Comparison of a high lipase pancreatic enzyme extract with a regular pancreatin preparation in adult cystic fibrosis patients

Background: Malabsorption due to exocrine pancreatic insufficiency is the main gastrointestinal problem in cystic fibrosis. Despite high doses of pancreatic enzyme supplements it is often not possible to normalize fat absorption. We compared a new high lipase pancreatic enzyme preparation (Pancrease-HL; Cilag, Brussels, Belgium), containing enteric coated microspheres with 25000 U of lipase, 22 500 U of amylase and 1250 U of protease per capsule, with regular Pancrease capsules, containing 5000 U of lipase, 2900 U of amylase and 330 U of protease per capsule. Methods: In a randomized double-blind crossover study, 13 cystic-fibrosis patients (6 male, 7 female, mean age 2 7.7 years) received either four capsules of Pancrease t.d.s. or one capsule of Pancrease-HL t.d.s. Patients took 20 mg omeprazole daily to raise intra-duodenal pH and thus optimize release of enzymes from the enteric coated microspheres. Results: With four capsules of Pancrease t.d.s., mean fat excretion was 15.4% and mean nitrogen excretion was 19.9% vs. 15.5% fat and 19.9% nitrogen excretion with one capsule Pancrease-HL t.d.s. Fat and protein energy loss (as a percentage of total daily intake) was 18.3% with Pancrease and 18.2% with Pancrease-HL. The differences were not statistically significant. Pancrease-HL was well tolerated, with no difference in abdominal pain or general well-being scores. The number and average weight of stools passed remained the same. Conclusions: One capsule of Pancrease-HL appears to be equivalent to four capsules of regular Pancrease. Treatment with less capsules per day with the same efficacy may facilitate patient compliance.     

Pancreatin preparations used in the treatment of cystic fibrosis-- lipase content and in vitro release.

BACKGROUND: Pancreatic extracts are essential in the treatment of the majority of cystic fibrosis patients. The clinical response to different preparations is often unpredictable and at present there is no sure method of determining the best preparation for a particular patient. METHODS: Creon, Nutrizym GR, Pancrease and the high-lipase versions, Creon 25,000, Nutrizym 22 and Pancrease HL, were investigated for lipase content and resistance to simulated gastric conditions. The rates of lipase release in response to pH change, bile salts and duodenal solids were investigated. The stability of lipase and its binding to duodenal solids were also investigated. RESULTS: Declared values for lipase content were exceeded in all preparations. All preparations were acid resistant. The release of lipase in response to pH change showed notable differences in release rates. After 20 min at pH 5.5, Creon released three times the amount of lipase compared with Pancrease, the other preparations coming within the range. Above pH 5.75, the release rates were comparable amongst the preparations. Bile salts influenced release variably whilst release in a solid-rich duodenal fluid was much slower than in buffers. The released lipase was susceptible to proteolysis and pH-dependent binding to duodenal solids; these effects may compromise lipolysis. CONCLUSIONS: These results show some factors contributing to variable clinical responses to pancreatic supplements. Improvements may result if a patient is assessed on different preparations.     

In vitro dissolution profiles of enteric-coated microsphere/microtablet pancreatin preparations at different pH values

Objectives : Enteric-coated microsphere/microtablet pancreatin should stay intact in the stomach and dissolve promptly on entering the duodenum. Post-prandial intraluminal pH in the distal duodenum is 5.75 and is lower in exocrine pancreatic insufficiency. The aim of the study was to measure in vitro dissolution times in buffer solutions with pH 4.0–6.0 for five currently available enteric-coated microsphere/microtablet pancreatin preparations.
Methods : The following preparations were tested: Creon, Creon Forte, Pancrease, Pancrease HL and Panzytrat. Two capsules were placed in the buffer solution at 37 °C in a USP dissolution testing apparatus. Buffer solutions with pH between 4.0 and 6.0 were used. Solutions were stirred at 125 r.p.m. and the rate of dissolution was monitored by taking 2-mL samples at regular intervals and measuring extinction at 280 nm. Measurements were repeated six times.
Results : All preparations failed to dissolve at pH 4.0. At pH 5.0 Pancrease HL showed 43% dissolution within 30 min, all other preparations 15% or less. Panzytrat and Pancrease HL showed more than 50% dissolution within 30 min at pH 5.2. Panzytrat, Pancrease HL and Creon Forte had more than 90% dissolution within 30 min at pH 5.6, and all preparations more than 90% dissolution within 30 min at pH 5.8 and higher.
Conclusions : For the treatment of exocrine panceatic insufficiency conventional strength enteric-coated microsphere/microtablet pancreatin preparations do not have an optimal dissolution profile. The newer, high lipase preparations such as Pancrease HL perform better, although still not optimally, at pH 5.4 and lower.     

A 2-year post-authorization safety study of high-strength pancreatic enzyme replacement therapy (pancreatin 40,000) in cystic fibrosis

Objective: At the request of the Medicines and Healthcare Regulatory Agency and in agreement with the appropriate authorities, an observational, multi-center, non-interventional, post-authorization safety study of high-strength pancreatic enzymes was conducted.

Research design and methods: Patients with exocrine pancreatic insufficiency due to cystic fibrosis (CF) who had previously taken high doses of pancreatic enzymes received pancreatin 40,000 capsules (Creon 40,000 Minimicrospheres, Abbott GmbH, Hanover, Germany) as part of their normal treatment for up to 2 years. Initial doses were calculated to match previous established doses in lipase units, with adjustment if required.

Main outcome measures: Safety focused on serious suspected adverse drug reactions. Maldigestion symptoms and body weight were also monitored. Patients were managed according to general guidelines common to all major CF units in the UK, although minor variations were expected. The coefficient of fat absorption was not assessed as this was a safety rather than an efficacy study.

Results: Sixty-four patients were enrolled at nine UK centers. Two deaths occurred during the study, which were considered unrelated to therapy by investigators. There were no further serious suspected adverse drug reactions related to pancreatin 40,000 and no cases of fibrosing colonopathy. Daily lipase doses were reduced by 11% after switching to pancreatin 40,000. Maldigestion symptoms improved and mean body weight increased from baseline to last observation (mean + 6.1 kg in patients < 18 years old).

Conclusions: No safety concerns were identified with pancreatin 40,000 therapy for up to 2 years. Daily lipase doses were not increased when switching to pancreatin 40,000.     

Effects of product formulation on in vitro activity of pancreatic enzymes

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.     

Control of malabsorption in cystic fibrosis

Intestinal malabsorption is severe and of early onset in virtually all people who have cystic fibrosis. The main cause is deficiency of pancreatic enzymes, but bicarbonate deficiency, abnormalities of bile salts, mucosal transport and motility, and anatomical structural changes are other contributory factors. Appropriate pancreatic replacement therapy will achieve normal or near normal absorption in many patients. It is important to identify both malabsorption and evidence of a pancreatic lesion in all patients who are to receive pancreatic enzymes. All who have evidence of fat malabsorption are deemed pancreatic insufficient and candidates for enzyme replacement therapy. Effective treatment should allow a normal diet to be taken, control symptoms, correct malabsorption and achieve a normal nutritional state and growth. The occurrence of fibrosing colonopathy in some patients receiving very high doses of those enzymes that have the copolymer Eudragit L30 D55 in their covering has resulted in guidelines in the UK to avoid dosages greater than the equivalent of 10,000 IU lipase/kg/day for all patients and also to avoid preparations containing this copolymer in children and adolescents. For patients not responding to 10,000 IU lipase/kg/day, review of adherence to treatment, change of enzyme preparation, variation of the time of administration and reduction in gastric acid may improve absorption. The importance of excluding other gastrointestinal disorders as a cause of the patient's symptoms and the need for early investigations, rather than merely increasing the dosage of enzymes, is stressed. With modern enzymes, adequate control of gastrointestinal symptoms and absorption can be achieved at dosages of 10,000 IU lipase/kg/day or only slightly more, and a normal nutritional state and growth rate maintained in most patients with cystic fibrosis.     

A 6-month, open-label clinical trial of pancrelipase delayed-release capsules (Creon) in patients with exocrine pancreatic insufficiency due to chronic pancreatitis or pancreatic surgery

Aliment Pharmacol Ther 2011; 33: 1152–1161

Summary

Background Pancreatic enzyme replacement therapy (PERT) is necessary to prevent severe maldigestion and unwanted weight loss associated with exocrine pancreatic insufficiency (EPI) due to chronic pancreatitis (CP) or pancreatic surgery (PS). Aim To assess the long‐term safety and efficacy of pancrelipase (pancreatin) delayed‐release capsules (Creon) in this population. Methods This was a 6‐month, open‐label extension of a 7‐day, double‐blind, placebo‐controlled study enrolling patients ≥18 years old with confirmed EPI due to CP or PS who were previously receiving PERT. Patients received individualised pancrelipase doses as directed by investigators (administered as Creon 24 000‐lipase unit capsules). Results Overall, 48 of 51 patients completed the open‐label phase; one withdrew due to the unrelated treatment‐emergent adverse event (TEAE) of cutaneous burns and two were lost to follow‐up. The mean age was 50.9 years, 70.6% of patients were male, 76.5% had CP and 23.5% had undergone PS. The mean ± s.d. pancrelipase dose was 186 960 ± 74 640 lipase units/day. TEAEs were reported by 22 patients (43.1%) overall. Only four patients (7.8%) had TEAEs that were considered treatment related. From double‐blind phase baseline to end of the open‐label period, subjects achieved a mean ± s.d. body weight increase of 2.7 ± 3.4 kg (P < 0.0001) and change in daily stool frequency of ?1.0 ± 1.3 (P < 0.001). Improvements in abdominal pain, flatulence and stool consistency were observed. Conclusions Pancrelipase was well tolerated over 6 months and resulted in statistically significant weight gain and reduced stool frequency in patients with EPI due to CP or PS previously managed with standard PERT.

     

Ultrase MT12 and Ultrase MT20 in the treatment of exocrine pancreatic insufficiency in cystic fibrosis: safety and efficacy

BACKGROUND: Cystic fibrosis causes exocrine pancreatic insufficiency, leading to malabsorption. Supplemental pancreatic enzyme therapy alleviates the concomitant malnutrition experienced by cystic fibrosis patients. It is recognized that patients experience variations in clinical response to different brands of enzymes. This has prompted the US Food and Drug Administration to require that enzyme supplements be subjected to New Drug Applications. AIM: To investigate the safety and efficacy of supplemental pancreatic enzyme therapy in cystic fibrosis subjects. METHODS: We compared two doses of one formulation of enteric-coated pancreatic enzymes: Ultrase MT12 (12,000 lipase units per capsule) and Ultrase MT20 (20,000 lipase units per capsule), to placebo in two separate safety and efficacy studies. RESULTS: Mean total fat, protein and carbohydrate intake did not differ significantly between the groups. A significant difference in both fat and protein absorption occurred with the enzyme therapy groups. The Ultrase MT12 and Ultrase MT20 groups experienced a mean fat and protein absorption 79.4% and 83.8%, and 87.3% and 88.6%, respectively. No adverse events related to study drug were reported. CONCLUSIONS: This study further supports the use of enzymes to treat pancreatic insufficiency in cystic fibrosis. Excellent fat and protein absorption was achieved with minimal adverse events and safe doses.     

Altered pharmacokinetics of cyclosporin in heart-lung transplant recipients with cystic fibrosis

The cyclosporin dose versus blood concentration relationship for 11 heart-lung transplant recipients with cystic fibrosis was studied retrospectively. Eleven patients, closely matched for age and gender, who received heart-lung transplantation for other diseases were selected as controls. Cystic fibrosis patients received 16.7 (SD 7.2) mg/kg/day of oral cyclosporin compared with 8.2 (SD 1.9) mg/kg/day given to the control patients (p less than 0.01). Nine of the cystic fibrosis patients received higher mean daily doses of cyclosporin. Mean blood cyclosporin concentrations were, however, not significantly different (p = 0.58), and there were no apparent differences in clinical outcome in terms of rejection, infection, and nephrotoxicity in the two groups. The apparent oral clearance of cyclosporin was significantly higher (p less than 0.01) in cystic fibrosis patients. Cyclosporin dosage individualization with the aid of cyclosporin blood concentration measurements is critically important in this subpopulation of heart-lung transplant recipients.     

In vitro comparative study of three pancreatic enzyme preparations: dissolution profiles, active enzyme release and acid stability

Background  Various pancreatic enzyme preparations are used for the treatment of pancreatic insufficiency but their bioequivalence is often unknown.
Aim  To determine in vitro the pH-dependent release and acid resistance of enzymes from three commercially available pancreatin capsules, two containing enteric-coated (Creon 25000; Eurobiol 25000) and one uncoated (Eurobiol 12500) microspheres.
Methods  Dissolution experiments were performed at pH values ranging from 4.0 to 5.8. Lipase, chymotrypsin and amylase activities were measured in the solution as a function of time.
Results  Eurobiol 25000 started to release its enzymes significantly at pH 5.0 ( t _1/2 = 71 min), whereas the enzymes from Creon 25000 were only released at higher pH value (5.4; t _1/2 = 49.2 min). Unlike chymotrypsin, lipase and amylase were highly sensitive to acidic conditions at the lowest pH values tested. Both enzymes were also found to be sensitive to proteolytic inactivation at the highest pH values tested. Overall, Eurobiol 25000 released higher amounts of active amylase and lipase than Creon 25000 at the pH values usually found in duodenal contents. The uncoated Eurobiol 12500 preparation was, however, the only one that could immediately release rather high levels of active chymotrypsin and lipase at low pH (4.5).
Conclusion  These findings suggest that pH-sensitive enteric-coated pancreatin products containing similar amounts of enzymes might not be bioequivalent depending on the pH of duodenal contents.     

Tramadol sustained-release capsules

Tramadol is a synthetic, centrally acting analgesic. A sustained-release (SR) capsule formulation of tramadol gradually releases active drug, allowing for twice-daily dosing. Compared with tramadol SR tablets, tramadol SR capsules produced a smoother plasma concentration profile, with more gradual absorption and lower peak concentrations. There was less intra- and intersubject variability in tramadol plasma concentrations with SR capsules versus SR. Tramadol SR capsules had identical bioavailability to tramadol immediate-release (IR) capsules with lower peak concentrations and less fluctuation in plasma concentrations. Tramadol SR 100 mg capsules administered twice daily had equivalent efficacy to tramadol IR 50 mg capsules administered four times daily in the treatment of moderate to severe chronic low back pain in a well designed study. Patients receiving tramadol SR capsules were significantly less likely than those receiving tramadol IR capsules to report nausea. Starting treatment with tramadol SR capsules at a dosage of 50 mg twice daily with subsequent dose escalation resulted in improved tolerability in patients with moderate to severe chronic pain. The lowest tramadol SR capsule dosage of 50 mg twice daily (administered to 35% of patients with moderate to severe non-oncological pain) significantly improved pain intensity and frequency in 83.4% and 70.4% of patients, respectively, in a postmarketing observational study evaluating tramadol SR capsules 50-200 mg twice daily (n = 3888).     

Treatment of steatorrhoea in cystic fibrosis: a comparison of enteric-coated microspheres of pancreatin versus non-enteric-coated pancreatin and adjuvant cimetidine

Enteric-coated microspheres of pancreatin were compared with non-enteric-coated pancreatin combined with cimetidine taken 40 min before meals in the treatment of patients with cystic fibrosis. Fourteen adults with steatorrhoea due to cystic fibrosis were investigated in an open, randomized crossover study, over two consecutive 28-day treatment periods. Lipase intake was adjusted to each patient's previous requirements and was the same during both months; they were instructed to continue with their normal diet. Patients collected faeces for 72 h at the end of each month and completed diary cards daily throughout. Bowel actions were less frequent on enteric-coated microspheres of pancreatin than on non-enteric-coated pancreatin/cimetidine (1.7 vs. 2.4/day; P less than 0.001) and stool character was improved (P less than 0.001). Mean daily faecal weight was similar on enteric-coated microspheres of pancreatin to that on the combination (254 g vs. 291 g; N.S.), whereas daily faecal fat excretion tended to be less on enteric-coated microspheres of pancreatin (21 g vs. 27 g; N.S.), and percentage fat absorption tended to be greater (81% vs. 73%; N.S.). Mean body weight increased by 0.3 kg on enteric-coated microspheres of pancreatin and fell by 0.1 kg on the combination (N.S.). These data indicate that enteric-coated microspheres of pancreatin are at least as effective as non-enteric-coated pancreatin with cimetidine in the treatment of steatorrhoea in cystic fibrosis.     

Population pharmacokinetics of itraconazole and its active metabolite hydroxy-itraconazole in paediatric cystic fibrosis and bone marrow transplant patients

OBJECTIVE: The objective of the study was to characterise the population pharmacokinetic properties of itraconazole and its active metabolite hydroxy-itraconazole in a representative paediatric population of cystic fibrosis and bone marrow transplant (BMT) patients and to identify patient characteristics influencing the pharmacokinetics of itraconazole. The ultimate goals were to determine the relative bioavailability between the two oral formulations (capsules vs oral solution) and to optimise dosing regimens in these patients. METHODS: All paediatric patients with cystic fibrosis or patients undergoing BMT at The Royal Children's Hospital, Brisbane, QLD, Australia, who were prescribed oral itraconazole for the treatment of allergic bronchopulmonary aspergillosis (cystic fibrosis patients) or for prophylaxis of any fungal infection (BMT patients) were eligible for the study. Blood samples were taken from the recruited patients as per an empirical sampling design either during hospitalisation or during outpatient clinic visits. Itraconazole and hydroxy-itraconazole plasma concentrations were determined by a validated high-performance liquid chromatography assay with fluorometric detection. A nonlinear mixed-effect modelling approach using the NONMEM software to simultaneously describe the pharmacokinetics of itraconazole and its metabolite. RESULTS: A one-compartment model with first-order absorption described the itraconazole data, and the metabolism of the parent drug to hydroxy-itraconazole was described by a first-order rate constant. The metabolite data also showed one-compartment characteristics with linear elimination. For itraconazole the apparent clearance (CL(itraconazole)) was 35.5 L/hour, the apparent volume of distribution (V(d(itraconazole)) was 672 L, the absorption rate constant for the capsule formulation was 0.0901 h(-)(1) and for the oral solution formulation was 0.96 h(-1). The lag time was estimated to be 19.1 minutes and the relative bioavailability between capsules and oral solution (F(rel)) was 0.55. For the metabolite, volume of distribution, V(m)/(F . f(m)), and clearance, CL/(F . f(m)), were 10.6L and 5.28 L/h, respectively. The influence of total bodyweight was significant, added as a covariate on CL(itraconazole)/F and V(d(itraconazole))/F (standardised to a 70 kg person) using allometric three-quarter power scaling on CL(itraconazole)/F, which therefore reflected adult values. The unexplained between-subject variability (coefficient of variation %) was 68.7%, 75.8%, 73.4% and 61.1% for CL(itraconazole)/F, V(d)((itraconazole)())/F, CL(m)/(F . f(m)) and F(rel), respectively. The correlation between random effects of CL(itraconazole) and V(d(itraconazole)) was 0.69. CONCLUSION: The developed population pharmacokinetic model adequately described the pharmacokinetics of itraconazole and its active metabolite, hydroxy-itraconazole, in paediatric patients with either cystic fibrosis or undergoing BMT. More appropriate dosing schedules have been developed for the oral solution and the capsules to secure a minimum therapeutic trough plasma concentration of 0.5 mg/L for these patients.     

Intestinal inflammation is a frequent feature of cystic fibrosis and is reduced by probiotic administration

AIMS: To assess the incidence of intestinal inflammation in children with cystic fibrosis and to investigate whether probiotics decrease it. STUDY DESIGN: In this two-phase, controlled, prospective study, faecal calprotectin was measured by enzyme-linked immunosorbent assay in 30 children with cystic fibrosis, 30 healthy controls and 15 children with active inflammatory bowel disease. Ten children with cystic fibrosis received Lactobacillus GG, and faecal calprotectin was re-measured 4 weeks later. Rectal nitric oxide production was measured with the rectal dialysis bag technique in 20 children with cystic fibrosis, 20 healthy controls and 15 children with inflammatory bowel disease. Five children with cystic fibrosis received Lactobacillus GG and nitric oxide was re-measured 4 weeks later. RESULTS: Mean faecal calprotectin was significantly higher in the two groups of patients than in controls. Abnormal values were detected in 27 of 30 cystic fibrosis and in 15 of 15 inflammatory bowel disease children. Also mean nitric oxide production was increased in both group of patients, and abnormal values were detected in 19 of 20 cystic fibrosis and in 15 of 15 inflammatory bowel disease children. Calprotectin and nitric oxide concentrations were reduced after probiotics administration. CONCLUSIONS: Intestinal inflammation is a major feature of cystic fibrosis and is reduced by probiotics. The latter finding suggests that intestinal microflora play a major role in intestinal inflammation in cystic fibrosis children.     

Comparison between a standard pancreatic supplement and a high enzyme preparation in cystic fibrosis

This study compared the relative effectiveness of a standard pancreatic enzyme supplement ('Creon', Duphar) and a new preparation ('Pancrease HL', Cilag) containing about 3 times the lipase and more than 5 times the protease activity. Capsule dosage was adjusted to a ratio of approximately 3:1. Fat balances showed that absorption of fat did not change significantly on conversion to the new high-lipase product, and the coefficient of absorption of total energy was similarly maintained. The coefficient of protein absorption was significantly enhanced with the high enzyme preparation (P less than 0.01), which may explain the reported subjective improvement in stool odour. No adverse effects were recorded. Patient acceptability of the new compound was high; the great reduction in the number of capsules required at each meal was cited by all patients as the reason for their preference.     

Pharmacokinetics of ibuprofen enantiomers in children with cystic fibrosis

Chiral inversion of R(-)- to S(+)-ibuprofen in children with cystic fibrosis was investigated. Children with cystic fibrosis (n = 38, ages 2-13 years) were administered a single oral dose of racemic ibuprofen (20 mg/kg), and the pharmacokinetics of ibuprofen was found to be stereoselective. Mean Cmax, AUC, apparent CL/F, and Varea/F of S-ibuprofen were significantly different from those of R-ibuprofen. The enantiomeric ratio of plasma AUC (S:R = 2.09:1) and of free and conjugated ibuprofen in urine (S:R = 13.9:1) of children with cystic fibrosis was not different from reported values for healthy children and adults. No significant gender difference was observed for any of the pharmacokinetic parameters determined. However, there was an inverse linear relationship between the CL/F of R-ibuprofen and age in children with cystic fibrosis. Apparent CL/F was higher in children with cystic fibrosis than previously reported for healthy children; therefore, higher doses of ibuprofen would be necessary for children with cystic fibrosis.     

Cyclosporin pharmacokinetics in heart-lung transplant recipients with cystic fibrosis

Cyclosporin (CsA) is currently the main immunosuppressive agent used in organ transplantation with considerable improvement in graft survival. Oral CsA solution is highly lipophilic, and its bioavailability may be reduced in cystic fibrosis (CF) heart-lung transplant recipients with pancreatic, gastrointestinal, and hepatic insufficiency. The bioavailability of oral CsA solution in 7 CF transplant recipients (5 male and 2 female with a mean age of 27 years and a mean weight of 49 kg) and 3 non-CF heart-lung recipients (1 male and 2 female with a mean age of 41 years and a mean weight of 60 kg) was studied.Following intravenous CsA administration, the kinetic curves were similar with no significant difference in the volume of distribution and clearance of CsA demonstrated between the CF and non-CF groups. The mean daily dose of oral CsA in 7 CF subjects (23.3 mg·kg^–1) was significantly higher than the 3 non-CF heart-lung recipients (4.8 mg·kg^–1). The mean maximum blood concentration of CsA for the oral dose was 776 ng·ml^–1 for the 7 CF subjects, which was comparable with the mean peak values of 789 ng·ml^–1 for the 3 non-CF control subjects. Poor enteral absorption of CsA probably accounts for the significantly lower mean bioavailability in the 7 CF subjects (14.9%) compared with the 3 non-CF control subjects (39.4%).The effects on the bioavailability of oral CsA solution by pancreatic enzymes (Creon) and histamine-2 antagonist (ranitidine) were also evaluated in the 7 CF subjects. No significant difference was demonstrated.     

Nebulised gentamicin-suitable for childhood bronchiectasis

Nebulised antibiotic therapy is an established, safe and effective therapy for cystic fibrosis with chronic pseudomonas infection resulting in improved pulmonary function and reduced hospitalisation. Despite similar respiratory disease, this therapy has not been evaluated in children with non cystic fibrosis bronchiectasis. This study evaluates the suitability of a gentamicin solution and nebuliser combination for use in this population. MATERIALS AND METHODS: Four millilitres of gentamicin (80 mg) in saline delivered by a PARI LC plus nebuliser and PARI Turboboy N compressor was used. The pH, osmolarity, chloride concentration and aerosol particle size was determined. Ten children with non cystic fibrosis bronchiectasis received nebulised antibiotic and had peak gentamicin concentrations measured in sputum and serum. Pulmonary function was measured pre and post nebulisation. RESULTS: The solution had an osmolarity of 199 mOsm/l, pH of 4.1, chloride concentration of 75 mmol/l and the aerosol a mass median aerodynamic diameter of 3.3 microm. Nebulisation was well tolerated, with no significant change in FEV1. Peak serum levels were at the threshold of detectability (0.3 mg/l). Sputum concentrations had a mean of 624 mg/g and lower 95th confidence interval 25 times the minimum inhibitory concentration for the predominant infecting organism, Haemophilus influenzae. CONCLUSION: Nebulisation of 80 mg of gentamicin in saline achieved bactericidal concentrations in sputum, was well tolerated and had negligible systemic absorption making it a suitable choice for this population.     

The bioavailability and pharmacokinetics of cimetidine and its metabolites in juvenile cystic fibrosis patients: Age related differences as compared to adults

Summary The pharmacokinetics and metabolism of cimetidine were studied in five cystic fibrosis patients (mean age 12.6 years) after oral and intravenous administration. As compared to healthy adult volunteers, cystic fibrosis children had an elevated cimetidine total body clearance (474 vs 300 ml/min/m²) as well as renal clearance (293 vs 232 ml/min/m²) whether normalized for body weight or surface area differences. Cimetidine elimination was elevated in juvenile cystic fibrosis patients as compared to adult volunteers, however, it did not differ significantly from that previously seen in age matched children. There were no appreciable differences in cimetidine metabolism after either route of administration. Differences between adults and cystic fibrosis children were attributed to developmental and age related differences between the two groups. The recommended pediatric dose of 15 to 20 mg/kg, although four-fold greater than that used in adults, produces serum concentrations similar to those seen in adults, and is adequate for most juvenile cystic fibrosis patients.     

The effect of dietary fiber on the bioavailability of digoxin in capsules

Sixteen healthy volunteers were regularly given 0.4 mg of digoxin daily as two capsules with breakfast. After ten days during which breakfast was supplemented with 11 g of bran fiber, steady-state predose mean serum digoxin was lower (0.89 +/- 0.19 versus 0.84 +/- 0.18 ng/mL, P less than .05) and mean 24-hour area under curve determination was lower (30.5 +/- 6.1 versus 28.4 +/- 6.0 ng X hr/mL, P less than .05) than during the control period without bran. Height and time of peak serum digoxin, and 24-hour urinary digoxin were not significantly different. The 6 to 7% reduction in digoxin absorption from capsules is less than that reported from tablets and is probably clinically unimportant.