Hydroxypropyl-β-Cyclodextrin and β-Cyclodextrin as Tablet Fillers for Direct Compression

Ten years of the manufacturing classification system: a review of literature applications and an extension of the framework to continuous manufacture

The MCS initiative was first introduced in 2013. Since then, two MCS papers have been published: the first proposing a structured approach to consider the impact of drug substance physical properties on manufacturability and the second outlining real world examples of MCS principles. By 2023, both publications had been extensively cited by over 240 publications. This article firstly reviews this citing work and considers how the MCS concepts have been received and are being applied. Secondly, we will extend the MCS framework to continuous manufacture. The review structure follows the flow of drug product development focussing first on optimisation of API properties. The exploitation of links between API particle properties and manufacturability using large datasets seems particularly promising. Subsequently, applications of the MCS for formulation design include a detailed look at the impact of percolation threshold, the role of excipients and how other classification systems can be of assistance. The final review section focusses on manufacturing process development, covering the impact of strain rate sensitivity and modelling applications. The second part of the paper focuses on continuous processing proposing a parallel MCS framework alongside the existing batch manufacturing guidance. Specifically, we propose that continuous direct compression can accommodate a wider range of API properties compared to its batch equivalent.

Development of Oral Tablets of Nebivolol with Improved Dissolution Properties, Based on Its Combinations with Cyclodextrins

New oral tablets of nebivolol have been developed aiming to improve, by cyclodextrin (CD) complexation, its low solubility/dissolution properties-the main reason behind its poor/variable oral bioavailability. Phase-solubility studies, performed using βCD and highly-soluble βCD-derivatives, indicated sulfobutylether-βCD (SBEβCD) as the best solubilizing/complexing agent. Solid drug-SBEβCD systems were prepared by different methods and characterized for solid-state and dissolution properties. The coevaporated product was chosen for tablet development since it provided the highest dissolution rate (100% increase in dissolved drug at 10 min) and almost complete drug amorphization/complexation. The developed tablets reached the goal, allowing us to achieve 100% dissolved drug at 60 min, compared to 66% and 64% obtained, respectively, with a reference tablet without CD and a commercial tablet. However, the percentage dissolved after 10 min from such tablets was only 10% higher than the reference. This was ascribed to the potential binding/compacting abilities of SBEβCD, reflected in the greater hardness and longer disintegration times of the new tablets than the reference (7.64 vs. 1.06 min). A capsule formulation with the same composition of nebivolol-SBEβCD tablets showed about a 90% increase in dissolved drug after 5 min compared to the reference tablet, and reached 100% dissolved drug after only 20 min.

Unravelling the Role of Uncommon Hydrogen Bonds in Cyclodextrin Ferrociphenol Supramolecular Complexes: A Computational Modelling and Experimental Study

We sought to determine the cyclodextrins (CDs) best suited to solubilize a patented succinimido-ferrocidiphenol (SuccFerr), a compound from the ferrociphenol family having powerful anticancer activity but low water solubility. Phase solubility experiments and computational modelling were carried out on various CDs. For the latter, several CD-SuccFerr complexes were built starting from combinations of one or two CD(s) where the methylation of CD oxygen atoms was systematically changed to end up with a database of ca. 13 k models. Modelling and phase solubility experiments seem to indicate the predominance of supramolecular assemblies of SuccFerr with two CDs and the superiority of randomly methylated β-cyclodextrins (RAMEβCDs). In addition, modelling shows that there are several competing combinations of inserted moieties of SuccFerr. Furthermore, the models show that ferrocene can contribute to high stabilization by making atypical hydrogen bonds between Fe and the hydroxyl groups of CDs (single bond with one OH or clamp with two OH of the same glucose unit).

Quercetin inclusion complex gels ameliorate radiation-induced brain injury by regulating gut microbiota

Radiation-induced brain injury (RIBI) is a serious adverse effect of radiotherapy. RIBI has garnered considerable clinical attention owing to its powerful effects on brain function and cognition; however, no effective treatment is available. The microbiota-gut-brain axis theory is a novel concept of treating RIBI by regulating gut microbiota. Quercetin, a particularly common flavonoid compound, has a wide range of biological activities and can regulate gut microbiota; however, it has poor solubility and dispersibility. In the present study, oral gels of inclusion complex comprising quercetin and HP-β-CD were prepared, which increased quercetin dispersion and extended its release time in the intestinal tract. First, the relative abundance and diversity of gut microbiota in RIBI mice changed after oral administration of quercetin inclusion complex gels (QICG). Second, the spontaneous activity behavior and short-term memory ability as well as anxiety level were improved. Third, changes in physical symptoms were observed, including a decrease in TNF-α and IL-6 levels. H&E staining revealed that gut epithelial injury and intestinal inflammation as well as hippocampal inflammation were ameliorated. Antibiotics treatment (Abx) mice were developed to disrupt the mice's original gut microbiota composition. No significant improvement was observed in behavior or histopathology after oral administration of QICG in Abx mice of RIBI, indicating that the effect of QICG on improving RIBI was regulated by intestinal microbiota. Finally, the QICG preparation is efficient, exerting a protective effect on RIBI by regulating gut microbiota via the microbiota-gut-brain axis, which provides a novel idea for RIBI treatment.

Buccal Resveratrol Delivery System as a Potential New Concept for the Periodontitis Treatment

The health benefits of resveratrol have been proven to inhibit the development of numerous diseases. A frequent limitation in its use is a low bioavailability stemming from a poor solubility and fast enterohepatic metabolism. Thus, the aim of the research was to investigate the possibility to formulate mucoadhesive cyclodextrin- and xanthan gum-based buccal tablets in order to increase the solubility of resveratrol and to eliminate bypass enterohepatic metabolism. Systems of resveratrol with α-cyclodextrin (α-CD), β-cyclodextrin (β-CD), γ-cyclodextrin (γ-CD) and 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) prepared by the dry mixing method (ratio 1:1) were selected for the of tablets where xanthan gum was used as a mucoadhesive agent. They were identified on the basis of PXRD, FT-IR analysis. Tablets F1 (with α-CD), F2 (with β-CD) and F3 (with γ-CD) were characterized by the highest compactibility as well as by favorable mucoadhesive properties. Resveratrol release from these tablets was delayed and controlled by diffusion. The tablets prepared in the course of this study appear to constitute promising resveratrol delivery systems and are recommended to increase the effectiveness of the treatment in many diseases, particularly periodontitis.

Mechanochemical activation with cyclodextrins followed by compaction as an effective approach to improving dissolution of rutin

Rutin is one of the most important flavonoids with poor bioavailability. This work aimed at addressing the issue of poor biopharmaceutical performance of rutin by applying a combination of complexation with secondary processing into tablets. Mechanical activation was the most suitable method of rutin complex formation with (2-hydroxypropyl)-β-cyclodextrin (HP-β-CD), while the β-cyclodextrin (β-CD) complex successfully formed by kneading with an ethanol/water mixture. Complexation was confirmed by thermal analysis, powder X-ray diffraction and vibrational spectroscopy. Dynamic vapour sorption showed that stability of powders at high humidity conditions was satisfactory, however, the β-CD complex retained around 8% of moisture. The complexes were compacted with or without tricalcium phosphate (TRI-CAFOS) filler at a range of compression pressures (19-113 MPa). The best tabletability was determined for rutin/HP-β-CD, compressibility for the TRI-CAFOS blends with complexes and compactibility for the rutin/HP-β-CD + TRI-CAFOS mix. Dissolution studies showed quicker and more complete dissolution (pH 1.2) of rutin/HP-β-CD tablets, however the compacts comprising the filler were superior than pure complexes. The tablets manufactured in this study appear to be promising delivery systems of rutin and it is recommended to combine rutin/HP-β-CD with TRI-CAFOS and compact at 38-76 MPa.

Orodispersible Carbamazepine/Hydroxypropyl-β-Cyclodextrin Tablets Obtained by Direct Compression with Five-in-One Co-processed Excipients

The development of orodispersible tablets (ODTs) for poorly soluble and poorly flowable drugs via direct compression is still a challenge. This work aimed to develop ODTs of poorly soluble drugs by combining cyclodextrins that form inclusion complexes to improve wetting and release properties, and directly compressible co-processed excipients able to promote rapid disintegration and solve the poor flowability typical of inclusion complexes. Carbamazepine (CBZ) and hydroxypropyl-β-cyclodextrin (HPβCD) were used, respectively, as a model of a poorly soluble drug with poor flowability and as a solubilizing agent. Specifically, CBZ-an antiepileptic and anticonvulsant drug-may benefit from the studied formulation approach, since some patients have swallowing difficulties or fear of choking and are non-cooperative. Prosolv® ODT G2 and F-Melt® type C were the studied five-in-one co-processed excipients. The complex was prepared by kneading. Flow properties of all materials and main properties of the tablets were characterized. The obtained results showed that ODTs containing CBZ/HPβCD complex can be prepared by direct compression through the addition of co-processed excipients. The simultaneous use of co-processing and cyclodextrin technologies rendered ODTs with an in vitro disintegration time in accordance with the European Pharmacopoeia requirement and with a fast and complete drug dissolution. In conclusion, the combination of five-in-one co-processed excipients and hydrophilic cyclodextrins may help addressing the ODT formulation of poorly soluble drugs with poor flowability, by direct compression and with desired release properties.

Physicochemical Profiling of Baicalin Along with the Development and Characterization of Cyclodextrin Inclusion Complexes

Baicalin is a flavone glycoside extracted from Scutellaria baicalensis, a traditional Chinese herbal medicine. Numerous pharmacological effects of baicalin were reported (e.g. antioxidant, anxiolytic); nevertheless, the most important physicochemical properties influencing the pharmacokinetic behaviour and the concomitant oral bioavailability have not yet been described in a comprehensive study. The aim of this project was to characterize the acid-base, lipophilicity, biorelevant solubility and permeability properties of the drug substance and providing scientific data to support the dosage form design. Another important objective was the comparative evaluation of six various baicalin-cyclodextrin (CD) inclusion complexes along with the creation of a suitable Drug Delivery System (DDS) for this BCS IV drug. Biorelevant profiling was carried out by NMR-pH titrations, saturation shake-flask and distribution coefficients (logP) measurements, while CD inclusion studies were fulfilled by experimental methods (phase solubility, ¹H/¹³C NMR, 2D ROESY) and computational approaches. Due to low aqueous solubility (67.03 ± 1.60 μg/ml) and low permeability (P_app = 0.037 × 10⁻⁶ cm/s), baicalin is classified as BCS IV. The γ-CD complexation significantly increased the solubility of baicalin (~ 5 times). The most promoted chemical shift change occurred in baicalin-γ-CD complex. Computational studies showed disparate binding pattern for baicalin in case of β- and γ-CD; furthermore, the calculated complexation energy was − 162.4 kJ mol⁻¹ for β-CD, while it was significantly stronger for γ-CD (− 181.5 kJ mol⁻¹). The physicochemical and structural information of baicalin and its CD complexes introduced herein can create molecular basis for a promising DDS with enhanced bioavailability containing a bioactive phytopharmacon.