Stability Comparison Between Microglassification and Lyophilization Using a Monoclonal Antibody.

Producing solid-state formulations of biologics remains a daunting task despite the prevalent use of lyophilization and spray drying technologies in the biopharmaceutical industry. The challenges include protein stability (temperature stresses), high capital costs, particle design/controllability, shortened processing times and manufacturing considerations (scalability, yield improvements, aseptic operation, etc.). Thus, scientists/engineers are constantly working to improve existing methodologies and exploring novel dehydration/powder-forming technologies. Microglassification™ is a dehydration technology that uses solvent extraction to rapidly dehydrate protein formulations at ambient temperatures, eliminating the temperature stress experienced by biologics in traditional lyophilization and spray drying methods. The process results in microparticles that are spherical, dense, and chemically stable. In this study, we compared the molecular stability of a monoclonal antibody formulation processed by lyophilization to the same formulation processed using Microglassification™. Both powders were placed on stability for 3 months at 40 °C and 6 months at 25 °C. Both dehydration methods showed similar chemical stability, including percent monomer, charge variants, and antigen binding. These results show that Microglassification™ is viable for the production of stable solid-state monoclonal antibody formulations.

In-Silico Aided Screening and Characterization Results in Stability Enhanced Novel Roxadustat Co-Crystal.

Roxadustat (RXD) is an approved drug substances for the treatment of renal anemia. It has poor aqueous solubility and photochemical stability. This study employs a comprehensive approach to enhance the stability and physicochemical properties RXD through coformer selection and characterization. The investigation integrates delta pKa analysis, molecular complementary assessment, molecular electrostatic potential surface analysis, and machine learning techniques to predict potential co-crystal formation and binding interactions between drug molecules and coformers. The co-crystal screening which lead to in a novel RXD-nicotinamide co-crystal (RXD-NA). Experimental characterization underscores the physical and chemical stability of the co-crystals. To elucidate the supramolecular synthons and understand the intermolecular interactions in the RXD-NA co-crystal, Hirshfeld surfaces analysis, quantum theory of atoms in molecules (QTAIM) analysis and non-covalent interaction (NCI) analysis were performed. Computational analysis of photo-isomer formation aligns with experimental observations, further enhancing our understanding of RXD-coformer interactions. RXD-NA co-crystal was found photo-chemically stable as compared to free base API drug substance. This integrated methodology provides a systematic framework for informed co-crystal design, holding promise for optimizing RXD formulations based on molecular interactions and stability considerations. Consequently, this study contributes valuable insights to the field of rational drug design and formulation optimization.

Solid Forms of The New Antitrypanosomal 1-(4-Acetamide-Benzenesulfonyl)-Benzimidazole: Preparation and Physicochemical Characterization.

This study aimed to investigate the polymorphism of 1-(4-acetamide-benzenesulfonyl)-benzimidazole (PABZI), a newly developed compound with significant activity against Trypanosoma cruzi, the parasite which causes American trypanosomiasis (Chagas disease). Three different crystalline forms of PABZI [a solvent-free form (form I), three isostructural solvates (from isopropanol; acetonitrile-dichloromethane, and methanol-benzene) and a non-isostructural solvate from methanol] were isolated and characterized. The crystal structure of form I was resolved at 173 K and 300 K by single crystal X-ray diffraction. Physicochemical properties, including solubility, dissolution rate, wettability, and solid-state stability were assessed for the two most viable solid forms of PABZI, viz. form I and the isopropanol solvate (PABZI-isoOH). Form I exhibited a higher solubility and dissolution rate, and superior stability towards moisture (40 °C/75 % relative humidity) and UV-Visible light than PABZI-isoOH. Based on the solid-state stability results, form I was selected over PABZI-isoOH for further preclinical studies.

Study on polycyclic macromolecular drug solid stability: A case exploration of methylcobalamin.

As one of derivatives of Vitamin B12, methylcobalamin (MeCbl) is an indispensable "Life Element" and plays an essential role in maintaining human normal physiology function and clinical medicine application. Because of the intricate molecular structure, strong hygroscopicity and optical instability, maintaining its solid stability is a great challenge in pharmaceutical preparation. Based on the structure features of MeCbl hydrates, this study explored the drug solid stability by designing solid-solid phase transformation (SSPT) experiments. Three hydrate powders of MeCbl that had special structure with isolated site and channel water molecules were discovered. It was found that drying condition and surrounding humidity were controlling factors influencing the final solid form. The inter-conversion relations relevant to heating-induced and humidity-induced structure changes were established among the three hydrate powders. Powder X-ray diffraction, thermogravimetric analysis, differential scanning calorimetry, high performance liquid chromatography and dynamic vapor sorption were used to characterize the differences and related properties of stably prepared MeCbl hydrate powders. The particle size of product could be regulated and controlled by optimizing operating conditions of crystallization process, where ultrasound-assisted and seeding-introduced were applied as promising strategies to enhance solution crystallization process. This study opens up the possibility for the stable preparation and large-scale production of polycyclic macromolecular bulk drugs like methylcobalamin.

Review of industrially recognized polymers and manufacturing processes for amorphous solid dispersion based formulations.

Evolving therapeutic landscape through combinatorial chemistry and high throughput screening have resulted in an increased number of poorly soluble drugs. Drug delivery strategies quickly adapted to convert these drugs into successful therapies. Amorphous solid dispersion (ASD) technology is widely employed as a drug delivery strategy by pharmaceutical industries to overcome the challenges associated with these poorly soluble drugs. The development of ASD formulation requires an understanding of polymers and manufacturing techniques. A review of US FDA-approved ASD-based products revealed that only a limited number of polymers and manufacturing technologies are employed by pharmaceutical industries. This review provides a comprehensive guide for the selection and overview of polymers and manufacturing technologies adopted by pharmaceutical industries for ASD formulation. The various employed polymers with their underlying mechanisms for solution-state and solid-state stability are discussed. ASD manufacturing techniques, primarily implemented by pharmaceutical industries for commercialization, are presented in Quality by Design (QbD) format. An overview of novel excipients and progress in manufacturing technologies are also discussed. This review provides insights to the researchers on the industrially accepted polymers and manufacturing technology for ASD formulation that has translated these challenging drugs into successful therapies.

Highly protein-loaded melt extrudates produced by small-scale ram and twin-screw extrusion - evaluation of extrusion process design on protein stability by experimental and numerical approaches.

Understanding of generation, extent and location of thermomechanical stress in small-scale (< 3 g) ram and twin-screw melt-extrusion is crucial for mechanistic correlations to the stability of protein particles (lysozyme and BSA) in PEG-matrices. The aim of the study was to apply and correlate experimental and numerical approaches (1D and 3D) for the evaluation of extrusion process design on protein stability. The simulation of thermomechanical stress during extrusion raised the expectation of protein degradation and protein particle grinding during extrusion, especially when TSE was used. This was confirmed by experimental data on protein stability. Ram extrusion had the lowest impact on protein unfolding temperatures, whereas TSE showed significantly reduced unfolding temperatures, especially in combination with kneading elements containing screws. In TSE, the mechanical stress in the screws always exceeded the shear stress in the die, while mechanical stress within ram extrusion was generated in the die, only. As both extruder designs revealed homogeneously distributed protein particles over the cross section of the extrudates for all protein-loads (20-60%), the dispersive power of TSE revealed not to be decisive. Consequently, the ram extruder would be favored for the production of stable protein-loaded extrudates in small scale.

Micro-Scale Vacuum Compression Molding as a Predictive Screening Tool of Protein Integrity for Potential Hot-Melt Extrusion Processes.

Hot-melt extrusion (HME) is used for the production of solid protein formulations mainly for two reasons: increased protein stability in solid state and/or long-term release systems (e.g., protein-loaded implants). However, HME requires considerable amounts of material even at small-scale (>2 g batch size). In this study, we introduced vacuum compression molding (VCM) as a predictive screening tool of protein stability for potential HME processing. The focus was to identify appropriate polymeric matrices prior to extrusion and evaluation of protein stability after thermal stress using only a few milligrams of protein. The protein stability of lysozyme, BSA, and human insulin embedded in PEG 20,000, PLGA, or EVA by VCM was investigated by DSC, FT-IR, and SEC. The results from the protein-loaded discs provided important insights into the solid-state stabilizing mechanisms of protein candidates. We demonstrated the successful application of VCM for a set of proteins and polymers, showing, in particular, a high potential for EVA as a polymeric matrix for solid-state stabilization of proteins and the production of extended-release dosage forms. Stable protein-polymer mixtures with sufficient protein stability after VCM could be then introduced to a combination of thermal and shear stress by HME and further investigated with regard to their process-related protein stability.

Solid-state properties of pink clay from Jequitinhonha Valley in Brazil for pre-formulation study

Abstract Clay minerals are still widely used in pharmaceutical products for human health and cosmetic purposes. Pre-formulation studies were conducted to identify solid-state properties of pink clay, a sample from Diamantina, Brazil. Among the solid properties to be analyzed, we have selected type identification, iron phases, crystallinity, powder flow characteristics, thermal behavior, and non-isothermal phase transition kinetics. The pink clay is composed of (1:1) clay type and kaolinite as the main component. The Mössbauer spectrum of pink clay shows Fe3+(α-Fe2O3) Clay minerals are still widely used in pharmaceutical products for human health and cosmetic purposes. Pre-formulation studies were conducted to identify solid-state properties of pink clay, a sample from Diamantina, Brazil. Among the solid properties to be analyzed, we have selected type identification, iron phases, crystallinity, powder flow characteristics, thermal behavior, and non-isothermal phase transition kinetics. The pink clay is composed of (1:1) clay type and kaolinite as the main component. The Mössbauer spectrum of pink clay shows Fe3+(α-Fe2O3) hematite, Fe2+, and Fe3+ with large Δ/2ξq of about 2.80 and 2.69 mm.s-1 respectively, related to iron silicates, most likely pyroxene, and a superparamagnetic Fe3+. Pink clay exhibits poor flow properties. The thermal behavior indicates a phase-transition between 400 - 600 ºC associated with the dehydroxylation of the pink clay system requiring ~300 kJ mol-1, being constant until the process reaches a conversion of ~50% when the energy is enhanced to ~530 kJ mol-1, concluding the whole dehydroxylation process (α=80%). Solid-state properties and characteristics found for the pink clay must be considered for the proper design of formulations. This type of clay shows unique pharmaceutical properties that can be favorably exploited by the cosmetic industry

Gefitinib-resveratrol Cocrystal with Optimized Performance in Dissolution and Stability.

Gefitinib (GEF) is an anti-tumor oral solid formulation with a superior advantage for lung tumors. However, it has poor aqueous solubility which limits its utility in vivo. Herein, a novel cocrystal (GEF-RES) assembled by GEF and RES (Resveratrol) has been successfully prepared and comprehensively characterized by differential scanning calorimetry, thermogravimetric analysis, Raman spectroscopy and powder X-ray diffraction. A single-crystal structure of the GEF-RES cocrystal was solved and illustrated in detail. In aqueous hydrochloric acid, the GEF-RES cocrystal showed that the maximum concentration of GEF was slightly higher than that of raw GEF. Furthermore, the thermal and physical stability of the GEF-RES cocrystal were also evaluated in this paper. The enhanced solubility and excellent solid-state stability results may provide new potential to the application of key GEF in clinical.

A Simple Non-Linear Kinetic Model to Evaluate Stability of a Pressure Sensitive Drug.

Candesartan cilexetil is challenging to formulate due to pressure induced chemical degradation. We report a statistical model based on stability data set of a marketed tablet formulation. Impurity increase over time was fitted to a reparametrized second-order kinetic model. Both kinetic model parameters have mechanistic interpretation: parameter a relates to the overall extent of pressure induced instability (the ceiling impurity level) and parameter b relates to the initial rate of degradation (how fast the ceiling is reached). A hierarchical model was then used to quantify sensitivity to tableting pressure and humidity-corrected Arrhenius equation quantified sensitivity to temperature and moisture. An overall model, based on four predictors and five estimated parameters allowed fitting of the entire stability dataset (694 stability data points) with good accuracy. Learnings allowed development of a stable formulation (soft tableting, increasing tablet size/shape and reducing moisture) and resulted in a confident stress stability test to evaluate any future product changes in a timely manner.

Selection and Optimization of an Innovative Polysaccharide-Based Carrier to Improve Anthocyanins Stability in Purple Corn Cob Extracts.

The extraction process of alcohol-insoluble polysaccharides from exhausted Moradyn cob (Zea mays L. cv. Moradyn) (EMCP), camelina cake (Camelina sativa L. Crantz) (CCP), and common bean seeds (Phaseolus vulgaris L.) (CBP) was investigated and optimized by Response Surface Methodology. Each fraction was tested at different core/carrier ratios in the encapsulation of Moradyn cob extract (MCE), a rich source of antioxidant anthocyanins, and the obtained ingredients were screened for their encapsulation efficiency (EE%) and extraction process sustainability. The ingredients containing 50% and 75% CCP had EE% higher than 60% and 80%, respectively, and were selected for further studies. Preliminary structural analysis indicated CCP was mostly composed of neutral polysaccharides and proteins in a random-coiled conformation, which was also unchanged in the ingredients. CCP-stabilizing properties were tested, applying an innovative stress testing protocol. CCP strongly improved MCE anthocyanins solid-state stability (25 °C, 30% RH), and therefore it could be an innovative anthocyanins carrier system.

Comparison of Differential Scanning Calorimetry, Powder X-ray Diffraction, and Solid-state Nuclear Magnetic Resonance Spectroscopy for Measuring Crystallinity in Amorphous Solid Dispersions - Application to Drug-in-polymer Solubility.

The widespread use of amorphous solid dispersions (ASDs) dictates that analytical methods are required to accurately quantify crystallinity and characterize crystals formed in order to help design a stable ASD. Current crystallinity quantitation methods are limited to ASDs of moderate drug loadings, single polymorphs, and fast crystallization kinetics. The ability of multiple differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and solid-state nuclear magnetic resonance (SSNMR) techniques were compared for quantifying crystallinity in ASDs in varying conditions. Determining crystallinity by DSC is limited by its ability to measure Tg or heat of fusion. PXRD was relatively robust in determining crystalline and amorphous ratios for drug-polymer systems in the absence of other excipients. SSNMR provides both quantitative information and reveal how crystal quality changes with crystallization conditions and helps to explain the failure of DSC methods. The results of five different methods using three techniques were directly applied to measure drug-in-polymer solubility with four agreeing well with the literature. PXRD and SSNMR are therefore proposed as alternative methods to quantify crystallinity and predict drug-in-polymer solubility when DSC methods do not work. In-situ and ex-situ annealing was also compared, and equivalent crystallinity data was acquired.

Going green: Development of a sustainable lipid-based enteric coating formulation for low-dose aspirin multiparticulate systems.

There is a rising awareness of pharmaceutical industry of both patient-centric and sustainable product development. Manufacturing of multiparticulate systems (MPS) with functional coating via solvent-free hot melt coating (HMC) can fulfill both requirements. An innovative lipid-based formulation was developed with the composition of palmitic acid and Grindsted® citrem BC-FS (BC-FS) for enteric coating of acetylsalicylic acid (ASA). The ASA crystals were directly hot melt coated to produce user-friendly low-dose ASA MPS for thromboembolism prophylaxis. Prior to HMC, rational boundaries for the process temperature were defined based on the melting and crystallization behavior of coating blend. Stability of coating in terms of resistance to heat stress and solidstate stability were screened via Fourier-transform infrared spectroscopy and x-ray diffraction. Exposure of coating blend to 100 °C for two hours did not cause any chemical degradation. Crystal growth of palmitic acid and polymorphic transformation in BC-FS were observed after storage under accelerated conditions, however did not significantly affect the ASA release from coating. The developed formulation is a unique solvent-free, lipid-based enteric composition and paves the way for sustainable green pharmaceutical manufacturing.

Influence of commonly used excipients on the chemical degradation of enalapril maleate in its solid state: The role of condensed water.

The physicochemical stability of enalapril maleate was investigated in the presence of fourteen different excipients divided into four different classes. The extent of a drug-excipient interaction was investigated by following the chemical stability using HPLC. It was found that there is a certain order in the stability of enalapril maleate. Enalapril maleate remained most stable in the presence of: disaccharides > celluloses > starches > superdisintegrants. The amount of degradation can be related to the excipient characteristics. A material with a higher water sorption capacity and lower crystallinity presents a more reactive particle surface. It was revealed that the condensation layer deposited on the surface of the excipient is responsible for the degradation of enalapril maleate. A confirmation was found by changing the surface of the excipient and influencing the environmental humidity that allowed a variable build-up of the condensation layer. For this particle-particle interaction, the microenvironmental pH only presents a minor effect as it was found to not be a determining factor for degradation. Moreover, there appears to be a firm relationship between the degradation of enalapril maleate and the water sorption-activity of excipients.

Solid-State Overview of R-Baclofen: Relative Stability of Forms A, B and C and Characterization of a New Heterosolvate.

A new polymorphic form (Form C) of enantiopure Baclofen was isolated and characterized. Crystal structures of R-Baclofen Form A and Form C were resolved from powder diffraction data, and cell parameters by profile matching for Form B. The relative stability of these three forms is proposed based on structural data, thermal analyses and solvent-mediated conversions. The experiments highlight the stability order A < C < B at 25 °C (A is the most stable form), whereas above 180 °C it would likely be: C < A < B (C being the stable modification). Moreover, a new heterosolvate of the molecule is observed in N,N-DMF/water mixture. This heterosolvate offers a new pathway to isolate pure R-Baclofen Form B provided the lactam impurity does not exceed 3%. Upon mechanical stress Form B tends to evolve to Form C.

Assessment and Development of the Antifungal Agent Caspofungin for Aerosolized Pulmonary Delivery.

Invasive Pulmonary Aspergillosis (IPA) and Pneumocystis jiroveci Pneumonia (PCP) are serious fungal pulmonary diseases for immunocompromised patients. The brand name drug CANCIDAS® (Caspofungin acetate for injection) is FDA approved to treat IPA, but is only 40% effective. Efficacious drug levels at the lung infection site are not achieved by systemic administration. Increasing the dose leads to toxicity. The objective, here, is to reformulate caspofungin for aerosolization to high drug concentration by lung targeted delivery and avoid systemic distribution. Described in this paper is a new, room temperature-stable formulation that meets these goals. The in vitro antifungal activity, solid state and reconstituted stability, and aerosol properties of the new formulation are presented. In addition, pharmacokinetic parameters and tissue distribution data are determined from nose-only inhalation studies in rats. Plasma and tissue samples were analyzed by High Performance Liquid Chromatography-tandem Mass Spectrometry (HPLC-MS-MS). Inhaled drug concentrations for caspofungin Active Pharmaceutical Ingredient (API), and the new formulation, were compared at the same dose. In the lungs, the parameters Cmax and Area Under Curve (AUC) showed a 70%, and 60%, respective increase in drug deposition for the new formulation without significant systemic distribution. Moreover, the calculated pharmacodynamic indices suggest an improvement in efficacy. These findings warrant further animal toxicology studies and human clinical trials, with inhaled caspofungin, for treating IPA.

Stability of antibody drug conjugate formulations evaluated using solid-state hydrogen-deuterium exchange mass spectrometry.

Antibody drug conjugates (ADCs) have been at the forefront in cancer therapy due to their target specificity. All the FDA approved ADCs are developed in lyophilized form to minimize instability associated with the linker that connects the cytotoxic drug and the antibody during shipping and storage. We present here solid-state hydrogen-deuterium exchange with mass spectrometric analysis (ssHDX-MS) as a tool to analyze protein structure and matrix interactions for formulations of an ADC with and without commonly used excipients. We compared results of the ssHDX-MS with accelerated stability results using size-exclusion chromatography and determined that the former technique was able to successfully identify the destabilizing effects of mannitol and polysorbate 80. In comparison, Fourier-transform infrared spectroscopy results were inconclusive. The agreement between ssHDX-MS and stressed stability studies supports the potential of ssHDX-MS as a method of predicting relative stability of different formulations.

Study on the Mechanism Responsible for the Incompatibility of Enalapril Maleate with Sodium Starch Glycolate.

Enalapril maleate (EM) is known to suffer from incompatibilities in the solid state. This study investigates the destabilizing effect of sodium starch glycolate (SSG) on EM. This was done by varying the mixing ratio and moisture content of binary mixtures. Differential scanning calorimetry and microscopy show a loss of crystallinity of EM at the contact surface with SSG. It is shown that this is followed by decomposition of E to diketopiperazine (DKP). These phenomena are modulated by moisture. The environmental pH turned out to be crucial; when the zwitterion is formed at the appropriate pH, ring closure into DKP is promoted.

Characterization of excipient enhanced growth (EEG) tobramycin dry powder aerosol formulations.

Spray drying can be utilized to produce highly dispersible powder aerosol formulations. However, these formulations are known to be hygroscopic, leading to potential solid-state stability and aerosol performance issues. This study aims to investigate if control of the spray drying particle formation conditions could be employed to improve the solid-state stability and alter the aerosol performance of tobramycin EEG formulations. Eight formulations were prepared, each had the same drug:excipient ratio of 60%w/w tobramycin, 20% w/w l-leucine, 18% w/w mannitol, and 2% w/w poloxamer 188. An experimental design matrix was performed with drying air water content of 1 or 10 g/m3 and spray drying solution l-leucine concentrations of 4.6, 7.6, 15.2 or 23.0 mmol/L. The particle size, morphology and crystallinity of spray dried formulations were characterized together with their dynamic moisture vapor sorption and aerosol performance. Higher crystallization and glass transition %RH were observed for the formulations spray dried using drying air with higher water content indicating more stable characteristics. Initial screening using a handheld dry powder inhaler of the realistic aerosol performance revealed that neither changing l-leucine concentration nor the drying gas water content affect the in-vitro expected lung dose. However, using a novel positive pressure inhaler, formulations produced using spray drying solutions with lower l-leucine concentrations showed better aerosol performance with MMAD around 2 µm and FPF < 5 µm around 80%.

Exploring the Complexity of Processing-Induced Dehydration during Hot Melt Extrusion Using In-Line Raman Spectroscopy.

The specific aim in this study was to understand the effect of critical process parameters on the solid form composition of model drug compounds during hot melt extrusion using in-line Raman spectroscopy combined with Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) modeling for semi-quantitative kinetic profiling. It was observed that the hydrate and anhydrate solid forms of two model drugs in the melts of nitrofurantoin (NF):polyethylene oxide (PEO) and piroxicam (PRX):PEO could be resolved from a MCR-ALS model without an external calibration dataset. Based on this model, the influence of two critical process parameters (shear and temperature) on the solid form composition could be evaluated in a real-time mode and the kinetics of complex transformation pathways could be explored. Additionally, the dehydration pathways of NF monohydrate and PRX monohydrate in molten PEO could be derived. It can be concluded that dehydration of both hydrates in PEO occurs via competing mechanisms-a solution-mediated transformation pathway and a solid-solid transformation, and that the balance between these mechanisms is determined by the combined effect of both temperature and shear. Another important observation was that the water released from these hydrate compounds has a detectable effect on the rheological characteristics of this mixture.