Class experiment with student volunteers illustrating the influence of formulation on absorption of aspirin [proceedings].
Explore the source record for details and available documents.
SEARCH · PubMed Health
Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
A new enteric-coated pancreatic enzyme preparation (microspheres) was compared with traditional enzyme tablets in six subjects with severe exocrine pancreatic insufficiency. The microspheres were found to be as effective as traditional enzyme supplements. In most patients in balance studies, the lowest fecal fat values were obtained with microsphere therapy in spite of a smaller amount of lipase administered (6015 vs 10,800-43,200 lipase units per meal). In contrast to enteric-coated tablets, microspheres can be recommended in the treatment of pancreatic steatorrhea.
The clofibric acid levels in blood are studied after the oral administration of 500 mg of etofibrate given as a unique dose in three different delayed-release tablets. These are enteric-coated, obtained by granule compression. An inert matrix containing the drug is the basis of these granules, differentiated by their granulometry and the chemical treatment applied. One of the three tablets presents a very interesting KE, which permits the substitution of three intakes throughout the day by only one dose daily.
Clinical trials comparing H2-receptor antagonists and bismuth-containing regimens in ulcer healing, ulcer relapse, or dyspepsia have not been double-blind, because bismuth darkens stools. This study was designed to determine whether enteric-coated charcoal could darken stools of subjects taking an H2-receptor antagonist without interfering with absorption of the drug. Twelve healthy volunteers participated in a randomized, double-blind, crossover trial of oral ranitidine (300 mg at bedtime) alone, ranitidine plus bismuth (30 ml Pepto-Bismol four times daily), and ranitidine plus enteric-coated charcoal (four tablets daily). Mean stool colors both with ranitidine plus charcoal and with ranitidine plus bismuth were significantly darker than with ranitidine alone, but were not significantly different from each other. Blood levels of ranitidine during the 10 h after its administration did not differ significantly among the three regimens. We conclude that enteric-coated charcoal can be used to blind clinical trials comparing an H2-receptor antagonist (e.g., ranitidine) and a bismuth regimen.
A formulation containing cellulose acetate phthalate for preparing enteric-coated granules was developed with the use of granulation and microencapsulation techniques. Drug release from tablets or tableted microcapsules was measured in a disintegration apparatus and an in vitro variable-pH release simulator of the flow type. The release mechanism for the tablets or tableted microcapsules was determined with the Higuchi matrix model, a first-order kinetic model, and the Weibull distribution function. Adding acetone directly to the mixture of sulfamethoxazole and cellulose acetate phthalate resulted in enteric-coated granules with more prolonged release than other granulation methods. Microencapsulation of the granules significantly delayed the drug release and enhanced the effectiveness of the enteric coating. Microencapsulated granules show release patterns that are sustained and can be simulated with three different release models, i.e., with square-root time plotting, diffusional first-order plotting, and Weibull distribution plotting. The enteric-coating behavior of the tablets was more clearly demonstrated with the variable-pH release stimulator than with a fixed-pH dissolution method.
A retrospective study at surgical clinics in Stockholm County disclosed 22 cases of small-bowel ulceration in which a connection with use of slow-release potassium chloride tablets was probable. Most ulcers had caused stenosis of 1-2 cm of gut, and in four of these cases there was also perforation of the bowel wall. Five patients had perforation without signs of stenosis. The pathology of the ulcers was similar to that described after use of enteric-coated potassium chloride tablets. Since 1970 the frequency of potassium-induced ulceration has been low--3 cases per 100 000 patient-years of slow-release tablet use. On the other hand, this complication of drug therapy can be serious--the mortality in the present series was 27%. Other types of potassium chloride preparations should therefore be tested. Microencapsulated potassium chloride tablets have been reported to be less irritating to the gastrointestinal tract.
The effect of magnesium, given orally as enteric-coated magnesium chloride tablets, on the ECG of 25 randomly selected patients was investigated. Each patient, who served as his own control, was given 4--6 tablets, each containing 0,5 g MgCl26H2O, at night for periods varying from 6 weeks to 2 years. Findings included (i) a statistically significant decrease in OTc and QUc intervals; (ii) a progressive shortening of QTc and QUc intervals with continuing therapy; (iii) reversion to normal of ECG abnormalities, especially of ST segments and T waves.
Enteric-coated granules with different densities and tablets of different sizes were prepared in order to study the effect of these physical properties of dosage forms on the gastric emptying rates in humans. The effect of food on the gastric emptying rate was also studied. Aspirin contained in an enteric-coated product as a marker drug was used to determine the gastric emptying rate by measuring salicylates excreted into the urine. The larger the size of the dosage form, the larger were the values of parameters for estimating the gastric emptying rate such as tlag, tmax and the mean absorption time. There was a significant correlation between the gastric emptying rates and sizes of dosage forms. On the other hand, no effects of density of enteric-coated granules on the gastric emptying rate were observed. The gastric emptying of dosage forms of various sizes or densities tested were prolonged by food. However, the gastric emptying rate of granules was less affected by food than that of tablets.
41,299 patients entering 914 hospitals up to 24 h (median 4 h) after the onset of suspected acute myocardial infarction were randomised between streptokinase (SK: 1.5 MU infused over about 1 h), tissue plasminogen activator (tPA, duteplase: 0.60 MU/kg infused over about 4 h), or anisoylated plasminogen-streptokinase activator complex (APSAC), anistreplase: 30 U over about 3 min). All patients were to receive aspirin (162 mg/day enteric-coated), with the first tablet chewed for rapid and full antiplatelet effect. Half of all patients were randomly allocated subcutaneous calcium heparin (12,500 IU starting at 4 h and given twice daily for 7 days or until prior discharge) in addition to aspirin, and the other half were to receive aspirin alone. ASPIRIN PLUS HEPARIN VERSUS ASPIRIN ALONE--The addition of heparin to aspirin was associated with an excess of transfused or other major non-cerebral bleeds (1.0% aspirin plus heparin vs 0.8% aspirin alone; 2p < 0.01) and of definite or probable cerebral haemorrhage (0.56% vs 0.40%; 2p < 0.05), but with no significnat differences in total stroke (1.28% vs 1.18%). Reinfarctions were slightly less common among those allocated aspirin plus heparin (3.16% vs 3.47%; 2p = 0.09). There was no signficant difference in the pre-specified endpoint of 35-day mortality (2132 [10.3%] aspirin plus heparin vs 2189 [10.6%] aspirin alone). During the scheduled heparin treatment period there were slightly fewer deaths in the aspirin plus heparin group (days 0-7 in hospital: 1534 [7.4%] vs 1633 [7.9%]; 2 p = 0.06), with a slight convergence by day 35 (598 further deaths [3.1% of survivors] vs 556 [2.9%]). The pattern was similar to that observed in the GISSI-2 trial, so that in both trials combined there was a significant reduction in mortality during the scheduled treatment period (2071 [6.8%] vs 2239 [7.3%]; 2p < 0.01). This indicates avoidance of 5 deaths (SD 2) per 1000 patients allocated this high-dose subcutaneous heparin regimen in addition to aspirin, but some of any early benefit may be lost after heparin ceases, with no significant mortality advantage in days 0-35 (both trials: 3100 [10.0%] vs 3172 [10.2%]) or during follow-up to 6 months. SK VERSUS APSAC--APSAC was associated with significantly more reports of allergy causing persistent symptoms and of non-cerebral bleeds, but not of transfused bleeds or of reinfarctions. There was a slight excess of strokes with APSAC (1.04% SK vs 1.26% APSAC; 2p = 0.08), much of it appearing soon after treatment started (strokes during days 0-1: 0.50% SK vs 0.73% APSAC; 2p < 0.02) and being attributed to cerebral haemorrhage (0.24% SK vs 0.55% APSAC; 2p < 0.0001). No significant difference was observed in reinfarction (3.47% SK vs 3.55% APSAC). There was no significant mortality difference during days 0-35, either among all randomised patients (1455 [10.6%] SK vs 1448 [10.5%] APSAC) or among the pre-specified subset presenting within 0-6 h of pain onset and with ST elevation on the electrocardiogram in whom fibrinolytic treatment may have most to offer (861 [10.0%] SK vs 855 [9.9%] APSAC). No significant difference in 6-month survival was apparent overall or in the subset.(ABSTRACT TRUNCATED AT 400 WORDS)
The lipase activity of two enteric-coated and two uncoated pancreatic enzyme formulations was evaluated in vitro at different pH values and compared with postprandial duodenal pH data in cystic fibrosis patients. Lipase activity was measured over a pH range of 4-8 in four formulations: Viokase tablets and Viokase powder (Viobin), Cotazym-S (Organon), and Pancrease enteric-coated spherules (McNeil). A pH-stat technique was used in which the amount of hydroxyl ion that must be added to maintain a preset pH value is measured to determine the amount of lipase substrate (tributyrin) that is split into butyric acid. At least three determinations of activity were made at each pH. Six capsules of each enteric-coated formulation were subjected to disintegration testing at various pH values. These data were then compared with data available for postprandial duodenal pH in patients with cystic fibrosis. The lipase activity of all formulations studied decreased when pH decreased, especially when the pH was below 5.75. At a pH value between 5 and 5.5, which represents the postprandial duodenal pH in cystic fibrosis patients, activity was reduced 50% or more for all formulations tested. The two enteric-coated products displayed no activity at pH 5.5 and below because the coating did not dissolve in this pH range. Lipase activity in enteric-coated pancreatic enzyme preparations is limited because the enteric coating of these products dissolves slowly in the duodenal pH range (5-5.75) that is found in patients with cystic fibrosis.
Erythromycin base and its salts are frequently used in clinical practice. The most frequent side effects of oral erythromycin preparations are gastrointestinal. Various salts and enteric coatings have been developed without adequate comparison in regard to gastrointestinal side effects. The overall incidence of gastrointestinal side effects (abdominal pain and cramps, nausea, vomiting, diarrhea, and gas) of two common erythromycin base formulations, Erythromycin Base Filmtab (Abbott), a nonenteric-coated base tablet, and Eryc (Parke-Davis), a pelletized, encapsulated, enteric-coated base capsule, were compared in 368 adults at two dosage levels (1 g/d and 2 g/d). Minimal differences were found when target symptoms were compared by preparation coating. In contrast, subjects receiving erythromycin at the 2-g/d dosage level reported higher incidence rates for each of the target symptoms, regardless of product coating, than did those patients treated at the 1-g/d dosage level. Enteric coating of erythromycin base offers little protection from the common dose-related gastrointestinal adverse effects of oral erythromycin.
The formulation of an oral iron tablet may influence its therapeutic efficacy in correcting iron deficiency. In order to determine the oral iron preparations patients in a Canadian urban center were receiving, a questionnaire was circulated to family physicians, internists, surgeons, and obstetrician-gynecologists to determine their prescribing practices. A survey of pharmacies in the city was also conducted to determine which brand of each iron salt (sulfate, gluconate, fumarate) they dispensed for a generic oral iron prescription. Most physicians (74 percent) chose ferrous sulfate as their drug of first choice. The majority of prescribers would not specifically request either enteric-coated/slow-release or nonenteric-coated preparations as first or second choices (71 and 64 percent, respectively). Enteric-coated or slow-release preparations were specified by 10 and 19 percent of physicians as first and second choices, respectively. Most pharmacies (96 percent) dispensed an enteric-coated preparation of ferrous sulfate for a generic prescription. We believe that many patients are receiving iron tablets with altered release properties (enteric-coated/slow-release). These tablets may fail to provide the desired therapeutic benefit based on the known physiology of iron absorption.
In a trial of 48 patients with rheumatoid arthritis, enteric-coated aspirin (4.55 g daily( and micro-encapsulated aspirin (4.50 g daily) proved to be equally effective in reducing morning stiffness, relieving pain, increasing grip strength, reducing ESR, and reducing the need for additional analgesic tablets, compared with placebo. Reduction of joint tenderness was also found, but this was not statistically significant. Proximal interphalangeal joint circumference altered little during the trial. Tinnitus and deafness were commoner with enteric-coated aspirin, but gastric side-effects were similar. Of 39 patients completing the trial, there was an equal patient preference for enteric-coated aspirin and micro-encapsulated aspirin. Salicylate side-effects necessitated withdrawal of six patients from the trial and dose reduction in nine patients. It was concluded that the efficacy and side-effects in rheumatoid arthritis of both aspirin preparations were similar.
In Heilmeyer's iron-loading test the iron preparation SA (Eryfer) proved greatly superior to a commercially available effervescent tablet (iron preparation SC), to an iron preparation in a sustained release from (iron preparation SD) and to an iron preparation in the form of enteric-coated pellets (iron preparation SE), in producing and maintaining an increased serum iron level. As compared to a sodium bicarbonate-free preparation (iron preparation SB) the iron preparation SA must be considered equivalent. The results of our investigations made with iron preparation SA are supported by experiences made by other authors with therapeutic application.
The absorption of quinidine from single and multiple doses of an enteric-coated preparation (Systodin) was studied in seven healthy subjects, and was compared with the pharmacokinetics of intravenously administered quinidine and the results of in vitro dissolution tests of the tablets. Absorption of quinidine began after a variable delay, 2-8 h (mean 4.8) after fasting and 3-10 h (mean 6.1) after food. The rate of absorption varied both in and between individuals. It appeared to be lower when the drug was administered after food. Multiple doses after food gave a pattern of plasma concentration-time curves similar to that found on administration of single doses after food. The delay prior to absorption was prolonged at night. The ratio between the maximum and minimum concentration of quinidine during a dose interval varied from 1.3 to 3.2 (mean 2.0). Bioavailability of quinidine in fasting subjects ranged from 69 to 95% (mean 83); variation was greater when doses were administered after food. The release of quinidine from the enteric-coated preparation was pH dependent and was sustained at low pHs as may be found in the intestines. The results indicate that the absorption of quinidine from the enteric-coated formulation was dependent on the highly variable rate of gastric emptying and the pH of intestinal fluid, and it varied greatly both within and between individuals.
Treatment of exocrine pancreatic insufficiency with the use of eight tablets of pancreatin with meals consisting of 25 g of fat per meal will generally abolish azotorrhea. Although steatorrhea is not totally corrected, satisfactory nutritional status and relative relief of symptoms are usually achieved. For the occasional patient who continues to lose weight or remains symptomatic even after reduction of dietary fat, the addition of cimetidine to the standard pancreatin treatment will usually provide relief from the steatorrhea and alleviate troublesome diarrhea. In certain circumstances in which gastric pH is more than 4 for 1 hour after a meal, altering the dosage schedule to two tablets hourly may be effective in alleviating the steatorrhea. Conversely, in patients whose upper gastrointestinal tract is acidic for long periods postprandially (gastric pH less than 5, duodenal pH less than 4), Pancrease, an enteric-coated preparation, may be effective. In difficult cases in which symptoms and steatorrhea continue, special intraluminal studies need to be performed to ensure that intraluminal conditions are, in fact, present for certain dosage schedules to be effective or that intraluminal conditions have been altered by adjunctive therapy.
Endoscopy was done in 82 patients with rheumatic disease who were receiving chronic aspirin therapy. Fifty-eight patients were taking at least eight aspirin tablets daily for 3 or more months; 24 patients were taking, in addition to the aspirin, a maximum of one other antiinflammatory, nonsteroidal medication. Endoscopy in 45 normal subjects not taking aspirin showed no ulcers or erosions and a 4% incidence of gastric erythema. In the 82 patients with rheumatic disease, 14 (17%) had gastric ulcers, 33 (40%) had gastric erosions, and 62 (76%) had gastric erythema. Regular aspirin and buffered aspirin users had an ulcer incidence of 23% and 31% respectively, compared with a 6% incidence in enteric-coated aspirin users (P less than 0.05). One third of all patients with gastric ulcer had no gastrointestinal symptoms. Patients taking chronic aspirin therapy for rheumatic diseases have a higher than suspected incidence of gastric ulcer and erosions. Gastric ulcer may exist without symptoms in such patients.