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Biomedical subjects

J M Aiache

Publications and source records attributed to J M Aiache.

At least 37 records · Page 2Linked to original sources
PubMed1991

The ideal drug delivery system: a look into the future.

In the very near future, the CFC manufacturers are going to be obliged to stop their production as a result of the "Montreal protocole on substances that deplete the ozone layer". The replacement of these propellants by other fluorinated ones will be possible as soon as their lack of toxicity has been demonstrated. Other substitution substances like haliphatic hydrocarbons (butane, propane) or compressed air generated by the device system itself or the user himself are also under development. The pulverisation can also be obtained by the pressure of a classical propellant onto an aluminum or plastic bag. The dispersion is achieved by means of a regulator which is positioned into the valve. The hand-operated spray pumps with or without compression will also allow the obtention of very small particles though the delivered doses are reduced. However, as few of the new devices have metered valves, they are not yet suitable for pulmonary administration.

Administration, Inhalation↗
PubMed1991

In vivo-in vitro correlation of salbutamol release from a controlled release osmotic pump delivery system.

The drug release of salbutamol from a controlled release (osmotic pump) tablet was determined in vitro by four different dissolution apparatuses. From published in vivo data, percent of drug absorbed and percent of drug released in vivo were estimated. The highest correlation was obtained between percentage released in vitro versus percentage released in vivo using polynomial regression.

Administration, Oral↗
PubMed1991

Comparison of continuous, constant rate enteral tube feeding in supine patients to bolus food intake in ambulatory, healthy subjects regarding bioavailability of perorally administered cefroxadine.

Stabilized, bedridden, inactive trauma patients on enteral nutrition via continuous, constant rate tube feeding (2 different formulas) were given a single dose of cefroxadine p.o. There were no differences in the pharmacokinetic parameters between the groups on different enteral nutrition. These patients were compared to cefroxadine absorption in ambulatory healthy subjects after a standardized meal (bolus-fed). The mean residence time was significantly longer in the patients, and the extent of absorption was slightly reduced with one enteral nutrition formulation and significantly reduced with the other. The other pharmacokinetic parameters were not significantly different. The difference is believed to be caused by reduction in splanchnic blood flow in the immobilized patients, weakening of migrating motor complex due to tube feeding and the lower temperature (4 degrees C) of enteral nutrition.

Administration, Oral↗
PubMed1991

Peroral absorption of cefroxadine in patients within the first day after severe trauma: comparison to cefroxadine pharmacokinetics in fasted, healthy volunteers.

Peroral absorption of cefroxadine given to 7 24-h fasted trauma patients by nasogastric tube within the first day of admission was compared to that obtained in fasted healthy volunteers. The trauma patients exhibited significantly lower Cmax and reduced AUC. Even though rate and extent of bioavailability cannot be determined from these two different population groups since the total clearance must be assumed to be different in patients and healthy subjects, a reduced bioavailability is assumed based on pathophysiologic reflections.

Administration, Oral↗
PubMed1990

French and/or European perspectives on biopharmaceutical characterization of drug dosage forms.

In order to bring definitions of drug dosage forms up to date, it was necessary for the French Pharmacopoeia to propose assays allowing the quality control of the dosage forms to be based on the kinetics of drug release in vitro. Currently, five examples can be cited of dosage forms that can be characterized by release in vitro. (1) Oral solid dosage forms--for tablets, all the parameters of powders before compression (e.g., flowability, tableting properties) are being studied in addition to the dissolution tests, (2) Rectal dosage forms--the disintegration test of suppositories will be discarded and a new dissolution test using a special flow-through cell is now being studied. (3) Inhalations--since particle diameter is the most important factor for inhalation activity, a method has been developed to give the correct answer to this question. (4) Modified release drug dosage forms--these have been defined separately from the conventional forms. For the peroral route, they are: (i) accelerated release drug dosage forms, (ii) sustained release drug dosage forms and (iii) delayed release drug dosage forms. To emphasize the differences in the release kinetics, use of the paddle method, well known in the USP, and the flow-through cell has been suggested and described in the European Pharmacopoeia. Some associations and/or in vitro-in vivo correlations have increased the interest in the last method. (5) Transdermal delivery systems--these are defined separately from plaster and sticking-plaster. The use of a cell method was suggested to study the drug release and some comparisons between different techniques are presented.

Biopharmaceutics↗
PubMed1989

Gastrointestinal scintigraphy with 99mTc-DTPA labeled tablets in fed and fasting subjects.

The in vitro and in vivo dissolution of a sustained release theophylline formulation labeled with 99mTc-diethyltriaminepentaacetic acid (DTPA) has been monitored in six subjects with a scintillation camera. The study was performed in fasting conditions and was repeated after ingestion of a standardized meal. Results showed that the presence of food in the stomach dramatically increased the oesoduodenal transit time of the tablet (74 +/- 27 min vs 352 +/- 77 min, P less than 0.001) but did not modify the biodisponibility of theophylline. This study is another example when scintigraphy can be of definite value in pharmacokinetics.

Adult↗
PubMed1987

The influence of food on the bioavailability of a slow release theophylline preparation.

Food-induced changes in the absorption of Theostat 300, a controlled release formulation of theophylline, have been studied in healthy volunteers. This open, randomised, 3-way, single-dose study involved 12 volunteers who received the drug either while fasting, or with a standardised low-fat (10g), or high-fat (60g) breakfast. Each subject was studied over a 3-week period, with 3 separate days of oral treatment and a 7-day washout period between treatments. The results showed no differences in AUC0-24 and tmax values between the 3 kinds of diet. The only differences observed concerned absorption. Food intake increased Cmax values by 20%. The steady-state peak concentration obtained by means of simulated plasma levels was not influenced by food intake. This slight food-drug interaction of Theostat 300 seemed to be of no clinical significance.

Adult↗
PubMed1987

Dissolution rate and transit times of technetium-99m DTPA-labeled tablets.

In this study we demonstrate that the dissolution rate and gastroduodeno-cecal transit time of radiolabeled tablets of theophylline can be determined in vivo using technetium-99m (99mTc). Six healthy male volunteers ingested a tablet containing 300 mg of theophylline mixed with 3.7 MBq of [99mTc]DTPA. Anterior and posterior scintigraphic views of the abdomen were collected serially over 8 hr, after which a 200-ml solution containing 37 MBq of [99mTc] pertechnetate was ingested in order to visualize the contours of the stomach. The in vivo activity contained in the tablet was calculated from the scintigraphic views after correction of background activity, radioactive decay, and depth attenuation. The dissolution rate of [99mTc] DTPA was also measured in vitro and compared with the dissolution rate of theophylline. The results showed close dissolution rates between [99mTc]DTPA and theophylline in vivo (T1/2 184 min and 176 min, respectively), and a faster early dissolution rate of [99mTc]DTPA in vitro (T1/2 92 min versus 156 min for theophylline). The mean gastroduodenal and duodenocecal times were 72 +/- 25 min (m +/- s.d.) and 245 +/- 15 min, respectively. Scintigraphic imaging of labeled formulations with 99mTc present useful applications in pharmaceutics and pharmacology.

Gastrointestinal Motility↗
PubMed1985

[Extrinsic allergic alveolitis and hematologic diseases (lymphoproliferative syndromes)].

The authors report 2 cases of hypersensitivity pneumopathy associated with haematological abnormalities: benign lymphoproliferative syndrome in one case, and malignant lymphadenopathy with fatal outcome in the other case. Such cases, now observed with increasing frequency, can be regarded either as chance associations of 2 types of disease, or as the results of immune disorders with repercussions on the blood.

Adult↗
PubMed1984

[Not Available].

Explore the source record for details and available documents.

France↗
PubMed1983

Precipitins to inhaled avian antigens: results of an inter-laboratory study.

Precipitins against avian antigens in sera from patients with extrinsic allergic alveolitis, asymptomatic pigeon and chicken breeders and from control individuals were tested with different antigen extracts in six laboratories by a variety of different methods. Eighty percent of the results coincided in identifying the positive sera from patients and 90% in identifying the controls. It seems possible therefore to exchange results among experienced laboratories with fair confidence.

Adult↗