In vivo characterization of enTRinsic™ drug delivery technology capsule after intake in fed state: A cross-validation approach using salivary tracer technique in comparison to MRI.

The instability of various small molecules, vaccines and peptides in the human stomach is a complex challenge for oral drug delivery. Recently, a novel gastro-resistant capsule - the enTRinsic™ Drug Delivery Technology capsule - has been developed. In this work, the salivary tracer technique based on caffeine has been applied to study the in vivo disintegration of enTRinsic™ capsules in 16 healthy volunteers. In addition, magnetic resonance imaging (MRI) was used to visualize GI transit and to verify the disintegration times determined by using the salivary tracer technique. The enTRinsic™ capsules filled with 50mg of caffeine and 5mg of black iron oxide were administered in the fed state, i.e. 30min after a light meal (500kcal). In the first hour after capsule intake, the subjects were placed in supine position in the MRI scanner and scans were performed in short time intervals. After 1h, the subjects could leave the MRI scanner in between the MRI measurements, which were performed every 15min until disintegration of the capsule was confirmed (maximum observation time: 8h). Saliva samples were obtained simultaneously with MR imaging. Caffeine concentrations in saliva were determined by LC/MS-MS. The starting point of capsule disintegration was determined visually by inspection of the MR images as well as by the onset of salivary caffeine concentrations. In 14 out of 16 subjects, the capsule disintegrated in the small intestine. In one subject, the enTRinsic™ capsule was not emptied from the stomach within the observation time. In another subject, disintegration occurred during gastric emptying in the antropyloric region. In this study, we demonstrated that the enTRinsic™ capsules are also gastro resistant when taken under fed state conditions. Furthermore, we demonstrated the feasibility of using low dose caffeine as a salivary tracer for the determination of the disintegration of an enteric formulation.

Characterization of the gastrointestinal transit and disintegration behavior of floating and sinking acid-resistant capsules using a novel MRI labeling technique.

The application areas of hard capsules are currently widened by the introduction of acid-resistant capsule shells. In this study, the gastrointestinal behavior of acid-resistant hard capsule formulations as well as the influence of their density on the gastric residence time were characterized using magnetic resonance imaging (MRI). As labeling material for a reliable identification of the capsules in the MR images, small pieces of dried pineapple were used as they provide a high T1 signal. Tested products were DRcaps™ as capsule in capsule (Cap-in-Cap) system (outer capsule size 00). For the investigation of the influence of the capsule density on the gastric residence time, a floating low-density Cap-in-Cap capsule formulation and a sinking high-density Cap-in-Cap capsule formulation were investigated. The study was performed in eight healthy human subjects under fasting conditions. Besides the transit data of the capsule systems, the intraluminal fluid volume kinetics were determined using T2 weighted sequences. The gastric emptying times of the systems did not differ, with mean values of 45 ±â€¯35 min for floating DRcaps™ and 36 ±â€¯18 min for the sinking DRcaps™. The difference in density had no remarkable influence on gastric emptying. Thus, the concept of floating capabilities for gastroretentive dosage forms seems rather implausible. Furthermore, this assures transferability of common knowledge about dosage form transit for estimation of the performance of acid-resistant capsule shells, which most typically float. The mean disintegration times amounted to 139 ±â€¯35 min for the floating DRcaps™ Cap-in-Cap and 163 ±â€¯55 min for the sinking DRcaps™ Cap-in-Cap. In only one case, a sinking DRcaps™ Cap-in-Cap system disintegrated during gastric emptying, but all other capsules disintegrated in the small intestine, irrespective of their gastric residence time. The use of dried pineapple as labeling material could be successfully demonstrated as a reliable and easy method for the tracking of the transit and disintegration behavior of orally administered drug delivery systems, leading to a thorough understanding of their in vivo performance.

New binary solid dispersion of indomethacin with surfactant polymer: from physical characterization to in vitro dissolution enhancement.

This article investigated preparation of solid dispersions containing a poor water-soluble drug, indomethacin (IND), and a new surfactant polymer, polyoxyethylene 32 distearate (POED). Solid dispersions were prepared by the melting method and characterized by DSC, hot-stage microscopy (HSM), X-ray diffraction (XRD) and scanning electron microscopy (SEM). DSC and HSM analyses performed on IND/POED physical mixtures indicated that IND could dissolve in liquid POED. The materials showed complete miscibility at liquid state. Combination of DSC, XRD, and SEM revealed that these materials had limited miscibility at the solid state. Up to 20% w/w IND in POED, we did not detect significant modification of physical properties of the polymer. It supports the formation of a solid solution of IND in solid POED. Above 20% w/w, the solid dispersions presented particular behavior upon heating (recrystallization of IND) and at the solid state (presence of some IND crystallites). Under 3-month storage at 25 degrees C/53% RH, the solid dispersions demonstrated a good stability of the samples. Finally, in vitro dissolution studies showed that IND release was greatly improved (5.5-12 times as fast) by formation of solid dispersion. This enhancement was principally attributed to the high dispersion of IND in POED and to the polymer surfactant properties.