Predictors for the prescription of albuterol in infants hospitalized for viral bronchiolitis.

INTRODUCTION AND OBJECTIVES: Despite the recommendation against routine use of inhaled bronchodilators in infants with viral bronchiolitis given in the main clinical practice guidelines (CPGs) on viral bronchiolitis, albuterol is widely prescribed to patients with this disease. The aim of this study was to identify predictors of prescription of albuterol in a population of infants hospitalized for viral bronchiolitis. MATERIAL AND METHODS: An analytical cross-sectional study performed during the period from March 2014 to August 2015, in a random sample of patients <2 years old hospitalized in the Fundacion Hospital La Misericordia, a hospital located in Bogota, Colombia. After reviewing the electronic medical records, we collected demographic, clinical, and disease-related information, including prescription of albuterol at any time during the course of hospitalization as the outcome variable. RESULTS: For a total of 1365 study participants, 1042 (76.3%) were prescribed with albuterol therapy. After controlling for potential confounders, it was found that age (OR 1.11; CI 95% 1.08-1.15; p<0.001), and a prolonged length of stay (LOS) (OR 1.93; CI 95% 1.44-2.60; p<0.001) were independent predictors of prescription of albuterol in our sample of patients. By contrast, albuterol prescription was less likely in the post-guideline assessment period (OR 0.41; CI 95% 0.31-0.54; p<0.001), and in infants with RSV isolation (OR 0.71; CI 95% 0.52-0.97; p=0.035). CONCLUSIONS: Albuterol was highly prescribed in our population of inpatients with the disease. The independent predictors of prescription of albuterol in our sample of patients were age, implementation of a CPG on viral bronchiolitis, RSV isolation, and LOS.

Determination of albuterol sulfate and its related substances in albuterol sulfate inhalation solution, 0.5% by RP-HPLC.

An isocratic reversed-phase high performance liquid chromatographic (RP-HPLC) method has been developed and validated for the determination of albuterol sulfate and six of its related substances in albuterol sulfate inhalation solution, 0.5% (w/v). The separation was achieved using a YMC phenyl column (250 mm x 4.6 mm ID, 5 microm fitted with a direct connect YMC phenyl guard column (20 mm x 4 mm ID) maintained at ambient conditions, and a mobile phase of 25 mM monobasic potassium phosphate (pH 3.0) and methanol (95:5, v/v). The mobile phase flow rate was 1.5 mL/min and the detection wavelength was 225 nm. Albuterol is quantitated versus an external standard. The method was capable of resolving six of the seven known albuterol-related substances. Bis-ether albuterol, a drug substance process related impurity, is retained on the column due to its different hydrophilic character. The related substances are determined by area percent. However, a correction factor of 1.6 is applied for the determination of albuterol aldehyde, a potential impurity and a degradation product, since its molar absorptivity is about 1.6 times that of albuterol. The limits of detection and quantitation for albuterol and six of its related substances ranged between 0.01 and 0.21% of the assay concentration of 0.3 mg/mL as albuterol base. The method was found to be linear for albuterol over the range of 50-150% of the active label claim. The method was also found to be linear for the six related substances over the range 0.05-0.5%. No interferences from the blank, placebo (formulation matrix), related substances or force-degraded placebo samples were observed for the determination of the active or the individual related substances. The method was found to be accurate, precise, linear, specific, sensitive, rugged, robust, and stability-indicating.

Validation of a chiral HPLC assay for (R)-salbutamol sulfate.

A fast, reliable and specific method for the screening, confirmation, determination and quantitation of salbutamol enantiomers was developed and validated. The described procedure includes a single robust chiral HPLC determination employing a Teicoplanin stationary phase. The method was evaluated for specificity, robustness, linearity, precision and accuracy. Under the chromatographic conditions of the method, known impurities were separated from the active principle.

LC-MS method for the determination of albuterol enantiomers in human plasma using manual solid-phase extraction and a non-deuterated internal standard.

A sensitive enantioselective liquid chromatography-mass spectrometry (LC-MS) assay using a manual solid-phase extraction (SPE) procedure, a non-deuterated internal standard and an ion trap LC-MS was developed to measure (R)- and (S)-albuterol in plasma. Sample extraction from plasma was achieved by a manual SPE extraction procedure with methoxyphenamine added as the internal standard. Chiral separation was achieved using a teicoplanin-based stationary phase and a mobile phase consisting of methanol, acetic acid and 28% (w/v) ammonia (1000:5:1, v/v/v). Samples were analyzed by selected reaction monitoring of product ions from the protonated molecular ions. The detection limit of the assay was 0.1 ng/ml with a conservative lower limit of quantification of 0.25 ng/ml for each enantiomer. Recovery of albuterol enantiomers from plasma spiked at 10 ng/ml of racemate was determined to be 89+/-5.8% (mean+/-S.D.). Reproducibility at 10 ng/ml of racemate assessed by the coefficient of variation was found to be 6.5% (n=5). Instrument precision (measured as coefficient of variation) was 1.4% (n=5). The correlation coefficient r(2) determined from the calibration curve over the range 0.5-50.0 ng/ml racemate in plasma was 0.998. This assay allows adequate sensitivity, recovery and reproducibility for the application to studies of inhaled albuterol.

Principles for different modes of multiple-injection CZE.

This paper introduces four different modes of multiple-injection CZE (MICZE). The validity of these MICZE models was evaluated by the experimental data. Prior to the application of MICZE, the electrophoretic conditions are developed in the single-injection mode by adjusting different experimental parameters such as pH, type and concentration of buffer additives and temperature. Based on the migration time difference (Deltatmig) between the analyte and the internal standard or injection marker, one or more MICZE modes can be employed. The injection marker is added to the sample to compensate for injection-volume fluctuations. The inter-plug distance is regulated by applying an electrical field over the capillary for a short period of time between each injection. After the final injection, the separation is completed by electrophoresis for a time period corresponding to that in the single-injection mode.

Thermal analysis of trace levels of polymorphic impurity in salmeterol xinafoate samples.

PURPOSE: To quantify trace levels of polymorphic impurity in two salmeterol xinafoate (SX) Form I samples: granular SX (GSX) produced by fast-cooling crystallization and micronized SX (MSX) prepared from GSX by micronization. METHODS: SX-I and SX-II produced by solution enhanced dispersion by supercritical fluids (SEDS) were the reference polymorphs (100% pure) used for quantitative comparison. The percentage of polymorphic conversion, alpha, of each Form I sample to Form II was measured by differential scanning calorimetry (DSC) as a function of time (i.e., at different scanning speeds). The data were analyzed by the Avrami-Erofe'ev (AE) equation using an iterative fitting computer program. SX-I samples containing 1.24, 4.41, and 13.47% (w/w) of SX-II as physical mixtures were subjected to similar analysis and data treatment. A mathematical relationship based on an instantaneous nucleation model was derived to relate the AE rate constants, k, of pure SX-I and physical mixtures to weight percentage of SX-II. This relationship was then used to calculate the percentage polymorphic impurity of GSX and MSX from their k values. For relative comparison of the Form-II nuclei present, the k values of SX-I, GSX, and MSX were used to calculate their differences in free energy of nucleation. RESULTS: The AE equation affords good (r2 approximately equal to 0.81) to excellent (r2 approximately equal to 0.99) fits of data for the samples. The levels of polymorphic impurity in GSX and MSX are 0.16 and 0.62% (w/w), respectively. Based on the free energy differences of nucleation between the reference SX-I material and the other samples, the number (and size) of the Form II nuclei present in the samples rank in the order: MSX > GSX > SX-I. CONCLUSIONS: DSC is a useful tool for assessing the polymorphic purity of SX materials and possibly other enantiotropic pairs showing similar thermal behavior.

Safety and efficacy of salbutamol aerosol on Dermatophagoides farinae induced bronchospasm in asthmatic patients.

The effects of inhaled salbutamol in bronchial provocation with inhaled house dust mite allergen (HDM) were studied in 20 adult subjects with bronchial asthma and positive skin test to the allergen. There was a significant association between the skin test and the outcome of bronchial challenge, although the magnitude of the skin test reactivity was not significantly correlated with the degree of bronchial reactivity. Metered dose inhaler administration of salbutamol (200 gamma total) was started after antigen produced a fall in mean FEV1 to 31%. Salbutamol treatment returned the FEV1 within 5 min to 66%, and within 45 min to 91% of baseline in all but one patient. It appears that in most asthmatics inhaled salbutamol does significantly and immediately reverse HDM-induced bronchospasm.

Determination of the enantiomers of albuterol in human and canine plasma by enantioselective high-performance liquid chromatography on a teicoplanin-based chiral stationary phase.

A sensitive enantioselective high-performance chromatographic (HPLC) method was developed validated to determine low levels of (-)-R and (+)-S-albuterol in plasma. Baseline resolution was achieved by using a teicoplanin-based chiral stationary phase with a polar organic mobile phase consisting of methanol/ acetonitrile/glacial acetic acid/diethylamine, 40:60:0.3:0.2, (v/v/v/v) and a flow-rate of 1.0 ml/min. Enantioselectivity (alpha) equaled 1.18 and resolution (RS) equaled 1.8. By using fluorescence detection maximized at 230 and 310 nm for excitation and emission, respectively, concentrations of each enantiomer could be measured down to 125 pg/ml from a 1-ml plasma sample. Initially, the method was applied to plasma samples from a small single-dose inhalation study of racemic albuterol in a human volunteer and, later, to in vivo samples from a canine inhalation study of the single enantiomer, (-)-R-albuterol. Results from the canine study showed that no chiral inversion of (-)-R-albuterol occurs in the dog.

Evaluation of procaterol and albuterol (salbutamol) aerosol in the treatment of asthma.

Procaterol aerosol (10 micrograms/inhalation) was compared to albuterol (salbutamol) aerosol (100 micrograms/inhalation), two inhalations t.i.d. or q.i.d., in 333 outpatients with reversible bronchial airway obstruction over a 12-week period in a double-blind randomized and parallel study. Predose and postdose pulmonary function tests (PFTs) were performed initially and after 2, 4, 8, and 12 weeks of therapy. Patients maintained a daily diary of asthma symptom scores. A significantly higher percentage of patients receiving procaterol (59%) continued therapy on a t.i.d. schedule rather than a q.i.d. schedule compared with patients receiving albuterol (48%, P less than .05). Pulmonary function tests indicated similar improvement in both groups. Clinically significant improvement in mean FEV1 was maintained for four to seven hours postdose for procaterol and for three to six hours for albuterol. Adverse experiences were reported in 15% of procaterol-treated patients and 17% of albuterol-treated patients. Headache and tremor were most frequent, with no significant differences in frequencies between groups. Both procaterol and albuterol were highly effective in improving pulmonary function and controlling symptoms of asthma; both were well tolerated. Procaterol had a longer duration of action, and more patients were controlled on a t.i.d. dosage regimen.

Analysis of salbutamol and related impurities by derivative spectrometry.

Ultraviolet derivative spectrometry has been proposed for the analysis of salbutamol and related impurities. The assay of salbutamol aldehyde, 5-formyl-saligenin, and salbutamol ketone was performed in sodium hydroxide 0.1 mol/l solutions, using first and second derivative spectra. The method has been applied for the assay of related impurities of commercial samples of salbutamol sulfate.

Generic substitution: issues for problematic drugs.

The methodology and criteria for bioequivalence testing have been firmly established by the Food and Drug Administration (FDA). For certain drugs with a narrow therapeutic index (e.g., digoxin, levothyroxine, warfarin), generic substitution may not be advisable or even allowable, depending on the substitution laws of individual states. Digoxin and levothyroxine tablets are examples of drugs for which no New Drug Applications (NDAs) currently exist. However, commercially available generic products for both of these drugs have not been determined by the FDA to be therapeutically equivalent to the innovator products. Generic versions of warfarin have been approved by the FDA as being therapeutically equivalent to the innovator products, as have generic versions of the rescue inhaler albuterol. Yet, misinformation and myths persist regarding the adequacy and proven reliability of the FDA's determination of bioequivalence for these products.

Estabilidad del sulfato de salbutamol inyectable: parte III / Stability of injectable salbutamol sulfate: part III

Se describen los resultados obtenidos en el estudio cinético del sulfato de salbutamol inyectable empleando como antioxidante la tiourea. Se destaca la importancia del tipo de envase empleado en cuanto al incremento de la estabilidad del producto de acuerdo con la predicción de vida útil obtenida para la formulación inyectable