Stability Test Method Research Articles

Development of an ion pairing reversed-phase liquid chromatography-mass spectrometry method for characterization of clustered regularly interspaced short palindromic repeats guide ribonucleic acid

Guide ribonucleic acid (gRNA) is a critical reagent in clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 genome editing. The single stranded guide RNA (sgRNA) is the most commonly used gRNA in application. Evaluation of the impurity profile of synthetic sgRNA is important for any CRISPR genome editing experiments. However, the large molecular size, complex impurity profile and unique secondary structure pose many challenges in the analysis of sgRNA by ion pairing reversed-phase liquid chromatography (IP-RPLC), the commonly used method. In this work, we developed a generic IP-RPLC method for guide RNA analysis. We found that large pore size of stationary phase was the most critical column parameter to achieve high resolution separation of sgRNA while particle structure, particle size and surface chemistry had less impact. Our results indicated that charge interaction was the most critical mechanism for retention and mass transfer had less impact on the performance of separation. An IP-RPLC/mass spectrometry (MS) method was also developed with a specific practice to reduce adducts and enable intact MS analysis of sgRNAs. The generic IP-RPLC method demonstrates its feasibility to serve as a release, stability, characterization and in-process control testing method for synthetic sgRNA products.

Stability Testing of Pharmaceutical Products

Stability studies must be carried out according to the guidelines provided by the International Conference of Harmonization, World Health Organization, and other agencies in a scheduled manner. The pharmaceutical product’s stability can be defined as the ability, within its physical, chemical, microbiological, toxicology, protective, and informational requirements of a particular formulation in a specific container-closure system. It also guarantees that the performance, safety, and efficacy are maintained throughout the shelf life of any pharmaceutical product which is considered as pre-requisite for acceptance and approval. Different stability test methods have originated with the need for constant monitoring of drugs and products for their quality and purity. In this review, we have included the types of stability of drugs substances, the relevance of different methods used to test the stability of the pharmaceutical product, guidelines issued to test the stability of pharmaceuticals, stability testing protocols which describes the main components of a well-controlled and regulated stability test and other aspects of stability.

Development and Validation of UPLC-MS / MS Method for Obtaining Favipiravir Tablet Dosage form and Evaluation of its Behavior Under forced Conditions

Aims: Favipiravir (FVP) is a drug developed against RNA viruses. It is a drug that is used actively in the treatment of coronavirus. In vitro and in vivo investigations have shown that it inhibits the virus. In this study, a recovery study of tablet formulations was carried out by developing a UPLC-MS/MS method, which is used extensively in pandemic conditions. In addition, stability studies of favipiravir agent under forced conditions were conducted. The validated method is selective, robust, simple and applicable for tablet analysis. C18 (4.6 mm × 50 mm, 2.7 μm) column was used as the stationary phase and water-methanol (80-20 v/v) containing 0.1% formic acid was used as the mobile phase. UPLC optimization; It was conducted at a wavelength of 222 nm and a flow rate of 0.8 mL/min at 40 °C, retention time was 1.155 min. The electrospray jet stream ionization source was analyzed using mass spectrometry in negative ion mode. The molecular peak for Favipiravir was [M-1] 155.9, and the daughter ion determined 112.6. The stability test method was carried out in accordance with the ICH procedure. Reaction and degradation rates of the active substance under various forced conditions (acidic, basic, oxidative, UV light and thermal conditions) were investigated. The products formed by the decomposition of the active substance under stress conditions were determined by mass spectroscopy.

Detection method for stability of microcontroller accessories based on biosensor

In order to solve the problem of poor accuracy of traditional microcontroller attachment stability testing method, a microcontroller attachment stability testing method based on biosensor was designed to solve the existing problems. The reliability test index of the microcontroller is established, then the interference of the microcontroller accessory is detected and responded, and the interference detection signal of the microcontroller accessory is selected. The process design of stability detection of microcontroller accessories based on biosensor is completed. The experimental results show that the stability detection method based on biosensor designed in this paper can ensure the stability detection accuracy of microcontroller accessories above 80%, which is more accurate than traditional methods. It can be used to evaluate the stability, reliability and performance of microcontroller accessories in long-term operation.

Ex-Situ Technique to Measure the Chemical Stability of Anion Exchange Membranes Simulating in-Operando Anion Exchange Membrane Fuel Cell Test Environment

One of the major barrier in developing practical anion-exchange membrane fuel cells (AEMFCs) is the limited anion exchange membrane (AEM) chemical stability, since they usually undergo alkaline degradation at fuel cell operating conditions1,2. The existing ex situ stability testing methods in the literature do not allow for a reliable measurement of operando AEM stability (do not mimic the proper environment in an operating AEMFC)3–5. A common ex situ stability test is the long-term submersion of AEM in aqueous KOH solutions, but different groups use different conditions and characterization methods, making it difficult to compare the stability values reported in the literature. This KOH solution soaking method leads to inaccurate results because: (a) Different AEMs absorb liquid KOH electrolyte differently; (b) Carbonation can occur during the various experimental steps if CO2 not rigorously excluded; (c) Excess K+ and OH- co- and counter-ions are present unlike in an operating AEMFC; and mainly, (d) The AEMs are being degraded under maximum hydration conditions, which is not comparable to operando conditions. All of these give a false picture of degradation rates4.This presentation reports a unique ex situ method for determining the stability of AEMs under conditions that mimic the fuel cell operating environment. We apply our technique to determine the alkaline stability of AEMs with different cationic functional groups and polymer backbone configurations (Figure 1). It provides a new ex situ standard to measure AEM stabilities that gives a reliable picture of in situ alkaline stabilities (a meaningful simulation of the high pH, partially hydrated environment found operating AEMFCs).(1) Varcoe, J. R.; Atanassov, P.; Dekel, D. R.; Herring, A. M.; Hickner, M. A.; Kohl, P. A.; Kucernak, A. R.; Mustain, W. E.; Nijmeijer, K.; Scott, K.; Xu, T.; Zhuang, L. Anion-Exchange Membranes in Electrochemical Energy Systems. Energy Environ. Sci. 2014, 7 (10), 3135–3191. https://doi.org/10.1039/c4ee01303d.(2) Dekel, D. R. Review of Cell Performance in Anion Exchange Membrane Fuel Cells. J. Power Sources 2018, 375, 158–169. https://doi.org/10.1016/j.jpowsour.2017.07.117.(3) Willdorf-Cohen, S.; Mondal, A. N.; Dekel, D. R.; Diesendruck, C. E. Chemical Stability of Poly(Phenylene Oxide)-Based Ionomers in an Anion Exchange-Membrane Fuel Cell Environment. J. Mater. Chem. A 2018, 6 (44), 22234–22239. https://doi.org/10.1039/C8TA05785K.(4) Müller, J.; Zhegur, A.; Krewer, U.; Varcoe, J. R.; Dekel, D. R. Practical Ex-Situ Technique to Measure the Chemical Stability of Anion-Exchange Membranes under Conditions Simulating the Fuel Cell Environment. ACS Mater. Lett. 2020, 2 (2), 168–173. https://doi.org/10.1021/acsmaterialslett.9b00418.(5) Diesendruck, C. E.; Dekel, D. R. Water – A Key Parameter in the Stability of Anion Exchange Membrane Fuel Cells. Curr. Opin. Electrochem. 2018, 9, 173–178. https://doi.org/10.1016/j.coelec.2018.03.019. Figure 1

Capillary sodium dodecyl sulfate gel electrophoresis of proteins: Introducing the three dimensional Ferguson method

One of the most extensively utilized rapid characterization, release and stability testing methods of therapeutic proteins in the biopharmaceutical field today is capillary SDS gel electrophoresis using borate cross-linked high molecular weight dextran. In spite of its widespread use, however, the gel composition dependent separation characteristics of this very unique sieving matrix has not been investigated yet. Introduction of three dimensional (3D) Ferguson plots, based on simultaneous variation of the dextran (D) and borate (B) concentrations generating 16 different D/B ratio gels, allowed better understanding of the electromigration process of the SDS-protein complexes. As a result of this comprehensive study, non-linear 3D logarithmic mobility vs dextran and borate concentration surfaces were obtained. Both, the molecular weight protein standards and the new modality fusion protein etanercept resulted in concave 3D Ferguson plots. The interplay between the electroosmotic flow and the viscosity of the matrices played a key role in the resulting migration time and resolution. Selectivity values were defined and evaluated in 3D graph formats for the regular and de-N-glycosylated subunits of etanercept, as well as for the latter with the 10 kDa internal standard to understand both the dextran-borate complexation and sized based selectivities. KR plots of the retardation coefficients as the function of the logarithmic molecular weights were used to more precisely assess the Mw of the samples and to obtain information about the molecular characteristics of the electromigrating SDS-protein complexes.

Development and validation of a novel reporter gene assay for determination of recombinant human thrombopoietin

Recombinant human thrombopoietin (rhTPO) was approved by the National Medical Products Administration in 2010 for the treatment of thrombocytopenia in patients with immune thrombocytopenic purpura and chemotherapy-induced thrombocytopenia. Nevertheless, no method for determining rhTPO bioactivity has been recorded in different national/regional pharmacopoeia. Novel methods for lot release and stability testing are needed that are simpler, quicker, and more accurate. Here, we developed a novel reporter gene assay (RGA) for rhTPO bioassay with Ba/F3 cell lines that stably expressed human TPO receptor and luciferase reporter driven by sis-inducible element, gamma response region, and gamma-interferon activated sequence. During careful optimization, the RGA method demonstrated high performance characteristics. According to the International Council for Harmonization Q2 (R1) guidelines and the Chinese Pharmacopoeia 2020 edition, the validation results demonstrated that this method is highly time-saving, sensitive, and robust for research, development, manufacture, and quality control of rhTPO.

Plant Variety Protection: Current Practices and Insights.

Breeders persistently supply farmers with the best varieties in order to exceed consumer demand through plant-breeding processes that are resource-intensive. In order to motivate continuous innovation in variety development, a system needs to provide incentives for plant breeders to develop superior varieties, for example, exclusive ownership to produce and market those varieties. The most common system is the acquisition of intellectual property protection through plant variety protection, also known as the breeder’s right. Most countries have adopted the system established by the International Union for the Protection of New Varieties of Plants (UPOV). To be granted plant variety protection, the variety should prove to be unique by meeting three requirements: distinctness, uniformity, and stability. This review summarizes (1) the plant variety protection via UPOV convention, (2) technical methods for distinctness, uniformity, and stability testing via phenotype, molecular markers, and sequencing as well as their challenges and potentiality, and (3) additional discussions in essentially derived variety, value for cultivation and use testing, and open source seed initiative.

ID-MAM: A Validated Identity and Multi-Attribute Monitoring Method for Commercial Release and Stability Testing of a Bispecific Antibody.

Post-translational modifications (PTMs) that impact the safety or efficacy of protein therapeutics are critical quality attributes (CQAs) that need to be controlled to ensure product quality. Peptide mapping with online mass spectrometry (MS) is a powerful tool that has been used for many years to monitor PTM CQAs during product development. However, operating peptide mapping methods with high-resolution mass spectrometers in GMP compliant, commercial quality control (QC) labs can be difficult. Peptide mapping is also required as an identity test in several countries. To address these two different needs, we utilized high-resolution peptide mapping for comprehensive characterization during development and then developed and validated a targeted multi-attribute monitoring (MAM) method using the low-resolution Waters QDa MS system with a fully automated data processing workflow that is suitable for identity (ID) testing, sequence variant control, and CQA quantitation in commercial QC labs. The ID-MAM method was validated for the quantitation of three selected PTM CQAs (CDR isomerization, Fc Met oxidation, and CDR Met oxidation) to ensure control of the oxidation and isomerization degradation pathways of a bispecific antibody (BsAb). This ID-MAM method was successfully validated in six labs (three analytical development and three QC labs) across four countries for commercial release and stability testing of a BsAb. CQA results obtained with the ID-MAM method were similar to results obtained using high-resolution peptide mapping, and the method was robust and reproducible. To our knowledge, this ID-MAM method is the first MS-based peptide mapping method implemented in GMP compliant QC labs for commercial release and stability testing of a biotherapeutic.

Systematic stability analysis, evaluation and testing process, and platform for grid-connected power electronic equipment

The proportion of grid-connected power electronic equipment is already large enough to influence the dynamic characteristics of the modern power system. Ensuring the stability of grid-connected power electronic equipment in all relevant situations is one of the foundations for reliable power system operation. In contrast to conventional rotating machines, the stability of power electronic devices mostly depends on the applied control strategy, and a large diversity of different complex control strategies are in practical use. Also, the investigation of stability of such systems needs to take into account the non-linear behaviour of the power electronic equipment. These are the main reasons why the system behavior of grid-connected power electronic equipment cannot be reproduced satisfactorily when aplying a single method of stability analysis, evaluation and testing method. During the last years, faults which led to tripping of converters due to stability problems occurred frequently even though standardized fault compliance tests were performed on these converters. In this paper these stability issues are analyzed. Also, a three-dimensional stability analysis method is suggested in order to comprehensively cover system behavior. The three dimensions are the time/scale dimension, the equipment number dimension and the local or global range of the stability analysis dimension. Based on this three-dimensional framework, this paper proposes a stability evaluation as well as a test process applying a hardware-in-the-loop test concept. Through the verification and testing of the stability of the actual grid-connected power electronic equipment, the method proposed in this paper is verified for up-to-date equipment.

An improved reduction method for phase stability testing in the single-phase region

AbstractA new reduction method for mixture phase stability testing is proposed, consisting in Newton iterations with a particular set of independent variables and residual functions. The dimension of the problem does not depend on the number of components but on the number of components with nonzero binary interaction parameters in the equation of state. Numerical experiments show an improved convergence behavior, mainly for the domain located outside the stability test limit locus in the pressure–temperature plane, recommending the proposed method for any applications in which the problematic domain is crossed a very large number of times during simulations.

Determination and stability testing method of chlorpheniramine maleate in the presence of tartrazine using HPLC

The single-component CPM tablet mostly used sodium tartrazine as the yellow coloring agent. Sodium tartrazine is soluble in solvents used to extract CPM from tablet and suspected interference CPM determination especially after forced degradation for stability indication testing of CPM tablets. This study aimed to develop a selective, accurate and precise method for determination and stability testing of chlorpheniramine maleate (CPM) in the presence of tartrazine in the tablet. A µBondapak ® C18 column (3.9 x 300 mm, 10 µm) with diode array detector was used for separation. The mobile phase was a mixture of methanol and 0.2% triethylamine (90:10) with a flow rate of 2 mL/minutes. The validated HPLC method was used for CPM determination in tablet samples that had been forced degraded using dry heat at 105 o C, UV radiation of 254 nm, hydrolysis with 1N NaOH, 1N HCl and oxidation using 5% H 2 O 2 . The HPLC chromatogram showed that CPM split into chlorpheniramine (CP) and maleic acid (MA). Resolution (Rs) among CP and the other analytes especially with the products resulting from the forced degradation by heat, UV radiation, HCl, and H 2 O 2 were good. The CPM hydrolysis using NaOH caused the CP not completely separated from the degradation product due to tailing or overlapping peaks. The proposed HPLC method was valid for the determination of CPM in tablets containing tartrazine. Even though the stability-indicating method was inadequate especially for the result of the CPM hydrolysis process using NaOH.

A REVIEW ON STABILITY TESTING GUIDELINES OF PHARMACEUTICAL PRODUCTS

Stability studies must be carried out according to the guidelines provided by the International Conference of Harmonization, World Health Organization, and other agencies in a scheduled manner. The pharmaceutical product’s stability can be defined as the ability, within its physical, chemical, microbiological, toxicology, protective, and informational requirements of a particular formulation in a specific container-closure system. It also guarantees that the performance, safety, and efficacy are maintained throughout the shelf life of any pharmaceutical product which is considered as pre-requisite for acceptance and approval. Different stability test methods have originated with the need for constant monitoring of drugs and products for their quality and purity. In this review, we have included the types of stability of drugs substances, the relevance of different methods used to test the stability of the pharmaceutical product, guidelines issued to test the stability of pharmaceuticals, stability testing protocols which describes the main components of a well-controlled and regulated stability test and other aspects of stability.

Compatibility and thermal decomposition kinetics between HMX and some polyester-based polyurethanes

A polyester (PE)-based polyurethane (PU) is widely used as a polymeric binder with an energetic compound especially more energetic octhydro-1,3,5,7 tetranitro-1,3,5,7 tetrazocine (HMX) in many energetic composite formulation. Compatibility between PE-based PU containing various curatives and HMX was studied through vacuum stability test, thermogravimetry and differential scanning calorimetry methods. PUs were obtained from the reaction of the prepolymer PE with various diisocyanates as curatives especially 4,4′ methylenediphenyl diisocyanate (MDI), isophorone diisocyanate (IPDI), toluene diisocyanate (TDI) and 2,2,4 trimethylhexamethylene diisocyanate (TMDI), and these PUs were designated by PE/MDI, PE/IPDI, PE/TDI and PE/TMDI, respectively. The compatibility was judged through standardization agreement (STANAG) 4147. The results showed that the binary mixture of HMX with various PU, namely PE/MDI, PE/IPDI, PE/TDI and PE/TMDI, possessed a good compatibility. Kinetics of the binary mixture of HMX and PU was studied at three heating rates by means of the Ozawa and Kissinger methods. The calculated activation energy values of the binary mixture of HMX with PE/MDI, PE/IPDI, PE/TDI and PE/TMDI from the Kissinger method were found to be 483.9, 504.7, 502.2 and 485.3 kJ mol−1, respectively. For comparison, the values of neat PE and HMX were also calculated and were 118.2 and 299.3 kJ mol−1, respectively. The kinetic parameters were strongly depended on the type of the curative groups in the PE-based PU. Similar results were obtained from the Ozawa and ASTM E698 methods. The activation energy values calculated from the ASTM E698 method for the HMX/PE/MDI, HMX/PE/IPDI, HMX/PE/TDI and HMX/PE/TMDI samples were 204–215, 219–235, 145–157 and 172–246 kJ mol−1 in the low conversion of 0.05–0.15, respectively. Subsequently, these were demonstrated by a remarkable deviation in the activation energy in a range of 247–474, 235–499, 166–578 and 245–528 kJ mol−1 at the conversion (0.15–0.95), respectively.

Two Different Methods to Measure the Stability of Acetabular Implants: A Comparison Using Artificial Acetabular Models.

The total number of total hip arthroplasties is increasing every year, and approximately 10% of these surgeries are revisions. New implant design and surgical techniques are evolving quickly and demand accurate preclinical evaluation. The initial stability of cementless implants is one of the main concerns of these preclinical evaluations. A broad range of initial stability test methods is currently used, which can be categorized into two main groups: Load-to-failure tests and relative micromotion measurements. Measuring relative micromotion between implant and bone is recognized as the golden standard for implant stability testing as this micromotion is directly linked to the long-term fixation of cementless implants. However, specific custom-made set-ups are required to measure this micromotion, with the result that numerous studies opt to perform more straightforward load-to-failure tests. A custom-made micromotion test set-up for artificial acetabular bone models was developed and used to compare load-to-failure (implant push-out test) with micromotion and to assess the influence of bone material properties and press-fit on the implant stability. The results showed a high degree of correlation between micromotion and load-to-failure stability metrics, which indicates that load-to-failure stability tests can be an appropriate estimator of the primary stability of acetabular implants. Nevertheless, micromotions still apply as the golden standard and are preferred when high accuracy is necessary. Higher bone density resulted in an increase in implant stability. An increase of press-fit from 0.7 mm to 1.2 mm did not significantly increase implant stability.

Stability Testing of Compounding Capsule Combination between Paracetamol and Tramadol in a Private Hospital Semarang

A combination of Paracetamol and Tramadol is used in mild to severe pain management. In a private Hospital Semarang, this combination is included in fast-moving drugs that it is frequently compounded and prepared in advance. The study aims t o determine Beyond Use Date (BUD) in compounding capsules combination between Paracetamol and Tramadol samples. Beyond Use Date is a time limit indicating that a medicine beyond the expiration date must not be used and determined based on the results of stability testing. Samples were stored for 14 days in a tightly closed container far from direct sunlight in room temperature without AC (28 0 C) and without silica gel, room temperature with AC (25 0 C) without silica gel, and room temperature with AC (25 0 C) with silica gel. Furthermore, samples underwent physical and chemical stability testing. Physical stability testing was conducted using organoleptic testing by observing direct changes from the powder color in capsules, capsules form, and scent on the samples. Meanwhile, chemical stability testing was conducted by determining the content of active ingredient from the samples using reversed-phase HPLC method and C18 as the stationary phase, methanol and aquabidest (40:60) as the mobile phase, wavelength 271 nm, flow rate 0.6 mL/min and injection volume 10 μL. The result shows that s amples were physically stable for being able to retain the original physical properties showed by consistent powder color and capsules form, and there was no available scent. However, the chemical stability testing method was unable to separate and quantify the content of Paracetamol, Tramadol, and formed degradation products. It can be concluded that Beyond Use Date based on organoleptic and chemical stability testing for 14 days of compounding capsules combination between Paracetamol and Tramadol could not be determined. Nevertheless, this study showed favorable storage conditions in a tightly closed container far from direct sunlight in Room Temperature with AC (25 0 C) with Silica Gel.

Global Comparison of Stability Testing Parameters and Testing Methods for Finished Herbal Products.

Quality consistencies of drug products are essential to guarantee expected therapeutic activities, and achieving consistent qualities for herbal products is challenging because of their physicochemical complexities and inherent variabilities. Regulatory authorities worldwide have issued regulations or guidelines for stability testing parameters and testing procedures for herbal products stored in proposed conditions. These testing parameters and methods for finished herbal products are detailed in the guidelines and regulations issued by 5 global authorities and 15 countries, that is, the Association of Southeast Asian Nations (ASEAN), the Eurasian Economic Commission (EEC), the European Medicines Agency (EMA), the International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH), the World Health Organization (WHO), Australia, Brazil, Canada, China, Egypt, Hong Kong, India, Japan, Kenya, Republic of Korea, the Philippines, Qatar, Switzerland, USA, and Zambia. Physical, chemical, and biological stability tests were compared between different dosage forms, and the testing conditions (temperature and relative humidity) used for long-term, accelerated, or intermediate testing were included in the guidelines and regulations. Comparisons of global regulations and guidelines addressing stability testing are fundamental for the international harmonization of herbal product quality assessments. This review aids understanding of the global situation regarding the testing of herbal product quality with respect to storages.

Exploratory Analysis of Automotive Diesel Fuel Stability Test Methods by Infrared Spectroscopy and Parallel Factor Analysis

The stability of diesel fuel is a complex issue, and the blend of fossil fuels with biodiesel added new concerns to the problem. Many standard test methods exist to evaluate the tendency of thermal and oxidative degradation. These procedures perform specific stressing conditions to accelerate oxidation and rate fuels on a relative stability scale. In this work, 18 diesel fuel samples containing 8% v/v biodiesel collected in representative Brazilian gas stations spread across different states of the country were submitted to four standard stability tests and analyzed with mid-infrared (IR) spectroscopy. The stability studies were carried out according to the ASTM standard procedures D4625, D6468, and D7545 and the CEN standard EN15751. The data generated were evaluated with the chemometric tool parallel factor analysis (PARAFAC), which decomposes the data array in few independent factors that explain the main sources of variation and allow the evaluation of the differences in the physical and chemical modi...

Thermal decomposition and shelf-life of PETN and PBX based on PETN using thermal methods

The kinetics of exothermic reactions are important in assessing the potential of materials and systems for thermal explosion. In this paper, the thermal behavior and decomposition kinetics of pentaerythritol tetranitrate (PETN) and polymer-bonded explosives (PBXs) based on PETN were investigated using Thermogravimetric analysis (TGA) and Vacuum Stability Test (VST) methods. The Arrhenius activation energies and pre-exponential factors were determined by the Ozawa and Kissinger methods. Based on the overall kinetic parameters of decomposition reactions, the shelf-life of PETN and PBXs based on PETN could be calculated and predicted.

Variability after 15 Years of Vegetation Recovery in Natural Secondary Forest with Timber Harvesting at Different Intensities in Southeastern China: Community Diversity and Stability

The mixed Cunninghamia lanceolata (Lamb.) Hook., Pinus massoniana Lamb., and hardwood forest in southeastern China is a major assemblage in natural secondary forests, and of national and international importance in terms of both timber and ecosystem services. However, over-harvesting has threatened its long-term sustainability, and there is a knowledge gap relating to the effect of harvesting on the ecosystem. After conifer species were selected for harvesting, the mixed Chinese fir, pine, and hardwood forest was changed into mixed evergreen broadleaf forest. In this context, we observed the restoration dynamics of plant communities over a period of 15 years (1996 to 2011) with different levels of harvesting intensity, including selective harvesting at low (13.0% removal of growing stock volume), medium (29.1%), high (45.8%), and extra-high (67.1%) intensities, as well as clear-cut harvesting (100.0%), with non-harvesting as the control, based on permanent sample plots established in a randomized block design in these forests in southeastern China. The impact on the richness, diversity, and evenness of plant species derived from descriptive statistical analyses was shown to initially increase, and then decrease, with an increase in harvesting intensity. The most critical impacts were on the richness, diversity, and evenness of shrub and herb species. Richness, diversity, and evenness of plant species recovered and increased under selective harvesting at low and medium intensities, while these parameters had not recovered and significantly decreased under selective harvesting at high and extra-high intensities, as well as with clear-cut harvesting. The impact on the plant community stability was derived from the stability test method of the improved Godron M. The plant community stability was closest to the point of stability (20/80) under selective harvesting at medium intensity, followed by selective harvesting at low intensity. The plant community stability was far from the point of stability (20/80) under selective harvesting at high and extra-high intensities, as well as with clear-cut harvesting. Of these treatments, clear-cut harvesting had the greatest effect with regard to reducing stability. Therefore, these results indicate that the selective harvesting at low and medium intensities is conducive to preserve or increase the species diversity and community stability. In order to prioritize promoting plant species diversity, clear-cut harvesting and selective harvesting at high and extra-high intensities should be avoided with regard to this type of forest in this region. This study sheds light on the practice of forest operation in the study region and subtropical forests with the same environment.