[Research progress in ecological prevention of dental caries].

Dental caries is one of the most common oral diseases around the world. Dental plaque attached to the surfaces of teeth is the main biological factor leading to caries. Although fluoride is still one of the most commonly used methods to prevent caries, with the change of epidemiological characteristics of caries and the update of the understanding of caries etiology, it is necessary to use other ecological methods such as antimicrobial peptides, arginine, probiotics and natural products, etc. to enhance the effect of fluoride in preventing dental caries. The present article reviews the research progress on the ecological approaches for caries prevention in recent years.

[The imaging characteristics and prognosis of patients with cochlear implants whose cochlear nerves are not shown on MRI].

Objective: To analyze the temporal bone CT and inner ear magnetic resonance imaging characteristics of cochlear implant patients with no cochlear nerve display in the inner auditory canal under MRI. To retrospectively analyze the long-term hearing and speech rehabilitation effects of such patients after cochlear implant. And to analyze the correlation between the results of imaging examinations and the postoperative effects of cochlear implant patients with this type of cochlear nerve deficiency. Methods: A total of 88 children with cochlear nerve deficiency, who underwent cochlear implantation in Shandong Provincial ENT Hospital from May 2014 to October 2018, were enrolled. Patients with cochlear malformations were excluded,only the patients with cochlear nerve deficiency whose cochlear structure was normal and no cochlear nerve displayed in inner auditory canal under MRI were enrolled. There were 64 patients, including 4 bilaterally implanted, 68 ears in total, with an average age of (2.8±1.7) years (range 1-6 years) at the time of implantation. The implanted product was Cochlear, including 24RECA and 512 models. All patients underwent inner ear magnetic resonance imaging and temporal bone CT scan before operation. Auditory speech function assessments were performed at 12 months, 24 months, and 36 months after surgery, including categories of auditory performance (CAP), speech intelligibility rating (SIR) and hearing aid threshold test. The imaging evaluation content included the width of the cochlear nerve canal of temporal bone CT, the width of the internal auditory canal, the width of the auditory nerve at the cerebellopontine angle of the inner ear MRI, and the ratio of the facial nerve to the width of the auditory nerve at the cerebellopontine angle. The correlations between the results of postoperative hearing aid hearing threshold, CAP, SIR and imaging results were analyzed. Results: Among the 64 cases of cochlear nerve not shown under MRI, 56 ears with CT data showed that the width of the cochlear nerve canal in temporal bone CT was (0.72±0.30) mm (mean±standard deviation, the same below), and the width of the internal auditory canal was (4.07±1.10) mm; 66 ears with MRI data showed that the diameter of the auditory nerve at the cerebellopontine angle of the inner ear MRI was (1.58±0.27) mm, the diameter of the facial nerve was (1.57±0.27) mm, and the ratio of the diameter of the facial nerve to the auditory nerve was (1.02±0.23). The average hearing thresholds at 12, 24, and 36 months after surgery were (46.8±2.5) dB HL, (40.7±0.8) dB HL, and (36.8±1.5) dB HL, respectively. The preoperative and postoperative CAP scores at 12, 24 and 36 months were (1.0±1.0), (3.8±1.4), (4.5±1.4) and (5.1±0.7) points, respectively. The preoperative and postoperative SIR scores at 12, 24, and 36 months were (1.1±0.3), (1.9±0.9), (2.5±0.9), and (2.9±0.6) points, respectively. The hearing threshold at 24 months after surgery was negatively correlated with the width of the internal auditory canal of temporal bone CT (r=-0.349, P=0.037), and the hearing threshold at 36 months after surgery was positively correlated with the ratio of the diameter of the facial nerve to the auditory nerve at the cerebellopontine angle of the inner ear MRI (r=0.740, P=0.001). Conclusions: Children with cochlear implants whose cochlear nerves are not shown on MRI can benefit from cochlear implantation, and their speech and auditory functions can improve significantly after surgery. The width of the internal auditory canal in the temporal bone CT and the ratio of the diameter of the facial nerve to the auditory nerve at the cerebellopontine angle of the inner ear MRI may be related to the long-term hearing threshold after surgery.

[3D-FLAIR MRI findings in idiopathic sudden sensorineural hearing loss and the correlations with clinical features and prognosis].

Objective: To explore the correlations of different appearances of labyrinthine 3D-FLAIR MRI with clinical features and prognosis in patients with idiopathic sudden sensorineural hearing loss (ISSNHL). Methods: Clinical data of patients with unilateral ISSNHL hospitalized from May 2017 to January 2019 were retrospectively analyzed. According to the results of 3D-FLAIR MRI, the patients were divided into three groups including hyperintense with absorption, hyperintense without absorption and normal. The differences and correlations among the three groups in clinical characteristics (gender, age, deafness side, duration, treatment days, dizziness/vertigo, basic diseases, vestibular function, deafness classification and typing) and prognosis were analyzed by SPSS 20.0 software. Results: Data were collected from 1 245 cases, including 739 (59.36%) with normal signal, 288 (23.13%) hyperintense without absorption, and 218 (17.51%) hyperintense with absorption. The side ratio, treatment days, dizziness/vertigo incidence, vestibular dysfunction, deafness classification and typing were different among the three groups (P<0.001). The incidence of right side was significantly higher in both the hyperintense with and without absorption groups than that in the normal. The vestibular dysfunction was more common in the hyperintense with absorption group than in the normal and hyperintense without absorption groups. It showed statistical differences in the dizziness/vertigo incidence, deafness classification, treatment days, and deafness typing compared between groups, which was the most significant in the hyperintense with absorption group, followed by the hyperintense without absorption group. There was no statistical difference in the total effective rate among the three groups (P=0.139), whereas a significant difference in the recovery rate (P<0.001). The prognosis was significantly correlated with duration, age, treatment days and dizziness/vertigo in the normal group (all P<0.001), correlated with duration and treatment days in the hyperintense with absorption group (both P<0.001), only correlated with the duration in the hyperintense without absorption group (P<0.001). Conclusion: 3D-FLAIR MRI manifestation is closely related to the clinical features and efficacy of ISSNHL. It is helpful to clarify the pathology of inner ear, which is expected to be a new imaging indicator for disease evaluation.

Physician deaths from corona virus (COVID-19) disease.

BACKGROUND: The COVID-19 pandemic has caused much morbidity and mortality to patients but also health care providers. AIMS: We tabulated the cases of physician deaths from COVID-19 associated with front-line work in hopes of mitigating future events. METHODS: On 15 April 2020, a Google internet search was performed using the keywords 'doctor', 'physician', 'death', 'COVID' and 'coronavirus' in English and Farsi, and Chinese using the Baidu search engine. The age, sex and medical speciality of physicians who died from COVID-19 in the line of duty were recorded. Individuals greater than 90 years of age were excluded. RESULTS: We found 278 physicians who died with COVID-19 infection, but complete details were missing for 108 individuals. The average age of the physicians was 63.7 years with a median age of 66 years, and 90% were male (235/261). General practitioners and emergency room doctors (108/254), respirologists (5/254), internal medicine specialists (13/254) and anaesthesiologists (6/254) comprised 52% of those dying. Two per cent of the deceased were epidemiologists (5/254), 2% were infectious disease specialists (4/254), 6% were dentists (16/254), 4% were ENT (9/254) and 3% were ophthalmologists (8/254). The countries with the most reported physician deaths were Italy (121/278; 44%), Iran (43/278; 15%), Philippines (21/278; 8%), Indonesia (17/278; 6%), China (16/278; 6%), Spain (12/278; 4%), USA (12/278; 4%) and UK (11/278;4%). CONCLUSIONS: Physicians from all specialities may die from COVID. Lack of personal protective equipment was cited as a common cause of death. Consideration should be made to exclude older physicians from front-line work.

Construction of a new fusion anti-caries DNA vaccine.

Mutans streptococci (MS) are generally considered to be the principal etiological agent of dental caries. MS have two important virulence factors: cell- surface protein PAc and glucosyltransferases (GTFs). GTFs have two functional domains: an N-terminal catalytic sucrose-binding domain (CAT) and a C-terminal glucan-binding domain (GLU). A fusion anti-caries DNA vaccine, pGJA-P/VAX, encoding two important antigenic domains, PAc and GLU, of S. mutans, was successful in reducing the levels of dental caries caused by S. mutans in gnotobiotic animals. However, its protective effect against S. sobrinus infection proved to be weak. Does the DNA vaccine need an antigen of S. sobrinus to enhance its ability to inhibit infection? To answer this question, in this study, we cloned the catalytic (cat) fragment of S. sobrinus gtf-I, which demonstrated its ability to inhibit water-insoluble glucan synthesis by S. sobrinus, into pGJA-P/VAX to produce a new anti-caries DNA vaccine.

Mucosal and systemic immunization with targeted fusion anti-caries DNA plasmid in young rats.

Early life vaccination is necessary to protect young children from dental caries. Our group had previously reported that a plasmid DNA vaccine pGJA-P/VAX against the glucosyltransferase (GTF) enzyme and cell surface antigen AgI/II (PAc) of Streptococcus mutans (S. mutans) elicited a specific and protective immunity in adult experimental animal models. In this report, early life immunization with the same plasmid was studied following intranasal (i.n.) and intramuscular (i.m.) delivery in murine models. The potential of inducing mucosal and systemic immune responses to special antigens was measured by ELISA. In addition, cytokine production and protection effectiveness against dental caries formation were also investigated. In the i.n. route, rats were primed when they were 5 days old, and boosted after 10 and 20 days with either plasmid pGJA-P/VAX-bupivacaine complexes, or pGJA-P/VAX alone, or empty vector. The pGJA-P/VAX-bupivacaine combination was able to mount the immune responses characterized by increased antibody levels of specific salivary IgA and serum IgG, preferential IFN-gamma production and significant reduction in the dental caries lesions. In the i.m. route, rats were vaccinated with either pGJA-P/VAX alone or empty vector with the same immunization schedule as the i.n. route. Plasmid pGJA-P/VAX alone induced a significant increase in the serum IgG and IFN-gamma production. However, it was not effective in eliciting specific salivary IgA and in decreasing the dental caries formation. All these findings indicate the feasibility of immunity with a targeted fusion DNA vaccine to a young immune system.

Fusion protein encoded by a CTLA-4 targeted DNA construct binds to human dendritic cells.

Fusing antigens to cytotoxic T-lymphocyte antigen 4 (CTLA-4) represents an effective approach to enhance DNA vaccine efficacy. It has been speculated that the direct targeting of CTLA-4 fusion antigens to antigen-presenting cells (APCs) causes antigens to be processed and presented to T cells more efficiently, leading to a stronger immune response. In the present study, dendritic cells (DCs), the most potent APCs, were generated from human monocytes. The specific binding of CTLA-4 fusion protein to DCs was investigated by flow cytometry. The results showed that the CTLA-4 fusion protein was capable of binding to the B7 molecules on human DCs with specificity.

Protective efficacy of a targeted anti-caries DNA plasmid against cariogenic bacteria infections.

We have previously reported that a targeted anti-caries DNA plasmid pGJA-P/VAX which was constructed against the antigenic determinants of Streptococcus mutans (S. mutans) successfully induced antibody responses in mice and monkeys. The present study explored the protective efficacy of pGJA-P/VAX against cariogenic bacterial challenge. Groups of rats were orally challenged with S. mutans or Streptococcus sobrinus (S. sobrinus) and then immunized with pGJA-P/VAX or the vector pVAX1 intranasally. Serum IgG and salivary IgA antibody levels were assessed by an enzyme-linked immunosorbent assay and caries activity was evaluated by the Keyes method. The results showed that specific salivary IgA antibody responses were induced following intranasal vaccination with pGJA-P/VAX. Moreover, immunization with pGJA-P/VAX resulted in significantly reduced enamel and dentinal caries lesions in rats after S. mutans infection and significantly reduced enamel caries lesions after S. sobrinus infection. Thus, pGJA-P/VAX was not only protective toward S. mutans infection, but also provided cross-strain protection against S. sobrinus infection in rats.

Immunogenicity and persistence of a targeted anti-caries DNA vaccine.

We have previously reported that a targeted anti-caries DNA vaccine, pGJA-P, induced accelerated and increased antibody responses compared with a non-targeted anti-caries DNA vaccine. Recently, pGJA-P/VAX, a new targeted anti-caries DNA vaccine for human trials, was constructed by replacing the pCI vector used in the construction of pGJA-P with pVAX1, the only vector authorized by the US Food and Drug Administration in clinical trials. Here, we report on our exploration of the kinetics of the antibody responses generated following pGJA-P/VAX immunization and the persistence of pGJA-P/VAX at both the inoculation site and the draining lymph nodes. Intranasal vaccination of mice with pGJA-P/VAX induced strong antibody responses that lasted for more than 6 months. Furthermore, pGJA-P/VAX could still be detected at both the inoculation site and the draining cervical lymph nodes 6 months after immunization. Thus, the persistent immune responses are likely due to the DNA depot in the host, which acts as a booster immunization.

Adequacy of a new chlorhexidine-bearing polyurethane central venous catheter for administration of 82 selected parenteral drugs.

OBJECTIVE: To screen 82 commonly used parenteral medications for compatibility with a new chlorhexidine-bearing central venous catheter, the ARROWg+ard Blue Plus. Evaluations were performed for completeness of drug delivery and impact, if any, of the drugs on the amount of chlorhexidine removed from the internal lumens. DESIGN: Drug solutions were prepared in dextrose 5% injection or NaCl 0.9% at common concentrations. Three 10-mL aliquots of each drug solution were delivered over 10 minutes, one aliquot through each lumen of the triple-lumen catheter. The initial drug concentrations of the admixtures and the effluent samples were analyzed by HPLC for chlorhexidine content and for the amount of drug delivered relative to its initial concentration. RESULTS: The delivery of the infusion solutions alone through sample catheters resulted in no more than trace amounts of chlorhexidine in the solution. Background amounts ranged from < 2.5 to 6.1 micrograms/mL in the first 10 mL of solution. Administration of none of the drugs tested resulted in a substantial increase in chlorhexidine delivery. Furthermore, delivery of most of the drugs was at least 95% and usually was in excess of 97% of the initial concentration. Concentrations of five drugs, amikacin sulfate, cefoperazone sodium, cefotaxime sodium, cefepime HCl, and netilmicin sulfate were somewhat lower than the initial concentration (range 91-95%), but were still considered acceptable. CONCLUSIONS: The ARROWg+ard Blue Plus central venous catheter can be recommended for use with all of the 82 parenteral drugs tested.

Compatibility and stability of linezolid injection admixed with three quinolone antibiotics.

OBJECTIVE: To evaluate the physical compatibility and chemical stability of linezolid 200 mg/100 mL admixed with ciprofloxacin 400 mg, ofloxacin 400 mg, and levofloxacin 500 mg for seven days at 4 and 23 degrees C. METHODS: The test samples were prepared by adding the required amount of the quinolone antibiotic to bags of linezolid injection. Evaluations for physical and chemical stability were performed initially and after one, three, five, and seven days of storage at temperatures of 4 and 23 degrees C. Physical stability was assessed using visual observation in normal light and using a high-intensity monodirectional light beam. In addition, turbidity and particle content were measured electronically. Chemical stability of the drugs was evaluated by using stability-indicating HPLC analytical techniques. RESULTS: The linezolid admixtures with levofloxacin and ofloxacin were clear and pale yellow when viewed in normal fluorescent room light, and slightly hazy with a green cast when viewed using a Tyndall beam. Measured turbidity and particulate content were low and exhibited little change. HPLC analysis found no loss of the drugs in any sample stored at either temperature throughout the study. The linezolid admixtures with ciprofloxacin stored at room temperature (23 degrees C) were clear and nearly colorless in normal room light and when viewed using a Tyndall beam. They exhibited little or no change in measured turbidity or particulate content during the study period. HPLC analysis found no loss of either drug in seven days. However, the refrigerated samples were only compatible for 24 hours and developed a gross white precipitate thereafter. CONCLUSIONS: Admixtures of linezolid 200 mg/100 mL with levofloxacin 500 mg and with ofloxacin 400 mg were physically compatible and chemically stable for at least seven days stored at 4 and 23 degrees C. Admixtures of linezolid with ciprofloxacin 400 mg were compatible and stable for seven days at 23 degrees C, but ciprofloxacin precipitation occurred after 24 hours stored under refrigeration. Linezolid/ciprofloxacin admixtures should not be stored under refrigeration.

Compatibility and stability of linezolid injection admixed with three cephalosporin antibiotics.

OBJECTIVE: To evaluate the physical compatibility and chemical stability of linezolid (Zyvox-Pharmacia) 200 mg/100 mL admixed with cefazolin sodium 1 gram, ceftazidime 2 grams, and ceftriaxone sodium 1 gram for 7 days at 4 degrees C and 23 degrees C. DESIGN: Controlled experimental trial. SETTING: Laboratory. INTERVENTIONS: The test samples were prepared by adding the required amount of the cephalosporin antibiotic to bags of linezolid injection 200 mg/100 mL. MAIN OUTCOME MEASURES: Physical stability and chemical stability based on drug concentrations initially and after 1, 3, 5, and 7 days of storage at 4 degrees C and 23 degrees C protected from light. RESULTS: All of the linezolid admixtures with cephalosporins were clear when viewed in normal fluorescent room light and with a Tyndall beam. Measured turbidity and particulate content were low and exhibited little change. The cefazolin sodium-containing samples were colorless throughout the study. The admixtures with ceftazidime and ceftriaxone sodium had a slight yellow tinge initially, and the room temperature samples became a frank yellow color after 5 days. The refrigerated samples did not change color. High-performance liquid chromatography analysis found little or no loss of linezolid in any sample stored at either temperature throughout the study. Cefazolin sodium and ceftazidime in the linezolid admixtures at 4 degrees C remained stable for 7 days, but at 23 degrees C cefazolin sodium was stable for 3 days and ceftazidime for only 24 hours before cephalosporin decomposition exceeded 10%. Ceftriaxone sodium was less stable in the admixtures; 10% loss occurred in 3 days at 4 degrees C and more than 20% loss occurred in 24 hours at 23 degrees C. CONCLUSION: Admixtures of linezolid 200 mg/100 mL with cefazolin sodium 1 gram and ceftazidime 2 grams were physically compatible and chemically stable for at least 7 days stored at 4 degrees C protected from light and for 3 days and 1 day, respectively, at 23 degrees C protected from light. Admixtures of linezolid with ceftriaxone sodium 1 gram exhibited a rapid rate of cephalosporin loss at 23 degrees C, which precludes admixture of the two drugs.

Compatibility and stability of linezolid injection admixed with aztreonam or piperacillin sodium.

OBJECTIVE: To evaluate the physical compatibility and chemical stability of linezolid (Zyvox-Pharmacia) 200 mg/100 mL admixed with aztreonam (Azactam-Squibb) 2 grams and separately with piperacillin sodium (Pipracil-Lederle) 3 grams over 7 days at 4 degrees C and 23 degrees C. DESIGN: Controlled experimental trial. SETTING: Laboratory. INTERVENTIONS: Test samples were prepared by adding the required amount of aztreonam or piperacillin sodium to separate bags of linezolid injection 200 mg/100 mL. MAIN OUTCOME MEASURES: Physical compatibility and chemical stability based on drug concentrations initially and after 1, 3, 5, and 7 days of storage at 4 degrees C and 23 degrees C. RESULTS: All of the linezolid admixtures with aztreonam and with piperacillin sodium were clear when viewed in normal fluorescent room light and with a Tyndall beam. Measured turbidity and particulate content were low and exhibited little change throughout the study at both storage temperatures. High-performance liquid chromatography analysis found little or no loss of linezolid in any sample stored at either temperature throughout the study. Aztreonam in the linezolid admixtures was stable for 7 days, exhibiting less than 5% loss at 4 degrees C and 9% loss at 23 degrees C. Piperacillin sodium in the linezolid admixtures was stable for 7 days at 4 degrees C, exhibiting no loss, but was stable for only 3 days at 23 degrees C with losses of about 5%. Losses had increased to 9% to 12% after 5 days of storage at room temperature. CONCLUSION: Admixtures of linezolid 200 mg/100 mL with aztreonam 2 grams or piperacillin sodium 3 grams were physically compatible and chemically stable for at least 7 days stored at 4 degrees C and for 7 days or 3 days, respectively, at 23 degrees C.

Compatibility and stability of linezolid injection admixed with gentamicin sulfate and tobramycin sulfate.

The purpose of this study was to evaluate the physical compatibility and chemical stability of linezolid 200 mg/100mL admixed with gentamicin sulfate 80 mg and tobramycin sulfate 80 mg over 7 days at 4 deg C and 23 deg C. The test samples were prepared by adding the required amount of the aminoglycoside antibiotic to bags of linezolid injection 200mg/100mL. Physical and chemical stability based on drug concentrations initially and after 1, 3, 5, and 7 days of storage at 4 deg C ad 23 deg C were evaluated. The linezolid-aminoglycoside admixtures were clear when viewed in normal fluorescent room light and with a Tyndall beam. Measured turbidity and particulate content were low and exhibited little change. The admixtures remained colorless throughout the study. High-performance liquid chromatography analysis indicated little or no loss of linezolid in any sample stored at either temperature throughtout the study. Gentamicin sulfate and tobramycin sulfate in the linezolid admixtures at 4 deg C remained stable for 7 days, but at 23 deg C gentamicin sulfate was stable for 5 days and tobramycin sulfate was stable for only 1 day before aminoglycoside losses exceeded 10%. Admixtures of linezolid 200mg/100mL with gentamicin sulfate 80 mg and tobramycin sulfate 80 mg were physically compatible and chemically stable for at least 7 days when stored at 4 deg C and for 5 days or 1 day, repectively, at 23 deg C.

Compatibility and stability of paclitaxel combined with doxorubicin hydrochloride in infusion solutions.

OBJECTIVE: To evaluate the physical compatibility and chemical stability of paclitaxel at concentrations of 300 and 1200 micrograms/mL with doxorubicin hydrochloride 200 micrograms/mL in NaCl 0.9% injection and dextrose 5% injection over 7 days at 4, 23, and 32 degrees C. DESIGN: The test samples were prepared in polyolefin bags of the infusion solutions at the required drug concentrations. Evaluations were performed initially and after 4 hours, and 1, 3, 5, and 7 days of storage at 4, 23, and 32 degrees C for physical and chemical stability. Physical stability was assessed by using visual observation in normal fluorescent light and a high-intensity monodirectional light beam. In addition, turbidity and particle content were measured electronically. Chemical stability of the two drugs was evaluated by using two stability-indicating HPLC analytic techniques. RESULTS: All samples were physically stable through 1 day. However, microcrystalline precipitation of paclitaxel occurred within 3 days in some samples and within 5 days in all samples. Paclitaxel concentrations remained at more than 97% in all samples throughout the study. Doxorubicin hydrochloride also was stable throughout the study period, remaining above 90% in all samples at all storage temperatures. CONCLUSIONS: Admixtures of paclitaxel 300 and 1200 micrograms/mL with doxorubicin hydrochloride are limited in their utility time by paclitaxel microcrystalline precipitation. All combinations were physically and chemically stable for at least 24 hours at 4, 23, and 32 degrees C.

Stability of cisatracurium besylate in vials, syringes, and infusion admixtures.

The stability of cisatracurium besylate was studied. Cisatracurium (as besylate) 2 mg/mL in 5- and 10-mL unopened vials and 10 mg/mL in 20-mL unopened vials, as well as 3 mL of solution from additional 2-mg/mL vials, repackaged in 3-mL sealed plastic syringes, was stored at 4 and 23 degrees C in the dark and in normal fluorescent room light. Admixtures of cisatracurium (as besylate) 0.1, 2, or 5 mg/mL in polyvinyl chloride (PVC) minibags of 5% dextrose injection or 0.9% sodium chloride injection were stored at 4 and 23 degrees C in normal fluorescent room light. Triplicate samples for each storage condition were taken initially and at 1, 3, 5, 7, 14, 21, and 30 days; samples from vials were also removed at 45 and 90 days. Solutions were stored in sterile vials at -70 degrees C and then thawed at room temperature before analysis of chemical stability by high-performance liquid chromatography. Physical stability was assessed as well. Cisatracurium besylate was physically stable in all samples throughout the study. Cisatracurium (as besylate) 2 mg/mL exhibited drug losses at 23 degrees C in vials at 45 days and in syringes at 30 days. Cisatracurium (as besylate) 0.1, 2, and 5 mg/mL in 5% dextrose injection and in 0.9% sodium chloride injection was stable for at least 30 days at 4 degrees C, but substantial drug losses occurred at 23 degrees C. Admixtures prepared with cisatracurium (as besylate) 0.1 mg/mL and with 5% dextrose injection exhibited the greatest losses. Cisatracurium besylate was stable in most samples for at least 30 days at 4 and 23 degrees C; admixtures containing cisatracurium (as besylate) 0.1 or 2 mg/mL exhibited substantial drug loss at 23 degrees C.

Paclitaxel Compatibility with the IV Express Filter Unit.

The purpose of this project was to evaluate the compatibility of paclitaxel infusions with the IV Expres filter unit, a 0.22-micrometer intravenous solution filter (Millipore Corporation, Bedford, MA). The potential for extraction of diethylhexyl phthalate platicizer from the filter unit by the Cremaophor EL surfactant present in the paclitaxel injection and the potential for loss of paclitaxel to filter unit components due to sorption were evaluated. Plasticizer extraction was tested using the paclitaxel diluent at a concentration equivalent to 1.2 mg/mL over a three-hour simulated infusion. Paclitaxel delivery was evaluated in admixtures containing paclitaxel 0.3 mg/mL. All samples were prepared in triplicate in polyolefin bags of 5% dextrose injections and delivered through IV Express filter units attached to nonpolyvinyl chloride administration sets designed for the adminstration of paclitaxel infusions. The samples were collected in glass collection flasks. Both plasticizer and paclitaxel content were determined using specific high-performance liquid chromatographic methods. None of the admixtures delivered over three hours through the IV Express filter unit exhibited any detectable plasticizer. Further, no loss of paclitaxel due to soption to any filter commponent occurred; the full amount of paclitaxel was deliverd in the simulated ifusions. The IV Express filter unit tested in this study is suitable for the administration of paclitaxel infusions over three hours.

Compatibility of Paclitaxel injection diluent with two reduced-phthalate administration sets for the acclaim pump.

The purpose of this project was to evaluate the compatibility of paclitaxel admixtures with the two reduced-phthalate administration sets designed for use with the Acclaim Infusion Control Device. The first is a nitroglycerin set composed of polyethylene tubing, while the second is made using tris(2-ethyl-hexyl) trimellitate (TOTM)-plasticized polyvinyl chloride tubing. Both sets utilize a diethylhexyl phthalate (DEHP)-plasicized pumping segment. The potential for extraction of DEHP from the pumping segments and TOTM plasticizer from the plastic matrix by the Cremophor EL surfactant present in the paclitaxel injection was evaluated. Diethylhexyl phthalate and TOTM plasticizer extraction was tested using the paclitaxel diluent at concentrations equivalent to 0.3 and 1.2 mg/mL over three-hour and four-day infusions. All samples were prepared in triplicate in polyolefin bags of 5% dextrose injection and deliverd through the administration sets into glass collection flasks. Both DEHP and TOTM content were determined using high-performance liquid chromatographic methods. None of the admixtures delivered rapidly over three hours or slowly over four days through the TOTM-plasticized set exhibited any detectable TOTM. Similarly, no DEHP was detected in the effluent form either set with the simulated 0.3-mg/mL admixtures delivered over three hours. The simulated 1.2-mg/mL admixture delivered over three hours yielded only a barely detectable, but not quantifiable, trace of DEHP. However, slow delivery of both concentrations over four days through both sets resulted in leached DEHP in concentrations ranging from about 30 to 150 micrograms/mL at both one and four days. The two reduced-phthalate administration sets tested in this study are suitable for the administration of paclitaxel infusions of short duration, for up to three hours. However, the sets cannot be recommended for administration over longer-duration delivery times ranging from one to four days due to leaching of DEHP plasticizer from the pumping segments.

Rapid loss of fentanyl citrate admixed with fluorouracil in polyvinyl chloride containers.

OBJECTIVE: To study the physical compatibility and chemical stability of fluorouracil 1 and 16 mg/mL with fentanyl citrate 12.5 micrograms/mL in dextrose 5% and in sodium chloride 0.9% injection. DESIGN: Test solutions of the drugs in dextrose 5% injection and in sodium chloride 0.9% injection were prepared in triplicate and stored at -20, 4, 23, and 32 degrees C. Samples were removed immediately and at various times over 7 days and stored at -70 degrees C until analyzed. Physical compatibility was assessed visually and by measuring turbidity with a color-correcting turbidimeter; particle content was measured with a light-obscuration particle sizer and counter. Chemical stability was determined by measuring the concentration of each drug in the test solutions in duplicate with stability-indicating HPLC. RESULTS: Fentanyl citrate was rapidly lost when admixed with fluorouracil in polyvinyl chloride (PVC) containers, losing about 25% in the first 15 minutes and about 50% in the first hour. The loss of fentanyl citrate was so rapid that accurate time zero determinations were not possible. The extent of fentanyl loss increased with time and occurred more rapidly at the higher temperatures (i.e., 23, 32 degrees C). Losses of 70% or more occurred in all samples within 24 hours. Fentanyl underwent rapid sorption to the containers at the high pH (9.0-9.5) of the fluorouracil admixtures. Adjusting the pH of a fentanyl citrate solution (containing no fluorouracil) in PVC containers to pH 9 with sodium hydroxide also resulted in rapid sorption loss. Fentanyl citrate sorption did not occur when admixtures were prepared in polyethylene containers. Fluorouracil remained stable for at least 7 days at all temperatures. There were no visual or subvisual changes in turbidity or particle content in any of the test solutions at any time. CONCLUSIONS: When admixed with fluorouracil 1 and 16 mg/mL in dextrose 5% injection and sodium chloride 0.9% injection, fentanyl citrate 12.5 micrograms/mL underwent rapid and extensive loss due to sorption to the PVC containers, making the combination unacceptable within minutes of mixing. The sorption results from the alkaline pH of the admixture and, presumably, could occur from the admixture of fentanyl citrate with any sufficiently alkaline drug.

Development of clonidine hydrochloride injections for epidural intrathecal administration.

The purpose of this study was to describe and document the development of several concentrations of clonidine hydrochloride injection for evaluation as epidural and intrathecal injections in clinical trials for the control of intractable pain. Bulk clonidine hydrochloride prepared under Good Manufacturing Practices conditions was formulated as simple aqueous solutions in 0.9% sodium chloride injection having concentrations of 0.15, 0.5 and 1.5 mg/mL. The low concentration served as the starting concentration for low drug delivery, with the highter concentrations needed to accommodate increasing rates of drug delivery. All three concentrations exhibited natural pH values of about 6 to 6.5 and were adjusted to a target pH of 6.5 with sodium hydroxide, if necessary. The measured osmolalities were about 285 mOsm/kg, nearly isotonic. The injections were filtered through 0.22 micormeter filters and packaged in 20mL, Type-1, flint glass vials with rubber stoppers. The vials were terminally sterilized by autoclaving at 121 deg C and 15 psi for 30 minutes. Using a stability-indicating, high-performance liquid chromatography analytical technique based on the official USP method, we observed no loss of clonidine hydrochloride in any of the development vials at the concentrations of 0.15, 0.5 and 1.5 mg/mL after preparation and autoclaving. Similarly, shelf-life studies on two small batches each of the 0.15- and 0.5-mg/mL concentrations have shown little or no loss of clonidine hydrochloride after three months' storage at 37 deg C and for up to 24 months at 4 and 23 deg C. Shelf-life studies are continuing. Clonidine hydrochloride 0.15-, 0.5-, and 1.5-mg/mL injections have been developed as epidural and intrathecal injections in clinical trials to control intractable pain. The injections are easily formulated and stable during compounding and storage.