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PubMed1992

Fat emulsion particle-size distribution in total nutrient admixtures.

The fat particle-size distribution in and physical stability of two commercially available lipid emulsions before and after their use in total nutrient admixtures (TNAs) are reported. Four TNAs without electrolytes and four TNAs with electrolytes were prepared; each type of TNA was prepared with Liposyn II and with Intralipid. Particle size was measured in the < 1-micron range by using photon correlation spectroscopy and in the 2-60-microns range by using light blockage. Admixtures with or without electrolytes were stored for two or nine days at 4 degrees C followed by one day at 25 degrees C. For the fraction of fat particles of < 1 micron in diameter, Intralipid and Liposyn II had a mean particle size of 374 and 313 nm, respectively. The admixtures containing electrolytes showed a decrease in mean particle size of about 7%. Admixtures with Intralipid contained 2 x 10(7) particles larger than 2 microns per milliliter (1.7% of total fat), compared with 1 x 10(6) particles per milliliter (0.05-0.15% of total fat) for admixtures with Liposyn II. The addition of electrolytes increased the particle counts for Liposyn II-containing admixtures. Upon storage, Intralipid-containing admixtures with electrolytes showed an initial increase followed by a decrease in the mean diameter of particles of < 1 micron. All the admixtures were stable in terms of pH and visual appearance. Intralipid-containing admixtures with electrolytes showed a decrease in the number of particles in the 2-60-microns size range, while Liposyn II-containing admixtures with electrolytes showed an increase.(ABSTRACT TRUNCATED AT 250 WORDS)

Drug Incompatibility↗

PubMed1990

Stability of ranitidine in intravenous admixtures stored frozen, refrigerated, and at room temperature.

The stability of ranitidine in concentrations of 0.5, 1.0, and 2.0 mg/mL in admixtures with commonly used i.v. fluids was studied. The admixture vehicles were 0.9% sodium chloride, 5% dextrose, 10% dextrose, 5% dextrose and 0.45% sodium chloride, and 5% dextrose with lactated Ringer's (DLR) injections in polyvinyl chloride bags. Three bags were prepared for each test solution and stored under each of the following conditions: seven days at room temperature (23 +/- 1 degrees C) in normal laboratory lighting, 30 days at 4 degrees C, and 60 days at -20 degrees C followed by either seven days at room temperature (in light) or 14 days at 4 degrees C. Ranitidine content was determined by high-performance liquid chromatography at several intervals. Color, clarity, and pH were also examined. Ranitidine concentrations remained greater than or equal to 90% of initial concentrations under all storage conditions except in the frozen DLR admixtures. Drug loss in the DLR admixtures was greatest at the lower ranitidine concentrations. The only visual changes were yellow color in the thawed DLR admixtures and those containing ranitidine 2.0 mg/mL in 5% dextrose and 0.45% sodium chloride. Slight increases in the pH of some admixtures were noted. Ranitidine is stable for seven days at room temperature and 30 days at 4 degrees C at all concentrations and in all vehicles studied. At the studied concentrations, the drug is stable in admixtures frozen for 60 days and stored for seven days at room temperature or 14 days refrigerated, except in DLR admixtures; these admixtures should not be stored frozen.

Drug Combinations↗

PubMed1991

Stability of amrinone and digoxin, procainamide hydrochloride, propranolol hydrochloride, sodium bicarbonate, potassium chloride, or verapamil hydrochloride in intravenous admixtures.

The stability of amrinone and digoxin, procainamide hydrochloride, propranolol hydrochloride, sodium bicarbonate, potassium chloride, or verapamil hydrochloride in intravenous admixtures was studied. Admixtures of amrinone and digoxin were studied at one concentration. Amrinone admixtures with propranolol hydrochloride, sodium bicarbonate, potassium chloride, and verapamil hydrochloride were studied at two concentrations. In general, 0.45% sodium chloride injection was used as the diluent; 5% dextrose injection was also used for the procainamide hydrochloride experiments. Duplicate solutions of each test admixture and single-drug control admixture were prepared and stored for four hours at 22-23 degrees C under fluorescent light. Samples were analyzed by visual inspection, tested for pH, and assayed by high-performance liquid chromatography. Admixtures containing amrinone 1.25 or 2.5 mg/mL (as the lactate salt) and sodium bicarbonate 37.5 mg/mL precipitated immediately or within 10 minutes. No changes in pH or visual appearance were noted for amrinone admixtures with procainamide hydrochloride, digoxin, propranolol hydrochloride, potassium chloride, and verapamil hydrochloride. Appreciable degradation of both amrinone and procainamide was observed after four hours when the two were mixed in 5% dextrose. No degradation of amrinone or procainamide was seen when the 5% dextrose was replaced by 0.45% sodium chloride. Amrinone and sodium bicarbonate were incompatible in intravenous admixtures. Amrinone was compatible with digoxin, propranolol hydrochloride, potassium chloride, and verapamil hydrochloride. Amrinone and procainamide were compatible in 0.45% sodium chloride injection but not in 5% dextrose injection.

Amrinone↗

PubMedDate not supplied

Emulsion stability in total nutrient admixtures containing a pediatric amino acid formulation.

Emulsion stability of total nutrient admixtures containing TrophAmine amino acid injection admixed with Intralipid, Nutrilipid, and Liposyn II was studied. High and low electrolyte concentrations were added to each total nutrient admixture before storage at 4 degrees C for 48 hours then at 20-22 degrees C for 24 hours. Stability studies were also performed on total nutrient admixtures containing higher concentrations of fat emulsion and total nutrient admixtures with added cysteine hydrochloride and carnitine. High electrolyte concentrations only were added to these total nutrient admixtures before being stored refrigerated for 24 hours then at room temperature for 24 hours. Visual assessment, pH determination, and particle size analysis were performed immediately after compounding and after refrigerated and room temperature storage. Particle size was assessed by measuring the mean diameter of the fat emulsion and the percent of oil volume in particles greater than 5 microns. Repeated-measures analyses of variance were used to determine significance of type or concentration of fat emulsion, electrolyte concentrations, or time on mean diameter or percent particles greater than 5 microns. There were minimal changes in pH values over time. Creaming was observed in all total nutrient admixtures at all sampling times except time zero. This was reversible upon agitation. Results of particle size analysis over time indicated little change in mean diameter or percent particles greater than 5 microns. These minimal changes did not seem to be clinically significant. It is concluded that total nutrient admixtures prepared with this pediatric amino acid formulation are stable when prepared and stored as reported.

Amino Acids↗

PubMed1976

Intropin (dopamine hydrochloride) intravenous admixture compatibility. Part 2: stability with some commonly used antibiotics in 5% dextrose injection.

The stability of dopamine hydrochloride (Intropin) and several commonly used antibiotics was studied as admixtures in 5% Dextrose Injection USP. The antibiotic-dopamine-dextrose 5% admixtures were assayed for dopamine by colorimetric and chromatographic procedures. The antibiotics were assayed by standard microbiological methods. Kanamycin sulfate, tetracycline hydrochloride, carbenicillin disodium and chloramphenicol sodium succinate were stable in the Intropin-5% dextrose admixture for a period of 24 hours at room temperature in fluorescent and natural (western exposure) light. Gentamicin sulfate, penicillin G potassium and cephalothin sodium were stable in Intropin-5% dextrose admixture for six hours. Ampicillin sodium was stable in the Intropin admixture for only one hour. Amphotericin B was physically unstable in the Intropin-dextrose 5% solution upon admixture. The potency of dopamine hydrochloride remained substantially unchanged in the presence of the above antibiotics. It is recommended that dopamine not be added to amphotericin B or ampicillin sodium admixtures. Further, in order to avoid a fixed combination of potent drugs, it is recommended that a "piggyback" administration set or administration into a second injection site be employed when another drug is to be administered with dopamine hydrochloride.

Anti-Bacterial Agents↗

PubMed1992

The magnitude and origin of European-American admixture in the Gila River Indian Community of Arizona: a union of genetics and demography.

Complementary genetic and demographic analyses estimate the total proportion of European-American admixture in the Gila River Indian Community and trace its mode of entry. Among the 9,616 residents in the sample, 2,015 persons claim only partial Native American heritage. A procedure employing 23 alleles or haplotypes at eight loci was used to estimate the proportion of European-American admixture, m(a), for the entire sample and within six categories of Caucasian admixture calculated from demographic data, md. The genetic analysis gave an estimate of total European-American admixture in the community of 0.054 (95% confidence interval [CI] .044-.063), while an estimate from demographic records was similar, .059. Regression of m(a) on md yielded a fitted line m(a) = .922md, r = .959 (P = .0001). When total European-American admixture is partitioned between the contributing populations, Mexican-Americans have provided .671, European-Americans .305, and African-Americans .023. These results are discussed within the context of the ethnic composition of the Gila River Indian Community, the assumptions underlying the methods, and the potential that demographic data have for enriching genetic measurements of human admixture. It is concluded that, despite the severe assumptions of the mathematical methods, accurate, reliable estimates of genetic admixture are possible from allele and haplotype frequencies, even when there is little demographic information for the population.

Alleles↗

PubMed1990

Stability of total nutrient admixtures in a dual-chamber flexible container.

The stability of total nutrient admixtures (TNAs) prepared from dextrose and amino acid injections commercially packaged in a dual-chamber container and a safflower-soybean oil fat emulsion was studied. The admixtures studied were divided into two groups. Group 1 admixtures represented 14 combinations of Aminosyn II, dextrose, and Liposyn II. Group 2 admixtures represented 10 combinations of Aminosyn II with Electrolytes, dextrose, and Liposyn II. Amino acid concentrations of 7, 8.5, and 10%, dextrose concentrations of 10, 20, 40, and 50%, and 10 and 20% fat emulsion were used. After the amino acid and dextrose injections were mixed in their original container (Nutrimix, Abbott Laboratories), the fat emulsion was added. One of two combinations of electrolytes and trace metals was then added. Multivitamins were added to each TNA just before 24-hour storage at room temperature (25 +/- 4 degrees C). Admixtures were tested initially and at the conclusion of storage periods of 24 hours at room temperature or nine days at 5 degrees C followed by 24 hours at room temperature. Measurements of pH, emulsion particle size, and weight percent of oil particles larger than 5 microns in diameter (HIAC) were made after visual inspection of each admixture. In selected admixtures, concentrations of individual amino acids and dextrose were determined by chromatographic techniques initially and at the conclusion of storage. The TNAs retained a uniform milk-like appearance throughout both storage periods. The pH values, particle size, HIAC measurements, and amino acid and dextrose concentrations remained essentially unchanged.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗

PubMed1979

Compounding times and contamination rates associated with the preparation of intravenous admixtures in three types of plastic containers.

The compounding times and contamination rates associated with the preparation of admixtures in three different plastic i.v. containers of dextrose 5% in water were compared. The time required for a technician to prepare, in a laminar air flow hood by the needle and syringe technique, 120 admixtures in each of three different plastic i.v. containers was measured and recorded by two investigators. The 360 admixtures were tested within one hour of preparation for sterility using an enriched brain heart infusion broth. The total time required to compound the i.v. admixtures varied significantly with container design (p less than 0.01), preparation being fastest with the Accumed container, followed by the LifeCare then the Viaflex containers. The major contributing factors to increased compounding time were (1) removal of outer wrap, (2) swabbing of LifeCare and Viaflex medication ports with isopropyl alcohol pads and (3) freeing of the hangar flap from the Viaflex container. Sterility tests revealed no detectable contamination of any of the admixtures. Container design of plastic i.v. containers did influence the preparation time for admixtures but did not influence admixture sterility.

Drug Combinations↗

PubMed1979

Adventitious contamination of intravenous admixtures during sterility testing.

The extent to which contamination of intravenous fluids measured by inhospital sterility-testing may be due to adventitious contamination (i.e., contamination introduced during the sterility-testing procedure) was studied. All one-liter admixtures prepared during a three-day period in a busy centralized i.v. admixture service were studied. Samples of i.v. admixtures were cultured before and after administration by direct ioculation or by culturing the membrane through which the admixture was filtered. Samples of similarly cultured large-volume parenterals served as controls. Contamination rates for control and admixture samples were not significantly different (p = 0.23). Of 10 control and test (admixture) solutions showing contamination before administration, only one test solution again showed contamination after administration but this was with a different microbe. The results suggest that adventitious contamination during sampling/culturing procedures is a component of, and possibly a dominant factor in, the contamination rates detected by inhospital sterility tests. Combined with infection surveillance, sterility tests may be of value when infections are possibly related to admixture contamination.

Bacteria↗

PubMed1975

Intropin (dopamine hydrochloride) intravenous admixture compatibility. Part 1: stability with common intravenous fluids.

The stability of dopamine hydrochloride (Intropin) in several large-volume parenteral solutions was studied. Admixtures of dopamine were assayed by colorimetric and chromatographic procedures. Admixtures (800 mug dopamine per ml) in the following intravenous fluids in glass bottles at pH 6.85 or below were found to be chemically and physically stable for at least 48 hours at room temperature: dextrose 5%, dextrose 5% and sodium chloride 0.9%, 5% dextrose in 0.45% sodium chloride, dextrose 5% in lactated Ringer's solution, lactated Ringer's injection, 0.9% sodium chloride, 1/6 molar sodium lactate, and 20% mannitol. The admixture of dopamine in 5% dextrose was stable for a minimum of seven days at 5 C. A 5% dextrose-dopamine admixture in a polyvinylchloride bag was stable for at least 24 hours at room temperature. The admixture of dopamine in 5% sodium bicarbonate solution produced an unstable solution of pH 8.20. A chemical and physical change (development of a pink color) was observed in this admixture. It is recommended that dopamine not be added to 5% sodium bicarbonate solution or any alkaline intravenous solution.

Chemical Phenomena↗

PubMed1979

Assuring the quality of intravenous admixture programs.

Several aspects of quality assurance (QA) methods in i.v. admixture programs are discussed, and a basic framework for developing QA programs for admixture services is presented. The objective of QA is to insure that admixture products: (1) are therapeutically and pharmaceutically appropriate to the patient; (2) are free from microbial and pyrogenic contaminants; (3) are free from undesirable levels of particulate or toxic contaminants; (4) contain drugs in correct amounts; and (5) are labeled, stored and distributed under principles of good drug control. Three types of QA criteria bases which may be used as indicators of quality are discussed (resources, facilities and organization; required procedures; end-products or results). Because end-product monitoring has certain limitations in the admixture setting, QA must rely heavily on procedure-centered review methods. General guidelines for developing QA programs are outlined. Adherence to procedure is the key to assuring the quality of admixture products. In developing a QA program, the highest priority should be given to the education and training of admixture personnel, particularly with respect to aseptic technique and pharmaceutical calculations.

Drug Combinations↗

PubMed2025

Nested Admixture During and After the Trans-Atlantic Slave Trade on the Island of São Tomé.

Human genetic admixture, involving the contact between two or more previously isolated populations, can be a complex process influenced by social dynamics. In this study, we aim to reconstruct complex admixture histories in São Tomé, an island in the Gulf of Guinea where the Portuguese established one of the first plantation-based slave societies. Since the 15th century, migration waves from Africa and Europe, slavery, marooning, and indentured labour led to profound demographic shifts and social stratification on the island. Examining 2.5 million SNPs newly genotyped in 96 São Toméans, we observed patterns of genetic differentiation that were more complex than those of other populations descended from enslaved Africans on either side of the Atlantic. Using local ancestry inference and Identical-by-Descent methods, we identified five genetic clusters in São Tomé and reconstructed shared ancestries between each cluster and 70 African and European population samples, including an extensive sample from the Cabo Verde archipelago. Our findings align with historical records, retracing the major slave trade routes and labour-driven migrations after the abolition of slavery. We also identified gene flow between recently admixed groups that were previously isolated on the island. We call this process, creating multiple layers of genetic ancestry in admixed genomes, nested admixture. We suggest that changing social structures in São Tomé transformed the genetic structure of its population and influenced the admixture process. This study demonstrates how successive admixture and isolation events during and after the Trans-Atlantic Slave Trade shaped extant genetic diversity patterns at local scale in Africa.

Humans↗

PubMed1991

The effects of admixture and population subdivision on cytonuclear disequilibria.

We examine the generation of cytonuclear disequilibria by admixture and continued gene flow. General formulas analogous to the nuclear case are first derived showing that the allelic and genotypic disequilibria from admixture or population subdivision equal their expected value across the contributing (sub) populations plus the covariance across these sources between the cytoplasmic gene frequency and the relevant nuclear frequency. A detailed study is then presented of the cytonuclear dynamics, in a random-mating population under two different migration scenarios. In both cases closed-form solutions are given for all variables as a function of the initial conditions and relevant migration parameters. The dynamics of the gene frequencies and allelic disequilibria, which dominate each system, are the same as those involving two unlinked nuclear loci, while the dynamics of the genotypic disequilibria and cytonuclear frequencies have no nuclear counterpart. The continent-island formulation focuses on a population receiving continued immigration from a large source of constant composition. A major discovery is that cytonuclear disequilibria can transiently build up on the "island" to levels far exceeding those found at equilibrium. In contrast, the admixture formulation focuses on the dynamics within two populations undergoing continued intermigration. Although in this case all cytonuclear associations must ultimately decay to zero, long-term transient disequilibria can develop which are many times their initial admixture values. For both migration scenarios it is shown that the time of population censusing relative to migration and reproduction dramatically affects both the amount and pattern of the nonrandom associations produced. The empirical relevance of these models is discussed in light of nuclear-mitochondrial data from a hybrid zone between European and North American eels and from a zone of racial admixture in humans.

Alleles↗

PubMed1990

Time-motion study of intravenous ranitidine admixtures.

This study determined the total preparation time, cost, and contamination rate associated with preparing 50-mL admixtures of ranitidine 50 mg from each of the following commercial source vials: 50 mg/2 mL unit-dose vial (treatment A), 50 mg/2 mL 10 mL multidose vial (treatment B), and 50 mg/2 mL 40 mL multidose vial (treatment C). The study consisted of two separate phases: phase I extemporaneous compounding and phase II batch manufacturing. Twelve technicians prepared ten admixtures from each source vial during each phase. All admixtures were tested for sterility; bacterial contamination was not observed. Multidose vials saved approximately $197 per 200 admixtures. Drug and personnel costs were reduced when batch manufacturing with 40-mL multidose vials was compared with extemporaneous compounding with unit-dose vials. Our study showed that multidose vials decreased the total preparation time and cost for making ranitidine admixtures during both extemporaneous compounding and batch manufacturing by reducing setup time, preparation time, and drug procurement cost.

Drug Compounding↗

PubMed1991

Parenteral nutrient admixtures as drug vehicles: theory and practice in the critical care setting.

Parenteral nutrient (PN) admixtures are the most complex, extemporaneously compounded formulations routinely prepared for hospitalized and home-based patients. In addition, drugs are added with increasing frequency to PN admixtures, thus presenting even greater physicochemical challenges to this highly complex pharmaceutical product. The continuous infusion of selected drugs may provide pharmacokinetic and therapeutic advantages over conventional, intermittent, bolus methods of administration. Fluid conservation, cost savings, and a possible decrease in the risk of infection through reduced catheter manipulation and simplification of therapy provide additional incentives to consider the use of PN admixtures. The many advantages of PN admixtures make them an attractive approach to cost-effective care, with special clinical benefits achieved in the critical care setting. This article reviews our clinical experience using PN admixtures as drug vehicles for selected drugs and presents some theoretical as well as actual benefits associated with this practice.

Aminophylline↗

PubMed1990

Osmolality of small-volume i.v. admixtures for pediatric patients.

The osmolalities of pediatric i.v. admixtures were measured to identify drug concentrations in selected vehicles that would conserve fluid while maintaining osmolality values of 400 mOsm/kg or less. Test solutions were prepared by diluting appropriate volumes of freshly reconstituted powdered drug products or commercially diluted drug products with 5% dextrose injection, 0.9% sodium chloride injection, or both to provide 5 mL of each admixture at desired drug concentrations. To reduce their osmolalities, trimethoprim-sulfamethoxazole and ampicillin sodium were also diluted in 0.45% sodium chloride injection; ticarcillin disodium was diluted only in 0.45% sodium chloride injection. A vapor pressure osmometer was used to measure osmolalities in triplicate for three solutions prepared for each admixture. Of the 63 different admixtures prepared with 5% dextrose injection or 0.9% sodium chloride injection or both, 47 (75%) had osmolalities of 400 mOsm/kg or less. At least one concentration of each selected drug diluted in these vehicles had an osmolality of less than 425 mOsm/kg, except for trimethoprim-sulfamethoxazole and ampicillin sodium. Selected concentrations of the latter two drugs and ticarcillin disodium in 0.45% sodium chloride injection resulted in acceptable osmolalities. For most drugs diluted to the same concentration in 5% dextrose injection and 0.9% sodium chloride injection, osmolalities were lower in the dextrose solutions. Selection of an appropriate vehicle and drug concentration can control the osmolality of i.v. admixtures when the volume of fluid must be minimized, as for pediatric patients.

Anti-Bacterial Agents↗

PubMed2026

Statistical test to compare the linkage model and the admixture model based on central limit results.

In the Admixture Model, the probability that an individual carries a certain allele at a specific marker depends on the allele frequencies in K ancestral populations and the proportion of the individual's genome originating from these populations. The markers are assumed to be independent. The Linkage Model is a Hidden Markov Model that extends the Admixture Model by incorporating linkage between neighboring loci. We prove consistency and asymptotic normality of maximum likelihood estimators for the ancestry of individuals in the Linkage Model, complementing earlier results by (Pfaff et al., 2004; Pfaffelhuber and Rohde, 2022; Heinzel, 2025) for the Admixture Model. These results are used to prove that a statistical test that allows for model selection between the Admixture Model and the Linkage Model is an asymptotic level-α-test. Finally, we demonstrate the practical relevance of our results by applying the test to real-world data from The 1000 Genomes Project Consortium (2015).

Genetic Linkage↗

PubMed2025

Sex-Biased Admixture Followed by Isolation and Adaptive Evolution Shaped the Genomic and Blood Pressure Diversity of the LopNur People.

The LopNur people are an ethnic group living on the edge of the Taklamakan Desert, and they are believed to demonstrate a unique genetic makeup due to their isolation and limited contact with neighboring populations. However, a lack of genetic studies on the LopNur people has resulted in limited knowledge about their ancestral origins and demographic history. Here, we conducted the first whole-genome sequencing study of 164 LopNur individuals (LOP) to gain insight into their genetic history and adaptive evolution in an isolated desert area. Our analysis revealed that the present-day LOP have experienced a complex history of admixture followed by long-term isolation, with their ancestry derived from East Asia (∼41.46%), West Eurasia (∼26.43%), Siberia (∼24.27%), and South Asia (∼7.82%). Notably, a remarkable sex-biased admixture occurred between Western males and Eastern females. In addition to complex admixture followed by long-term geographic isolation and further recent migrations, adaptive evolution jointly formed the gene pool and phenotypic diversity of the present-day LOP. Intriguingly, our analysis suggests that the USP35-GAB2 region may be correlated with blood pressure in LOP, based on a joint analysis of genomics and blood pressure data. Moreover, we identified two variants, rs7387065, and rs2229437, located on CSMD1 and PRCP, respectively. These variants exhibited frequency differences between Asian and European populations and were reported to be associated with antihypertensive drug absorption. Our results provide new insight into the complex history of the LOP, an admixed and isolated ethnic group residing at the crossroads of East and West, a case with ancient admixture, long-term isolation, adaptive evolution, and sex-biased gene flow.

Female↗