Formability and physical stability of high-drug-loading whole extract temporary prescription tablets based on direct powder compression technology

FANG Ying; HONG Yanlong; LIN Xiao; SHEN Lan; ZHAO Lijie

doi:10.13732/j.issn.1008-5548.2025.04.009

Abstract：Objective Temporary prescription preparation is key component of personalized pharmaceutical services,characterized by indi-vidualized formulations and diverse dosage forms.However,the strong odor and taste of traditional Chinese medicine(TCM)often reduce patient acceptance and utilization rates,limiting the formulation options for temporary prescription.Tablets,one of the most commonly used solid dosage forms,offer advantages such as color and taste masking and high drug loading.Among tab-let preparation methods,direct powder compression is preferred for its simplicity and efficiency,making it suitable for temporary prescription.However,the complexity and hygroscopicity of TCM powders pose significant challenges during tablet compres-sion,including cracking,sticking,and structural instability.These issues highlight the need for careful formulation design.Building on previous research that identified basic tablet-forming formulations,the study aims to evaluate the formability and physical stability of TCM temporary prescription tablets prepared using different base formulations.The findings will provide guidance for optimizing formulations and improving storage conditions for temporary prescription tablets. Methods In this study,two base formulations were investigated for their compressibility and compactibility using the direct pow-der compression technique.Tensile strength and disintegration time were used as key assessment indicators.Given that tempo-rary prescription preparations are not subjected to prolonged transportation and storage,the quality standards were set according to the Pharmacopoeia of the People's Republic of China:a minimum of tensile strength of 1.7 MPa and a disintegration time of less than 60 min.To assess physical stability,tablets were stored at a relative humidity of 60％and a temperature of 25℃.Key parameters,including tablet weight change,axial and radial expansion change,tensile strength,and disintegration time,were monitored to evaluate stability over time. Results and Discussion Using the expert formulation design system developed in previous research,two formulations(Formula-tion 1 and Formulation 2)suitable for the direct compression of TCM compound powders were successfully screened.Tablets prepared with both formulations exhibited good formability and met quality requirements.During the stability study,both formu-lations experienced different degrees of axial and radial expansion.Tablets prepared under controlled tensile strength showed more pronounced expansion during storage than those prepared under controlled compression force.The tensile strength of most tablets remained relatively stable or slightly increased at week 1,though a few showed a more pronounced decrease followed by an increase.Notably,Formulation 2 demonstrated greater tensile strength fluctuations than Formulation 1.Despite these varia-tions,all tablets maintained tensile strength values above 1.7 MPa throughout the 4-week stability study period,ensuring their suitability for handling and administration.Additionally,the disintegration time of most tablets stabilized after 1 week of stor-age,indicating that moisture absorption reached equilibrium with ambient humidity. Conclusion Moisture content is an important factor affecting product stability,especially for hygroscopic TCM powders.Tablets stored in high-humidity environments tend to absorb moisture to reach equilibrium with storage conditions.Storage humidity affects weight changes in tablets and leads to varying degrees of axial and radial expansion.These structural changes can affect inter-particle bonding,thereby influencing the internal structure and quality of the tablets.However,once equilibrium is reached,the physical properties of the tablets tend to stabilize.By utilizing a systematic formulation design approach,temporary prescription tablets with acceptable stability can be rapidly screened and developed.