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Jun Dai

Publications and source records attributed to Jun Dai.

At least 19 recordsLinked to original sources
PubMed2026

From Static to Dynamic: Fluorescence Imaging Technology Advances Precise Embryo Evaluation.

Live-cell imaging technology has revolutionized our understanding of preimplantation embryonic development, shifting the field from static morphological descriptions to dynamic functional analyses. This has tremendously advanced the fields of in vitro fertilization (IVF) and embryonic development. At the heart of this transition lies the strategic application of fluorescent probes, which provide the requisite sensitivity and specificity to resolve complex biological events. This review provides a comprehensive overview of fluorescent probe-based strategies designed to address four cardinal questions in peri-implantation embryology: genomic stability, cell fate determination, tissue morphogenesis, and embryo-maternal interactions. We systematically evaluate the chemical design principles and imaging modalities of various probes, which range from small-molecule organic fluorophores to genetically encoded reporters and nanoparticle-based sensors. Furthermore, we discuss how these tools facilitate the real-time visualization of chromosomal aberrations, lineage segregation, biomechanical forces, and enzymatic activities within the delicate embryonic microenvironment. This review summarizes methodological strategies for selecting and developing optimal probes across diverse application contexts. By identifying current technical bottlenecks and proposing future directions, such as NIR-II imaging and noninvasive labeling, it aims to drive the translation of basic embryonic research into advanced reproductive medicine.

Humans↗
PubMed2006

Comparison of drug eluting stents with bare metal stents in daily practice for bifurcation lesions in Chinese patients.

BACKGROUND: Recently, numerous randomized and controlled trials have demonstrated great advantages of drug eluting stents (DES) with respect to significant reduction of restenosis and recurrence of symptoms and improvement of clinical outcomes after percutaneous coronary intervention (PCI). Little is known about the comparative effects between DES and bare metal stents (BMS) for bifurcation angioplasty in the Chinese population. We compared the inpatient and 7-month follow-up outcomes between DES and BMS for the treatment of bifurcation lesions. METHODS: From April 2004 to October 2005, 291 Chinese patients [85.9% male, mean age (57.8 +/- 10.4) years] underwent DES (387 lesions) and/or BMS (297 lesions) implantation for bifurcation lesions. Clinical and angiographic follow-up was performed at 7 months. RESULTS: Compared with BMS group, patients in DES group had significantly lower rates of restenosis at main branch (9.5% vs 28.7%, P < 0.001) or side branch (14.5% vs 37.0%, P < 0.001) and major adverse cardiac events (MACE) (14.0% vs 26.3%, P = 0.000). The occurrence rate of late in-stent thrombosis did not differ between the two groups in both main (0.8% vs 0, P = 0.224) and side branches (1.4% vs 0, P = 0.198). Target lesion revascularization (TLR) was less frequent in DES group for main branch (8.3% vs 21.3%, P < 0.001) and for side branch (7.6% vs 23.5%, P < 0.001). Multivariate regression analysis revealed that total stent length (OR = 1.029, P = 0.01), postprocedural in-stent minimum lumen diameter (OR = 0.476, P = 0.03) and stent type (OR = 3.988, P = 0.0001) were independent predictors of TLR for main branch. Prior history of coronary intervention (OR = 2.424, P = 0.041), angulated lesion (OR = 2.337, P = 0.033), postdilation (OR = 0.267, P = 0.035) and stent type (DES vs BMS, OR = 5.459, P = 0.000) were independent predictors of TLR for side branch. CONCLUSION: The implantation of DES may be associated with greater reduction of restenosis and TLR than BMS in bifurcations angioplasty.

Adult↗
PubMed2006

A comparison of angiographic and clinical outcomes after sirolimus-eluting versus paclitaxel-eluting stents for the treatment of in-stent restenosis.

BACKGROUND: In-stent restenosis (ISR) remains a challenge for interventional cardiologists. Some data suggest that drug-eluting stents (DES) represent a promising new option for the treatment of patients with ISR. Currently, 2 DES platforms are available [sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES)], but the superiority of either approach for treating ISR has not been convincingly demonstrated. The aim of the present study was to retrospectively compare angiographic and clinical outcomes after treatment of ISR with SES or PES in a series of consecutive patients with ISR. METHODS: A total of 745 consecutive patients were treated with bare metal stents from April 12, 2004 to December 31, 2004 in our center. Of these, clinically driven target lesion revascularization (TLR) was performed in 54 ISR from 54 patients at 7 months. Of the 54 patients with ISR, 36 received SES and 18 received PES. Follow-up included angiography and assessment of clinical outcome, both performed 7 months after DES implantation. RESULTS: There were no significant differences in baseline clinical data (including medication usage and lesion characteristics) between the two groups. Except for overlapping of multiple stents, procedural parameters were also similar in both groups. Seven-month angiographic follow-up showed that the binary restenosis rate was higher in patients treated with PES than that in patients treated with SES (in-stent binary restenosis: 27.8% vs 5.6%, P < 0.023; In-segment binary restenosis: 44.4% vs 13.9%, P < 0.014). Major adverse cardiac events (MACE) occurring during hospitalization or during the follow-up period including thrombosis and TLR was similar in both groups (22.2% vs 8.3%, P > 0.05). CONCLUSIONS: Results from this small sample size, retrospective, single-center study showed that SES might be superior to PES in treating ISR because of lower 7-month restenosis rates (both in-stent and in-segment binary restenosis) with no increased incidence of MACE.

Adult↗
PubMed2006

A single center investigation of bare-metal or drug-eluting stent restenosis from 1633 consecutive Chinese Han ethnic patients.

BACKGROUND: Stents are widely used in China but the clinical impression is somehow that restenosis is less common because of the lower prevalence of coronary artery disease (CAD) and associated risk factors in Chinese populations. However, no large-sample published studies are available on angiographic stent restenosis including those of bare-metal stent (BMS) or drug-eluting stent (DES) in Chinese Han ethnic population. METHODS: A total of 1633 consecutive patients with CAD who had undergone coronary stenting, quantitative coronary angiography (QCA) were retrospectively studied. At the time of stent implantation and at 7 months post-stenting 675 patients had a follow-up angiography. Statistical analysis was made with the chi-square test for categorical variables, unpaired t test for continuous variables, univariate or multivariate regression for baseline and angiographic characteristics and the Kaplan-Meier method for rate of target lesion revascularization (TLR). RESULTS: Stent restenosis was defined as > or = 50% diameter stenosis in the dilated segment. A total of 675 patients with 1074 lesions were subjected to angiographic follow-up for 7 months on average. Of these lesions, 448 were implanted with BMS whereas 626 lesions with DES. At 7 months, bare-metal in-stent restenosis occurred in 148 lesions (33.0%), and bare metal in-segment restenosis in 155 lesions (34.6%) in contrast to drug-eluting in-stent restenosis in 48 lesions (7.7%) and drug-eluting in-segment restenosis in 73 lesions (11.7%) (P < 0.001 compared with BMS respectively). Late loss in both in-stent and in segment was higher in BMS than in DES groups [(1.00 +/- 0.69) vs (0.28 +/- 0.52); (0.78 +/- 0.71) vs (0.21 +/- 0.52), P < 0.001 respectively]. Angulated lesion, lesion length, pre-procedural minimal luminal diameter (MLD), and BMS were independent predictors for TLR, (P < 0.01 respectively), whereas current smoker, ostial lesion, and stent overlapping, post-procedure in-stent MLD, lesion length, and stent types were independent predictors for in-segment restenosis (P < 0.01 respectively). Standard coronary risk factors such as hypertension, hyperlipidemia, diabetes, and history of CAD were not associated with a higher rate of restenosis caused by BMS or DES implantation in our Chinese Han ethnic population. CONCLUSIONS: Coronary stenting including BMS or DES implantation in Chinese Han ethnic patients is associated with a restenosis rate comparable to that demonstrated in previous studies from the western countries, and predictors of stent restenosis are somehow different from those in the western population.

Adult↗
PubMed2006

A randomized comparative study of using enoxaparin instead of unfractionated heparin in the intervention treatment of coronary heart disease.

BACKGROUND: Low molecular weight heparin (LMWH) was more effective than unfractionated heparin (UFH) in treating acute coronary syndrome (ACS). However, it remains uncertain whether LMWH can be used in patients undergoing percutaneous coronary intervention (PCI) instead of UFH. This study aimed to evaluate the efficacy and safety of using enoxaparin instead of UFH in the intervention treatment of patients with coronary heart disease (CHD). METHODS: From October 2003 to Febuary 2005, 966 patients with CHD were enrolled into this study. Among 966 patients, 455 patients received the PCI, including 283 patients with Non-ST segment elevation ACS (NSTEACS), 511 patients did not received PCI due to mild, moderate lesions or were suitable for coronary artery bypass graft (CABG). The 966 patients were randomized to enoxaparin group (484 patients) and UFH group (482 patients). Patients in the enoxaparin group were given enoxaparin at least twice subcutaneously (1 mg/kg, q12 h) before catheterization. Plasma anti-Xa activity was determined 1 - 8 hours after the last dose of enoxaparin was determined. The catheterization was performed within 8 hours after the last dose of enoxaparin. The sheath was removed immediately after the procedure. Patients in the UFH group were given UFH 25 mg intravenously before coronary angiography. Additional 65 mg was given intravenously if PCI was to be performed. The sheath was removed 4 hours after the procedure. RESULTS: A total of 227 patients in the enoxaparin group and 228 patients in the UFH group received PCI. In the enoxaparin group, one patient developed acute thrombosis during PCI and resulted in acute myocardial infarction (AMI), no acute or subacute thrombosis was found during hospitalization. In the UFH group, no acute or subacute thrombosis occurred during PCI procedure and hospitalization. Therefore, the incidence of major adverse cardiovascular events (MACEs) during the hospitalization was 0.44% in the enoxaparin group and 0 in the UFH group. In the enoxaparin group, the sheath was removed immediately after the procedure and 8 patients had hematoma on the puncture site. In the UFH group, the sheath was removed 4 hours after the procedure and 20 cases had hematoma on the puncture site. The incidence of hematoma on the puncture site was significantly higher in the UFH group than that in the enoxaparin group (P < 0.05). Anti-Xa activity was determined in 174 patients in LMWH group. The mean anti-Xa activity was (0.87 +/- 0.23) U/ml, and 94.8% of them had anti-Xa activity >0.5 U/ml and 6.9% of the patient >1.2 U/ml. There was no death and AMI occurred in enoxaparin group, but one patient had AMI caused by subacute thrombosis in UFH group during 30-day follow-up. MACE rate at 30-day follow-up was 0 in enoxaparin group and 0.43% in UFH group. CONCLUSIONS: The results of the study suggest that it is safe and efficient to give enoxaparin at least twice before the PCI procedure, and the sheath can be removed immediately after PCI. For NSTEACS patient who has received enoxaparin more than twice during the hospitalization can undergo PCI directly and no UFH is necessary before or during PCI.

Angioplasty, Balloon, Coronary↗
PubMed2006

Development of acid stable, hyper-crosslinked, silica-based reversed-phase liquid chromatography supports for the separation of organic bases.

A new generation of extremely acid stable "hyper-crosslinked" (HC) phases have been developed with good plate counts for basic drug separations. In our previous work, we successfully developed an approach for synthesizing HC stationary phases on silica substrates using aluminum trichloride catalyzed Friedel-Crafts (F-C) chemistry to improve the stability of silica-based RPLC stationary phases at low pH. However, the performance of basic analytes on these HC phases under acidic conditions was unusually poor compared to that of conventional silica-based C18 phases. The effects of the specific F-C catalysts used and the specific silica substrate on the chromatographic properties of HC phases have been studied. Modified synthetic strategies that give both good observed plate counts for basic analytes under acidic conditions and very good low pH stability without compromising other chromatographic properties of the hyper-crosslinked phases have been developed. Replacement of aluminum trichloride with tin tetrachloride as the catalyst for the F-C chemistry and use of a very high purity silica result in significantly improved plate counts for basic analytes. In formic acid buffered mobile phases, which are highly compatible with electrospray ionization LC-MS, basic analytes showed much better performance on the tin tetrachloride catalyzed HC phases than on any conventional commercial phase tested. The tin tetrachloride catalyzed HC phase is as stable as the original aluminum trichloride catalyzed HC phases, and much more stable than the bench mark acid stable commercial phase.

Acids↗
PubMed2006

Comparison of short- and mid-term outcomes between CYPHER and TAXUS stents in patients with complex lesions of the coronary arteries.

BACKGROUND: Drug-eluting stent (DES) could obviously reduce in-stent restenosis, which has been proved by international multi-center clinical trials. However, the types of the lesions for stenting were highly selected in these trials. Up to now, there has been no large scale study on the effect of DES in treating complex lesions in real world. Although REALITY trial was just reported during American College of Cardiology Congress 2005, the entry criteria for lesions were limited to one or two de novo lesions. This study was conducted to compare the short- and mid-term clinical outcomes between sirolimus-eluting stent (CYPHER stent) and paclitaxel-eluting stent (TAXUS stent) in patients with complex lesion. METHODS: This is a retrospective study. From April 2002 to June 2004, a total of 1061 patients were treated with DES in Fu Wai Hospital, of which, 611 patients (642 lesions with 698 CYPHER stents) were in CYPHER group, and 450 patients (534 lesions with 600 TAXUS stents) were in TAXUS group. There was no significant difference in clinical data and lesion types between CYPHER group and TAXUS group. RESULTS: Success rates of stent implantation were 99.2% and 98.8% in CYPHER and TAXUS stent groups respectively. The major adverse cardiac events (MACE) during in-hospital and 6-8-month follow-up were 0.7% and 2.3% in CYPHER stent group versus 1.3% and 3.2% in TAXUS stent group. There was no significant difference in MACE rate between these two groups. Restenosis rate was a little higher in TAXUS stent group than that in CYPHER stent group (14.0% vs 7.3%), but there was no significant difference. The incidence of acute occlusion of side branch after implanting DES in main vessel was 6.9% in CYPHER group and 11.9% in TAXUS group (P < 0.05). CONCLUSIONS: CYPHER and TAXUS DES were safe and effective in patients with complex lesion. Clinical outcomes of CYPHER stent were better than TAXUS stent in bifurcation lesions. There was an increasing tendency in restenosis rate and late thrombosis in TAXUS group as compared with that of CYPHER group.

Coronary Disease↗
PubMed2006

Regulation of mitotic chromosome cohesion by Haspin and Aurora B.

In vertebrate mitosis, cohesion between sister chromatids is lost in two stages. In prophase and prometaphase, cohesin release from chromosome arms occurs under the control of Polo-like kinase 1 and Aurora B, while Shugoshin is thought to prevent removal of centromeric cohesin until anaphase. The regulatory enzymes that act to sustain centromeric cohesion are incompletely described, however. Haspin/Gsg2 is a histone H3 threonine-3 kinase required for normal mitosis. We report here that both H3 threonine-3 phosphorylation and cohesin are located at inner centromeres. Haspin depletion disrupts cohesin binding and sister chromatid association in mitosis, preventing normal chromosome alignment and activating the spindle assembly checkpoint, leading to arrest in a prometaphase-like state. Overexpression of Haspin hinders cohesin release and stabilizes arm cohesion. We conclude that Haspin is required to maintain centromeric cohesion during mitosis. We also suggest that Aurora B regulates cohesin removal through its effect on the localization of Shugoshin.

Aurora Kinase B↗
PubMed2006

[A randomized comparative study of using enoxaparin or UFH adjunctive to percutaneous coronary intervention in patients with CHD (ROUTE)].

OBJECTIVE: To evaluate the efficacy and safety of using Enoxaparin instead of UFH for patients with coronary heart disease (CHD) underwent coronary angiogram with or without percutaneous coronary intervention (PCI). METHODS: From Oct. 2003 to Feb. 2005, 966 patients with CHD underwent coronary angiogram (CAG) were randomized to receive enoxaparin (1 mg/kg subcutaneously, Q12 h, at least twice before CAG and the sheath was withdrawn immediately after the procedure, n = 484) or UFH (25 mg, iv, before CAG with additional 65 mg iv if PCI indicated and the sheath was withdrawn 4 hours after the procedure, n = 482). RESULTS: (1) PCI was not performed in 511 patients due to mild lesions or patients were suitable for CABG. In 455 patients underwent PCI (227 in enoxaparin and 228 in UFH group), 1 patient in enoxaparin group developed acute thrombosis and resulted in AMI during PCI and underwent successful urgent revascularization. The incidence of in-hospital major adverse cardiac events were 0.44% in the enoxaparin group and 0 in the UFH group. (2) Hematoma at the puncture site happened in 8 patients (3.5%) in enoxaparin group and in 20 patients (8.8%, P < 0.05) in UFH group. (3) One patient had AMI caused by subacute thrombosis in UFH group during 1 month follow-up. CONCLUSIONS: Our results suggest that the effects and safety are comparable for enoxaparin and UFH, it is also safe and efficient to give enoxaparin at least twice before CAG/PCI and the sheath can be withdrawn immediately after PCI. For ACS patients received more than twice enoxaparin and the last dose was given within 8 hours before PCI, PCI could be performed directly without additional UFH.

Angioplasty, Balloon, Coronary↗
PubMed2006

[Compare drug-eluting stent to bare-metal stent in prognosis on treating diffuse coronary lesions].

OBJECTIVE: Compare drug-eluting stent (DES) to bare-metal stent (BMS) in prognosis on treating diffuse coronary lesions and analysis risk factor of treating complex and diffuse lesions in PCI. METHODS: 205 consecutive patients with complex and diffuse coronary lesions enrolled our hospital, who were treated with more than 25 mm long DES or BMS. We exclude unsuccessful operation and location. All patients received medical treatment by guideline, and aspirin 300 mg and clopidogrel 75 mg once daily were continued at 6 months after the procedure. The patients were followed up after 6 months. RESULTS: The study population were consisted of 205 patients that there were 181 man, and 24 women, who got 382 stents for 227 target lesions in coronary. There were 93.8% C and 6.2% B2 ACC/AHA type lesion. There were 86.8% patients with binary or above vessel treated. The average reference vessel diameter was 2.88 +/- 0.43 mm. The average stent length of per lesion was 40.09 +/- 12.94 mm. There were 54.2% lesions treated with overlapping stent. There were not different between DES and BMS in patients baseline characteristics, but RVD of group DES less than of group BMS (2.80 +/- 0.37 mm, 3.10 +/- 0.48 mm, P = 0.005) in lesion baseline characteristics. After 6 months, restenosis rate in group DES was less than in group BMS (15.4%, 48.4%, P < 0.001). There were obvious superiority TVR of DES than of BMS (11.6%, 38.5%, P < 0.001). The rate of local restenosis in group of DES was higher than that in group of BMS (33.3%, 18.2%, P = 0.029). We analyzed the risk factors for diffuse lesion by a logistic regression model, the significant univariate clinical and angiographic predictors of restenosis were treating with overlapping stent (OR = 2.82, P = 0.017) and drug-eluting stent (OR = 5.71, P < 0.001). CONCLUSIONS: We find that implantation of DES in patients with diffuse lesions in coronary is relatively more safe and associated with more good clinical outcomes, than of BMS.

Aged↗
PubMed2006

[Synthesis and spectral properties of a new europium strontium oxide SrEu2O4].

A new europium strontium oxide was synthesized by high-temperature solid state reaction of SrCO3 with Eu2O3 in air. The new multiple oxide was characterized by use of XRD, TG/DTA and fluorescence spectra. The XRD results show that the molecular formula of the europium strontium oxide is SrEu2O4, whose structure is isostructural with that of BaEu2O4 reported earlier. The excitation spectrum of SrEu2O4 displays a broad double peaks band with one peak around 257 nm and the other around 280 nm. This broad band is attributed to the charge transfer transition of Eu3+-O2- bonds. Excited with a radiation of 280 nm, SrEu2O4 emits strong red light which is assigned to the 5D0-->7F2 electric dipole transition of Eu3+.

English Abstract↗
PubMed2005

[Short and long-term therapeutic effects of rapamycin-eluting stent and paclitaxel-eluting stent in treatment of coronary disease with complicated lesions].

OBJECTIVE: To compare the short and long-term clinical outcomes of rapamycin (sirolimus)-eluting stent (DES) (CYPHER stent) and paclitaxel-DES (TAXUS stent) in treatment of coronary heart disease (CHD) patients with complicated lesions. METHODS: 611 CHD patients with 642 lesions, were treated with 698 CYPHER stents, and 450 sex, age, clinical data and lesion type-matched patients, with 534 lesions, were treated with 600 TAXUS stents by means of percutaneous coronary intervention. The short and long term outcomes were compared between these 2 groups. RESULTS: The success rate of stent implantation was 99.2% (606/611) and 98.8% (445/450) in the CYPHER stent and TAXUS stent groups respectfully. The overall rate of major cardiac events, including death, acute myocardial infarction (AMI) target lesion revascularization (TLR), and major adverse cardiac event (MACE), during hospitalization and 6 - 8 month' follow-up were 0.65% and 2.3% in the CYPHER stent group, not significantly different from those of the TAXUS stent group (1.3% and 3.2% respectively). The restenosis rate of the TAXUS stent group was 7.3%, a little higher than that of the CYPHER stent group (14%), but without significant difference. CONCLUSION: CYPHER and TAXUS DES are both safe and effective in CHD patients with complicated lesions. There is an increasing tendency of restenosis rate in the TAXUS stent group in comparison with the CYPHER stent.

Angioplasty, Balloon, Coronary↗
PubMed2005

Haspin: a mitotic histone kinase required for metaphase chromosome alignment.

The fidelity of chromosome segregation during cell division is critical to maintain genomic stability and to prevent cancer and birth defects. A key set of kinases that regulates this process has been identified and characterized over the last few years, including the Aurora, Polo and Nek families. Recently we proposed that a little-studied kinase known as haspin is a new member of this important group. During mitosis haspin is phosphorylated, associates with the chromosomes, centrosomes and spindle, and is responsible for phosphorylation of histone H3 at threonine-3. Depletion of haspin using RNA interference prevents normal alignment of chromosomes at metaphase, suggesting that haspin plays a crucial role in chromosome segregation. Here we discuss possible mechanisms of haspin action and the function of histone phosphorylation in mitosis. We also outline some of the questions raised by these new findings and consider what role haspin might play in cancer.

Amino Acid Sequence↗
PubMed2005

Role of ion pairing in anionic additive effects on the separation of cationic drugs in reversed-phase liquid chromatography.

Mobile phase additives can significantly affect the separation of cationic drugs in reversed-phase liquid chromatography (RPLC). Although there are many applications for anionic additives in RPLC separations, the retention mechanism of basic drugs in the presence of inorganic and highly hydrophilic anionic species in the mobile phase is not at all well understood. Two major retention mechanisms by which anionic additives can influence the retention of cations are: (1) ion pair formation in the mobile phase with subsequent retention of the neutral ion pair; (2) pre-sorption of anionic additives on the stationary phase followed by "dynamic ion-exchange" or "electrostatic interaction" with the analytes. Because the use of ion pair chromatography in the separation of proteins, peptides, and basic drugs is rapidly increasing, understanding the retention mechanism involved is becoming more important, especially for the smaller commonly used hydrophilic anionic additives (e.g., formate HCOO, chloride Cl-, trifluoroacetate CF3COO-, perchlorate ClO4-, and hexafluorophosphate PF6-). In this work, we compared various anionic additives in light of their effects on the retention of basic drugs. As did many others we found that the addition of anionic additives (Cl-, CF3COO-, ClO4-, PF6-) profoundly influences the retention of basic drugs. In order to explain the data and differentiate the mechanisms by which the anionic additives perturb the chromatography, we used ion pair formation constants independently measured by capillary electrophoresis (CE) under the mobile phase conditions (pH, solvent composition) identical to those used in chromatography. Agreement between the predicted and experimental chromatographic data under various conditions was evaluated. Under specific circumstances (e.g., pH, stationary phase, and nature of anionic additive), we conclude that the ion pair mechanism is more important than the dynamic ion-exchange and at other conditions it remains a significant contribution.

Anions↗
PubMed2005

Effect of anionic additive type on ion pair formation constants of basic pharmaceuticals.

Due to their beneficial effect on selectivity, peak shape, and sample loading, the use of mobile phase anionic additives, such as formate (HCOO-), chloride (Cl-), and trifluoroacetate (CF3COO-), is increasing in both reversed-phase chromatography (RPLC) and liquid chromatography-mass spectrometry (LC/MS). Similarly, perchlorate is a common "ion pair" agent in reversed-phase separation of peptides. Although many studies have suggested that anions effect in chromatography is due to the formation of ion pairs in the mobile phase between the anions and cationic analytes, there has been no independent verification that ion pairs are, in fact, responsible for these observations. In order to understand the mechanisms by which anionic additives influence retention in chromatography and ionization efficiency in electrospray mass spectrometry, we studied the formation of ion pairs between a number of prototypical basic drugs and various additives by measuring the effect of anionic additives on the electrophoretic mobility of the probe drugs under solvent conditions commonly used in chromatography. For the first time, ion pair formation between basic drugs and anionic additives under conditions commonly used in reversed-phase liquid chromatography has been confirmed independently with all anions (i.e. hexafluorophosphate, perchlorate, trifluoroacetate, and chloride) used in this study. We measured ion pair formation constants (Kip) for different anionic additives using capillary electrophoresis (CE) and obtained quantitative estimates for the extent of ion pairing in buffered acetonitrile-water. The data clearly indicate that different anionic additives ion pair with cationic drugs to quite different extents. The ion pair formation constants show a clear trend with the order being: PF6- > ClO4- > CF3COO- > Cl-. However, the extent of ion pairing is not large. At a typical RPLC mobile phase additive concentration of 20mM, the percentages of the analytes that are present as ion pairs are about 15%, 6%, and 3% for hexafluorophosphate, perchlorate, and trifluoroacetate, respectively. The fraction of the analytes present as a chloride pair is even smaller.

Amitriptyline↗