OBJECTIVES

In response to the need for a simple and fast way of ensuring that generic drugs especially those that contain rifampicin are bioequivalent with reference drugs, this study validated an ultra-high-performance liquid chromatography (UHPLC) method of quantifying rifampicin in human plasma. The study also validated the method's selectivity, linearity, sensitivity, accuracy, precision, and the absence of a carry-over effect adhering to the Philippine Food and Drug Administration guidelines.

Plasma samples were prepared via protein precipitation using methanol containing ascorbic acid. Three microliters (3 uL) of the prepared samples were then analyzed in a Waters Acquity H-Class UPLC® system coupled to a tunable ultraviolet (TUV) detector with an attached UPLC® BEH C-18 column using a developed and optimized method. Briefly, the column temperature was set to 40°C and the sample temperature was set to 10°C. Elution was done using a linear gradient flow of a water-acetonitrile mixture that started with 45% acetonitrile increasing to 60% acetonitrile at 0.5 minutes and back to 45% acetonitrile at 3 minutes and having a constant flow rate of 0.5 mL/min. Detection was done at 340 nm. Method validation was performed following the ICH guidelines for Bioanalytical Method Validation, the same guidelines referenced by the ASEAN Guideline for Harmonisation of Standards and the Philippine Food and Drug Administration (FDA).

The method had an analysis time of 3 minutes wherein rifampicin eluted at 1.4 minutes while the internal standard, rifapentine (IS) eluted at 1.7 minutes. Since no co-eluting endogenous materials were observed for the rifampicin and the internal standard, the method was confirmed to be selective. Its linearity over the range of 2 ug/mL to 25 ug/mL has been validated where it has a limit of detection (LOD) and limit of quantification (LOQ) values of 0.64 ug/mL and 1.94 ug/mL, respectively. The interday and intraday precision, reported as % coefficient of variance (%CV), and interday and intraday accuracy, reported as %error all within the limits of ±20% for the LLOQ and ±15% for the rest indicating its reliability and reproducibility. Lastly, due to the nature of the injection of the sample into the system, wherein a blank immediately follows the highest concentration standard, the method has been cleared of a carry-over effect.

The study successfully validated a UHPLC method of quantifying rifampicin in human plasma. Due to the sample processing method used and the chromatographic conditions set, the method can prepare and analyze samples in a simple yet fast, sensitive, reliable, and reproducible manner. The method can be applied in bioavailability and bioequivalence studies of rifampicin.

Objectives: The Bioavailability/Bioequivalence Unit (BA/BE Unit) of the Department of Pharmacology and Toxicology, College of Medicine, University of the Philippines Manila which has not been operational since 2012, is due for renewal of its accreditation. To date, there are only three Philippine Food and Drug Administration-accredited laboratories that perform bioequivalence studies in the Philippines. One of the prerequisites of registering specific generic medicines is the conduct of Bioequivalence (BE) studies which are performed to ensure that the generic drug is at par with the innovator drug. Thus, this study aimed to determine the feasibility of re-establishing the BA/BE Unit as a bioequivalence testing center. Methods: The feasibility study done is a qualitative descriptive analysis based on expansive literature review and performance of SWOT analysis within the BA/BE unit. Literatures were selected based on its assessed relevance to the study. The databases checked were PubMed and Google Scholar. The terms used were from the Medical Subject Heading (MeSH) including feasibility studies, therapeutic equivalency, and generic drugs. Literature review was performed on the factors affecting the four types of feasibility studies (market, technical, financial, and organizational). A SWOT analysis of the BA/BE Unit was done through the review of records and documents of previous BE studies and focus group discussion among the BA/BE Unit team members. Results: The BA/BE Unit conducted 24 bioequivalence studies from 2006-2009 and still receives inquiries from drug companies. It implements its QMS throughout the pre-analytical, analytical, and post-analytical stages of the workflow. Its organizational structure consists of qualified professionals with updated GCP and GLP certificates. Because of the adequately equipped facility, lower honoraria for government-employed personnel, and lower expenses for laboratories and in-patient admissions, the cost of conducting a bioequivalence study in the BA/BE Unit will be lower than in other BE centers. Conclusion Based on the SWOT analysis and market, technical, financial, and organizational considerations, reestablishing the BA/BE Unit as a bioequivalence testing center is feasible.
Feasibility Studies ; Therapeutic Equivalency ; Drugs, Generic

OBJECTIVE: To develop a noninvasive method for prediction of 1p/19q codeletion in diffuse lower-grade glioma (DLGG) based on multimodal magnetic resonance imaging (MRI) radiomics. METHODS: We collected MRI data from 104 patients with pathologically confirmed DLGG between October, 2015 and September, 2022. A total of 535 radiomics features were extracted from T₂WI, T₁WI, FLAIR, CE-T₁WI and DWI, including 70 morphological features, 90 first order features, and 375 texture features. We constructed logistic regression (LR), logistic regression least absolute shrinkage and selection operator (LRlasso), support vector machine (SVM) and Linear Discriminant Analysis (LDA) radiomics models and compared their predictive performance after 10-fold cross validation. The MRI images were reviewed by two radiologists independently for predicting the 1p/19q status. Receiver operating characteristic curves were used to evaluate classification performance of the radiomics models and the radiologists. RESULTS: The 4 radiomics models (LR, LRlasso, SVM and LDA) achieved similar area under the curve (AUC) in the validation dataset (0.833, 0.819, 0.824 and 0.819, respectively; <i>Pi>>0.1), and their predictive performance was all superior to that of resident physicians of radiology (AUC=0.645, <i>Pi>=0.011, 0.022, 0.016, 0.030, respectively) and similar to that of attending physicians of radiology (AUC=0.838, <i>Pi>>0.05). CONCLUSION Multiparametric MRI radiomics models show good performance for noninvasive prediction of 1p/19q codeletion status in patients with in diffuse lower-grade glioma.
Humans ; Magnetic Resonance Imaging ; Chromosome Aberrations ; Area Under Curve ; Glioma/genetics* ; ROC Curve

Traditional Chinese medicine(TCM) has a long history and abundant experience in external therapy, which marks human wisdom. In the early history of human, people found that fumigation, coating, and sticking of some tree branches and herb stems can help alleviate scabies and remove parasites in productive labor, which indicates the emergence of external therapy. Pathogen usually enters the body through the surface, so external therapy can be used to treat the disease. External therapy is among the major characteristic of surgery of TCM. As one of the external therapies in TCM, external application to acupoints smooths the zang-fu organs through meridians and collaterals, thereby harmonizing yin and yang. This therapy emerged in the early society, formed the Spring and Autumn Period and the Warring States Period, improved in the Song and Ming dynasties, and matured in the Qing dynasty. With the efforts of experts in history, it has had a mature theory. According to modern research, it can avoid the first-pass effect of liver and the gastrointestinal irritation and improve the bioavailability of Chinese medicine. Based on the effect of Chinese medicine and the theory of meridian and collateral, it can stimulate the acupoints, exert regulatory effect on acupoints, and give full play to the efficacy of TCM and the interaction of the two. Thereby, it can regulate qi and blood and balance yin and yang, thus being widely used in the treatment of diseases. In this paper, the use of external application to acupoints, the effect on skin immunity, the regulation of neuro-inflammatory mechanism, the relationship between acupoint application and human circulation network, and the development of its dosage form were summarized through literature review. On this basis, this study is expected to lay a foundation for further research.
Humans ; Acupuncture Points ; Biological Availability ; Fumigation ; Medicine, Chinese Traditional ; Meridians

Huoluo Xiaoling Dan is a classical prescription commonly used for blood circulation and pain relief in clinic with obvious effects. To make it directly treat lesion and improve the effect, this research optimized the preparation process of Huoluo Xiaoling gel paste and further evaluated its in vitro transdermal absorption performance, so as to provide a scientific basis for its development and utilization. Using primary viscosity, holding viscosity, and sensory score as evaluation indexes, the matrix amount of gel paste was determined by the single factor test and Box-Behnken response surface method. The ultra-performance liquid chromatography(UPLC) method was established to determine the content of eight active ingredients, including Danshensu, ferulic acid, salvianolic acid B, salvianolic acid A, ligustilide, tanshinone Ⅱ_A, 11-keto-β-boswellic(KBA), and 3-acetyl-11-keto-β-boswellic acid(AKBA). A mo-dified Franz diffusion cell method was used to evaluate and compare the absorption properties of the gel paste without volatile oil and with volatile oil microemulsion. The results showed that the optimal prescription for Huoluo Xiaoling gel paste matrix was NP700(1.35 g), glycerol(7.00 g), micropowder silica gel(1.25 g), sodium carboxymethyl cellulose(0.20 g), tartaric acid(0.06 g), and glyceryl aluminum(0.04 g). The mass fractions of eight active ingredients in the paste were successively 0.48, 0.014, 0.95, 0.39, 0.57, 0.055, 0.35, and 0.97 mg·g~(-1). The results of the in vitro transdermal absorption test showed that the addition of the volatile oil or the volatile oil microemulsion promoted the transdermal absorption of the active ingredients, and the law of drug penetration conformed to the zero equation or the Higuchi equation. The gel paste prepared by the optimal prescription has good appearance and adhesion, with no residue, and has the characteristics of skeletal slow-release preparation, which is easy to reduce the number of administration, la-ying a foundation for the development of new external dosage forms of Huoluo Xiaoling Dan.
Administration, Cutaneous ; Skin Absorption ; Chromatography, Liquid ; Oils, Volatile ; Viscosity

Flavonoids have been reported to possess significant pharmacological activities,such as antioxidant, anti-inflammatory and anticancer effects. However, the low solubility and low bioavailability limits their clinical application. Nanocrystal technology can solve the delivery problems of flavonoids by reducing particle size, increasing the solubility of insoluble drugs and improving their bioavailability. This article summaries nanosuspension preparation methods and the stabilizers for flavonoid nanocrystals, and reviews the drug delivery routes including oral, Injection and transdermal of flavonoid nanocrystals, to provide information for further research on nanocrystal delivery system of flavonoids.
Flavonoids/pharmacology* ; Pharmaceutical Preparations/chemistry* ; Biological Availability ; Nanoparticles/chemistry* ; Anti-Inflammatory Agents ; Particle Size

Metformin has been used for the treatment of type II diabetes mellitus for decades due to its safety, low cost, and outstanding hypoglycemic effect clinically. The mechanisms underlying these benefits are complex and still not fully understood. Inhibition of mitochondrial respiratory-chain complex I is the most described downstream mechanism of metformin, leading to reduced ATP production and activation of AMP-activated protein kinase (AMPK). Meanwhile, many novel targets of metformin have been gradually discovered. In recent years, multiple pre-clinical and clinical studies are committed to extend the indications of metformin in addition to diabetes. Herein, we summarized the benefits of metformin in four types of diseases, including metabolic associated diseases, cancer, aging and age-related diseases, neurological disorders. We comprehensively discussed the pharmacokinetic properties and the mechanisms of action, treatment strategies, the clinical application, the potential risk of metformin in various diseases. This review provides a brief summary of the benefits and concerns of metformin, aiming to interest scientists to consider and explore the common and specific mechanisms and guiding for the further research. Although there have been countless studies of metformin, longitudinal research in each field is still much warranted.
Humans ; Metformin/pharmacokinetics* ; Diabetes Mellitus, Type 2/metabolism* ; Hypoglycemic Agents/pharmacology* ; AMP-Activated Protein Kinases/metabolism* ; Aging

OBJECTIVE: To observe the correlation between the four limbs perfusion index (PI) and blood lactic acid in patients with neurosis, and evaluate the predictive value of PI on microcirculation perfusion metabolic disorder in patients with neurosis. METHODS: A prospective observational study was conducted. Adult patients admitted to the department of neurological intensive care unit (NICU) of the First Affiliated Hospital of Xinjiang Medical University from July 1 to August 20 in 2020 were enrolled. Under the condition of indoor temperature controlled at 25 centigrade, all patients were placed in the supine position, and the blood pressure, heart rate, PI of both fingers and thumb toes and arterial blood lactic acid were measured within 24 hours and 24-48 hours after NICU. The difference of four limbs PI at different time periods and its correlation with lactic acid were compared. Receiver operator characteristic curve (ROC curve) was used to evaluate the predictive value of four limbs PI on patients with microcirculatory perfusion metabolic disorder. RESULTS: A total of 44 patients with neurosis were enrolled, including 28 males and 16 females; average age (61.2±16.5) years old. There were no significant differences in PI of the left index finger and the right index finger [2.57 (1.44, 4.79) vs. 2.70 (1.25, 5.33)], PI of the left toe and the right toe [2.09 (0.85, 4.76) vs. 1.88 (0.74, 4.32)] within 24 hours after entering the NICU, and the PI of the left index finger and the right index finger [3.17 (1.49, 5.07) vs. 3.14 (1.33, 5.36)], PI of the left toe and the right toe [2.07 (0.75, 5.20) vs. 2.07 (0.68, 4.67)] at 24-48 hours after NICU admission (all P > 0.05). However, compared to the PI of the upper and lower limbs on the same side, except for the 24-48 hours after ICU of the PI difference between the left index finger and the left toe (P > 0.05), the PI of the toe was lower than that of the index finger at the other time periods (all P < 0.05). The correlation analysis showed that the PI value of four limbs of patients in both time periods were significantly negatively correlated with arterial blood lactic acid (the r values of the left index finger, the right index finger, the left toe and the right toe were -0.549, -0.482, -0.392 and -0.343 respectively within 24 hours after entering the NICU; the r values of the left index finger, the right index finger, the left toe and the right toe were -0.331, -0.292, -0.402 and -0.442 respectively after entering the NICU 24-48 hours, all P < 0.05). Taking lactic acid ≥ 2 mmol/L as the diagnostic standard for metabolic disorder of microcirculation perfusion (total 27 times, accounting for 30.7%). The efficacy of four limbs PI in predicting microcirculation perfusion metabolic disorder were compared. ROC curve analysis showed that the area under the curve (AUC) and 95% confidence interval (95%CI) of left index finger, right index finger, left toe and right toe predicting microcirculation perfusion metabolic disorder were 0.729 (0.609-0.850), 0.767 (0.662-0.871), 0.722 (0.609-0.835), 0.718 (0.593-0.842), respectively. There was no significant difference in AUC compare with each other (all P > 0.05). The cut-off value of PI of right index finger for predicting microcirculation perfusion metabolic disorder was 2.46, the sensitivity was 70.4%, the specificity was 75.4%, the positive likelihood ratio was 2.86, and the negative likelihood ratio was 0.30. CONCLUSIONS There are no significant differences in PI of bilateral index fingers, bilateral toes in patients with neurosis. However, unilateral upper and lower limbs showed lower PI in the toe than in the index finger. There is a significantly negatively correlation between PI and arterial blood lactic acid in all four limbs. PI can predict the metabolic disorder of microcirculation perfusion, and its cut-off value is 2.46.
Adult ; Female ; Male ; Humans ; Middle Aged ; Aged ; Lactic Acid ; Microcirculation ; Perfusion Index ; Lower Extremity ; Area Under Curve ; Nervous System Diseases

Methanol has become an attractive substrate for the biomanufacturing industry due to its abundant supply and low cost. The biotransformation of methanol to value-added chemicals using microbial cell factories has the advantages of green process, mild conditions and diversified products. These advantages may expand the product chain based on methanol and alleviate the current problem of biomanufacturing, which is competing with people for food. Elucidating the pathways involving methanol oxidation, formaldehyde assimilation and dissimilation in different natural methylotrophs is essential for subsequent genetic engineering modification, and is more conducive to the construction of novel non-natural methylotrophs. This review discusses the current status of research on methanol metabolic pathways in methylotrophs, and presents recent advances and challenges in natural and synthetic methylotrophs and their applications in methanol bioconversion.
Humans ; Methanol/metabolism* ; Metabolic Engineering ; Metabolic Networks and Pathways ; Biotransformation

Objective To evaluate the performance of myPKFiT,a tool guiding the dosing of antihemophilic factor (recombinant) plasma/albumin-free method (rAHF-PFM),in maintaining the coagulation factor Ⅷ (FⅧ) level above a target threshold at the steady state and estimating the pharmacokinetics (PK) parameters in hemophilia A patients in China. Methods The data of 9 patients with severe hemophilia A in a trial (CTR20140434) assessing the safety and efficacy of rAHF-PFM in the Chinese patients with hemophilia A were analyzed.The myPKFiT was used to predict the adequate dose to maintain a patient's FⅧ level above target threshold at the steady state.Furthermore,the performance of myPKFiT in estimating the pharmacokinetics parameters of individuals was evaluated. Results Twelve combinations of two dosing intervals and six sparse sampling schedules were investigated,and 57%-88% of the patients remained the FⅧ level above the target threshold of 1 U/dl (1%) for at least 80% of the dosing interval.The clearance and time to FⅧ level of 1% obtained from sparse sampling by myPKFiT were similar to those obtained from extensive sampling. Conclusions The myPKFiT can provide adequate dose estimates to maintain the FⅧ level above the target threshold at the steady state in Chinese patients with severe hemophilia A.Moreover,it demonstrates good performance for estimating key pharmacokinetics parameters,including clearance and time to FⅧ level of 1%.
Humans ; China ; East Asian People ; Factor VIII/pharmacokinetics* ; Hemophilia A/drug therapy*