Determination of Sex Hormones in Antler Velvet by High Performance Liquid Chromatography Tandem Mass Spectrometry

Eighteen sex hormones in antler velvet were determined by high performance liquid chromatography tandem mass spectrometry.The solid phase extraction was applied to eliminating the matrix effect.The experimental conditions were examined and optimized.Under the optimal conditions,the proposed method provides the good linearities and determination limits（0.2―1.0 μg/kg） of the analytes investigated.The recoveries ranging from 72.3% to 149.5% were obtained for the target analytes at two concentration levels.This method was applied to the determination of eighteen sex hormones in different kinds of antler velvet samples and the obtained results are satisfactory.The results indicate that the proposed method is suitable for the determination of sex hormones in antler velvet samples.

Rapid Quantitative Determination of Isoprene Monomer in Living Taraxacum kok-saghyz by Ultra-High Performance Liquid Chromatography Tandem Mass Spectrometry

Taraxacum kok-saghyz(TKS)is rich in natural rubber(NR),a natural organic macromolecular compound composed of cis-1,4-polyisoprene,and may become the second NR-bearing plant for biochemical engineering development.In this paper,a rapid and quantitative ultra-high performance liquid chromatography tandem mass spectrometry(UHPLCMS/MS)method was established for determination of macromolecular biosynthesis substrate(dimethylallyl pyrophosphate,DMAPP)and initiator(farnesyl pyrophosphate,FPP)contained in TKS.A Kromasil C18 chromatographic column was used for separation,and the multi-reaction monitoring mode(MRM)of triple quadrupole mass spectrometry was used for detection.Quantification was performed by external calibration method.The results showed that the limit of detection(LOD)and the limit of quantitation(LOQ)of DMAPP were 2.42μg/L and 7.26μg/L,respectively,and the LOQ and the LOD of FPP were 1.02μg/L and 3.05μg/L,respectively.At a concentration of 1—1000μg/L,both analytes had good determination coefficients(>0.999)of calibration curve.The recoveries of DMAPP and FPP were between 99.0%and 117.1%.In real samples detection,the contents of DMAPP and FPP in TKS samples were between 23.32—82.77μg/L and 12.03—85.67μg/L,respectively.Thus,this approach is a reliable method to quantify DMAPP and FPP in TKS.

Rapid Analysis of Nicotine in Mushrooms Using QuEChERS Extraction and Liquid Chromatography Tandem Mass Spectrometry

A procedure based on the QuEChERS methodology and Liquid Chromatography Tandem Mass Spectrometry （LC/MS/MS） is described, for the determination of Nicotine in mushrooms. QuEChERS methodology was used to determine Nicotine in dried and fresh mushrooms under basic conditions with primary secondary amino sorbent （PSA） clean up. The chromatography was performed on C 18 reversed phase column using a gradient of acetonitrile and ammonium formiate lmM pH = 3.4 as mobile phase at a flow rate of 0.3 mL min^-1. Nicotine was determined by using Nicotine-d3 as internal standard. Limit of quantification （LOQ） was 0.01 mg kg^-1 for both fresh and dried mushrooms. Calibration curve was linear over the concentration range of 0.01-2.3 mg mL^-1, with r2 〉 0.99. As for recoveries in dried mushrooms, spiking levels of 0.32 mg kg^-1 and 2 mg kg^-1 were considered whereas for the fresh mushrooms the recoveries were determined at 0.036 mg kg^-1 and 0.36 mg kg^-1. Satisfactory results were obtained for both matrices and the recoveries proved to range from 105% to 135%, with a standard deviation in the range 17-20. The method was applied to the analysis of Nicotine to assess the levels of nicotine in fresh and dried mushrooms.

Liquid chromatography tandem mass spectrometry method for the estimation of lamotrigine in human plasma:Application to a pharmacokinetic study

A reliable,selective and sensitive liquid chromatography tandem mass spectrometry method was developed and validated for the quantification of lamotrigine in human plasma using lamotrigine13C3,d3 as an internal standard.Analyte and internal standard were extracted from human plasma by solid-phase extraction and detected in positive ion mode by tandem mass spectrometry with electrospray ionization（ESI） interface.Chromatographic separation was performed on a Chromolith s SpeedROD;RP-18e column（50-4.6 mm i.d.） using acetonitrile：570.1 mM ammonium formate solution（90：10,v/v） as the mobile phase at a flow rate of 0.500 mL/min.The calibration curves were linear over the range of 5.02-1226.47 ng/mL with the lower limit of quantitation validated at 5.02 ng/mL.The analytes were found stable in human plasma through three freeze（-20℃）-thaw（ice-cold water bath） cycles and under storage on bench-top in ice-cold water bath for at least 6.8 h,and also in the mobile phase at 10℃ for at least 57h.The method has shown good reproducibility,as the intra-and inter-day precisions were within 3.0%,while the accuracies were within 76.0% of nominal values.The validated LC-MS/MS method was applied for the evaluation of pharmacokinetic and bioequivalence parameters of lamotrigine after an oral administration of 50mg lamotrigine tablet to thirty-two healthy adult male volunteers.

Liquid chromatography electrospray ionization tandem mass spectrometry(LC/ESI-MS/MS) method for quantitative estimation of moxifloxacin in human plasma

A rapid and sensitive liquid chromatography tandem mass spectrometry(LC-MS/MS) method has been developed and validated for the determination of moxifloxacin(MOXI) in human plasma. After a simple protein precipitation using acetonitrile, the post treatment samples were analysed on a C18 column interfaced with a Triple Quadropole Tandem Mass Spectrometer. Positive electrospray ionization was employed as the ionization source. The mobile phase consisted of 0.1% formic acid–acetonitrile(60:40, v/v). Ciprofloxacin(CIPRO) was used as an internal standard. The analyte and internal standard(CIPRO) were monitored in the multiple reaction monitoring mode(MRM). The mass transition ion-pair has been followed as m/z 402→358.2 for MOXI and 332→288.1 for CIPRO. The method was linear in the concentration range of 25–5000 ng/mL. The lower limit of quantification was 25 ng/mL. The intra- and inter-day precision(relative standard deviation) and accuracy(relative error) values were within 12.4%. Each plasma sample was analyzed within 3 min.

A rapid and simple ultraperformance liquid chromatography coupled to tandem mass spectrometry(UPLC-MS/MS) method for the detection of glucuronic acid-conjugated steroid metabolites

In the present study, we effectively detected 10 steroids and glucuronic acid-conjugated steroid metabolites in 12 min by ultraperformance liquid chromatography coupled to tandem mass spectrometry （UPLC-MS/MS）. Steroids testosterone （T）, 5ct-dihydrotestosterone （DHT）, androsterone （ADT）, etiocholanolone （ETIO）, estradiol （E2） and their glucuronide conjugates were well-separated on an Eclipse Plus C18 column （2.1 mm×50 ram, RRHD 1.8μm）. The mobile phase consisted of a mixture of methanol and ultrapure water （containing I mM ammonium formate） at a ratio of 60：40 （v/v）, and the flow rate was set at 0.25 mL/min. The LC eluate was detected by electrospray ionization （ESI） source in both positive and negative ion modes. Neutral loss （NL of 176, 194, 211 and 229 Da in positive mode） and precursor ion （PI ofm/z 141,159 and 177 in positive mode and 75, 85 and 133 in negative mode） methods were applied for the detection of steroid glucuronides. The multiple reaction monitoring （MRM） transitions were m/z 289.3→97.1,291.3→105, 291.3→199.2, 273.2→145.4 and 255.2→159.1 for T, DHT, ADT, ETIO and E2 in positive mode, respectively; as well as m/z 463.3→85 for T glucuronide （T-G）, m/z 465.3→75 for DHT glucuronide （DHT-G）, ADT glucuronide （ADT-G）, ETIO glucuronide （ETIO-G） and m/z 447.3→271 for E2 glucuronide （Ez-G） in negative mode. In addition, the analytical method was also applied for the detection of steroid glucuronides in pooled human liver microsomes （HLM）, which might serve as a basis for further investigation of steroid metabolism in vivo and in vitro.

Simultaneous Determination of Six Compounds in Rat Plasma by Ultra-Performance Liquid Chromatography with Tandem Mass Spectrometry: Application in the Pharmacokinetic Study of Qing Gan-Shu Yu-Fang

A rapid and high selective ultra-performance liquid chromatography(UPLC)with tandem mass spectrometry method for simultaneous determination of six compounds including albiflorin,paeoniflorin,picroside I,picroside II,saikosaponin A,and saikosaponin D in rat plasma was developed and validated using butyl p-hydroxybenzoate as an internal standard.One-step direct protein precipitation with acetonitrile was used to extract the compounds from the rat plasma samples.Chromatographic separation was achieved using an ACQUITY UPLC BEH C18 column(100 mm×2.1 mm,1.7μm)at a flow rate of 0.4 m L/min,using gradient mode containing 0.1%formic acid in water and acetonitrile were used as the Mobile phase A and B.Electrospray ionization in negative ion mode and multiple reaction monitoring were used to identify and quantify active components.Calibration curves showed good linearity(R^2>0.9908)over a wide concentration range for all compounds.The intra-and interday precision(relative standard deviation)ranged 2.4%–7.0%and 2.6%–8.0%,respectively.The accuracy(relative error)was from-13.0%to 13.2%at all quality control levels.The recovery ranged from 81.1%to 92.5%.The validated method was successfully applied to pharmacokinetic study in rats after oral administration of Qing Gan-Shu Yu-Fang.The results show that one can draw a conclusion that these six active ingredients can be quickly absorbed and play a pharmacodynamic role rapidly in vivo.

Investigations on the degradation of aspartame using high-performance liquid chromatography/tandem mass spectrometry

Aspartame is a widely used sweetener, the long-term safety of which has been controversial ever since it was accepted for human consumption. It is unstable and can produce some harmful degradation products under certain storage conditions. A high-performance liquid chromatography/tandem mass spectrometry method was developed for the simultaneous analysis of aspartame and its four degradation products, including aspartic acid, phenylalanine, aspartyl-phenylalanine and 5-benzyl-3,6- dioxo-2-piperazieacetic acid in water and in diet soft drinks. Aspartame and its four degradation products were quantified by a matrix matched external standard calibration curve with excellent correlation coefficients. The limits of detection were 0.16-5.8 μg/L, which exhibited higher sensitivity than common methods. This method was rapid, sensitive, specific and capable of eliminating matrix interferences. It was also applied to the study of the degradation of aspartame at various pH and temperatures. The results indicated that aspartame was partly degraded under strong acidic or basic conditions and the extent of degradation increased with increasing temperature.

Rapid Determination of Tetrodotoxin in Human Plasma by Ultra Performance Liquid Chromatography-Tandem Mass Spectrometry

A sensitive analytical method was developed to determine tetrodotoxin（TTX） in human plasma samples using protein precipitation, followed by ultra performance liquid chromatography（UPLC） analysis coupled with tandem mass spectrometry（MS/MS） using 11-deoxytetrodotoxin（11-deoxyTTX） as an internal standard. The plasma samples were prepared using protein precipitation prior to being analyzed by UPLC-MSfMS to identify TTX over a zwitterionic-hydrophilic interaction liquid chromatography column. The retention time values of TTX and 11-deoxyTTX were 4.12 and 3.67 min, respectively. TTX and 11-deoxyTTX were monitored and quantitated on the basis of their ion transitions for their respective precursor ions to their product ions（i.e., m/z 320.0→162. l for TTX and m/z 304.0→176.0 for 11-deoxyTTX） in the multiple reaction-monitoring mode. The lower limit of quantification of this method was determined to be 0.0199 ug/mL. This method showed good linearity for plasma samples that contained TTX concentrations in the range of 0.0199--1.99 ng/mL. The specificity, precision, accuracy, matrix effect, and stability characteristics of this method were also examined. The intra-assay precision and accuracy ranged from 1.89% to 6.00% and from 92.21% to 100.00%, whereas the inter-assay precision and accuracy ranged from 0.64% to 7.75% and from 99.38% to 101.26%, respectively. This new method therefore represents a rapid, accurate, reliable, and highly sensitive method for the qualitative and quantitative analyses of a trace amount of TTX in human plasma samples.

GLOBAL ANALYSIS OF THE METABOLITES OF CURCUMIN IN RATS BY ULTRA PERFORMANCE LIQUID CHROMATOGRAPHY COUPLED WITH QUADRUPOLE TIME OF-FLIGHT TANDEM MASS SPECTROMETRY

Curcumin,a safe natural yellow pigment with a wide range of pharmacological activities,is used both in herbal drugs and as a food coloring agents.Studies have shown that curcumin would suffer from extensive metabolism in vivoand the predominant metabolic pathways are reduction and conjugation.In order to comprehensively study the metabolism and enrich the metabolic profile of cxurcumin in vivo,we carried out this research.A systematic method with highly sensitive UPLC-Q/TOF-MS was established to analyze different biological samples of rats after

Banxia xiexin decoction prevents the development of gastric cancer

BACKGROUND In China banxia xiexin decoction(BXD)has been used in treating gastric cancer(GC)for thousands of years and BXD has a good role in reversing GC histopathology,but its chemical composition and action mechanism are still unknown.AIM To investigate the mechanism of action of BXD against GC based on transcriptomics,network pharmacology,in vivo and in vitro experiments.METHODS The transplanted tumor model was prepared,and the nude mouse were pathologically examined after administration,and hematoxylin-eosin staining was performed.The active ingredients of BXD were quality controlled and identified using ultra-performance liquid chromatography tandem quadrupole electrostatic field orbitrap mass spectrometry(UPLC-Q-Orbitrap MS/MS),and traditional Chinese medicines systems pharmacology platform,drug bank and the Swiss target prediction platform to predict the relevant targets,the differentially expressed genes(DEGs)of GC were screened by RNA-seq sequencing,and the overlapping targets were analyzed to obtain the key targets and pathways.Cell Counting Kit-8,apoptosis assay,cell migration and Realtime fluorescence quantitative polymerase chain reaction were used for in vitro experiments.RESULTS All dosing groups inhibited the growth of transplanted tumors in laboratory-bred strain nude,with the capecitabine group and the BXD medium-dose group being the best.A total of 29 compounds and 859 potential targets in BXD were identified by UPLC-Q-Orbitrap MS/MS and network pharmacology,RNA-seq sequencing found 4767 GC DEGs,which were combined with network pharmacology and analyzed 246 potential therapeutic targets were obtained and pathway results showed that BXD may against GC through the Phosphoinositide 3-kinase(PI3K)/protein kinase B(AKt)signaling pathway.In vitro cellular experiments confirmed that BXDcontaining serum and LY294002 could inhibit the proliferation of GC cells,promote apoptosis,and inhibit the migration of GC cells by decreasing the expression of EGFR,PIK3CA,IL6,BCL2 and AKT1 in the PI3K-Akt pathway in MGC-803 expression.CONCLUSION BXD has the effect of inhibiting tumor growth rate and delaying the development of GC.Its mechanism of action may be related to the regulation of PI3K-Akt signaling pathway.

Determination of Periplocymarin in Human Blood and Urine by High-Performance Liquid Chromatography-Mass Spectrometry

A simple,rapid and sensitive liquid chromatography with tandem mass spectrometry method for the determination of periplocymarin in human blood and urine was developed.The digoxin‑d3 was used as an internal standard.Periplocymarin and digoxin‑d3(IS)were processed with ethyl acetate by liquid–liquid extraction.The chromatographic separation was performed on a Shim‑pack XR‑ODSIII C18 column with a 7 min gradient elution using methanol‑ammonium formate(5 mmol/L)as mobile phase at a flow rate of 0.3 mL/min(65:35,v/v).The detection was performed on a triple quadrupole tandem mass spectrometer using positive‑ion mode electrospray ionization in selected reaction monitoring mode.The periplocymarin was well separated from the internal standard.Two calibration curves were linear within the concentration range 0.01–1µg/mL.The limit of detection and quantification of blood and urine samples were both estimated at 0.005 and 0.01µg/mL.The interday and intraday precisions,accuracy,and recovery were assessed to verify this method.The results showed that the method was suitable for the determination of periplocymarin in forensic toxicological analysis and clinical diagnosis.

Conversion of Cellulose to 5-Hydroxymethylfurfural in Water- Tetrahydrofuran and Byproducts Identification

Conversion of cellulose into platform chemical 5-hydroxymethylfurfural （HMF） in water-tetrahydrofuran （THF） co-solvents under acidic condition was studied. 38.6% of HMF was obtained with low cellulose concentration of 2.4wt%, but levulinic acid （LA） and solid humins became the main products with high cellulose concentration. The soluble byproducts were analyzed by high performance liquid chromatography/multiple stage tandem mass spec-trometry, and chemicals with formula of C9H16O4、 C10H14O4、 C11H12O4、C12H10O5 and C12H16O8 were detected. THF could participate in the reaction via ring-opening into 1,4-butanediol followed by esterification with LA into C9H16O4 or etherification with HMF into C10H14O4. C11H12O4 was formed by esterification of HMF with LA, C12H10O5 was formed by self-etherification of HMF, while C12H16O8 was formed by acetalization of HMF with glucose. Self-etherification of HMF and etherification of HMF with 1,4-butanediol were identified as two main side reactions.

Hydrophobic protein in colorectal cancer in relation to tumor stages and grades

AIM: To identify differentially expressed hydrophobic proteins in colorectal cancer. METHODS: Eighteen pairs of colorectal cancerous tissues in addition to tissues from normal mucosa were analysed. Hydrophobic proteins were extracted from the tissues, separated using 2-D gel electrophoresis and analysed using Liquid Chromatography Tandem Mass Spectrometry (LC/MS/MS). Statistical analysis of the proteins was carried out in order to determine the significance of each protein to colorectal cancer (CRC) and also their relation to CRC stages, grades and patients’ gender. RESULTS: Thirteen differentially expressed proteins which were expressed abundantly in either cancerous or normal tissues were identified. A number of these proteins were found to relate strongly with a particular stage or grade of CRC. In addition, the association of these proteins with patient gender also appeared to be significant.CONCLUSION: Stomatin-like protein 2 was found to be a promising biomarker for CRC, especially in female patients. The differentially expressed proteins identified were associated with CRC and may act as drug target candidates.

Pharmacokinetics and Tolerability of Oral Dosage Forms of Huperzine A in Healthy Chinese Male Volunteers: a Randomized,Single Dose, Three-period, Six-sequence Crossover Study

Huperzine A is a potent, reversible, and blood-brain barrier permeable acetylcholinesterase inhibitor. The aim of this study was to compare the pharmacokinetics, tolerability, and bioavailability of two formulations with the established reference formulation of huperzine A in a fasting, healthy Chinese male population. This was a randomized, single-dose, 3-period, 6-sequence crossover study. The plasma concentrations of huperzine A were determined by liquid chromatography tandem mass spectrometry. Tolerability was assessed based on subject interview, vital sign monitoring, physical examination, and routine blood and urine tests. The mean（SD） pharmacokinetic parameters of the reference drug were Cmax, 1.550（0.528） ng/m L; t1/2, 12.092（1.898） h; AUC0-72 h, 17.550（3.794） ng·h/m L. Those of the test formulation A and test formulation B were Cmax, 1.412（0.467）, 1.521（0.608） ng/m L; t1/2, 12.073（2.068）, 12.271（1.678） h; AUC0-72 h, 15.286（3.434） ng·h/mL, 15.673（3.586） ng·h/m L. The 90% confidence intervals for the AUC0-72 h and Cmax were between 0.80 and 1.25. No adverse events were reported by the subjects or found with results of clinical laboratory test. The test and reference products met the regulatory criteria for bioequivalence in these fasting, healthy Chinese male volunteers. All three formulations appeared to be well tolerated.

液相色谱-串联质谱法测定人血浆中阿扑吗啡

盐酸阿扑吗啡(apomorphine hydrochloride)为吗啡的衍生物,系中枢多巴胺D2受体激动剂,其舌下片制剂是目前用于治疗男性勃起机能障碍的新药[1,2].为了研究该制剂中阿扑吗啡的药代动力学特性,我们建立了阿扑吗啡血药浓度测定的液相色谱-串联质谱法.测定了28名健康志愿者口服阿扑吗啡舌下片后阿扑吗啡的血药浓度.……

MTBSTFA derivatization-LC-MS/MS approach for the quantitative analysis of endogenous nucleotides in human colorectal carcinoma cells

Endogenous ribonucleotides(RNs)and deoxyribonucleotides(dRNs)are important metabolites related to the pathogenesis of many diseases.In light of their physiological and pathological significances,a novel and sensitive pre-column derivatization method with N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide(MTBSTFA)was developed to determine RNs and dRNs in human cells using high-performance liquid chromatography tandem mass spectrometry(HPLC-MS/MS).A one-step extraction of cells with 85%methanol followed by a simple derivatization reaction within 5 min at room temperature contributed to shortened analysis time.The derivatives of 22 nucleoside mono-,di-and tri-phosphates were retained on the typical C;column and eluted by ammonium acetate and acetonitrile in 9 min.Under these optimal conditions,good linearity was achieved in the tested calibration ranges.The lower limit of quantitation(LLOQ)was determined to be 0.1-0.4μM for the tested RNs and 0.001-0.1μM for dRNs.In addition,the precision(CV)was<15%and the RSD of stability was lower than 10.4%.Furthermore,this method was applied to quantify the endogenous nucleotides in human colorectal carcinoma cell lines HCT 116 exposed to 10-hydroxycamptothecin.In conclusion,our method has proven to be simple,rapid,sensitive,and reliable.It may be used for specific expanded studies on intracellular pharmacology in vitro.

Simultaneous determination of clopidogrel,2-oxo-clopidogrel,and the thiol metabolite of clopidogrel in human plasma by LC-MS/MS

Clopidogrel is a pro-drug which needs two-step metabolism to produce the active thiol metabolite.This study aimed to explore an efficient method to simultaneously determine the plasma clopidogrel,2-oxo-clopidogrel(2-Oxo-CLP),and the clopidogrel active metabolite(CAM).A high-throughput liquid chromatography tandem mass spectrometry(LC-MS/MS)was therefore developed.The analytes were extracted from plasma by using methyl tert-butyl ether(MTBE).Chromatographic separation was performed on a C18 column under an isocratic elution,accompanied with acetonitrile and deionized water containing 0.1%formic acid.After optimizing the condition of LC-MS/MS,a stable linearity was observed in the standard curves over the concentration ranges of 0.05 to 50.0 ng/mL for clopidogrel,0.5 to 50.0 ng/mL for 2-Oxo-CLP,and 0.5 to 100 ng/mL for clopidogrel active metabolite derivative(CAMD).The retention time was 4.78 minutes,3.79 minutes,3.59 minutes,and 4.82 minutes for clopidogrel,2-Oxo-CLP,CAMD,and internal standard,respectively.Both the relative standard deviation and the relative error were within the requirement of operating criteria.No significant degradation of clopidogrel,2-Oxo-CLP,and CAMD occurred under different storage conditions.This method was successfully validated in 3 patients with coronary artery disease.The results showed that the current LC-MS/MS method was efficient for simultaneously detecting clopidogrel,2-Oxo-CLP,and CAM with fine linearity,accuracy,precision,and stability.

Cytokines in adipose-derived mesenchymal stem cells promote the healing of liver disease

Adipose-derived mesenchymal stem cells （ADSCs） are a treatment cell source for patients with chronic liver injury. ADSCs are characterized by being harvested from the patient’s own subcutaneous adipose tissue, a high cell yield （ i.e. , reduced immune rejection res-ponse）, accumulation at a disease nidus, suppression of excessive immune response, production of various growth factors and cytokines, angiogenic effects, anti-apoptotic effects, and control of immune cells via cell-cell interaction. We previously showed that conditioned medium of ADSCs promoted hepatocyte proliferation and improved the liver function in a mouse model of acute liver failure. Furthermore, as found by many other groups, the administration of ADSCs improved liver tissue fbrosis in a mouse model of liver cirrhosis. A comprehensive protein expression analysis by liquid chromatography with tandem mass spectrometry show-ed that the various cytokines and chemokines produced by ADSCs promote the healing of liver disease. In this review, we examine the ability of expressed protein com-ponents of ADSCs to promote healing in cell therapy for liver disease. Previous studies demonstrated that ADSCs are a treatment cell source for patients with chronic liver injury. This review describes the various cytokines and chemokines produced by ADSCs that promote the healing of liver disease.

liver and the defects of cholesterol and bile acids biosynthesis: rare disorders many diagnostic pitfalls

In recent decades, biotechnology produced a growth of knowledge on the causes and mechanisms of metabolic diseases that have formed the basis for their study, diagnosis and treatment. Unfortunately, it is well known that the clinical features of metabolic diseases can manifest themselves with very different characteristics and escape early detection. Also, it is well known that the prognosis of many metabolic diseases is excellent if diagnosed and treated early. In this editorial we briefly summarized two groups of inherited metabolic diseases, the defects of cholesterol biosynthesis and those of bile acids. Both groups show variable clinical manifestations but some clinical signs and symptoms are common in both the defects of cholesterol and bile acids. The differential diagnosis can be made analyzing sterol profiles in blood and/or bile acids in blood and urine by chromatographic techniques(GC-MS and LC-MS/MS). Several defects of both biosynthetic pathways are treatable so early diagnosis is crucial. Unfortunately their diagnosis is made too late, due either to the clinical heterogeneity of the syndromes(severe, mild and very mild) that to the scarcity of scientific dissemination of these rare diseases. Therefore, the delay in diagnosis leads the patient to the medical observation when the disease has produced irreversible damages to the body. Here, we highlighted simple clinical and laboratory descriptions that can potentially make you to suspect a defect in cholesterol biosynthesis and/or bile acids, as well, we suggest appropriate request of the laboratory tests that along with common clinical features can help to diagnose these defects.