Rational Design of a Famotidine-Ibuprofen Coamorphous System: An Experimental and Theoretical Study

Monophasic coamorphous sulpiride: a leap in physicochemical attributes and dual inhibition of GlyT1 and P-glycoprotein, supported by experimental and computational insights

Study aimed to design and development of a supramolecular formulation of sulpiride (SUL) to enhance its solubility, dissolution and permeability by targeting a novel GlyT1 inhibition mechanism. SUL is commonly used to treat gastric and duodenal ulcers, migraine, anti-emetic, anti-depressive and anti-dyspeptic conditions. Additionally, Naringin (NARI) was incorporated as a co-former to enhance the drug's intestinal permeability by targeting P-glycoprotein (P-gp) efflux inhibition. NARI, a flavonoid has diverse biological activities, including anti-apoptotic, anti-oxidant, and anti-inflammatory properties. This study aims to design and develop a supramolecular formulation of SUL with NARI to enhance its solubility, dissolution, and permeability by targeting a novel GlyT1 inhibition mechanism, extensive experimental characterization was performed using solid-state experimental techniques in conjunction with a computational approach. This approach included quantum mechanics-based molecular dynamics (MD) simulation and density functional theory (DFT) studies to investigate intermolecular interactions, phase transformation and various electronic structure-based properties. The findings of the miscibility study, radial distribution function (RDF) analysis, quantitative simulations of hydrogen/π-π bond interactions and geometry optimization aided in comprehending the coamorphization aspects of SUL-NARI Supramolecular systems. Molecular docking and MD simulation were performed for detailed binding affinity assessment and target validation. The solubility, dissolution and ex-vivo permeability studies demonstrated significant improvements with 31.88-fold, 9.13-fold and 1.83-fold increments, respectively. Furthermore, biological assessments revealed superior neuroprotective effects in the SUL-NARI coamorphous system compared to pure SUL. In conclusion, this study highlights the advantages of a drug-nutraceutical supramolecular formulation for improving the solubility and permeability of SUL, targeting novel schizophrenia treatment approaches through combined computational and experimental analyses.Communicated by Ramaswamy H. Sarma.

Drug-drug co-amorphous systems: An emerging formulation strategy for poorly water-soluble drugs

Overcoming the poor water solubility of small-molecule drugs is a major challenge in the development of clinical pharmaceuticals. Amorphization of crystalline drugs is a highly effective strategy to improve their aqueous solubility. However, amorphous drugs are thermodynamically unstable and likely to crystallize during manufacturing and storage. Recently, drug-drug co-amorphous systems have emerged as a novel strategy to not only enable enhanced dissolution and physical stability of the individual drugs within the system but also to provide a strategy for combination therapy of the same or different clinical indications. This review serves to highlight advances in the methods used to manufacture and characterize drug-drug co-amorphous systems, summarize drug-drug co-amorphous applications reported in recent decades, and provide an outlook on future possibilities and perspectives.

Molecular complexes of drug combinations: A review of cocrystals, salts, coamorphous systems and amorphous solid dispersions

As the advancements in the medical technology and healthcare develop through the years, combinational therapy has evolved to be an important treatment modality in many disease settings, including cancer, cardiovascular disease and infectious diseases. In an effort to alleviate "pill burden" and improve patient compliance, fixed dose combinations (FDCs) have been developed to be used as effective therapeutics. Among all FDCs, the category of drug-drug molecular complexes has been proven an efficient methodology in designing and treating diseases, with many drugs being approved. Among all drug-drug molecular complexes, drug-drug cocrystals, salts, coamorphous systems and solid dispersions have been successfully developed and many have been approved by the FDA. In this review, we dwell deeply into the molecular mechanisms behind the different types of drug-drug molecular complexes, including the key functional groups involved in the intermolecular interactions, the applications of each category of molecular complexes, as well as the advantages and challenges thereof. This comprehensive review provides useful insights into the practical design and manufacture of drug-drug molecular complexes and points out the future direction for the development of new advantageous combinational therapies that benefit more patients.

Gelation Elimination and Crystallization Inhibition by Co-Amorphous Strategy for Amorphous Curcumin

In the previous study, the development of amorphous curcumin (CUR) aimed to enhance the solubility/dissolution of CUR by disrupting its crystal lattice, but it unexpectedly showed a decreased dissolution than its crystalline counterpart on account of gel formation in its dissolution process. Whether such gelation could be eliminated by co-amorphous strategy was answered in this study. Herein, CUR by co-amorphization with chlorogenic acid (CHA) was successfully prepared using quench cooling. The formed co-amorphous material (namely CUR-CHA CM) eliminated the gelation and hence performed superior dissolution performance than crystalline/amorphous CUR. Meanwhile, it exhibited higher physical stability than amorphous CUR during dissolution as well as under long-term/accelerated conditions. To further study the such enhancement mechanism, the internal molecular interactions were investigated for CUR-CHA CM in the solid state as well as in aqueous solution. FTIR and solid-state ¹³C NMR spectra confirmed that intermolecular hydrogen bonds formed between CUR and CHA after co-amorphization. Furthermore, the nucleation of CUR was significantly inhibited by CHA in an aqueous solution, thus maintaining the supersaturated dissolution for a long time. The present study offers a feasible strategy to eliminate gelation and enhance stability of amorphous solids by co-amorphization and crystallization inhibition.

Improving physicochemical properties and pharmacological activities of ternary co-amorphous systems

The formation of co-amorphous by combining low molecular weight compounds with drugs is a relatively new technology in the pharmaceutical field, which can significantly improve the solubility, dissolution, and stability of poorly water-soluble drugs. However, in our previous studies, the binary co-amorphous system of andrographolide-oxymatrine (AP-OMT) was found to have obvious recrystallization and poor dissolution behavior. Therefore, in this study, we designed three stable ternary co-amorphous systems to improve the physicochemical properties of the binary co-amorphous system of AP-OMT. The ternary co-amorphous systems were prepared with AP, OMT, and trans-cinnamic acid (CA), p-hydroxycinnamic acid (pHCA), or ferulic acid (FA). Intermolecular hydrogen bonds were confirmed by spectroscopy and molecular dynamics simulation. Solubility studies showed that the solubility of the ternary co-amorphous systems of AP-OMT-CA/pHCA/FA was significantly increased compared with that of crystalline AP. Dissolution experiments suggested that the ternary co-amorphous systems of AP-OMT-CA/pHCA/FA exhibited better dissolution behavior without significant recrystallization compared to the binary co-amorphous AP-OMT. The stability study confirmed that the ternary co-amorphous system of AP-OMT-CA/pHCA/FA maintained good physical stability in the long term for 18 months. In addition, pharmacological experiments revealed that the ternary co-amorphous systems of AP-OMT-CA/pHCA/FA have an excellent safety profile and its anti-Alzheimer's disease effects are significantly improved compared to that of the binary co-amorphous systems of AP-OMT. Moreover, this study also found that reducing the pKa value of low molecular weight co-formers would affect the intermolecular interactions and improve the solubility of drugs in the ternary co-amorphous systems. In conclusion, we have successfully prepared ternary co-amorphous systems of AP-OMT-CA/pHCA/FA by amorphization technique, which improves the physicochemical properties of the binary co-amorphous systems of AP-OMT and anti-Alzheimer's disease activity in the Caenorhabditis elegans model. The mechanism for the influence of the pKa value of the co-formers on the physicochemical properties of the ternary co-amorphous system was preliminarily explored, providing theoretical guidance for the development of the ternary co-amorphous system.

Self-gelation involved in the transformation of resveratrol and piperine from a co-amorphous system into a co-crystal system

Self-gelation of co-amorphous system promotes the transformation into its co-crystal system during dissolution.

Deaggregation and Crystallization Inhibition by Small Amount of Polymer Addition for a Co-Amorphous Curcumin-Magnolol System

Different from previously reported co-amorphous systems, a co-amorphous curcumin-magnolol (CUR-MAG CM) system, as compared with its crystalline counterparts, exhibited decreased dissolution due to its aggregation during dissolution. The main purpose of the present study is to deaggregate CUR-MAG CM to optimize drug dissolution and explore the deaggregation mechanism involved. Herein, a small amount of polymer (HPMC, HPC, and PVP K30) was co-formulated at 5% (w/w) with CUR-MAG CM as ternary co-amorphous systems. The polymer addition changed the surface properties of CUR-MAG CM including improved water wettability enhanced surface free energy, and hence exerted a deaggregating effect. As a result, the ternary co-amorphous systems showed faster and higher dissolution as compared with crystalline CUR/MAG and CUR-MAG CM. In addition, the nucleation and crystal growth of dissolved CUR and MAG molecules were significantly inhibited by the added polymer, maintaining a supersaturated concentration for a long time. Furthermore, polymer addition increased the T_g of CUR-MAG CM, potentially involving molecular interactions and inhibiting molecular mobility, resulting in enhanced physical stability under 25 °C/60% RH and 40 °C/75% RH conditions. Therefore, this study provides a promising strategy to optimize the dissolution and physical stability of co-amorphous systems by deaggregation and crystallization inhibition via adding small amounts of polymers.

Structure and Glass Transition Temperature of Amorphous Dispersions of Model Pharmaceuticals with Nucleobases from Molecular Dynamics

Glass transition temperature (Tg) is an important material property, which predetermines the kinetic stability of amorphous solids. In the context of active pharmaceutical ingredients (API), there is motivation to maximize their Tg by forming amorphous mixtures with other chemicals, labeled excipients. Molecular dynamics simulations are a natural computational tool to investigate the relationships between structure, dynamics, and cohesion of amorphous materials with an all-atom resolution. This work presents a computational study, addressing primarily the predictions of the glass transition temperatures of four selected API (carbamazepine, racemic ibuprofen, indomethacin, and naproxen) with two nucleobases (adenine and cytosine). Since the classical non-polarizable simulations fail to reach the quantitative accuracy of the predicted Tg, analyses of internal dynamics, hydrogen bonding, and cohesive forces in bulk phases of pure API and their mixtures with the nucleobases are performed to interpret the predicted trends. This manuscript reveals the method for a systematic search of beneficial pairs of API and excipients (with maximum Tg when mixed). Monitoring of transport and cohesive properties of API-excipients systems via molecular simulation will enable the design of such API formulations more efficiently in the future.

Influence of the pK a Value of Cinnamic Acid and P-Hydroxycinnamic Acid on the Solubility of a Lurasidone Hydrochloride-Based Coamorphous System

Coamorphization of a poorly water-soluble active pharmaceutical ingredient (API) has been proven to be effective in improving its solubility. Generally, API can form multiple coamorphous systems with different coformers. However, it remains unclear how the pK _a value of different coformers influences the solubility of the API. In this study, structurally related cinnamic acid (CA, pK _a = 4.37) and p-hydroxycinnamic acid (pHCA, pK _a = 4.65) were chosen as coformers for the coamorphization of lurasidone hydrochloride (LH). To investigate the influence of the pK _a value of the coformers on the solubility of LH, LH-CA/pHCA coamorphous systems were prepared by the vacuum rotary evaporation method and characterized by powder X-ray diffraction and differential scanning calorimetry. Fourier-transform infrared spectroscopy, Raman spectroscopy, and molecular dynamics (MD) simulations were employed to investigate the intermolecular interaction of the coamorphous systems. It was found that the solubility of LH in the coamorphous LH-pHAC with a higher-pK _a coformer was higher than that of the coamorphous LH-CA. In addition, according to the solubility product principle-based formula derivation, we established the functional relationship between the solubility of LH and the pK _a of the coformers at different-pH buffering solution. It was found that the coformer with a larger pK _a value would be more beneficial to improve the solubility profile of LH. Collectively, the current study offers an effective strategy to improve the poor solubility of drugs by increasing the pK _a value of the coformer in coamorphous systems.

Molecular Dynamics Simulations in Drug Discovery and Pharmaceutical Development

Molecular dynamics (MD) simulations have become increasingly useful in the modern drug development process. In this review, we give a broad overview of the current application possibilities of MD in drug discovery and pharmaceutical development. Starting from the target validation step of the drug development process, we give several examples of how MD studies can give important insights into the dynamics and function of identified drug targets such as sirtuins, RAS proteins, or intrinsically disordered proteins. The role of MD in antibody design is also reviewed. In the lead discovery and lead optimization phases, MD facilitates the evaluation of the binding energetics and kinetics of the ligand-receptor interactions, therefore guiding the choice of the best candidate molecules for further development. The importance of considering the biological lipid bilayer environment in the MD simulations of membrane proteins is also discussed, using G-protein coupled receptors and ion channels as well as the drug-metabolizing cytochrome P450 enzymes as relevant examples. Lastly, we discuss the emerging role of MD simulations in facilitating the pharmaceutical formulation development of drugs and candidate drugs. Specifically, we look at how MD can be used in studying the crystalline and amorphous solids, the stability of amorphous drug or drug-polymer formulations, and drug solubility. Moreover, since nanoparticle drug formulations are of great interest in the field of drug delivery research, different applications of nano-particle simulations are also briefly summarized using multiple recent studies as examples. In the future, the role of MD simulations in facilitating the drug development process is likely to grow substantially with the increasing computer power and advancements in the development of force fields and enhanced MD methodologies.

A novel lurasidone hydrochloride–shikimic acid co-amorphous system formed by hydrogen-bonding interaction with the retained pH-dependent solubility behavior

The current study was aimed at investigating the lurasidone hydrochloride–shikimic acid co-amorphous system using a new type of organic acid.