Formulation of ionic liquid APIs via spray drying processes to enable conversion into single and two-phase solid forms

Rationalizing Counterion Selection for the Development of Lipophilic Salts: A Case Study with Venetoclax

The use of lipid-based formulations (LBFs) can be hindered by low dose loading due to solubility limitations of candidate drugs in lipid vehicles. Formation of lipophilic salts through pairing these drugs with a lipophilic counterion has been demonstrated as a potential means to enhance dose loading in LBFs. This study investigated the screening of appropriate counterions to form lipophilic salts of the BCS class IV drug venetoclax. The physical properties, lipid solubility, and in vitro performance of the salts were analyzed. This study illustrated the versatility of alkyl sulfates and sulfonates as suitable counterions in lipophilic salt synthesis with up to ∼9-fold higher solubility in medium- and long-chain LBFs when compared to that of the free base form of venetoclax. All salts formulated as LBFs displayed superior in vitro performance when compared to the free base form of the drug due to the higher initial drug loadings in LBFs and increased affinity for colloidal species. Further, in vitro studies confirmed that venetoclax lipophilic salt forms using alkyl chain counterions demonstrated comparable in vitro performance to venetoclax docusate, thus reducing the potential for laxative effects related to docusate administration. High levels of the initial dose loading of venetoclax lipophilic salts were retained in a molecularly dispersed state during dispersion and digestion of the formulation, while also demonstrating increased levels of saturation in biorelevant media. The findings of this study suggest that alkyl chain sulfates and sulfonates can act as a suitable alternative counterion to docusate, facilitating the selection of counterions that can unlock the potential to formulate venetoclax as an LBF.

Study on Improving the Performance of Traditional Medicine Extracts with High Drug Loading Based on Co-spray Drying Technology

The purpose of this study is to develop modified particles with different structures to improve the flowability and compactibility of Liuwei Dihuang (LWDH) powder using co-spray drying technology, and to investigate the preparation mechanism of modified particles and their modified direct compaction (DC) properties. Moreover, tablets with high drug loading contents were also prepared. Particles were designed using polyvinylpyrrolidone (PVP K30) and hydroxypropyl methylcellulose (HPMC E3) as shell materials, and sodium bicarbonate (NaHCO3) and ammonium bicarbonate (NH4HCO3) as pore-forming agents. The porous particles (Ps), core-shell particles (CPs), and porous core-shell particles (PCPs) were prepared by co-spray drying technology. The key DC properties and texture properties of all the particles were measured and compared. The properties of co-spray drying liquid were also determined and analyzed. According to the results, Ps showed the least improvement in DC properties, followed by CPs, and PCPs showed a significant improvement. The modifier, because of its low surface tension, was wrapped in the outer layer to form a shell, and the pore-forming agent was thermally decomposed to produce pores, forming core-shell, porous, and porous core-shell composite structures. The smooth surface of the shell structure enhances fluidity, while the porous structure allows for greater compaction space, thereby improving DC properties during the compaction process.

A Comparison of Spray-Drying and Co-Precipitation for the Generation of Amorphous Solid Dispersions (ASDs) of Hydrochlorothiazide and Simvastatin

Co-processing of APIs, the practice of creating multi-component APIs directly in chemical processing facilities used to make drug substance, is gaining increased attention with a view to streamlining manufacturing, improving supply chain robustness and accessing enhanced product attributes in terms of stability and bioavailability. Direct co-precipitation of amorphous solid dispersions (ASDs) at the final step of chemical processing is one such example of co-processing. The purpose of this work was to investigate the application of different advanced solvent-based processing techniques - direct co-precipitation (CP) and the benchmark well-established spray-drying (SD) process - to the production of ASDs comprised of a drug with a high T_g (hydrochlorothiazide, HCTZ) or a low T_g (simvastatin, SIM) molecularly dispersed in a PVP/VA 64 or Soluplus® matrix. ASDs of the same composition were manufactured by the two different methods and were characterised using powder X-ray diffraction (PXRD), modulated differential scanning calorimetry (mDSC), attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and scanning electron microscopy (SEM). Both methods produced ASDs that were PXRD amorphous, with some differences, depending on the process used, in glass transition temperature and particle size distribution. Irrespective of manufacturing method used, all ASDs remained PXRD amorphous when subjected to high relative humidity conditions (75% RH, 25°C) for four weeks, although changes in the colour and physical characteristics were observed on storage for spray-dried systems with SIM and PVP/VA 64 copolymer. The particle morphology differed for co-precipitated compared to spray dried systems, with powder generated by the former process being comprised of more irregularly shaped particles of larger particle size when compared to the equivalent spray-dried systems which may enable more streamlined drug product processes to be used for CP materials. These differences may have implications in downstream drug product processing. A limitation identified when applying the solvent/anti-solvent co-precipitation method to SIM was the high antisolvent to solvent ratios required to effect the precipitation process. Thus, while similar outcomes may arise for both co-precipitation and spray drying processes in terms of ASD critical quality attributes, practical implications of applying the co-precipitation method and downstream processability of the resulting ASDs should be considered when choosing one solvent-based ASD production process over another.

Combining Isolation-Free and Co-processing Manufacturing Approaches to Access Room Temperature Ionic Liquid Forms of APIs

The addition of non-active components at the point of active pharmaceutical ingredient (API) isolation by means of co-processing is an attractive approach for improving the material properties of APIs. Simultaneously, there is increased interest in the pharmaceutical industry in continuous manufacturing processes. These often consist of liquid feeds which maintain materials in solution and mean that solids handling is avoided until the final step. Such techniques enable new forms of APIs to be used in final dosage forms which have been overlooked due to unfavourable material properties. API-based ionic liquids (API-ILs) are an example of a class of compounds that exhibit exceptional solubility and stability qualities at the cost of their physical characteristics. API-ILs could benefit from isolation-free manufacturing in combination with co-processing approaches to circumvent handling issues and make them viable routes to formulating poorly soluble APIs. However, API-ILs are most commonly synthesised via a batch reaction that produces an insoluble solid by-product. To avoid this, an ion exchange resin protocol was developed to enable the API-IL to be synthesised and purified in a single step, and also produce it in a liquid effluent that can be integrated with other unit operations. Confined agitated bed crystallisation and spray drying are examples of processes that have been adapted to produce or consume liquid feeds and were combined with the ion exchange process to incorporate the API-IL synthesis into isolation-free frameworks and continuous manufacturing streams. This combination of isolation-free and co-processing techniques paves the way towards end-to-end continuous manufacturing of API-IL drug products.

FDA/M-CERSI Co-Processed API Workshop Proceedings

These proceedings contain presentation summaries and discussion highlights from the University of Maryland Center of Excellence in Regulatory Science and Innovation (M-CERSI) Workshop on Co-processed API, held on July 13 and 14, 2022. This workshop examined recent advances in the use of co-processed active pharmaceutical ingredients as a technology to improve drug substance physicochemical properties and drug product manufacturing process robustness, and explored proposals for enabling commercialization of these transformative technologies. Regulatory considerations were discussed with a focus on the classification, CMC strategies, and CMC documentation supporting the use of this class of materials from clinical studies through commercialization. The workshop format was split between presentations from industry, academia and the FDA, followed by breakout sessions structured to facilitate discussion. Given co-processed API is a relatively new concept, the authors felt it prudent to compile these proceedings to gain further visibility to topics discussed and perspectives raised during the workshop, particularly during breakout discussions. Disclaimer: This paper reflects discussions that occurred among stakeholder groups, including FDA, on various topics. The topics covered in the paper, including recommendations, therefore, are intended to capture key discussion points. The paper should not be interpreted to reflect alignment on the different topics by the participants, and the recommendations provided should not be used in lieu of FDA published guidance or direct conversations with the Agency about a specific development program. This paper should not be construed to represent FDA's views or policies.

Formulation Strategies to Improve the Stability and Handling of Oral Solid Dosage Forms of Highly Hygroscopic Pharmaceuticals and Nutraceuticals

Highly hygroscopic pharmaceutical and nutraceutical solids are prone to significant changes in their physicochemical properties due to chemical degradation and/or solid-state transition, resulting in adverse effects on their therapeutic performances and shelf life. Moisture absorption also leads to excessive wetting of the solids, causing their difficult handling during manufacturing. In this review, four formulation strategies that have been employed to tackle hygroscopicity issues in oral solid dosage forms of pharmaceuticals/nutraceuticals were discussed. The four strategies are (1) film coating, (2) encapsulation by spray drying or coacervation, (3) co-processing with excipients, and (4) crystal engineering by co-crystallization. Film coating and encapsulation work by acting as barriers between the hygroscopic active ingredients in the core and the environment, whereas co-processing with excipients works mainly by adding excipients that deflect moisture away from the active ingredients. Co-crystallization works by altering the crystal packing arrangements by introducing stabilizing co-formers. For hygroscopic pharmaceuticals, coating and co-crystallization are the most commonly employed strategies, whereas coating and encapsulation are popular for hygroscopic nutraceuticals (e.g., medicinal herbs, protein hydrolysates). Encapsulation is rarely applied on hygroscopic pharmaceuticals, just as co-crystallization is rarely used for hygroscopic nutraceuticals. Therefore, there is potential for improved hygroscopicity reduction by exploring beyond the traditionally used strategy.

Application of Ethyl Cellulose and Ethyl Cellulose + Polyethylene Glycol for the Development of Polymer-Based Formulations using Spray-Drying Technology for Retinoic Acid Encapsulation

Ethyl cellulose (EC)-based microparticles, with and without the incorporation of polyethylene glycol (PEG) as a second encapsulating agent, were prepared using the spray-drying process for the encapsulation of retinoic acid (RA). The production of a suitable controlled delivery system for this retinoid will promote its antitumor efficiency against acute promyelocytic leukemia (APL) due to the possibility of increasing the bioavailability of RA. Product yield ranged from 12 to 28% in all the microparticle formulations, including unloaded microparticles and RA-loaded microparticles. Microparticles with a mean diameter between 0.090 ± 0.002 and 0.54 ± 0.02 µm (number size distribution) and with an irregular form and rough surface were obtained. Furthermore, regarding RA-loaded microparticles, both polymer-based formulations exhibited an encapsulation efficiency of around 100%. A rapid and complete RA release was reached in 40 min from EC− and EC + PEG-based microparticles.

Ionic Liquids-Based Drug Delivery: a Perspective

Ionic liquids (ILs) recently draw attention for addressing unmet needs in biomedicines. By converting solids into liquids, ILs are emerging as novel platforms to overcome some critical drawbacks associated with the application of solid or crystalline active pharmaceutical ingredients (APIs). ILs have shown promise in liquidizing or solubilizing APIs, or as green solvents, novel permeation enhancers or active ingredients, alone or synergistically with APIs. Meanwhile, challenges turn up in company with the deepening understanding of ILs as drug delivery carrier systems. This perspective aims to provide a sketchy overview on the status quo with specific attention paid to new problems arising from the utilization of ILs-based technologies in drug delivery.