BRAVO pH
A LIMENTAR Y T RACT:C LINICAL R ESEARCH
Day-to-Day Variability in Acid Re?ux Patterns Using the BRAVO pH Monitoring System Sushil K.Ahlawat,MD,David J.Novak,MD,Dionne C.Williams,RN,BSN, Kathleen A.Maher,RN,BSN,CERN,Franca Barton,MS,and Stanley B.Benjamin,MD
Background&Goals:The wireless pH monitoring system such as the BRA VO pH system is a signi?cant advancement in the evaluation of patients with gastroesophageal re?ux because of its potentially better tolerability and the ability to record data over a48-hour period.The aim of our study was to evaluate safety,per-formance,tolerability,and day-to-day variability in acid re?ux patterns using the BRA VO pH system.
Methods:A total of90consecutive patients(48men and42 women)with persistent re?ux symptoms underwent BRA VO pH capsule placement from October2002to August2003at a tertiary care hospital.The BRA VO pH capsule was deployed6cm proximal to the squamocolumnar junction under endoscopic guidance.The pH recordings over48hours were obtained after uploading data to a computer from the pager-like device that recorded pH signals from the BRA VO pH capsule.
Results:Successful pH data over48hours was obtained in90%of patients.Nearly two thirds of patients experienced a variety of symptoms ranging from a foreign body sensation to chest discomfort or pain.Four patients had severe chest pain,3of whom required endoscopic removal of the BRA VO pH capsule.In74.4%of patients, number of re?ux events as well as time(%)pH,4correlated from the?rst24-hour period to the second24-hour period.However,in 28%of patients,no predictable pattern of(%)time pH,4in the supine position was reproduced from one24-hour period to the next 24-hour period.
Conclusions:The BRA VO pH system appears a safe and effective method of recording esophageal acid exposure.It is an acceptable alternative for patients who are unwilling or unable to tolerate naso-pharyngeal catheter-based pH studies,and it has a potential advan-tage of the2-day recording period.
Key Words:gastroesophageal re?ux,wireless pH monitoring, esophageal pH monitoring
(J Clin Gastroenterol2006;40:20–24)E sophageal pH recording is widely available and provides
quantitative data on both esophageal acid exposure and temporal correlation between patient symptoms and re?ux events.The standard or conventional ambulatory esophageal pH recording is obtained by passing a pH electrode through a nostril and positioning it5cm above the superior margin of the lower esophageal sphincter(LES).The pH electrode is connected via a transnasal catheter to a lightweight,battery-powered unit(data logger)that can be worn on waist belts or shoulder straps.Esophageal acid exposure and gastroesoph-ageal re?ux pattern can be evaluated by using this technique for periods of16to24hours.Extended esophageal pH monitoring over a48-hour period can be extremely useful in managing patients with gastroesophageal re?ux whose symp-toms are refractory to medical therapy.1
Conventional nasoesophageal catheter-based ambula-tory esophageal pH monitoring is the most reliable technique for quantifying esophageal acid exposure.However,this tech-nique has signi?cant limitations;the nasoesophageal pH catheter is uncomfortable and aesthetically unappealing because of the social stigma.This often results in patients modifying their diets and/or daily physical activities,such that the test is not representative of their normal daily life.This in turn may result in a false-negative test result.The proper placement of the pH electrode is of crucial methodologic detail for ambulatory pH studies.Placement of the electrode pro-ximal or distal to LES reduces the sensitivity of the test.2 Current AGA recommendation requires initial esophageal manometry to localize the position of the LES.1
The BRA VO pH monitoring system(Medtronic,Shore-view,MN)is a new wireless pH monitoring system that has recently been approved by the U.S.Food and Drug Admin-istration.This esophageal pH monitoring system has the advantage of being wireless and thus avoids the discomfort and social stigmata of nasoesophageal catheter.The esoph-ageal pH can be recorded over an extended period of48hours with the BRA VO pH monitoring system;and in addition, this pH monitoring system doesn’t require an initial esoph-ageal manometry study because the radiotelemetry pH capsule is deployed5cm proximal to the squamocolumnar junction (Z-line).A preliminary study,comparing catheter-based pH monitoring and BRA VO pH monitoring,showed that the two techniques are comparable in quantifying esophageal expo-sure.3However,except for one small study,no data exist on safety,performance,and tolerability of this pH monitoring system.4The primary aim of this study was to evaluate safety, performance,tolerability,and day-to-day variability in acid
Received for publication January27,2005;accepted April26,2005. From the Division of Gastroenterology,Department of Medicine,Georgetown University Hospital,Washington,DC.
Presented in part in poster form at Digestive Disease Week,Orlando,FL, May2003.
Reprints:Sushil K.Ahlawat,MD,10630Kenilwoeth Ave.,#103,Bethesda, MD20814(e-mail:sushilka@https://www.wendangku.net/doc/fe13822406.html,).
Copyrightó2005by Lippincott Williams&Wilkins
re?ux patterns using the BRA VO esophageal pH monitoring system.
MATERIALS AND METHODS Subjects
The medical records of all patients undergoing ambulatory24-hour esophageal pH monitoring using the BRA VO capsule at Georgetown University Hospital’s Motility Laboratory from October2002to August2003were reviewed after obtaining an approval from the local institutional review board.A total of90patients(48men and42women;age range,18–80years),with persistent re?ux symptoms despite maximal medical therapy with proton pump inhibitors(PPI), underwent placement of BRA VO capsule during the speci?ed time period.All patients who underwent the BRA VO pH capsule placement for24hour esophageal pH monitoring were either intolerant to conventional nasoesophageal pH catheter placement or had normal24-hour esophageal pH monitoring despite https://www.wendangku.net/doc/fe13822406.html,rmed consent was obtained from each participant prior to the BRA VO capsule placement.Patients with bleeding diathesis,strictures,severe esophagitis,varices, obstructions,pacemakers,or implantable cardiac de?brilla-tors,and those with surgical manipulations of the upper gastrointestinal tract were excluded from the placement of BRA VO pH monitoring capsule.
All patients were instructed to discontinue proton pump inhibitors(PPIs)1week and H2blockers1day prior to placement of the BRA VO pH capsule,not to use PPIs or antacid during the48-hour study period,and record symptoms and daily activities in a provided diary.
BRAVO pH Capsule and Monitoring System The BRA VO pH capsule was deployed6cm proximal to the squamocolumnar junction using a prepackaged assembly that included both a delivery system and the capsule itself.The actual pH capsule is oblong in shape measuring635.53 25mm.An antimony pH electrode and reference electrode are located on the distal tip of the BRA VO capsule.In addition, the BRA VO capsule contains an internal battery and a trans-mitter that sends a data signal to the external receiver via radiofrequency telemetry.Prior to deployment of the BRA VO capsule,it was activated by a magnetic switch and calibrated according to the BRA VO pH Receiver User Guide. Placement of the BRAVO pH Capsule
All patients underwent an upper endoscopy in the left lateral decubitus position after an overnight fast.Conscious sedation with propofol(Diprivan)was used in all patients.No other sedative was used.The squamocolumnar junction or the Z-line was identi?ed endoscopically,and the distance be-tween the incisors and squamocolumnar junction was mea-sured.After completion of an upper endoscopy,the endoscope was removed and the BRA VO pH delivery system passed orally into the esophagus under direct vision using the upper endoscope.The BRA VO pH capsule was deployed6cm proximal to the Z-line using endoscopic measurement of the Z-line or squamocolumnar junction.The6-cm distance was considered based on a previously published study?nding that the proximal extent of the LES high pressure zone was typically in close proximity(1–1.5cm)of the Z-line;thus, placement of the BRA VO pH capsule6cm above the Z-line simulated the conventional placement method.
The BRA VO pH delivery system was passed orally with patient in left lateral decubitus position and positioned so that the BRA VO pH capsule was6cm above the Z-line and then the external vacuum pump was turned on to apply suction to the well of the pH capsule,sucking in the adjacent esophageal mucosa.The plastic safety guard on the BRA VO pH delivery system was removed and the activation button switched once the vacuum gauge on the pump stabilized at a value.510mmHg for30seconds.This process resulted in attachment of the BRA VO pH capsule to the esophageal wall by a stainless steel pin that secured the esophageal mucosa within the well tangential to the esophageal axis.The BRA VO pH capsule was then released from its attachment point on the delivery system by twisting the activation button on the handle clockwise.In all but a few cases,upper endoscopy was repeated to con?rm capsule attachment without dislodging it and then pH re-cording was started.
Recording Protocol
The esophageal pH data were received and stored in the receiver over48hours in all patients.All patients were in-structed to engage in their usual activities,without dietary restriction,except all patients were asked to eat at least one high fat meal.Every patient was provided with a daily diary/log and instructed to record their symptoms,food intake, daily activities,period of sleep,etc.After2days,patients returned to the motility/pH laboratory to turn in their receivers and diaries/log.
Data Recording
Once the receivers were returned after completion of the recording,the BRA VO pH data were uploaded to a computer via Datalink(Medtronic).Symptoms,food intake,and supine/upright period data were extracted from patients’diaries/log and then manually merged with the pH recording data.A summary of pH data was then generated,including a pH tracing.All pH tracings were reviewed for accuracy.Data from patients were analyzed for number of re?ux events and time pH,4(%)for day1and day2in supine,upright positions.
Statistical Methods
The relationship of number of re?ux events in each day of the48-hour observation period(supine and upright,day1 and day2)was correlated between positions and between days and also correlated to the percent time pH,4of the moni-tored periods(supine and upright,day1and day2).First, comparisons were made univariately using Pearson correlation analysis.Guidelines used were mild association(r,0.25),mod-erate association(0.25–0.4),and strong association(.0.50), as well as the strength of the association(nominal P value for the correlation coef?cient being equal to zero).Events and percent time pH,4.0were compared between day1and day 2as well as between positions.Multivariate regression models were also run(eg,upright number of events day2vs.upright
J Clin Gastroenterol Volume40,Number1,January2006Variability in Acid Re?ux Patterns
number of events day1,supine events day1vs.supine events day2,%time pH,4.0upright day2vs.supine day1,etc.) The factors that were strong and signi?cant univariately were not eliminated in the multivariate models.Additional factors that were not signi?cant univariately also found to be non-signi?cant multivariately.Thus,only the important univariate relationships are shown.
RESULTS
Attachment Ef?cacy,Data Procurement,
and Tolerability
A total of90patients underwent BRA VO capsule placement over an8-month period,with82patients included in the?nal statistical analysis.Eight patients were excluded from the analysis for following reasons:the BRA VO capsule failed to transmit data to the receiver immediately after de-ployment in2patients,the BRA VO capsule failed to deploy from the catheter in1patient,the BRA VO capsule was re-moved after8hours secondary to chest pain in1patient,and the BRA VO capsule transmitted less than24hours of data to the receiver in4patients.Of the82patients included in the data analysis,2patients required a second pH capsule place-ment during the same endoscopic session.The?rst patient’s capsule did not attach to the esophagus and fell into the stomach,and a second capsule was then deployed in the proper position in the esophagus.The second patient’s capsule did not transmit a signal and was snared from the esophagus,and the second capsule was deployed with successful transmission of a signal.
In our cohort of patients,tolerability of the BRA VO capsule was a signi?cant problem.Out of82patients,4pa-tients reported signi?cant chest pain following placement of the capsule.Three patients required endoscopic removal of the capsule.Two of these patients required an overnight admission to the hospital for pain management.They had a computerized tomography of chest that ruled out the presence of esophageal perforation but required intravenous narcotic analgesia over-night in the hospital.One of the three patients had upper endoscopy with removal of the capsule the day after placement of the capsule,and the other2patients were discharged home the following day with the capsules still present in the esophagus.However,both of these patients completed the 48-hour study but returned within5days to have the capsules removed endoscopically secondary to continued chest dis-comfort.The capsule was removed by placing a cold snare around the capsule,and the snare was closed around the small nipple of tissue in the base of the capsule.The mucosa was cold snared from the capsule,and then the capsule was retrieved by using Roth basket.
The fourth patient repeatedly complained of chest pain following placement of the capsule despite a normal chest x-ray.The patient’s pain ultimately dissipated after a week, presumed secondary to sloughing of the capsule from the esophagus.Review of our nursing notes revealed that63% (53of82)were physically aware of the presence of the pH capsule in the esophagus during the study period.The symp-toms reported ranged from a foreign body sensation to a mild discomfort,to chest pain as described above.In follow-up, most patients could estimate the day when the capsule was no longer present in the esophagus.However,this could not be veri?ed.
Recording Ef?cacy and Esophageal Acid Exposure Values
The pH data were interpretable in82of90capsules deployed.In the82patients included in the data analysis,all subjects had48hours of interpretable pH recordings.
Day-to-Day Variability in Esophageal Acid Exposure Values
The82patients analyzed in the study had interpretable recordings for2consecutive days,allowing for analysis of day-to-day variability in esophageal acid exposure,to de-termine if a48-hour study increases the ability to differentiate pathologic re?ux(pH,4,%time supine).Pearson correlation coef?cients were calculated.In the majority of patients (74.4%),there was signi?cant correlation in the re?ux patterns in patients from the?rst24-hour period to the second24-hour period.Signi?cant correlation was seen in both the number of re?ux events in the supine and upright positions(Figs.1,2), and(%)time pH,4in the supine and upright positions(Figs. 3,4).However,there was no predictable pattern of re?ux seen in28%(23of82)patients.Among these23patients,(%)time pH,4,in the supine position,was not predictable from one 24-hour period to the next24-hour period.
DISCUSSION
In our study,successful24-hour ambulatory pH recordings were obtained in91%of patients using this
new
Upright re?ux events(day1to day2).Linear regression with95%con?dence interval.
Ahlawat et al J Clin Gastroenterol Volume40,Number1,January2006
wireless esophageal pH recording system.Similar success rate has been reported in studies on healthy subjects as well as in patients with gastroesophageal re?ux disease (GERD)using the BRA VO pH monitoring system.4,5Ninety percent of
patients in our study had successful extended,ie,48-hour pH recording;a similar rate was reported by Pondol?no et al.4Successful placement of the BRA VO pH capsule was achieved by identifying endoscopic landmarks such as the Z-line or squamocolumnar junction to simulate the conventional position of 5cm proximal to the superior margin of the manometrically de?ned LES.The BRA VO pH capsule deployment was easily learned and usually required 10to 15minutes including the upper endoscopy.Severe chest pain occurred in 4patients following the placement of the BRA VO pH capsule;3of these patients required endoscopic removal of the BRA VO pH capsule.Pondol?no et al 4reported 3patients with esophageal discomfort out of 85individuals,2of whom required endo-scopic removal of the pH probe.In keeping with the ?ndings of other studies,our patients did not report throat discomfort or impedance of daily activities.4,6
However,esophageal discomfort described as a foreign body sensation or chest pain occurred in a signi?cant pro-portion of patients in our study (55%).Ours and Richter 6reported 10of 22patients with esophageal discomfort with the BRA VO pH system compared with 5of 30patients with the nasopharyngeal catheter.Abnormal visceral nociception and/or ‘‘visceral sensitivity,’’ie,a decreased threshold for symptom elicitation and perception,is likely to play a role in the pathogenesis of chest pain or esophageal discomfort caused by the placement of the BRAVO pH capsule in the distal esophagus.7–9It is reasonable to suggest that the BRA VO cap-sule will be less well tolerated in patients with visceral sen-sitivity (whether central or peripheral).
The positioning of the pH electrode 5cm proximal to the superior margin of the LES is crucial methodological detail
of
FIGURE 4.Time pH ,4.0supine (day 1to day 2).Linear regression with 95%con?dence
interval.
FIGURE 2.Supine re?ux events (day 1to day 2).Linear regression with 95%con?dence
interval.
FIGURE 3.Time pH ,4upright (day 1to day 2).Linear regression with 95%con?dence interval.J Clin Gastroenterol Volume 40,Number 1,January 2006Variability in Acid Re?ux Patterns
conventional nasopharyngeal pH monitoring system.How-ever,precise positioning is probably less important with the wireless BRA VO pH recording system because the BRA VO pH capsule is physically attached to the esophageal mucosa that maintains a constant position relative to the Z-line throughout the study period.This placement method has been validated.4 Day-to-Day Variability in Esophageal Acid
Exposure Values
The24-hour esophageal pH monitoring is considered the gold standard for diagnosing GERD.However,the lower esophageal acid exposure is reported to exhibit day-to-day variability,10which can affect reliability of the24-hour pH monitoring.Several factors,including diet,posture(supine or upright),physical activity,and position of the pH probe,affect the acid content of the esophagus.Franzen et al11reported signi?cant day-to-day variability in esophageal acid exposure under standardized conditions.Twenty-two adult patients were investigated twice,6weeks apart,under identical conditions. Six patients were found to have discordant results(ie,they had normal total re?ux time on one test day,but pathologic results on the other).The day1and day2concordance of BRA VO pH measurement was fair,being good in the upright but poor in the supine position.However,no predictable pattern of pathologic re?ux(%time pH,4in supine position)was seen in28%of patients.Among these23patients,pathologic re?ux was not predictable from day1to day2or vice versa.
Johnson and Joelsson12found77%concordance in the amount of acid re?ux(expressed as%of time with esophageal pH,4during two24-hour periods).The upright and recumbent period measurement showed different degrees of concordance,83%and62%,respectively.Pondol?no et al4also reported signi?cant day-to-day variability using the BRA VO esophageal pH monitoring in normal individuals,those with GERD and those with nonerosive GERD.Nearly27%patients with GERD had discordant results,ie,abnormal acid exposure on day1and a normal esophageal acid exposure the next day and vice versa.The sensitivity and speci?city of the BRA VO esophageal pH monitoring in differentiating esophagitis patients from controls were comparable to the existing data1when analyzed by results obtained from24hours of recording;how-ever,using data from the worst day of recording maximized the sensitivity of the test.The sensitivity of esophageal pH monitoring improved from74%to100%when analyzed results were obtained from the worse day of recording compared with the?rst24hours of esophageal pH recording.
Our?ndings are consistent with the results obtained by Pondol?no et al4but appear less favorable than those reported for conventional catheter-based systems.12No comparison between the BRA VO and catheter-based pH measurement was made in our study.The BRA VO capsule is an acceptable alternative to catheter-based pH studies(especially in patients who are unwilling to tolerate a nasopharyngeal catheter). Extended recording period(48hours)is a potential advantage of the BRA VO pH system.The sensitivity of the esophageal monitoring is actually improved when analyzed by the results obtained from the worst day of recording as shown by Pandol?no et al.4This method of data analysis takes advantage of the observation that esophageal acid exposure can show signi?cant day-to-day variability as demonstrated in our study and by others.4,10–12In addition,the2-day recording period can be used to obtain a better assessment of symptom correlation over an extended period.
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三氟化硼及硼酸的理化性质
三氟化硼及硼酸的理化性质 1、三氟化硼理化性质 三氟化硼(Boron trifluoride)是一种无色气体，吸入可窒息。其可与潮湿空气发生化学反应而生成白色烟雾。三氟化硼的晶体结构是平面三角形。其中的硼原子受极性共价键作用，且为spasp杂化，使其分子间结构具备一定的对称性，偶极矩被完全抵消，表现为非极性分子性质。三氟化硼性质较为活泼，能与多种物质反应，其理化性质见表1。 表1三氟化硼理化性质 三氟化硼易溶于浓硫酸、三氯甲烷和四氯化碳等常见有机溶剂，可以与水反应而生成氟硼酸和硼酸，是放热反应。三氟化硼气体可与某些金属及有机物发生反应，亦可与某些物质发生加成反应或络合反应。其酸碱性表现为路易斯酸，因此可与氟化物或醚类物质发生酸碱反应。 三氟化硼能作为酯化、烷基化等有机反应的催化剂，也能作为防氧化剂来生产某些合金，其作为原料亦可生产卤化硼、单质硼、硼烷等硼相关产品。高纯三氟化硼在电子、核工业及光纤工业中有重要的应用，同时作为重要掺杂源，在半导体工艺中也有广泛的应用。除此之外，硼化合物可以作为固化剂应用于环氧树脂中，在光纤预制件中也有一定使用。 三氟化硼是一种高毒物质，兼具硼与氟化氢两者毒性，气体具有强刺激性，在加热条件
下或接触潮湿空气会发生反应而生成有毒且有腐蚀性的白烟(HF) ,可以腐蚀眼睛、皮肤等器官，如不慎吸入毒烟可导致死亡。与其接触后表观感受为咽喉刺痛、呼吸困难、视力模糊等症状。 2、硼酸理化性质 硼酸(H}BO})多为白色粉末状晶体，味微酸而略带甜味，相对密度1.43 5g/cm3(15℃)，熔点185℃(可分解)，3 00℃时失水而生成硼醉，无臭味。能溶于常见有机溶剂中，如酒精、乙醚、甘油等。硼酸在水中的溶解度与温度成正比，常温下，其溶解度较低。同时，硼酸在溶液中的溶解度会因某些无机酸的存在而显著降低。硼酸作为溶质通常不解离，以B(OH)3分子的形式存在于水溶液中，而在某些硼酸盐溶液中则通常以B(OH)4一离子的形式存在。通常，硼酸在其水溶液中会按式(1)进行电离: (1) 硼酸溶液具有一定的挥发性。常压下，沸腾的硼酸水溶液产生的蒸汽中，有约千分之三浓度的硼酸随蒸汽挥发而损失。硼酸在176℃, 201℃和236℃时可分别生成三种不同变体。加热硼酸至107.5℃时，如上文的氧化硼三水合物会失去部分结晶水，首先生成偏硼酸，继续失去部分结晶水而最终生成正硼酸。随着结晶水的失去，挥发性随之增大，在3 00℃时完全失去结晶水而生成硼酸醉(B203),如果继续加热，会继续脱水完全而最终生成氧化硼，其完全熔化的温度为450℃。将无定型氧化硼加热至325℃时开始软化，当温度升高至500℃时则以液态形式存在，因此，熔点对于无定型氧化硼来说是不固定的。 硼酸是一元弱酸，电离常数为，当其分子浓度达到0.llg时，溶液的pH约为5左右。因此，可利用置换反应以某些无机酸为原料来制备硼酸，无机酸亦可选择某些弱酸，如碳酸及硫化氢之类仍可保证置换反应进行。某些多经基化合物可以与硼酸进行反应而生成硼酸络合物，由于络合物离解度较大，因此一定程度上强化了硼酸的酸性。如甘 露醇与硼酸反应生成的络合物离解常数为，比硼酸的电离常数高104倍。硼酸水溶液中加入某些中性盐也可以大大提高其酸性，尤其是某些含高水合物的中性盐。 硼酸在某些酸作为催化剂或脱水剂存在下可以与某些低级醇反应而生成酯化物。例如，在浓硫酸存在时，硼酸会与甲醇反应生成硼酸三甲酯。硼酸作为反应物可与HF发生反应而生成一种中，同时硼酸与氢氧化物或金属氧化物亦可形成氟硼酸盐。硼酸也会和磷酸反应生成磷酸硼，此时的硼酸会表现出微弱的碱性。 硼酸有毒，会影响消化器官及神经中枢等人体组织。吸入硼酸的中毒表现为食欲不振、腹痛腹泻、虚脱等症状。最低致死量:皮肤接触8600mg/kg，口服640mg/kg，静脉注射29mg/kg，最高允许浓度为l0mg/m3。
pH敏感型脂质体的研究进展
pH敏感型脂质体的研究进展 10072855 王剑磊高材075 摘要：本文对脂质体，着重对pH敏感型脂质体以及pH敏感型类脂组的系统组成作了一个较简单的介绍，并阐述了临界pH的影响因素及其应用。 关键词：pH敏感型脂质体、pH敏感型类脂组成的系统、临界pH的影响因素 脂质体（Liposome）是利用磷脂双分子层膜所形成的囊泡包裹药物分子而形成的制剂。由于生物体质膜的基本结构也是磷脂双分子层膜，脂质体具有与生物体细胞相类似的结构，因此有很好的生物相容性。脂质体进入人体内部之后会作为一个“入侵者”而启动人体的免疫机制，被网状内皮系统吞噬，从而在肝、脾、肺和骨髓等组织中靶向性地富集。这就是脂质体的被动靶向性。脂质体主要成分是磷脂和胆固醇，其类似细胞膜的微球体。20世纪年代末Rahman等人首先将脂质体作为药物载体应用。70年代初用脂质体作为药物载体包埋淀粉葡萄糖甘酶治疗糖原沉积病首次获得成功。脂质体作为药物载体具有使药物靶向网状内皮系统、延长药效、降低药物毒性、提高疗效、避免耐受性、改变给药途径等优点，但脂质体作为药物载体仍存在对有些疾病的靶向特征不理想、体内稳定性和贮存稳定性欠佳等缺点，因而限制了脂质体的临床应用和工业化生产。近年来人们逐渐研制出长循环脂质体、前体脂质体、聚合膜脂质体等新犁脂质体以提高脂质体的稳定性;设计开发了温度敏感脂质体、pH敏感脂质体、免疫脂质体、磁性脂质体等新型脂质体以提高脂质体的靶向性。本文将着重对pH敏感型脂质体的研究进展做一综述。 1．pH敏感型脂质体(pH—sensitive Liposomes ) pH敏感型脂质体是指在低pH时脂肪酯羧基质子化而引起六角相形成，导致膜融合而达到细胞内靶向和控制药物释放的功能性脂质体，是用含有pH敏感基团的脂质制备的，可在一定程度上避免溶酶体降解并增加包封物摄取量和稳定性，有效地将包封物转运到胞浆。基于肿瘤间质液pH比正常组织低，应用pH敏感型脂质体载药能获得较非pH敏感型脂质体更好的转移效果。此外，PH敏脂质体在基因治疗中也得到了应用。Dzau VJ等利用病毒细胞融合脂质体的特点，将日本血细胞凝集病毒( HVJ )与脱氧寡核苷酸或质粒DNA脂质体复合，能诱导DNA直接进入细胞浆。pH敏感型脂质体的开发为大分子药物人工基因片段的胞内投递提供了手段。随着脂质体生产工艺研究的深入和不断完善，pH敏脂质体将成为临床治疗中的一种重要手段。pH敏感型脂质体在酸性环境中不稳定，而在细胞内吞过程中，在核内体始降低，所以设计合适的pH敏感型可以使其到达溶酶体前将内容物释放中，从而保证药物的活性。此外，炎染区域，某些肿瘤组织或局部缺血时异常酸化现象，所以在pH7 .4 ～6 .5范围内的pH敏感型脂质体对于药物的传递释很大的临床应用价值。 2．pH敏感型类脂组成的系统
硼酸
硼酸洗液说明书 [药品名称] 通用名：硼酸洗液 曾用名： 商品名： 英文名：Boric Acid Solution 汉语拼音：Pengsuan Xiye 本品主要成分及其化学名称：正硼酸 分子式：H3BO4 分子量：61.8 [性状] 本品为无色澄清溶液，呈弱酸反应。 [药理毒理] 本品为弱防腐剂，与细菌蛋白质中的氨基结合，对细菌及真菌抑制作用较弱，但无刺激性。 [药代动力学] 完整皮肤不易穿透，可从破损皮损及粘膜吸收，吸收量在12小时内从尿中排出约50％，其余于3～7天内排出。在体内排泄较慢，可致蓄积中毒。 [适应证] 可用于皮肤、粘膜损害的清洁剂，及急性皮炎、湿疹渗出的湿敷液，也可用于口腔、咽喉漱液，外耳道、慢性溃疡面、褥疮洗液，及真菌、脓疱疮感染杀菌液。 [用法用量] 3～4％溶液用于皮肤、粘膜(腔)、膀胱、角膜伤口的冲洗清洁，口腔炎和咽喉炎时含漱，急性湿疹和急性皮炎伴大量渗液时湿敷。 [不良反应] 外用一般毒性不大。用于大面积损害，吸收后可发生急性中毒，早期症状为呕吐、腹泻、皮疹、中枢神经系统先兴奋后抑制，可有脑膜刺激症状和肾损伤，严重者发生循环衰竭或（和）休克，于3～5天死亡。致死量成人约为15～20g，小儿为3～6g。 由于本品排泄缓慢，反复应用可产生蓄积，导致慢性中毒，表现为厌食、乏
力、精神错乱、皮炎、秃发和月经紊乱。 [禁忌证] 禁止内服，禁用于大面积损害。 [注意事项] 一般外用毒性不大，但不能口服，不宜作药品、食品防腐剂。不宜用于大面积创伤及连续灌洗。不宜做药品、食品防腐剂。 [孕妇及哺乳期妇女用药] 不可用于清洗哺乳妇女乳房。 [儿童用药] [药物相互作用] 禁忌与聚乙烯醇和鞣酸配伍。 [药物过量] 大面积外用吸收过量可发生急性中毒，可有呕吐、腹泻、皮疹、中枢神经系统先兴奋后抑制，可发生脑膜刺激症状和肾损伤。严重者可发生循环障碍和(或)休克，可于3～5天内死亡。成人致死量约为硼酸15～20g，小儿为3～6g。慢性中毒表现为厌食、乏力、精神错乱、皮炎、秃发和月经紊乱。 [规格] 硼酸溶液 3％。 [贮藏] 密闭保存。 [包装] [有效期] [批准文号] [生产企业](地址、联系电话)
中药内服结合3%硼酸溶液湿敷治疗风热毒内蕴型面部糖皮质激素依赖性皮炎疗效观察
中药内服结合3%硼酸溶液湿敷治疗风热毒内蕴型面部糖皮质激素 依赖性皮炎疗效观察 目的观察中药内服结合3%硼酸溶液湿敷治疗面部糖皮质激素依赖性皮炎的疗效，探讨中药对患者免疫水平的影响。方法选择71例确诊为面部激素依赖性皮炎的患者，随机分为两组，治疗组予以中药汤剂口服，2次/d，3%硼酸溶液湿敷，3次/d；对照组予氯雷他啶分散片口服，10mg/d，3%硼酸溶液湿敷，3次/d治疗。两组疗程均为4w。分别于就诊当日及治疗后7、14、28d观察疗效。结果治疗组在综合疗效上明显优于对照组（P＜0.05）。结论中药内服结合3%硼酸溶液湿敷治疗面部糖皮质激素依赖性皮炎疗效满意。 标签：中药内服；3%硼酸溶液湿敷；激素依赖性皮炎 2009年11月～2012年7月，我科采用中药内服结合3%硼酸溶液（定西市人民医院自配）湿敷治疗面部糖皮质激素依赖性皮炎，并与氯雷他啶分散片（北京双鹭药业股份有限公司生产，规格10mg，批号：H20030208）口服结合3%硼酸溶液湿敷，进行随机、对照研究，现将结果报道如下。 1 资料与方法 1.1一般资料所有入组病例均为2009年11月～2012年7月我院皮肤科门诊患者，诊断为面部激素依赖性皮炎。入组患者中男性2例，女性69例，平均年龄为37.5岁，病程为1个月～8年，按照编号（1-71）随机分为治疗组（39例）和对照组（32例）。 西医诊断标准[1]：①在同一部位长期（>1个月）使用皮质类固醇特别是强效制剂；②停药后症状（灼热、瘙痒、疼痛）出现反跳现象，即病情迅速加重，重复用药后症状减轻；③以红斑或潮红、丘疹、干燥及脱屑为基本损害的多样性皮损，难以用其他皮肤病解释；④部分病例需与相关疾病鉴别，特别是寻常痤疮、酒渣鼻、脂溢性皮炎及过敏性皮炎等。 中医证候诊断标准（参考《中华人民共和国国家标准·中医临床诊疗术语》）：①主症：瘙痒、灼热感，颜面部潮红、红斑、丘疹、皮肤干燥、脱屑、毛细血管扩张；②次症：心烦，口渴或口干，便秘，尿黄，舌质红、苔黄、脉数。 病例入选标准：①符合上述中医及西医诊断标准者；②年龄18～60岁，男女不限；③符合中医风热毒内蕴的证候诊断标准；④能够按时复诊及接受随访者。 病例排除标准：①排除不能遵医嘱用药者；②对治疗药物过敏者；③患有脂溢性皮炎、痤疮等影响疗效观察者；④妊娠或哺乳期妇女；⑤伴有严重的系统性疾病者；⑥治疗前1w口服过糖皮质激素及抗组胺药物者。
pH敏感双亲性聚合物分析
pH敏感双亲性聚合物的研究进展 摘要：pH敏感双亲性聚合物由于具有多种潜在的用途而引起广泛关注。本文综述了pH敏感双亲性聚合物的概念，组成，分类，合成方法以及在药物输送中的应用，并对其发展趋势进行了展望。 关键词：pH敏感；双亲性；聚合物；共聚物；胶束；脂质体；纳米粒 两亲性聚合物是指同一高分子中同时具有对两种性质不同的相(如水相与油相，两种油相，两种不相容的固相等)皆有亲和性的聚合物。pH敏感性聚合物是其溶液相态能随环境pH、离子强度变化的聚合物。已有理论研究结果表明，聚合物分子内及分子间交联作用力可以分为以下几种:氢键、范德华力、静电作用和疏水作用力[1]。在pH响应体系中四种作用力共同起作用引发pH敏感性，其中离子间作用力起主要作用，其它三种作用力起到相互影响、相互制约的作用。一般来说，具有pH响应性的高分子中含有弱酸性(弱碱性)基团，随着介质pH值、离子强度改变，这些基团发生电离，造成聚合物内外离子浓度改变，并导致大分子链段间氢键的解离，引起体相分子构型或溶解度的改变。 1．pH敏感双亲性聚合物的分类 pH敏感双亲性聚合物有两大类：一是聚合物中包含弱酸、弱碱基团和聚电解质的化合物；二是聚合物中有能在酸性条件下水解的连接段[2]。 1.1包含有可离子化的弱酸、弱碱基团的聚合物和聚电解质化合物 羧基是典型的弱有机酸聚合物取代基。这一类可在较低pH下接受质子并在中性和较高pH下放出质子，如聚丙烯酸(PAA)或聚甲基丙烯酸（PMAA）。弱有机碱聚合物如聚(4-乙烯基吡啶)在较高pH下接受质子，在较低pH下放质子，如聚[甲基丙烯酸-2-(N,N-二甲氨基)乙酯](PDMAEMA)，侧基带有取代氨基，因而在中性或酸性条件下可获得质子[3,4]。 药物载体在酸性或碱性条件下，聚合物中pH敏感基团会水解断裂或极性发生变化，使得聚合物纳米粒子破裂，同时负载其中的药物会被释放出来[5-7]，释放过程中没有药物和载体之间没有化学键的变化。 Armes等[8]制备了聚[2-(二甲基胺基)甲基丙烯酸乙酯]-聚[2-(二乙基胺基)甲基丙烯酸乙酯](DMAEMA-DEAEMA)，DMAEMA-聚[2-(N-吗啉)甲基丙烯酸乙
硼酸
硼酸 硼酸的详细说明: CAS:10043-35-3 分子式: B(OH)3 分子质量: 61.83 熔点: 169℃ 中文名称: 硼酸(医药级) 英文名称: Boric acid Boracic acid basilit b boric acid borofax boron trihydroxide 性质：硼酸实际上是氧化硼的水合物（B2O3.3H2O）,为白色粉末状结晶或三斜轴面鳞片状光泽结晶，有滑腻手感，无臭味。比重1.435（15ºC）。溶于水、酒精、甘油、醚类及香精油中，水溶液呈弱酸性。硼酸在水中的溶解度随温度升高而增大，并能随水蒸汽挥发；在无机酸中的溶解度要比在水的溶解度小。加热至70～100ºC时逐渐脱水生成偏硼酸，150～160ºC时生成焦硼酸，300ºC 时生成硼酸酐（B2O3）. 硼酸对人体有毒，内服影响神经中枢。 其酸性来源不是本身给出质子，由于硼是缺电子原子，能加合水分子的氢氧根离子，而释放出质子。利用这种缺电子性质，加入多羟基化合物（如甘油醇和甘油等）生成稳定配合物，以强化其酸性。 OH | B(OH)3+2H2O====[HO--B<---OH]- + H3O+ | OH 用途：硼酸大量用于玻璃（光学玻璃、耐酸玻璃、耐热玻璃、绝缘材料用玻璃纤维）工业，可以改善玻璃制品的耐热、透明性能，提高机械强度，缩短溶融时间。在搪瓷、陶瓷业中，用以增强搪瓷产品的光泽和坚牢度，也是釉药和颜料的成份之一。在医药工业、冶金工业中作添加剂、助溶剂，特别是硼钢具有高硬度和良好的轧延性，以代替镍钢。硼酸有防腐性，可做防腐剂，如木材防腐。在金属焊接、皮革、照相等行业以及染料、耐热防火织物、人造宝石、电容器、化妆品的制造方面都用到它，还可作杀虫剂和催化剂用。在农业上作含硼微量元素肥料，对许多作物有肥效，可提高油菜籽的含油率。由硼酸可制造多种硼化物，广泛用于国防和其他工业部门和科研单位。 制法及工艺流程
pH敏感药物传递系统的研究进展
pH敏感药物传递系统的研究进展 发表时间：2016-08-03T13:56:01.367Z 来源：《医药前沿》2016年7月第21期作者：王鹏[导读] 各种不同的酸敏感基团的使用，人们可以根据需要来获取不同pH响应行为的聚合物分子，进而在不同的体系中加以应用。王鹏 （国药控股天津有限公司天津 300040） 【中图分类号】R94 【文献标识码】A 【文章编号】2095-1752（2016）21-0376-02 人们已经认识到，在许多治疗方案中，药物比如抗癌药等要想发挥高效作用。药物运载系统要想将药物运载到靶向部位，需要克服重重困难，总体概括为细胞外与细胞内。在细胞外，运载体在血液中的稳定性，血液中的循环时间，靶向组织部位的累积情况等等。在细胞内，运载体如何高效进入细胞，内含体逃逸问题，药物可控释放等等。 下面简单介绍几种具有酸敏感的聚合物分子的合成以及特点。首先是在主链上引入酸敏感基团。在主链上引入酸敏感基团，设计合成的聚合物分子在中性条件（pH=7.4）具有稳定的结构，而在酸性条件（pH=5.0-6.0）下会发生降解为小分子的行为。缩醛结构在pH敏感药物运载体中得到了广泛的研究，这是由于其在酸性条件下比较快速的水解反应，而且其水解产物为可生物降解的醇与醛。Jin-Ki Kim等合成出一种新颖的pH敏感的基于缩醛结构的两亲性嵌段聚合物的药物运载分子PEG–PEtG–PEG，同时使用水溶性极差的药物分子紫杉醇PTX作为药物控制释放实验。经实验得知，该嵌段聚合物由于具有缩醛结构，所以在酸性条件可酸催化水解[1]。在不同的pH条件下，经过24h，考察释药环境的pH对载药体释药的影响。通过实验结果可以看出，pH很大程度上影响着药物分子的释放行为。在PEtG–PEG500聚合物胶束中，在pH=5.0时，1h内的PTX释药量达到了50%，而对于pH=7.4，在1h内的PTX释药量仅仅为20%。在释药6h后，对应pH=7.4，6.5以及5.0的条件下，PTX的累积释放百分率分别为49.3%，71.7%以及94.1%。对于聚合物胶束PEtG–PEG750而言，其释药行为也有类似的趋势。在释药6h后，对应不同的pH=7.4，6.5以及5.0，其PTX释药率分别为54.4%，68.3%以及89.1%。总的实验结果证明，具有缩醛结构的聚合物胶束搭载药物后的释药行为是收到释药体系的pH条件控制的。在弱酸条件下，聚合物胶束中的酸敏感基团的水解速率较快，导致药物分子的释放速率大为增加。 另外，与缩醛结构类似，缩酮结构也常常被用于聚合物结构中，赋予聚合物分子酸敏感功能。Dongwon Lee等人合成出具有pH敏感的两亲性聚合物分子聚缩酮己二酸-co-聚乙二醇嵌段共聚物（PKA-PEG）[2]。在该聚合物的疏水骨架中，具有酸敏感的缩酮键结构。该两亲性聚合物分子可以自组织成核/壳层结构，利用其疏水内腔可以搭载疏水性药物分子。搭载药物后，在酸性条件下，药物运载体结构破坏，从而将药物分子释放，即在弱酸性条件下具有可控药物释放功能。该嵌段共聚物（PKA-PEG）的结构示意图如下，作为对比，作者又合成出没有酸敏感基团的聚合物胶束聚环己基己二酸-co-聚乙二醇（PCA-PEG），结构示意图1如下。 * 图1 PKA-PEG与PCA-PEG示意图 两聚合物胶束均可经自组织形成壳层结构，都可在疏水内腔搭载药物分子。为了研究其对pH的响应性，作者采用模型分子尼罗红Nile Red来研究其释放行为。Nile Red是一种疏水性荧光探针，在水溶液中其荧光强度很低，然而在疏水性环境中，其荧光强度变得很高[3]。据此，研究聚合物胶束在中性条件以及弱酸性条件下的结构变化。下图为聚合物胶束PKA-PEG与Nile Red复合物的荧光强度随pH变化情况。从图2中可以看出，对于pH=7.4，在观察18h后，体系的荧光强度没有明显变化，然而对于pH=5.4而言，荧光强度有着显著的下降。这说明，在弱酸性条件（pH=5.4）条件下，聚合物胶束中的缩酮结构水解从而胶束结构被破坏，导致疏水性荧光分子从胶束中转移到水溶液中，从而降低了荧光强度。这说明两亲性嵌段共聚物由于具有缩酮结构从而对酸敏感，可以根据体系的pH来控制药物分子的释放行为。 *
pH敏感和非pH敏感的抗肿瘤纳米载药体系的合成与研究
pH敏感和非pH敏感的抗肿瘤纳米载药体系的合成与研究 癌症是对人类生命健康最大的威胁之一,是世界上第二大死亡原因。化学治疗作为目前癌症治疗最有效的全身治疗手段,主要应用于中晚期癌症,然而常规抗肿瘤药物的一系列不良特性限制了其在临床中的应用,例如生物利用度低,稳定性和水溶性差等。 紫杉醇作为一种有效的常见化疗药物之一,具有优异的抗肿瘤活性,但其治疗功效因其溶解性差和缺乏选择性对细胞毒性大而受到影响。为了克服这些缺陷,本文针对性的设计并合成新型的纳米载药体系负载紫杉醇。 纳米技术虽然在上个世纪末才刚刚崛起,但已被广泛应用于药物输送和癌症治疗等生物医学领域。与传统的载药体系相比,纳米载药体系在很多领域具有更大的潜力,例如可以延长体内循环时间和实现药物全身控制释放等等。 在纳米载药体系中引入不同的刺激响应性是实现灵活给药的有效方式,由于肿瘤细胞代谢活跃,肿瘤组织相比于正常组织其微环境是高度酸性的,因此具有pH响应性的纳米载药体系是最常见的刺激响应性纳米载药体系之一,其可以通 过EPR效应在肿瘤部位聚集,实现在肿瘤部位快速释放药物,同时防止药物在血液循环中过早释放,降低药物毒性减少副作用,增强抗肿瘤效果。本文设计并成功合成的新型纳米载药体系以葡聚糖-聚乳酸-聚乙二醇聚合物为主要骨架结构,聚合物缩醛化后得到pH敏感的纳米载药体系ADPP,为了直接比较基于相同骨架的pH敏感和非pH敏感的纳米载药体系之间的药物输送效果,通过丙酸酐对聚合物改性获得非pH敏感的纳米载药体系PDPP,两者都可以在水中自组装形成稳定的球形纳米粒子。 随后将疏水性抗肿瘤药物紫杉醇负载到这两种纳米载体体系中,得到
硼酸
硼酸P601 本品按干燥品计算，含H3BO3不少于99.5%。 【性状】本品为无色微带珍珠光泽的结晶或白色疏松的粉末，有滑腻感；无臭。 本品在乙醇或水中溶解；在沸水或沸乙醇中易溶。 【鉴别】本品的水溶液显硼酸盐的鉴别反应(通则0301)。 【检査】酸度取本品l.0g，加水30ml溶解后，依法测定（通则0631)，pH值应为3.5?4.8。溶液澄清度与颜色取本品l.0g，加水30ml使溶解，依法检査（通则0901第一法与通则0902)，溶液应澄清无色；如显浑浊，与1号浊度标准液（通则0902第一法）比较，不得更浓。 乙醇溶液的澄清度取本品l.0g，加乙醇25ml使溶解，溶液应澄清。 氯化物取本品0.50g，依法检査（通则0801)，与标准氯化钠溶液5.0ml制成的对照液比较，不得更浓（0.01%)。 硫酸盐取本品0.50g，依法检査(通则0802)，与标准硫酸钾溶液2.0ml制成的对照液比较，不得更浓(0.04%)。 磷酸盐取本品0.50g，加水15ml溶解后，加2，4-二硝基苯酚的饱和溶液2滴，滴加硫酸溶液（12→100）至黄色消失，加水稀释至20ml，再加硫酸溶液（12→100)4ml、5%钼酸铵溶液1ml与磷试液1ml，摇匀，于60℃水浴中保温10分钟，如显色，与标准磷酸盐溶液(精密称取磷酸二氢钾0.1430g，置1000ml量瓶中，加水溶解并稀释至刻度，摇匀，精密量取10ml，置100ml量瓶中，加水稀释至刻度，摇匀，即得。每lml溶液相当于10ug的P04)5.0ml 用同一方法制成的对照液比较，不得更深(0.01%)。 钙盐取本品0.50g，加水10ml溶解后，加氨试液使成碱性，再加草酸铵试液0.5ml与乙醇5ml，加水至20ml，摇匀，如显浑浊，与标准钙溶液（精密称取在105℃干燥至恒重的碳酸钙0.125g，置500ml量瓶中，加水5ml与盐酸0.5ml使溶解，用水稀释至刻度，摇匀，即得。每lml相当于10ug的Ca)5.0ml用同一方法制成的对照液比较，不得更浓(0.01%)。 镁盐取本品0.50g，加水8ml溶解后，用8%氢氧化钠溶液中和至中性，加水至10ml，再加8%氢氧化钠溶液5ml与0.05%太坦黄溶液0.2ml，摇匀；如显色，与标准镁溶液(精密称取经800℃灼烧至恒重的氧化镁lS.6mg，加盐酸2.5ml与水适量使溶解成1000ml，摇匀，即得。每lml相当于10ug的Mg)5.0ml用同一方法制成的对照液比较，不得更深(0.01%)。铁盐取本品l.0g，加水25ml溶解后，依法检査（通则0807)，与标准铁溶液1.0ml制成的对照液比较，不得更深（0.001%)。 铵盐取本品2g，依法检査（通则0808)，不得过0.001%。 干燥失重取本品1g，置硅胶干燥器中放置5小时，减失重量不得过0.5%(通则0831)。重金属取本品l.0g，加水23ml溶解后，加醋酸盐缓冲液（pH3.5)2ml，依法检査(通则0821第一法），含重金属不得过百万分之十。 砷盐取本品0.40g，加水23ml溶解后，加盐酸5ml，依法检査(通则0822第一法），应符合规定(0.0005%)。 【含置测定】取本品0.lg，精密称定，加20%的中性甘露醇溶液（对酚酞指示液显中性）25ml，微温使溶解，迅速放冷，加酚酞指示液3滴，用氢氧化钠滴定液（0.lmol/L)滴定。每lml氢氧化钠滴定液（0.lmol/L)相当于6.183mg的H3B03。 【类别】药用辅料，抑菌剂和缓冲剂。 【贮藏】密封保存。
硼酸用途
进口硼酸 硼酸，为白色粉末状结晶或三斜轴面鳞片状光泽结晶，有滑腻手感，无臭味。溶于水、酒精、甘油、醚类及香精油中，水溶液呈弱酸性。大量用于玻璃（光学玻璃、耐酸玻璃、耐热玻璃、绝缘材料用玻璃纤维）工业，可以改善玻璃制品的耐热、透明性能，提高机械强度，缩短溶融时间。 应用领域和效益 玻璃和玻纤 用于生产光学玻璃、耐酸玻璃、有机硼玻璃等高级玻璃和玻璃纤维，可改善玻璃的耐热性和透明性，提高机械强度，缩短熔融时间。B2O3在玻璃和玻纤的制造中扮演着助熔剂和网络形成体的双重角色。例如，在玻纤生产中经可降低熔融温度从而有助于拉丝。一般来讲，B2O3可以降低粘度、控制热膨胀、阻止失透、提高化学稳定性、提高抗机械冲击和热冲击能力。在要求钠含量较低的玻璃生产中硼酸常常与钠硼酸盐（如五水硼砂或无水硼砂）混合使用以调节玻璃中的钠硼比。这对硼硅酸盐玻璃来说很重要，因为氧化硼在低钠高铝的情况下表现为良好的助溶性。 搪瓷和陶瓷 搪瓷、陶瓷工业用于生产釉药，能减少釉的热膨胀、降低釉药的固化温度，从而防止龟裂和脱釉，提高制品的光泽和坚牢度。对于陶瓷、搪瓷釉料，氧化硼是很好的助熔剂和网络形成体。它可形成玻璃（在低温时），提高坯釉适应性，降低粘度和表面张力，提高折射率，提高机械强度，耐久性耐磨性，它是无铅釉的重要组成。高硼熔块熟化快，形成光滑釉面的速度快，有利于着色。在快速烧成釉面砖熔块中，B2O3以硼酸引入，以保证低钠含量的要求。 医药工业 用于生产硼酸软膏、消毒剂、收敛剂、防腐剂等。 阻燃 加入赛璐璐材料中的硼酸盐可改变其氧化反应，促进“碳化”的形成。因此可阻燃。硼酸单独或者与硼砂一起使用，对减少赛璐璐绝缘材料、木器、床垫中的棉花胎的可燃性有特殊的效果。 冶金
盐酸和硼酸混合液的分析
2 盐酸和硼酸混合液的分析 一：实验原理 H3BO3是极弱酸，Ka=5.6×10-10，不能用NaOH标准溶液直接滴定。因此，可用NaOH 标准溶液滴定混合液中的HCl。终点时，由于H3BO3 的存在，溶液的pH值约5.3，可用甲基红作指示剂。得到：n(HCl)= n(NaOH)；记下消耗的氢氧化钠体积为V1 H3BO3可以与多元醇反应生成酸性较强的络合酸，可被NaOH标准溶液直接滴定，称之为弱酸的强化，此处我们选择甘露醇作为强化剂。在滴定HCl后的溶液中加入强化试剂甘露醇，稍加放置，用NaOH标准溶液直接滴定。化学计量点的pH值约为9.2左右,可选酚酞或百里酚蓝为指示剂。借此进行试样中硼酸含量的测定，记下消耗氢氧化钠体积为V2 则 ρHcl={(CV1)NaoH M Hcl}/(V s*1000) ρH3BO3={1/3(CV1)NaoH M H3BO3}/(V s*1000) V S为所取试样溶液的体积 二：试剂与仪器 1．0.1mol·L-1NaoH标准溶液 ① 0.1mol·L-1NaoH溶液的配制：准确称取4~6gNaoH固体于大烧杯中，加入200~300ml 水，稍许加热使固体溶解，以蒸馏水稀释至1000mL，储于试剂瓶中，摇匀，备用。 ② 0.1mol·L-1NaoH溶液浓度标定： 准确称取邻苯二甲酸氢钾三份，每份质为量0.4克左右，加入30~40mL水溶解，加入1~2滴酚酞指示剂，用配制的NaoH溶液滴定至由红色为终点，计算NaoH标准溶液浓度： C NaoH=1000*m邻苯二甲酸氢钾/(M邻苯二甲酸氢钾*V naoH) 2.甘露醇试剂 3.酚酞指示剂 4.甲基红指示剂 5.基准物质：邻苯二甲酸氢钾 6.仪器：称量瓶、滴定管、移液管、量筒锥形瓶等等 三：实验步骤 1. 初步试验?实验方法的考察及取样量的确定 用1.0-2.0mL移液管取试液于250mL锥形瓶中，加30mL水,加2滴甲基红指示剂，用NaoH标准溶液滴定至红色色变黄色为终点。记下滴下消耗NaoH体积为V1(mL)，加入强化剂邻苯二甲酸氢钾少许，再加入酚酞指示剂1~2滴，继续用NaoH标准溶液滴定至溶液由黄色变红色为终点。记下第二次消耗NaoH体积为V2(mL)。计算当消耗滴定剂体积符合分析V2至少其一≥20m L）的取样量。 要求时（V1 ， 据终点变色是否敏锐考察指示剂是否合适； 据消耗滴定剂体积确定正式实验的取样量及方式。方法如下： 设试样分析时消耗滴定剂体积≥20m L： V（取样体积）/mL= V(初试) ×20/V1，(1) 或：V（取样体积）/mL= V(初试) ×20/V2 ，(2) 当V（取样体积）≥20m L时，取小样进行正式实验; 当V（取样体积）＜10mL，则应采用取大样法进行实验 2. 试样分析 (1)用移液管准确移取原试液Vs mL于250 mL容量瓶中→定容→摇匀，得待测液。 (2)用移液管准确移取待测液于250mL锥形瓶中→加入2滴甲基红指示剂，用NaoH标准溶
硼酸化合物的介绍
硼酸化合物的精细化工产品广泛应用于日用化工、医药、轻纺、玻璃、陶瓷(釉)、搪瓷、冶金、机械、电子、建材、石油化工及军工、尖端技术等各部门的各学科领域中。随着科学技术和工业生产的x跃发展，消费量在不断扩大和增长。 许多硼化合物(如KB02、caB40?、BzO s、Alz03·B20a)可以用作硅酸盐涂料或磷酸盐涂料的固化剂；氮化硼是超硬、耐高温、耐腐蚀材料；改性偏硼酸钡是一种新型的防锈颜料，有防霉、防粉化、耐热等优良性能；低水合硼酸锌是无机添加型阻燃剂，具有热稳定性高、粒度细及无毒等优点；硼氢化钠、硼氢化捏是很好的储包材料；过硼酸钠广泛用于洗涤助剂，以及消毒、杀菌剂、媒染剂、脱臭剂等。 金属硼化物具有许多独特性能，特别引人注目。硼能与多种金属形成硼化物，不仅熔点高、硬度大，而且有良好的导电性。如硼化钙、硼化钥和硼化钡都具有极好的耐热性，低密度及高强度等性能，广泛用于轻质耐热合金、热阴极及阂温热电偶材料。硼化铝具有良好的耐热性，半导体及吸收中子能力较强，用于制造半导体及原子反应堆材料。硼化钥、硼化钨具有较好的耐热性及较高的导热能力，可作为精密铸型材料及耐热合金。硼化钦、6B化铬具 有较高的强度及耐磨性，可作为金属切削工具、钻头及喷嘴材料等。碳化硼最吸引入的性质是质量轻，具有抵抗穿甲弹穿透热压涂层或整体防层的能力。作为军舰和直升机等的陶瓷徐层，在现代战争中发挥了独特作用。 一、过硼酸钠 过硼酸钠的用途很广，常用作染料显色的氧化剂，织物的漂白和脱脂剂，用作消毒剂、杀菌剂、媒染剂、洗涤剂、脱臭剂、电镀溶液的添加剂、分析试剂、有机合成聚合剂以及制造牙膏、化妆品等。作为一种优良的漂染剂，用于天然纤维的漂染，性能温和，对织物的损伤小；用于羊皮和皮毛的漂白时，有脱臭作用。以它作为掺和剂的合成洗衣剂用量少，去垢效果好，洗过的织物富有光泽。随着洗衣机的普及以及日益严格的环保条例的制定，对合成洗涤剂提出了新的要求，这些都为优良的活性氧载体一一过硼酸钠提供广泛的市场。过硼酸钠的制备分化学法和电解法两种。目前，工业生产过硼酸钠主要是以化学法为主，该法是将硼砂或硼酸与氢氧化钠及过氧化氢作用制得过硼酸钠，反应式为， Na2Bd()?·10H 20十2NaOH十4Hz()?十H zO一4(NaBOz·H202·3HzU) (2—9)或H3B03十N80H十H202十H 20*NaB(〕2·H20?·3H20 (2—10) 将化学计量多20％的硼砂加入到30％的NaoH溶液中，再向制得的偏硼酸钠(NaBo：)溶液中缓慢加入3％的过氧化氢水溶液，其量应过剩10％一15％，反应温度应低于10℃；另在反应器中加入食盐，以便在冷却到o℃时，使生成的过硼酸钠析出，然后在离心机中脱水，并低温干燥得到产品。 二、硼酸锌 低水合硼酸锌的结构式为2Zn()‘3B20：·3．EH20，是无机添加型阻燃剂。由于热稳定性高，粒度细及无毒，在元机阻燃剂中得到应用。 目前工业生产低水合硼酸锌的主要方法是硼砂—锌盐法，即以硼砂和硫酸锌为原料，在水溶液中搅拌加热合成。操作是先将硫酸锌和水加入反应器配成溶液，升温，搅拌下投入硼砂和氧化锌，在高于70℃温度下保温搅拌反应6—7h，然后冷却、过滤、用温水洗涤滤饼，在100一110℃下干燥，即得成品。其反应式为： 3．5znS04十3．5Na2B4〔)7十0．52n()十10H2〔34 2(2zn()‘3B203‘3．5Hzt))十3．5N9z 5(3d十2H2B03