Self-micellizing solid dispersions enhance the properties and therapeutic potential of fenofibrate: Advantages, profiles and mechanisms

Self-micellizing solid dispersion of thymoquinone with enhanced biopharmaceutical and nephroprotective effects

The present study was designed to develop a self-micellizing solid dispersion (SMSD) containing Thymoquinone (TQM), a phytonutrient obtained from Nigella sativa seeds, aiming to improve its biopharmaceutical and nephroprotective functions. The apparent solubility of TQM in polymer solutions was used to choose an appropriate amphiphilic polymer that could be used to make an SMSD system. Based on the apparent solubility, Soluplus® was selected as an appropriate carrier, and mixing with TQM, SMSD-TQM with different loadings of TQM (5-15%) was made by solvent evaporation and freeze-drying techniques, respectively, and the formulations were optimized. The optimized SMSD-TQM was evaluated in terms of particle size distribution, morphology, release characteristics, pharmacokinetic behavior, and nephroprotective effects in a rat model of acute kidney injury. SMSD-TQM significantly improved the dissolution characteristics (97.8%) of TQM in water within 60 min. Oral administration of SMSD-TQM in rats exhibited a 4.9-fold higher systemic exposure than crystalline TQM. In a cisplatin-induced (6 mg/kg, i.p.) acute kidney-damaged rat model, oral SMSD-TQM (10 mg/kg) improved the nephroprotective effects of TQM based on the results of kidney biomarkers and histological abnormalities. These findings suggest that SMSD-TQM might be efficacious in enhancing the nephroprotective effect of TQM by overcoming biopharmaceutical limitations.

Co-Amorphization, Dissolution, and Stability of Quench-Cooled Drug-Drug Coamorphous Supersaturating Delivery Systems with RT-Unstable Amorphous Components

Background: Supersaturating drug delivery systems (SDDSs) have gained significant attention as a promising strategy to enhance the solubility and bioabsorption of Biopharmaceutics Classification System (BCS) II drugs. To overcome challenges associated with polymer-based amorphous SDDS (aSDDS), coamorphous (CAM) systems have emerged as a viable alternative. Among them, "drug-drug" CAM (ddCAM) systems show considerable potential for combination drug therapy. However, many drugs in their pure amorphous forms are unstable at room temperature (RT), complicating their formation and long-term stability profiles. Consequently, limited knowledge exists regarding the behavior of ddCAMs containing RT-unstable components formed via quench cooling. Methods: In this study, we used naproxen (NAP), a RT-unstable amorphous drug, in combination with felodipine (FEL) or nitrendipine (NTP), two RT-stable amorphous drugs, to create "FEL-NAP" and "NTP-NAP" ddCAM pairs via quench cooling. Our work used a series of methods to perform a detailed analysis on the co-amorphization, dissolution, solubility, and stability profiles of ddCAMs containing RT-unstable drugs, contributing to advancements in co-amorphization techniques for generating SDDS. Results: This study revealed that the co-amorphization and stability profiles of ddCAMs containing RT-unstable components produced via a quench-cooling method were closely related to drug-drug pairing types and ratios. Both quench-cooling and incorporation into coamorphous systems improved the dissolution, solubility, and physical stability of individual APIs. Conclusions: Our findings provide deeper insight into the co-amorphization, dissolution, and stability characteristics of specific drug-drug coamorphous systems FEL-NAP and NTP-NAP, offering valuable guidance for developing new ddCAM coamorphous formulations containing some RT-unstable drugs.

Simple preparation and greatly improved oral bioavailability: The supersaturated drug delivery system of quercetin based on PVP K30

Quercetin, as a representative flavonoid, is widely present in daily diet and has been developed as a dietary supplement due to its beneficial physiological activities. However, the application of quercetin is limited due to its poor water solubility and extensive metabolism. So far, the nano-drug delivery systems designed to improve its bioavailability generally have the shortcomings of low drug loading content and difficulty in industrial production. In order to tackle these problems, quercetin supersaturated drug delivery system (QSDDS) was successfully prepared using solvent method, for which PVP K30 was employed as a crystallization and precipitation inhibitor to maintain the supersaturated state of quercetin in aqueous system. The obtained QSDDS, with a relative high drug loading content of 13%, could quickly disperse in water and form colloidal system with the mean particle size of about 200 nm, meanwhile induce the generation of supersaturated quercetin solution more than 12 h. In vivo pharmacokinetic study proved that QSDDS achieved a high absolute bioavailability of 36.05%, 10 times as that of physical quercetin suspension, which was dose-dependent with higher bioavailability at higher dose. Considering the simple preparation method, QSDDS provided a feasible strategy and a simple way to improve oral absorption of insoluble flavonoids.

Self-nanomicellizing solid dispersion: A promising platform for oral drug delivery

Amorphous solid dispersion (ASD) has been widely used to enhance the oral bioavailability of water-insoluble drugs for oral delivery because of its advantages of enhancing solubility and dissolution rate. However, the problems related to drug recrystallization after drug dissolution in media or body fluid have constrained its application. Recently, a self-nanomicellizing solid dispersion (SNMSD) has been developed by incorporating self-micellizing polymers as carriers to settle the problems, markedly improving the ability of supersaturation maintenance and enhancing the oral bioavailability of drug. Spontaneous formation and stability of the self-nanomicelle (SNM) have been proved to be the key to supersaturation maintenance of SNMSD system. This offers a novel research direction for maintaining supersaturation and enhancing the bioavailability of ASDs. To delve into the advantages of SNMSDs, we provide a concise review introducing the formation mechanism, characterization methods and stability of SNMs, emphasizing the advantages of SNMSDs for oral drug delivery facilitated by SNM formation, and discussing relevant research prospects.

Eudragit L100-coated nintedanib nanocrystals improve oral bioavailability by reducing drug particle size and maintaining drug supersaturation

The aim of this study was to prepare nintedanib nanocrystals (BIBF-NCs) to lower the solubility of the drug in the stomach, maintain the supersaturation of the drug in the intestine, and improve the oral absorption of nintedanib (BIBF). In this study, BIBF-NCs were prepared by acid solubilization and alkaline precipitation following nano granding method, with a particle size of 290.80 nm and a zeta potential of -49.13 mV. Subsequently, Nintedanib enteric-coated nanocrystals (BIBF-NCs@L100) were obtained by coating with Eudragit L100. The microscopic morphology, crystalline characteristics, stability, and in vitro dissolution of BIBF-NCs and BIBF-NCs@L100 were also studied. In addition, the in vivo pharmacokinetic behaviors of Samples prepared according to the prescription process of commercially available soft capsules (soft capsules), BIBF-NCs, and BIBF-NCs@L100 were further investigated. The results showed that the oral bioavailability of BIBF-NCs and BIBF-NCs@L100 were increased by 1.43 and 2.58 times, compared with that of the soft capsules. BIBF-NCs@L100 effectively reduced the release of BIBF in the formulation in the stomach, allowing more drug to reach the intestine in the form of nanocrystals, maintaining the supersaturation in the intestine, thereby improving the oral bioavailability of the drug.

Solid amorphous formulations for enhancing solubility and inhibiting Erlotinib crystallization during gastric-to-intestinal transfer

The objective of this study was to improve the solubility and inhibit the crystallisation during the gastric-to-intestinal transfer of Erlotinib (ERL), a small molecule kinase inhibitor (smKI) compound class, which is classified as class II drug in the Biopharmaceutical Classification System (BCS). A screening approach combining different parameters (solubility in aqueous media, inhibitory effect of drug crystallisation from supersaturated drug solutions) was applied to selected polymers for the development of solid amorphous dispersions of ERL. ERL solid amorphous dispersions formulations were then prepared with 3 different polymers (Soluplus®, HPMC-AS-L, HPMC-AS-H) at a fixed drug: polymer ratio (1:4) by two different production methods (spray drying and hot melt extrusion). The spray-dried particles and cryo-milled extrudates were characterized by thermal properties, shape and particle size, solubility and dissolution behavior in aqueous media. The influence of the manufacturing process on these solid characteristics was also identified during this study. Based on the obtained results, it is concluded that the cryo-milled extrudates of HPMC-AS-L displayed better performance (enhanced solubility, reduced ERL crystallization during the simulated gastric-to-intestinal transfer) and represents a promising amorphous solid dispersion formulation for oral administration of ERL.

Development of Lipid Polymer Hybrid Drug Delivery Systems Prepared by Hot-Melt Extrusion

This study sought to develop polymer-lipid hybrid solid dispersions containing the poorly soluble drug lopinavir (LPV) by hot-melt extrusion (HME). Hence, the lipid and polymeric adjuvants were selected based on miscibility and compatibility studies. Film casting was used to assess the miscibility, whereas thermal, spectroscopic, and chromatographic analyses were employed to evaluate drug-excipient compatibility. Extrudates were obtained and characterized by physicochemical tests, including in vitro LPV dissolution. Preformulation studies led to select the most appropriate materials, i.e., the polymers PVPVA and Soluplus®, the plasticizers polyethylene glycol 400 and Kolliphor® HS15, phosphatidylcholine, and sodium taurodeoxycholate. HME processing did not result in LPV degradation and significantly increased entrapment efficiency (93.8% ± 2.8 for Soluplus® extrudate against 19.8% ± 0.5 of the respective physical mixture). LPV dissolution was also increased from the extrudates compared to the corresponding physical mixtures (p < 0.05). The dissolution improvement was considerably greater for the Soluplus®-based formulation (24.3 and 2.8-fold higher than pure LPV and PVPVA-based extrudate after 120 min, respectively), which can be attributed to the more pronounced effects of HME processing on the average size and LPV solid-state properties in the Soluplus® extrudates. Transmission electron microscopy and chemical microanalysis suggested that the polymer-lipid interactions in Soluplus®-based formulation depended on thermal processing.

Increasing Cellular Uptake and Permeation of Curcumin Using a Novel Polymer-Surfactant Formulation

Several therapeutically active molecules are poorly water-soluble, thereby creating a challenge for pharmaceutical scientists to develop an active solution for their oral drug delivery. This study aimed to investigate the potential for novel polymer-surfactant-based formulations (designated A and B) to improve the solubility and permeability of curcumin. A solubility study and characterization studies (FTIR, DSC and XRD) were conducted for the various formulations. The cytotoxicity of formulations and commercial comparators was tested via MTT and LDH assays, and their permeability by in vitro drug transport and cellular drug uptake was established using the Caco-2 cell model. The apparent permeability coefficients (Papp) are considered a good indicator of drug permeation. However, it can be argued that the magnitude of Papp, when used to reflect the permeability of the cells to the drug, can be influenced by the initial drug concentration (C₀) in the donor chamber. Therefore, Papp (suspension) and Papp (solution) were calculated based on the different values of C₀. It was clear that Papp (solution) can more accurately reflect drug permeation than Papp (suspension). Formulation A, containing Soluplus^® and vitamin E TPGs, significantly increased the permeation and cellular uptake of curcumin compared to other samples, which is believed to be related to the increased aqueous solubility of the drug in this formulation.

Hot Melt Extrusion-Triggered Amorphization as a Continuous Process for Inducing Extended Supersaturable Drug Immediate-Release from saSMSDs Systems

Hot melt extrusion (HME), a continuous manufacturing process for generating supersaturating amorphous self-micellizing solid dispersion systems (saSMSDs), holds promise for achieving amorphization of many pharmaceutical formulations. For saSMSDs generation, HME-triggered continuous processes offer advantages over traditional non-continuous processes such as fusion/quench cooling (FQC) and co-precipitation (CP). Here we employed HME, FQC, and CP to generate saSMSDs containing the water-insoluble BCS II drug nitrendipine (NIT) and self-micellizing polymer Soluplus^®. Scanning electron microscopy, powder X-ray diffraction, and differential scanning calorimetry results revealed that saSMSDs formed when NIT–Soluplus^® mixtures were subjected to the abovementioned amorphization methods. All saSMSDs outperformed crystalline NIT preparations and physical mixtures in achieving extended supersaturable immediate release states with superior solubility, “spring-parachute” process characteristics, and dissolution behaviors. Notably, Fourier transform-infrared spectroscopic results obtained for saSMSDs detected hydrogen bonding interactions between the drug and the carrier. Ultimately, our results revealed the advantages of HME-triggered amorphization as a continuous process for significantly improving drug dissolution, increasing solubility, and maintaining supersaturation as compared to traditional amorphization-based techniques.

Effect of Soluplus® on γ-cyclodextrin solubilization of irbesartan and candesartan and their nanoaggregates formation

The poor aqueous solubility of irbesartan (IRB) and candesartan cilexetil (CAC) may hamper their bioavailability when orally or topically administered. Among several attempts, the promising nanoaggregate formation by γ-cyclodextrin (γCD) complexation of drugs in aqueous solution with or without water-soluble polymers was investigated. According to phase solubility studies, Soluplus® showed the highest complexation efficiency (CE) of drug/γCD complexes among the polymers tested. The aqueous solubility of IRB and CAC was markedly increased as a function of Soluplus^® concentrations. The binary drug/γCD and ternary drug/γCD/Soluplus^® complex formations were supported and confirmed by solid-state characterizations, including differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and Fourier transform infrared (FT-IR) spectroscopy. The true inclusion mode was also proved by proton nuclear magnetic resonance (¹H-NMR) spectroscopy. The nanoaggregate size and morphology of binary and ternary systems were observed using dynamic light scattering (DLS), and transmission electron microscopy (TEM) techniques. The size of these nanocarriers depends on the concentration of Soluplus^®. The use of Soluplus^® could significantly enhance drug solubility and stabilize complex nanoaggregates, which could be a prospective platform for drug delivery systems.

"Felodipine-indomethacin" co-amorphous supersaturating drug delivery systems: "Spring-parachute" process, stability, in vivo bioavailability, and underlying molecular mechanisms

Amorphous solid dispersions (ASD) are one of most commonly used supersaturating drug delivery systems (SDDS) to formulate insoluble active pharmaceutical ingredients. However, the development of polymer-guided stabilization of ASD systems faces many obstacles. To overcome these shortcomings, co-amorphous supersaturable formulations have emerged as an alternative formulation strategy for poorly soluble compounds. Noteworthily, current researches around co-amorphous system (CAS) are mostly focused on preparation and characterization of these systems, but more detailed investigations of their supersaturation ("spring-parachute" process), stability, in vivo bioavailability and molecular mechanisms are inadequate and need to be clarified. In present study, we chose pharmacological relevant BCS II drugs to fabricate and characterize "felodipine-indomethacin" CAS. To enrich the current inadequate but key knowledge on CAS studies, we carried out following highlighted investigations including dissolution/solubility, semi-continuous "spring-parachute" process, long-term stability profile of amorphous state, in vivo bioavailability and underlying molecular mechanisms (molecular interaction, molecular miscibility and crystallization inhibition). Generally, the research provides some key information in the field of current "drug-drug" CAS supersaturable formulations.

Improvement of the bioavailability of curcumin by a supersaturatable self nanoemulsifying drug delivery system with incorporation of a hydrophilic polymer: in vitro and in vivo characterisation

OBJECTIVES

The current study was focused on preparing curcumin (CUR) supersaturated self-nano-emulsion (PI-CUR-SNEDDS) using hydrophilic polymer and to study the influence of polymer precipitation inhibitor on the physicochemical and biopharmaceutical properties of the PI-CUR-SNEDDS.

METHODS

PI-CUR-SNEDDS were prepared using hydrophilic polymer in order to maintain the supersaturation of CUR in nano-emulsion solution, artificial gastrointestinal fluid (AGF), and the precipitates formed, and characterised by in vitro dispersion tests, in vitro intestinal absorption and in vivo pharmacokinetic and compared with CUR-SNEDDS.

KEY FINDINGS

PI-CUR-SNEDDS prepared with 2% hydroxypropyl methylcellulose 55-60 (HPMC55-60) as precipitation inhibitor (PI) significantly improved the viscosity, physical stability and CUR's equilibrium solubility of nanoemulsion. HPMC55-60 and CUR interact in AGF through intermolecular interactions, form hydrogen bonds, and produce amorphous precipitates. Compared with CUR-SNEDDS, the proportion of CUR in the hydrophilic phase increased by about 3-fold, and apparent permeability coefficient (Papp) in duodenum, jejunum, ileum, and colon increased by 2.30, 3.65, 1.54 and 2.08-fold, respectively, and the area under the plasma concentration-time curve0-12h of PI-CUR-SNEDDS also increased by 3.50-fold.

CONCLUSIONS

Our results suggested that HPMC55-60 maintained the CUR supersaturation state by forming hydrogen bonds with CUR, increasing the solution's viscosity and drug solubilisation, thus improving the absorption and bioavailability of CUR.

Nano-sized Solid Dispersions for Improving the Bioavailability of Poorly Water-soluble Drugs

It has been well established that solid dispersions have a high potential to increase the release rate of poorly water-soluble drugs, resulting in high drug bioavailability. Solid dispersions have been vigorously investigated with various practical approaches in recent decades. Improvements in wettability, molecular interactions and drugs being held in an amorphous state in solid dispersions are the main mechanisms underlying the high drug release rate. Moreover, the synergistic effect of incorporating nanotechnology in solid dispersions is expected to lead to an advanced drug delivery system for poorly water-soluble drugs. However, to date, there is still a lack of reviews providing outlooks on the nano-sized solid dispersions that have been substantially investigated for improving the bioavailability of poorly water-soluble drugs. In the current review, we aim to overview key advantages and approaches for producing nano-sized solid dispersions. The classification of key strategies in developing nano-sized solid dispersions will advance the creation of even more efficient solid dispersions, which will translate into clinical studies.

An integrated computational methodology with data-driven machine learning, molecular modeling and PBPK modeling to accelerate solid dispersion formulation design

Drugs in solid dispersion (SD) take advantage of fast and extended dissolution, thus attains a higher bioavailability than the crystal form. However, current development of SD relies on a random large-scale formulation screening method with low efficiency. Current research aims to integrate various computational tools, including machine learning (ML), molecular dynamic (MD) simulation and physiologically based pharmacokinetic (PBPK) modeling, to accelerate the development of SD formulations. Firstly, based on a dataset consisting of 674 dissolution profiles of SD, the random forest algorithm was used to construct a classification model to distinguish two types of dissolution profiles: "spring-and-parachute" and "maintain supersaturation", and a regression model to predict the time-dependent dissolution profiles. Both of the two prediction models showed good prediction performance. Moreover, feature importance was performed to help understand the key information that contributes to the model. After that, the vemurafenib (VEM) SD formulation in previous report was used as an example to validate the models. MD simulation was used to investigate the dissolution behavior of two SD formulations with two polymers (HPMCAS and Eudragit) at the molecular level. The results showed that the HPMCAS-based formulation resulted in faster dissolution than the Eudragit formulation, which agreed with the reported experimental results. Finally, a PBPK model was constructed to accurately predict the human pharmacokinetic profile of the VEM-HPMCAS SD formulation. In conclusion, combined computational tools have been developed to in silico predict formulation composition, in vitro release and in vivo absorption behavior of SD formulations. The integrated computational methodology will significantly facilitate pharmaceutical formulation development than the traditional trial-and-error approach in the laboratory.

Preparation of stabilized submicron fenofibrate crystals on niacin as a hydrophilic hydrotropic carrier

Fenofibrate is antihyperlipidemic which has low and variable oral bioavailability due to erratic dissolution characteristics. Niacin showed a potential atheroprotective effects suggesting possible co-administration with fenofibrate with a potential for development of fixed dose combination. The chemical structure of both drugs highlights the opportunity for interaction upon co-processing due to the existence of complementary hydrogen bonding sites. Accordingly, fenofibrate and niacin were co-processed by wet co-grinding and the resulting product was assessed using scanning electron microscopy, FTIR, thermal analysis and X-ray diffraction in addition to dissolution studies. The instrumental analysis indicated the development of submicron fenofibrate crystals stabilized over the surface of niacin crystals. The developed submicron crystals showed fast dissolution of fenofibrate depending on the relative proportions of fenofibrate to niacin. Co-processing of both drugs at dose ratio which contained higher proportion of niacin resulted in further enhancement in the dissolution rate. This further enhancement was attributed to the hydrotropic effect of niacin which was proved by solubility study in addition to size reduction. This supposition was confirmed from the inferior dissolution of fenofibrate from the physical mixture. The study introduces fenofibrate/niacin as potential fixed dose combination for augmented dissolution rate and pharmacological effects.

Micellisation Mechanism and Behaviour of Soluplus®⁻Furosemide Micelles: Preformulation Studies of an Oral Nanocarrier-Based System

In this study, self-assembling Soluplus^® micelles were examined for inherent properties. Through calorimetric analysis, the critical micelle concentration (CMC) could be determined at 25 and 37 °C, and the influence of three media (Milli-Q water, phosphate-buffered saline (PBS) with a pH of 7.4 and 0.1 M HCl) on the lower critical solution temperature (LCST) was detected. Furthermore, the solubilisation of a poorly soluble drug, furosemide, into the Soluplus^® micelles was studied. The concentration-dependent properties of the micellar system were assessed through an examination of the micellar size, polydispersity, morphology, viscosity and solubilising properties, which were all found to be affected by the concentration, but temperature, pH and the composition of the test medium were also found to have an effect. Homogeneity in the estimated micellar size and morphology was shown for monophasic micelle dispersions in lower concentrations and with a shift towards more complex structures or aggregates in higher concentrations. The micelles were further investigated in terms of drug release and biocompatibility with mucus-producing HT29-MTX cells, where no biocompatibility issues were found. In this research, the implications for oral drug delivery are discussed and valuable preformulation information is provided on the micellar properties of a Soluplus^® drug system in a liquid or semi-solid form.

Novel self-nanomicellizing solid dispersion based on rebaudioside A: a potential nanoplatform for oral delivery of curcumin

Purpose

Rebaudioside A (RA) has nanocarrier characteristics that allow it to self-assemble into micelles in aqueous solutions. The purpose of this study was to determine if a self-nanomicellizing solid dispersion based on RA could be utilized as an oral nano-drug delivery system.

Materials and methods

Curcumin (Cur) served as a model hydrophobic drug, and a Cur-loaded self-nanomicellizing solid dispersion based on RA (RA-Cur) was formulated. The properties of RA-Cur in the solid state and in aqueous solution were characterized. The antioxidant activity and mechanism of RA-Cur endocytosis were also investigated. The pharmacokinetics, biodistribution in the intestinal tract, and anti-inflammation properties were also evaluated in vivo.

Results

RA-Cur could be easily fabricated, and it self-assembled into ultrasmall micelles (particle size ~4 nm) in a homogeneous distribution state (polydispersity index <0.2) when dissolved in water. Cur was readily encapsulated into RA micelles and this improved its water solubility (to 14.34±1.66 mg/mL), as well as its in vitro release and membrane permeability. The antioxidant activities of Cur in RA-Cur were also significantly improved. Biodistribution in the intestinal tract confirmed a significant enhancement of Cur absorption in the duodenum, jejunum, and ileum by encapsulation in RA-Cur, and the absorption of RA-Cur was governed by mixed transcytosis mechanisms. Pharmacokinetic tests of RA-Cur in rats revealed a dramatic 19.06-fold enhancement of oral bioavailability when compared to free Cur. More importantly, oral administration of RA-Cur could efficiently ameliorate ulcerative colitis in a mouse model induced by dextran sodium sulfate.

Conclusion

Self-nanomicellizing solid dispersions based on RA have great potential as novel oral nano-drug delivery systems for hydrophobic drugs such as Cur.

Supersaturated polymeric micelles for oral silybin delivery: the role of the Soluplus-PVPVA complex

Increasing the degree of supersaturation of drugs and maintaining their proper stability are very important in improving the oral bioavailability of poorly soluble drugs by a supersaturated drug delivery system (SDDS). In this study, we reported a complex system of Soluplus–Copovidone (Soluplus–PVPVA) loaded with the model drug silybin (SLB) that could not only maintain the stability of a supersaturated solution but also effectively promote oral absorption. The antiprecipitation effect of the polymers on SLB was observed using the solvent-shift method. In addition, the effects of the polymers on absorption were detected by cellular uptake and transport experiments. The mechanisms by which the Soluplus–PVPVA complex promotes oral absorption were explored by dynamic light scattering, transmission electron microscopy, fluorescence spectra and isothermal titration calorimetry analyses. Furthermore, a pharmacokinetic study in rats was used to demonstrate the advantages of the Soluplus–PVPVA complex. The results showed that Soluplus and PVPVA spontaneously formed complexes in aqueous solution via the adsorption of PVPVA on the hydrophilic-hydrophobic interface of the Soluplus micelle, and the Soluplus–PVPVA complex significantly increased the absorption of SLB. In conclusion, the Soluplus–PVPVA complex is a potential SDDS for improving the bioavailability of hydrophobic drugs.

The Influence of Cellulosic Polymer's Variables on Dissolution/Solubility of Amorphous Felodipine and Crystallization Inhibition from a Supersaturated State

The collective impact of cellulosic polymers on the dissolution, solubility, and crystallization inhibition of amorphous active pharmaceutical ingredients (APIs) is still far from being adequately understood. The goal of this research was to explore the influence of cellulosic polymers and incubation conditions on enhancement of solubility and dissolution of amorphous felodipine, while inhibiting crystallization of the drug from a supersaturated state. Variables, including cellulosic polymer type, amount, ionic strength, and viscosity, were evaluated for effects on API dissolution/solubility and crystallization processes. Water-soluble cellulosic polymers, including HPMC E15, HPMC E5, HPMC K100-LV, L-HPC, and MC, were studied. All cellulosic polymers could extend API dissolution and solubility to various extents by delaying crystallization and prolonging supersaturation duration, with their effectiveness ranked from greatest to least as HPMC E15 > HPMC E5 > HPMC K100-LV > L-HPC > MC. Decreased polymer amount, lower ionic strength, or higher polymer viscosity tended to decrease dissolution/solubility and promote crystal growth to accelerate crystallization. HPMC E15 achieved greatest extended API dissolution and maintenance of supersaturation from a supersaturated state; this polymer thus had the greatest potential for maintaining sustainable API absorption within biologically relevant time frames.

Lacidipine Amorphous Solid Dispersion Based on Hot Melt Extrusion: Good Miscibility, Enhanced Dissolution, and Favorable Stability

The present study aimed to increase the in vitro dissolution rate of lacidipine, a poorly water-soluble drug, by formulating amorphous solid dispersions (ASDs) using hot-melt extrusion (HME). Differential scanning calorimetry, powder X-ray diffraction, polarized light microscopy, and Fourier transform infrared were used to characterize the optimal formulations and evaluate the physical stability for the stress test. Film-casting method and hot-stage microscopy were applied to study the miscibility of lacidipine and the drug carriers. In vitro dissolution tests were conducted as the final evaluation index. The optimal formulations were successfully obtained with Soluplus and PVP VA64 at a drug/carrier ratio of 1:10 (w/w), Fourier transform infrared studies revealed the hydrogen bonding between drug and polymers, and in vitro dissolution rates of the optimal formulations were extremely enhanced compared to bulk lacidipine and physical mixtures, similar with that of the commercial tablet. The ASD formulated with Soluplus showed better physical stability than that with PVP VA64. A strong hydrogen bonding and good drug-polymer miscibility were essential to hinder the recrystallization of lacidipine ASDs. In conclusion, the lacidipine ASD formulated with Soluplus showed a significant increase in in vitro dissolution rate and favorable physical stability in the stress test.

Copper-catalyzed diarylation of Se with aryl iodides and heterocycles

The site-selective copper-catalyzed three-component coupling reaction of electron-deficient heterocycles, Se powder and aryl iodides is disclosed, providing an efficient and practical pathway to access 2-arylselenated heterocycles.