and enhanced mechanical resistance of the tablet. The coating exhibits acid‐resistant properties, with no drug release in the pH of 1.2 during the first 120 min of dissolution testing. In the pH of 6.8, the release profile shows zero‐order kinetics with a constant release rate of 0.249% min⁻¹ (in the time interval from 255 to 480 min). At the time point of 720 min, 92% of the drug is released. Dissolution testing thus demonstrates delayed and prolonged drug release. Combining both 3D printing methods shows great potential for personalized treatment of intestinal inflammatory diseases.

This study shows the possibility of processing carbohydrate-based composite material (hypromellose and pectin from citrus peel) by a hot-melt extrusion (HME) process for bio-based filament preparation. Filaments with suitable mechanical and physicochemical properties were applied for fused deposition modeling (FDM) of peroral drug forms. The emphasis is placed on two 3D-printed forms applicable in pharmacy: FDM-printed coatings for matrix tablets (prepared by direct compression method) and capsules, both designed in appropriate software (Fusion®360). Each studied form was subjected to dimensional analysis to verify the reproducibility and stability of the 3D printing (3DP) process. Poly(vinylalcohol) (PVA) filament (the only commercial filament suitable in the pharmacy field) was used as a reference for the eligibility assessment of the designed 3D models. Two groups of the prepared dosage forms (coated matrix tablets, capsules) were tested by in vitro dissolution studies following European Pharmacopoeia. Detailed results of the dissolution study are summarized in this article. 3D printed coatings and capsules from bio based filament enable delayed drug release, which is in high demand for colon-targeted drug delivery. Next, the dosage forms made of PVA show lower lag times, whereas PVA capsules show potential in stomach-targeted drug delivery. Moreover, scanning electron microscopy analysis of the drug forms revealed the influence of the pectin particles on the consistency of the 3D-printed layers. Thermal stability of the processing materials was also studied by differential scanning calorimetry. No less important part is the practical application of a one-screw manual extruder for the preparation of biocomposite-based filaments. Obtained practical knowledge of HME and FDM 3DP processes are discussed and compared with the available machine learning prediction model M3DISEEN.