Choice Of Diluent Research Articles

A practical guide for nurses in diluent selection for subcutaneous infusion using a syringe driver

Appropriate diluent selection in continuous subcutaneous infusion optimises symptom management and client well-being. The responsibility of diluent selection is commonly one of the attending nurse. This paper was developed with the intention of providing nurses with practical instruction for diluent selection when preparing medications for administration subcutaneously using a syringe driver. A literature review was undertaken of published journal databases and published guidelines sites. Recommendations regarding diluent choice were reviewed in two iterations by an expert panel of palliative care nurse clinicians. The principles for diluent selection are presented. They are based primarily on expert opinion level of evidence given a lack of primary research evidence in the area of diluent selection. There is a pressing need for manufacturers' guidance on diluent selection and independent research to establish the impact of diluents on drug and drug combinations when using syringe drivers. Until such time that this evidence is available to guide practice, clinicians need to be trained to inspect solutions and assess the effectiveness of the medication in controlling symptoms. The capacity of this paper to provide practical instruction has been limited by the lack of rigorous evidence available, and indeed, the process of developing this guide identified perhaps more questions than answers available at the present time.

Extraction of chromium (VI) from sulphuric acid aqueous solutions by a liquid surfactant membrane (LSM)

Experimental results for the batch extraction of chromium (VI) from sulphuric acid aqueous solutions using a liquid surfactant membrane (LSM) are presented. Effects of various parameters such as time and speed of emulsification, internal phase concentration, extractant concentration, choice and concentration of surfactant, contact time, stirring speed, choice of diluent, and volume ratios of the membrane phase to internal stripping phase and that of the water-in-oil emulsions to the aqueous external phase on the membrane stability were studied. The membrane phase consists of hexane as diluent, tributyl phosphate, as extractant, and sorbiton monooleate (Span 80) as surfactant. A NaOH solution is the internal aqueous phase. Results show that with proper adjustment of experimental conditions the stability of the membrane can be enhanced to a great extent. This study also examined the effects of the concentrations of feed phase acid, metal ions, and carrier on the extraction of Cr(VI) ions. Further, the extraction kinetics of the metal ions by LSMs was examined. The results also showed that by appropriate selection of the extraction and stability conditions, nearly all of the Cr(VI) ions present in the continuous phase were extracted within a few minutes. The influence of the NaOH concentration on stripping efficiency was investigated.

Detection of red cell antibodies: comparison of two low ionic strength diluents

Various low ionic strength diluents are used routinely for red cell alloantibody detection in the antiglobulin test to increase the rate of antibody association to antigen, thereby allowing a reduction in the incubation time while achieving optimal agglutination. Two commercial low ionic strength diluents (DiaMed ID-CellStab and Inverclyde LISS) were assessed using the DiaMed-ID LISS Coombs’ microtube column system, to assess whether or not the choice of diluent influences red cell antibody detection. Effects of two low ionic strength diluents after 15-min incubation were assessed in 150 samples containing a wide range of typical red cell alloantibodies. Inverclyde LISS gave significantly higher reaction strengths in 25% of samples when compared with the same red cells suspended in ID-CellStab. Variation in reaction strengths ranged from 1+ to 2+, using Inverclyde LISS versus CellStab. Of 131 red cell alloantibodies directed against Rh, Kell, Kidd and Duffy antigens, Inverclyde LISS detected 90% after 15-min incubation, whereas 83% were detected with CellStab. This study suggests that Inverclyde LISS provides better red cell alloantibody detection than does ID-CellStab, and this may be due to the higher ionic strength of ID-CellStab.

Diluent choice for subcutaneous infusion: a survey of the literature and Australian practice

Continuous subcutaneous infusion is a method frequently used in palliative care to manage patient symptoms. To deliver the dose required and prevent subcutaneous sites from becoming inflamed and painful, the drug is often diluted in a solution, most commonly sterile water for injection or sodium chloride. The use of sterile water for injection has been recommended for cyclizine yet beyond this example there appears to be limited clinical direction regarding diluent selection. Inconsistency or lack of guidelines can be problematic if a diluent that may enhance the effectiveness of a drug compared with an alternate is not used because of lack of knowledge or guidance. This investigation considered existing literature, drug databases and directories, and involved a survey of palliative care services to examine evidence and experience relating to diluent selection. A number of inconsistencies emerged in both the literature and practice. With the exception of five drugs for which only saline was recommended, there appeared to be an inclination to use water unless contraindicated. Given an increasing reliance on this method of symptom management, the absence of formal clinical evidence or recommendations and ambiguity in relation to the use of diluents highlights the need for these deficits to be addressed as quickly as possible.

Hydrotreating of diluted Maya crude with NiMo/Al 2O 3-TiO 2 catalysts: effect of diluent composition

This work analyzes the changes in hydrodesulfurization (HDS), hydrodenitrogenation (HDN), hydrodeasphaltenization (HDAs) and hydrodemetallization (HDM) activities, when a NiMo/TiO 2/Al 2O 3-catalyst is evaluated under three different feedstocks containing heavy Maya petroleum, i.e., Maya-diesel (M-D), hydrodemetallized Maya-diesel (HM-D) and hydrodemetallized Maya-naphtha (HM-N). A NiMo/Al 2O 3 catalyst was also tested using HM-N as feed, in order to enquire on the effect of changing the nature of the support from Al 2O 3 to TiO 2/Al 2O 3. The results show that the choice of diluent when performing catalytic activity tests for the ranking of catalyst formulations for hydrotreatment of heavy petroleum like Maya is critical. The incorporation of Ti to the support of the conventional NiMo/Al 2O 3 catalyst improves the functionalities of the catalyst (HDS, HDN, HDAs), possibly due to Ti-enhanced hydrogenating and hydrodesulfurization functions. The number of coordinatively unsaturated sites (CUS) on the surface of the sulfided phase was higher in the Ti-containing catalyst.

Drugs used in combination in the syringe driver-a survey of hospice practice

A survey of hospices in the UK revealed a wide range of drugs being given in combination by subcutaneous infusion. The reported maximum doses were, in general, higher than those used in previous in vitro studies of drug compatibility. Very wide interhospice variation in the maximum doses of many of the drugs was found. Potential problems relating to the choice of diluent, protection of drugs from light and the method of setting up different models of syringe driver are discussed. The great majority of syringe driver infusions are given over a period of less than 48 hours, but it is possible to set machines to run for much longer periods without refilling. As the number and variety of drugs used in combination in the syringe driver increase, so the need for more studies of the compatibility of these drugs becomes more pressing to avoid the potential for adverse interaction. Whilst these results report current hospice practice they must not be regarded as an endorsement of such practice, but rather as a source of information for those concerned with finding out more about the compatibility of drugs in combination in the syringe driver.

Calibration of Lyophilized Standards for Ristocetin Cofactor Activity of von Willebrand Factor (vWF) Requires vWF-Deficient Plasma as Diluent for Dose-Response Curves

Calibration of local standards for ristocetin cofactor activity of von Willebrand's factor (vWF:Rcof) against reference preparations is required to achieve a better standardization of this measurement. We have observed that in calibration assays (multiple line parallel bioassay) for vWF:Rcof, measured aggregometrically, the type of diluent used to obtain the dose-response curves exerted a critical influence on the final potency estimation when a fresh-frozen plasma against a lyophilized standard or two lyophilized preparations were to be compared. This pattern was observed with various commercial standards and also with the First International Reference Preparation for Factor VIII-Related Activities in Plasma. The choice of diluent was not relevant if two fresh-frozen plasma preparations were to be calibrated. Systematic experiments using as diluents Tris-saline, Tris-buffered-albumin solution or vWF-deficient plasma (vW-plasma) showed that the ratio lyophilized/fresh-frozen preparations was invariably lower with albumin solution than with vW-plasma. Tris-saline partially corrected this discrepancy, but yielded less precise estimates. Preliminary results with cryosupernatant-plasma seems to indicate that this material is a valid substitute for vW-plasma, but confirmatory experiments are required. For the moment, plasma obtained from patients with severe type III vW-disease should be considered the "ideal" diluent for calibration assays involving lyophilized preparations.

Effect of inositol hexaphosphate on the transient behavior of red cells following a DMSO-induced osmotic pulse.

An osmotic pulse can be used to incorporate inositol hexaphosphate (IHP) into red cells. The pulse is induced by equilibrating a red cell suspension with DMSO and then rapidly diluting with an isotonic IHP solution. Since IHP binds to hemoglobin and lowers the affinity for oxygen, this method may find application in the preparation of low-affinity cells for experimental and clinical use. The experiments reported here examined the dynamic changes of several red cell variables immediately following the osmotic pulse. The effect of IHP, which has been shown to dissociate red cell cytoskeletons, was evaluated by comparison with a matched phosphate-buffered saline (PBS) diluent. Red cell morphology, volume, and hemoglobin permeability were studied by fixing the cells at times ranging from 0.06 to 300 sec after dilution. Mechanical fragility was measured by subjecting the cells to a short period of shear stress at the same times after dilution. With both diluents, the cells underwent a rapid increase in volume followed by a return towards normal volume with a maximum at less than 250 msec. With IHP diluent, the period of hemoglobin permeability immediately followed the size peak and was completed by about 1 sec after dilution. PBS also induced a second leakage at longer times (10-120 sec), which resulted in a morphological dichotomy with ghosts and intact cells. The choice of diluent also affected sensitivity to shear stress. The IHP-treated cells had a mechanical fragility maximum at about 1 sec. The PBS-treated cells exhibited no enhanced mechanical fragility. An unexpected result was the inhibition of the second phase of lysis in PBS-treated cells by a properly timed shear stress.

Antibiotic granules for reconstitution as syrups: product uniformity and stability dependent upon reconstitution procedure

The penicillin content and stability of diluted antibiotic syrups, prepared according to the manufacturers' recommendations and other, non-approved, methods have been investigated. Methods which involve portioning the granules before reconstitution are hazardous and may result in preparations which range from very little antibiotic content to a double strength preparation. The choice of diluent controls the stability of the preparation. Phenoxymethylpenicillin syrups become less stable as the sucrose content increases. This is not always true with ampicillin syrups where the system is more complex. Although syrups prepared according to the manufacturers' instructions are not always the most stable, the effect of different diluents on the stability of syrups, especially suspensions, suggests that syrups should always be reconstituted and diluted according to the directions provided with the product.

Effects of endotracheally administered distilled water and normal saline on the arterial blood gases of dogs

The effects of endotracheally (ET) administered distilled water (DW) and normal saline solution (NSS) on the arterial blood gases of dogs were compared. When distilled water was administered endotracheally, arterial pH was depressed to 99.36% of baseline values within 5 minutes. When compared to pH changes following ET administration of NSS the depression of pH following DW administration was significant (P less than .05). Following ET injection of DW, arterial PO2 was depressed to 61% of baseline values and remained significantly depressed throughout the experiment. In comparison, following ET NSS administration, PO2 was depressed substantially less, and remained at significantly higher levels for the entire experiment. In dogs, administration of NSS by the ET route produces less detrimental effects on arterial blood gases than does the ET administration of DW. This may have implications for the choice of diluent for human drug administration using the ET route.

Effect of Formulation and Process Variables on Bioequivalency of Nitrofurantoin I: Preliminary Studies

Fifty-two combinations of nitrofurantoin were developed to assess the effect of dosage form type, particle size, diluent, and process on in vitro availability. With the official procedure and conditions, dissolution rates fell in a 66-fold range. Statistical analysis of the dissolution rates indicated no significant differences as a result of particle size, processing method, or compression force. The diluent choice and dosage form type significantly influenced the dissolution rate. Based on in vitro screening, six formulations presenting a broad range of dissolution rates were selected for further study relating to human bioavailability and bioequivalence.

Extraction of magnesium chloride from brines using mixed ionic extractants

Abstract Data are presented on the distribution of magnesium chloride between aqueous phases and solvents comprising various mixed ionic extractants involving equimolar mixtures of amines and carboxylic acids. Aliquat-336/acid-810 is shown to have promise for the extraction of magnesium chloride from bitterns. The co-extraction of sodium, calcium, sulphate and bromide ions is considered. The system is shown to be insensitive to changes in pH and temperature but the choice of diluent can have an appreciable effect.

Commercially prepared infant cereals: Nutritional considerations

Nutritional properties of infant dry cereals vary with the brand and variety of cereal and with the choice of diluent (formula, milk, or water). In a study of a group of 34 women, it was found that approximately 6 parts of diluent were mixed with one part (by weight) of dry cereal. Many dry cereals are relatively good sources of protein, iron, thiamin, niacin, and riboflavin. Wet-packed cereals with fruit generally provide fewer calories and less protein and iron per unit of weight than do dry cereals diluted with milk or formula.

EFFECT OF DILUENTS ON THE RECOVERY OF MICROOGANISMS FROM FOODS

Two aspects of the recovery of bacteria from foods were examined: a comparison of the effects of two diluents, phosphate-buffered dilution water and 0.1% peptone on the recovery of eight bacterial strains and the total counts; and the effect of these diluents on the recovery during a period of 1 hr. No marked superiority of either diluent in terms of initial recoveries or of protection over a 1-hr time period was noted. On the average, however, recovery was as good or better in 0.1% peptone as in phosphate-buffered dilution water; the choice of diluent, therefore, is slightly in favor of 0.1% peptone, which seemed to yield higher recovery on more samples.

Effects of ionic radius and organic diluents on the equilibrium phenomena of some lanthanide thiocyanate-TBP adducts

Adduct of lanthanide thiocyanates and tributyl phosphate (TBP) have been prepared by the action of TBP on solid thiocyanates and the resultant solutions examined by infrared spectroscopy to determine the stability constants of the adducts. Cyclohexane, carbon tetrachloride, and benzene were employed as diluents for the TBP. The results show a variation in the number of TBP molecules solvating the lanthanide thiocyanates and while a solvation number of 3–4 is observed for yttrium and the heavier lanthanides (i.e. erbium and dysprosium), 4–5 was obtained for the lighter lanthanides (i.e. lanthanum and cerium). The stability constants of the adducts K 3,4 and K 4,5 increase numerically with increasing ionic radius of the lanthanides and the magnitude of the individual stability constants depends on the choice of diluents. The order of stability constants with respect to the ionic radius is the opposite of that found for lanthanide complexes in aqueous solution. Where a single lanthanide thiocyanate-TBP species is present in solution, a splitting of the PO stretching band can be attributed to the presence of more than one ligand isomer and the relative amount of the two isomers appears to depend on the ionic radius of the central metal ion, the solvation number and the nature of the diluent employed.

Effects of salts and colloids on potency of botulinum toxin.

SummaryAttention is called to discrepancies arising in mouse assays of botulinum toxin when the method of dilution and choice of diluent are not standardized. As much as 50-fold variation in the toxicity determinations resulted from the use of various diluents in the preparation of the serial dilution. Explanations of some of the discrepancies are suggested.