Transmucosal drug delivery systems can be an attractive alternative to conventional oral dosage forms such as tablets. There are numerous in vitro methods to estimate the behavior of mucoadhesive dosage forms in vivo. In this work, a tensile test system was used to measure the mucoadhesion of polyvinyl alcohol films. An in vitro screening of potential influencing variables was performed on biomimetic agar/mucin gels. Among the test device-specific factors, contact time and withdrawal speed were identified as influencing parameters. In addition, influencing factors such as the sample area, which showed a linear relationship in relation to the resulting work, and the liquid addition, which led to an abrupt decrease in adhesion, could be identified. The influence of tissue preparation was investigated in ex vivo experiments on porcine small intestinal tissue. It was found that lower values of F_max and W_ad were obtained on processed and fresh tissue than on processed and thawed tissue. Film adhesion on fresh, unprocessed tissue was lowest in most of the animals tested. Comparison of ex vivo measurements on porcine small intestinal tissue with in vitro measurements on agar/mucin gels illustrates the inter- and intra-individual variability of biological tissue.

There are no methods for specific local application of active substances to the mucosa of the esophagus to treat eosinophilic esophagitis or other esophageal diseases. This publication describes the principal in vivo functionality and acceptance of a novel modular drug delivery concept, called EsoCap system, by 12 healthy volunteers. For the first time, the EsoCap system enables targeted placement on the esophageal mucosa of a mucoadhesive polymer film. Acceptance was determined by means of a standardized questionnaire after administration and functionality of the device by MRI scans. Two different setups of the EsoCap system were tested: one setup with a density of 0.4 g/cm³ and one with a density of 1.0 g/cm³. Acceptability of the dosage form was also confirmed in addition to functionality, by measuring the applied film length. It was found that acceptance of the variant with the higher density was significantly better. This novel drug delivery technology could enable a targeted, local and long-lasting therapy of the esophagus for the first time, depending on the polymer film used.

Sparkling water is said to increase gastric motility by the release of carbon dioxide, thereby potentially affecting the pharmacokinetics of orally administered drugs. The hypothesis of the present work was that the induction of gastric motility by intragastric release of carbon dioxide from effervescent granules could promote the mixing of drugs into the chyme under postprandial conditions, resulting in a prolonged drug absorption. For this purpose, an effervescent and a non-effervescent granule formulation of caffeine as a marker for gastric emptying were developed. In a three-way crossover study with twelve healthy volunteers, the salivary caffeine pharmacokinetics, after administration of the effervescent granules with still water and the administration of the non-effervescent granules with still and sparkling water, were investigated after intake of a standard meal. While the administration of the effervescent granules with 240 mL of still water led to a significantly prolonged gastric residence of the substance compared to the administration of the non-effervescent granules with 240 mL still water, the application of the non-effervescent granules with 240 mL sparkling water did not prolong gastric residence via mixing into caloric chyme. Overall, the mixing of caffeine into the chyme following the administration of the effervescent granules did not seem to be a motility mediated process.

The absorption of drugs with narrow absorption windows in the upper small intestine can be improved with a mucoadhesive drug delivery system such as enteric films. To predict the mucoadhesive behaviour in vivo, suitable in vitro or ex vivo methods can be performed. In this study, the influence of tissue storage and sampling site on the mucoadhesion of polyvinyl alcohol film to human small intestinal mucosa was investigated. Tissue from twelve human subjects was used to determine adhesion using a tensile strength method. Thawing of tissue frozen at −20 °C resulted in a significantly higher work of adhesion (p = 0.0005) when a low contact force was applied for one minute, whereas the maximum detachment force was not affected. When the contact force and time were increased, no differences were found for thawed tissue compared to fresh tissue. No change in adhesion was observed depending on the sampling location. Initial results from a comparison of adhesion to porcine and human mucosa suggest that the tissues are equivalent.

Background/Objectives: The oral delivery of large-molecule drugs remains challenging due to poor solubility, perdemeability, and stability in the gastrointestinal tract, resulting in low bioavailability. In this study, hot melt extrusion (HME) was investigated as a solvent-free manufacturing technique for mucoadhesive bilayer films to improve drug absorption. Methods: Polyvinyl alcohol (PVA) and polyethylene oxide (PEO) were evaluated as mucoadhesive film-forming polymers, in conjunction with Eudragit^® RS as a water-insoluble backing layer. Paracetamol and lactase were utilized as small and large molecule APIs, respectively. The resulting films were assembled into bilayer film samples and examined for mechanical properties, mucoadhesion, and dissolution behavior. A novel dissolution model was developed to evaluate unidirectional drug transport. Results: The results showed that bilayer films could be successfully fabricated using HME, with different mechanical properties depending on the polymer and drug content. Tests with the newly developed dissolution model showed a unidirectional drug release. The model also confirmed the need for biorelevant dissolution test systems because of a better differentiation between polymers compared to standard test methods such as the paddle-over-disk method. Furthermore, the investigation revealed that the activity of enzymes was retained after extrusion, thus indicating the feasibility of processing biologics. Conclusions: This study highlights the potential of HME to produce bilayer films as an innovative drug delivery platform offering improved bioavailability for both small and large molecules.

Fibers and yarns are part of everyday life. So far, fibers that are also used pharmaceutically have mainly been produced by electrospinning. The common use of spinning oils and the excipients they contain, in connection with production by melt extrusion, poses a regulatory challenge for pharmaceutically usable fibers. In this publication, a newly developed small-scale direct-spinning melt extrusion system is described, and the pharmaceutically useful polyvinyl filaments produced with it are characterized. The major parts of the system were newly developed or extensively modified and manufactured cost-effectively within a short time using rapid prototyping (3D printing) from various materials. For example, a stainless-steel spinneret was developed in a splice design for a table-top melt extrusion system that can be used in the pharmaceutical industry. The direct processing of the extruded fibers was made possible by a spinning system developed called Spinning-Rosi, which operates continuously and directly in the extrusion process and eliminates the need for spinning oils. In order to prevent instabilities in the product, further modifications were also made to the process, such as a the moisture encapsulation of the melt extrusion line at certain points, which resulted in a bubble-free extrudate with high tensile strength, even in a melt extrusion line without built-in venting.