Hypertonic saline cough provocation test with salbutamol pre-treatment: evidence for sensorineural dysfunction in asthma.

BACKGROUND: Cough is one of the most common symptoms of asthma. However, studies using capsaicin, citric acid, or tartaric acid to document cough threshold have repeatedly failed to show statistically significant differences between asthmatic and healthy subjects. The studies using hypertonic aerosols as the cough stimulant have suggested an enhanced sensitivity in asthmatic subjects but the induced bronchoconstriction has made the interpretation of the results difficult. OBJECTIVE: To determine the cough sensitivity to hypertonicity in healthy subjects, patients with chronic cough, and patients with asthma in a setting where the induction of bronchoconstriction is prevented. METHODS: Nineteen healthy subjects, 21 non-asthmatic patients with chronic cough, and 26 asthmatic patients with chronic cough underwent an incremental hypertonic saline challenge including a pre-treatment with 0.4 mg of salbutamol. Spirometry was performed before the challenge, after salbutamol, and after the challenge. The patients with cough also underwent skin testing, histamine challenge, exhaled nitric oxide measurement, ambulatory peak flow monitoring, kept cough diary, and filled in the Leicester Cough Questionnaire. Eighteen patients repeated the saline challenge. RESULTS: The challenge did not induce bronchoconstriction in any group. The osmolality to provoke 15 cumulative coughs was significantly smaller in the asthmatic patients than in the healthy subjects (P<0.001) and in the cough patients without asthma (P=0.04). According to multivariate analysis among all the 47 patients with cough, female sex (P<0.001) and large spontaneous peak flow variation in the ambulatory recording (P=0.001) were associated with high sensitivity to saline. The saline challenge response was well repeatable (intraclass correlation coefficient 0.90). CONCLUSION: The findings of the present study are not affected by induced bronchoconstriction. Asthma or, more specifically, spontaneous, reversible airway obstruction is associated with an enhanced sensitivity to the cough-provoking effect of hypertonic saline. This suggests a pathological function of the sensorineural apparatus in this disorder.

Nifedipine capsules may provide a viable alternative to oral powders for paediatric patients.

BACKGROUND AND OBJECTIVE: To compare content uniformities between different sizes of extemporaneously compounded nifedipine oral powders and capsules, in order to find out if capsules could be used instead of oral powders as paediatric medications. METHODS: Actual content and content uniformity of extemporaneously compounded 1-mg nifedipine oral powders and capsules were evaluated by a high performance liquid chromatographic assay. Capsules and powders were prepared by triturating 10-mg nifedipine tablets with different amounts of lactose or microcrystalline cellulose with a mortar and pestle using a standard geometric dilution technique. Oral powders were weighed individually and capsules were filled by a hand-operated capsule-filling machine. Four different sizes of powders (500, 300, 100 and 50 mg) and three different sizes of capsules (numbers 1, 3 and 4) were prepared. Ten oral powders and 10 capsules from each batch were randomly selected and individually assayed for nifedipine amount. RESULTS AND DISCUSSION: The extemporaneously prepared nifedipine oral powders and capsules were within acceptable limits for content uniformity, as defined by the European Pharmacopoeia, but the results indicate that the loss of nifedipine during the preparation process may be considerable for both preparations. The concentration on nifedipine decreased while the total mass of the oral powder decreased. These results demonstrate that nifedipine oral powders can be replaced by capsules, whose contents are emptied for use, in paediatric medications. Compounding small capsules, such as size number 3 or 4, is acceptable when considering the average drug content. The total weight of the oral powder should be at least 300 mg. CONCLUSION: The preparation of nifedipine in all studied capsule sizes was safe with either lactose monohydrate or microcrystalline cellulose as excipients. Thus, emptied capsules seem to be a good choice for delivering a paediatric medication. The loss of nifedipine was considerable in oral powders with low total weight.

Enteral suspension of nifedipine for neonates. Part 1. Formulation of nifedipine suspension for hospital use.

OBJECTIVE: To formulate an oral suspension of nifedipine for paediatric use and to assess its content uniformity as well as the microbiological and physical stabilities of the hypromellose solution that was used in the formulation. METHOD: Six concentrations (0.5-3.0%) of hypromellose colloids and water as a blank were compounded with nifedipine, both as a powder and as crushed tablets, to a concentration of 1 mg/mL. Four different screening tests were used to find the most homogenous and dose-accurate combination. First, nifedipine suspensions were stored in vials for one month and visual homogenity of the redispersed suspensions was observed. Second, the homogenity of the suspensions was studied by measuring the nifedipine concentration from upper, middle and lower parts of the redispersed suspension. Next, the nifedipine concentration was measured from the suspensions immediately, 1 min and 2 min after shaking to ensure dose accuracy during the administration period. Finally, suspensions were packaged into oral disposable syringes and nifedipine concentrations were determined after one month of storage. Content uniformity of the packaged single-dose syringe suspensions was studied according to a method established by the European Pharmacopoeia. Microbiological stability, density, pH, osmolality, viscosity and surface tension of the hypromellose solution were studied over a 12-month storage period. RESULTS: From the results of the screening tests of hypromellose solution, 1.0% hypromellose was chosen as the vehicle for nifedipine enteral suspensions, made from both crushed tablets and nifedipine powder. Nifedipine suspensions made from hypromellose 1.0% were easiest to redisperse as a homogenous solution, and it also appeared best on visual inspection. The content uniformity of the suspension complied with the test recommended by the European Pharmacopoeia. The 1.0% hypromellose solution was found to be microbiologically stable for 6 months and physically stable for 12 months.

Enteral suspension of nifedipine for neonates. Part 2. Stability of an extemporaneously compounded nifedipine suspension.

OBJECTIVE: To investigate the chemical, microbiological and physical stability of an extemporaneously prepared nifedipine oral suspension, packaged in disposable syringes and prepared in a hospital pharmacy for paediatric use. METHODS: Two different suspensions were prepared, from nifedipine tablets and drug powder, by using an autoclaved 1.0% solution of hypromellose as the vehicle. The final theoretical drug concentration was 1 mg/mL. Doses of 1.0 ml were packaged into a 2 ml syringe with a cap. Nifedipine suspensions were stored under three conditions: at room temperature (22 degrees C), in a refrigerator (6 degrees C) protected from light, and at room temperature (22 degrees C) exposed to artificial daylight (400 lux) under controlled circumstances. The nifedipine concentration was measured in suspensions protected from light on days 0, 1, 3, 5, 7, 14, 21 and 28, and in suspensions exposed to light at 0, 3, 6, 18 and 24 h, and on days 2, 3, 5 and 7 after preparation. Nifedipine was analysed by a reproducible and validated stability-indicating HPLC-method. Microbiological and physical stability of the nifedipine suspension samples protected from light were examined for 28 days. RESULTS: Mean nifedipine concentration remained over 90% of the initial concentration throughout the 4-week study period in light-protected unit-dose suspensions, prepared from either crushed tablets or drug powder with hypromellose 1.0%. When exposed to light, however, nifedipine decomposed rapidly. Photodegradation of nifedipine exceeded 25% within 3 h and was essentially complete within 7 days. CONCLUSION: In the University Hospital of Kuopio, newborns have been treated with nifedipine suspension prepared from tablets, and preliminary experiences with administration of suspension have been encouraging. It may also be possible to apply this methodology to other medicines used in paediatrics.

The effect of prophylactic use of famotidine, ranitidine, and sodium citrate in upper abdominal surgery.

The effects of famotidine (40 mg), ranitidine (300 mg) and sodium citrate (30 ml) on the gastric pH and volume were tested in 114 patients undergoing upper abdominal surgery. Gastric content was aspirated through a multiorifice tube immediately after intubation, at the end of operation and after a recovery room period of one hour. All three drug regimens significantly increased the mean gastric pH value compared with the control group. Famotidine and ranitidine reduced the volume of gastric content in comparison with sodium citrate and the control group. However, the difference was significant only in the recovery room sample.