As a pharmaceutical excipient with low caloric value, low hygroscopicity, and high stability, mannitol is widely used in various dosage forms, such as solid, lyophilized and inhalation preparations, etc. It has different crystal structures (α, β and δ) and cocrystal, and the changes in the crystal structure will affect formulation properties of pharmaceutical formulations. This paper reviews structural features, physicochemical properties, and preparation methods of mannitol polymorphs and cocrystal formation, with emphasis on polymorphic transformation pathways, monitoring methods and the effect of polymorphic transformation on properties and application in pharmaceutical formulations, including tabletability, disintegration and dissolution properties. By systematically summarizing the crystallographic study of mannitol, this study attempts to provide new ideas for the development of novel pharmaceutical excipients and applications in pharmaceutical formulations.

As a pharmaceutical excipient with low caloric value, low hygroscopicity, and high stability, mannitol is widely used in various dosage forms, such as solid, lyophilized and inhalation preparations, etc. It has different crystal structures (α, β and δ) and cocrystal, and the changes in the crystal structure will affect formulation properties of pharmaceutical formulations. This paper reviews structural features, physicochemical properties, and preparation methods of mannitol polymorphs and cocrystal formation, with emphasis on polymorphic transformation pathways, monitoring methods and the effect of polymorphic transformation on properties and application in pharmaceutical formulations, including tabletability, disintegration and dissolution properties. By systematically summarizing the crystallographic study of mannitol, this study attempts to provide new ideas for the development of novel pharmaceutical excipients and applications in pharmaceutical formulations.

Abstract: It is well-known that crystal form of a drug is a key factor impacting the physicochemical properties of the drug, which in turn affects its in vivo efficacy, safety and stability. The study on crystal forms of solid-state drugs is crucial for drug quality control, selection of production process and evaluation of clinical efficacy. The combination of chemometric and analytical techniques exhibited its great ability to analyze a large amount of multidimensional data, providing the possibility for quantification of trace amount of crystals (< 1%). Meanwhile, using the process analytical technology (PAT) to monitor the crystal content real-time during prescription preparation process can further realize the control on formulation quality and serve as a core technology to support the patent protection of crystalline forms. In this review, the combined application of crystal analytical techniques and chemometric methods for the quantitative analysis of trace crystals were summarized, aiming to provide guidance for the manufacturing of pharmaceutical preparations and their quality control.

Pharmaceutical excipients, as an indispensable part of drug preparation, play crucial roles as drug carriers, improving drug release, ensuring drug stability, and enhancing patient compliance. Traditional Chinese Medicine (TCM) boasts a rich developmental history. With the modernization of technology, the deep integration of pharmacy, chemistry, and materials science has provided broader opportunities for innovative research in TCM. Simultaneously, the demand for high-quality excipients has become increasingly critical.This paper aims to review current research and applications of excipients in TCM preparations, including pre-mixed and co-processed excipients, modified excipients, and the unification of drugs and excipients, such as flavoring agents, fillers, penetration enhancers, and delivery systems. A meticulous synthesis and analysis of existing research aims to provide a reference for selecting excipients in TCM preparations, stimulate innovation in excipient development for TCM, and advocate for the development of personalized excipients.

Taking the Ligustrum lucidum extract as an example, this study investigated the influence of external mechanical forces under different processing conditions on the crystallographic solid form and the key parameter of drug dissolution rate, so as to provide guidance for the preparation and quality control of traditional Chinese medicine preparations. Under different pulverization and tableting conditions, the change of crystallographic solid form of L. lucidum extract was observed by polarizing light microscope. Meanwhile, the effect of this change on the dissolution rate was investigated, and the mathematical relationship between crystal content and dissolution rate was analyzed. The results showed that the process of ball milling and tableting had a significant impact on the crystallographic solid form of L. lucidum extract. The amorphous extract displayed crystal transformation, which induced a significant decline in dissolution rate. Further studies revealed that there was a negative linear relationship between crystal content and dissolution rate. The results of this study indicated that the crystallographic solid form transformation of traditional Chinese medicine extracts might occur during the preparation process, which may cause potential risks to the quality of traditional Chinese medicine preparations. It is suggested that we should pay attention to and strengthen the investigation of the crystallographic solid form during the preparation process, so as to guarantee the safety, effectiveness, and quality controllability of traditional Chinese medicine preparations.

In recent years, bio-metal organic frameworks (Bio-MOFs) synthesized with biocompatible ligands have been widely investigated as a potential drug delivery carrier due to their large specific surface area and porosity, rich host-guest intermolecular interactions, and good biocompatibility.In this review, we summarized the design methods of Bio-MOFs including structural and toxic factors, as well as a variety of drug loading methods including click chemistry, with particular focus on recent research advances in Bio-MOFs for pulmonary drug delivery systems, improving pharmaceutical properties of drugs, sustained and controlled drug release, stimulation response and targeted drug delivery systems.Finally, we summarized the bottlenecks that constrain the development of Bio-MOFs in clinical studies of actual pharmaceutical formulations and their future directions for approved formulations, aiming to provide some theoretical reference for promoting the application of Bio-MOFs in drug delivery systems.

In order to guarantee the quality of traditional Chinese medicines (TCMs), the crystallization transformation of complex extracts of TCMs and the influence of solid form on their physicochemical properties were studied.The extract of total flavonoids from Pueraria lobata was taken as a model.Crystallization transformation happened when lofting under different conditions, and the intrinsic dissolution tests were carried out.It was found that humidity was the key factor to induce crystallization of total flavonoids from Pueraria lobata.The greater the wettability was, the more the crystallization was.The dissolution rate of total flavonoids from Pueraria lobata with the most crystallization amount significantly decreased by 96.51% compared to the sample without crystallization.After further simulating the preparation process of total flavonoids from Pueraria lobata, it was found that the wet granulation process with introduced water would also lead to crystallization and reduced dissolution rate.As for all crystallization samples, there was an inversely proportional relationship between the dissolution rates and the amount of crystallization.The risk of crystallization existed both in the storage and preparation process of TCM extracts.Crystallization would significantly affect the dissolution rate, and thus the quality of TCM products.In this study, the crystallization transformation of amorphous complex TCM extracts was discovered, and the effect of the crystallization transformation on its dissolution behavior was systematically studied, which provides a new research idea for assuring the quality of TCM products and promoting the improvement of TCM preparation level.

Topical preparations for skin, including the commonly used dosage forms of ointments, creams, gels, patches and plasters, are convenient and can avoid the first-pass effect of drugs.Rheological study, which describes the flow characteristics and mechanical properties of products relevant to their Critical Quality Attributes, has become the main focus for topical preparations.Liquid and solid behaviors of products are usually investigated via steady rheology as well as dynamic rheology.This article reviews the research on topical preparations for skin and the data analysis models based on two rheological methods, aiming to provide some references for the rheological evaluation of topical preparations.

Lenvatinib mesylate (LF), a multi-target tyrosinase inhibitor mainly used in the treatment of a variety of cancers, has low oral bioavailability mainly due to its gelation during the dissolution process. In the current study, in order to enhance dissolution and eliminate gelation of LF, a supramolecular coamorphous system of LF-baicalein (BAI) (molar ratio, 1∶1) was prepared by rotary evaporation and characterized by PLM, PXRD, DSC and FTIR. Results indicated the formation of coamorphous system with a single Tg of 118 °C. Different from original LF crystal, no gelation phenomenon was observed during the dissolution of coamorphous LF-BAI. In addition, the dissolution rate of LF was increased by 2.2-fold after coamorphization. Meanwhile, the dissolution rate of the co-former BAI was also enhanced by more than 25.4-fold. Stability test showed that the prepared coamorphous system had a good physical stability for at least 90 days under 25 °C/ 60%RH and 40 °C /75%RH conditions.

Baicalein(BE), a natural flavonoid mainly extracted from Radix Scutellaria, has comprehensive pharmacological actions such as anti-inflammation, anti-virus and anti-cancer activities. It belongs to BCS class II compound with relatively low oral bioavailability. The current study aims to improve its aqueous solubility and dissolution and hence to enhance its oral absorption by cocrystallization technique. Slurry crystallization method was employed to prepare baicalein cocrystal with co-former caffeine(CA), followed by physicochemical characterizations with DSC, XRPD and FTIR. Compared to BE and physical mixture of BE and CA, BE-CA cocrystal had a significantly higher dissolution of BE. In addition, in comparison to BE, this cocrystal achieved reduced time to peak(tmax)as well as significantly higher peak plasma concentrations(cmax)and area under the curve(AUCs)for both BE and its active metabolite baicalin(BI)in rats, suggesting enhanced the oral bioavailability of BE.