Simulating the Hydrodynamic Conditions of the Human Ascending Colon: A Digital Twin of the Dynamic Colon Model

The performance of solid oral dosage forms targeting the colon is typically evaluated using standardised pharmacopeial dissolution apparatuses. However, these fail to replicate colonic hydrodynamics. This study develops a digital twin of the Dynamic Colon Model; a physiologically representative in vitro model of the human proximal colon. Magnetic resonance imaging of the Dynamic Colon Model verified that the digital twin robustly replicated flow patterns under different physiological conditions (media viscosity, volume, and peristaltic wave speed). During local contractile activity, antegrade flows of 0.06–0.78 cm s−1 and backflows of −2.16–−0.21 cm s−1 were measured. Mean wall shear rates were strongly time and viscosity dependent although peaks were measured between 3.05–10.12 s−1 and 5.11–20.34 s−1 in the Dynamic Colon Model and its digital twin respectively, comparable to previous estimates of the USPII with paddle speeds of 25 and 50 rpm. It is recommended that viscosity and shear rates are considered when designing future dissolution test methodologies for colon-targeted formulations. In the USPII, paddle speeds >50 rpm may not recreate physiologically relevant shear rates. These findings demonstrate how the combination of biorelevant in vitro and in silico models can provide new insights for dissolution testing beyond established pharmacopeial methods.

Requirements for Additional Strength Biowaivers for Modified Release Solid Oral Dosage Forms in International Pharmaceutical Regulators Programme Participating Regulators and Organisations: Differences and Commonalities

This article describes an overview of waivers of in vivo bioequivalence studies for additional strengths in the context of the registration of modified release generic products and is a follow-up to the recent publication for the immediate release solid oral dosage forms. The current paper is based on a survey among the participating members of the Bioequivalence Working Group for Generics (BEWGG) of the International Pharmaceutical Regulators Program (IPRP) regarding this topic. Most jurisdictions consider the extrapolation of bioequivalence results obtained with one (most sensitive) strength of a product series as less straightforward for modified release products than for immediate release products. There is consensus that modified release products should demonstrate bioequivalence not only in the fasted state but also in the fed state, but differences exist regarding the necessity of additional multiple dose studies. Fundamental differences between jurisdictions are revealed regarding requirements on the quantitative composition of different strengths and the differentiation of single and multiple unit dosage forms. Differences in terms of in vitro dissolution requirements are obvious, though these are mostly related to possible additional comparative investigations rather than regarding the need for product-specific methods. As with the requirements for immediate release products, harmonization of the various regulations for modified release products is highly desirable to conduct the appropriate studies from a scientific point of view, thus ensuring therapeutic equivalence.

3D Printing: an appealing technology for the manufacturing of solid oral dosage forms

Objectives The traditional manufacturing methods of solid oral dosage forms (SODFs) are reported to be time-consuming, highly expensive and not tailored to the patient’s needs. Three-dimensional printing (3DP) is an innovative emerging technology that can help to overcome these issues. The aim of this review is to describe the most employed 3DP technologies, materials and the state of the art on 3DP SODFs. Characterization techniques of 3DP SODFs, challenges and regulatory issues are also discussed. Key findings The interest in the investigation of the suitability of 3DP as an alternative strategy for the fabrication of SODFs is growing. Different 3DP technologies and starting materials have been investigated for the development of SODFs. Numerous SODFs with complex geometries and composition, and with different release patterns, have been successfully manufactured via 3DP. Despite that, just one 3DP SODF has reached the market. Summary 3DP can be a promising alternative to the classical SODFs manufacturing methods. However, numerous technically and regulatory challenges still need to be addressed in order 3DP to be extensively used in the pharmaceutical sector.

Review: Continuous Manufacturing of Small Molecule Solid Oral Dosage Forms

Continuous manufacturing (CM) is defined as a process in which the input material(s) are continuously fed into and transformed, and the processed output materials are continuously removed from the system. CM can be considered as matching the FDA’s so-called ‘Desired State’ of pharmaceutical manufacturing in the twenty-first century as discussed in their 2004 publication on ‘Innovation and Continuous Improvement in Pharmaceutical Manufacturing’. Yet, focused attention on CM did not really start until 2014, and the first product manufactured by CM was only approved in 2015. This review describes some of the benefits and challenges of introducing a CM process with a particular focus on small molecule solid oral dosage forms. The review is a useful introduction for individuals wishing to learn more about CM.