Comparison of the coating process and in vitro dissolution of 3 mm gastro-resistant minitablets and 5 mm gastro-resistant tablets with pantoprazole

Minitablets are solid oral forms, which, due to their size (1-3 mm), may be easily swallowed by children. The administration of minitablets in a certain number of units allows for flexible dosing for a broad age group of paediatric patients, which is particularly important for modified-release drugs. In this study, enteric-coated minitablets (3 mm) with pantoprazole were developed and compared to conventional tablets (5 mm). Eudragit L 30D 55^® and Acryl Eze II^® films, which were 50 and 80 μm thick, respectively, were applied using two different fluid bed systems. The increase in the pantoprazole release rate occurred not only due to the application of a thinner film but also due to the reduction in the size of the core independent of the coating apparatus that was used. In contrast to minitablets, the thin film's thickness was insufficient for 5 mm tablets and a loss of gastro-resistance was observed. The insertion of minitablets into a hard gelatine capsule did not affect drug release from the minitablets under in vitro conditions.

Skeletal status assessment by quantitative ultrasound and bone densitometry in children with different renal conditions

Two methods of skeletal status assessment-quantitative ultrasound (QUS) and densitometry (DXA)-were applied and compared in a group of children with different renal disorders. Skeletal assessments in children with different renal conditions should rather not be based on a single diagnostic tool. Lumbar spine DXA is very effective to reveal disturbances secondary to glucocorticoids, whereas total body DXA and QUS are both better in identification of disturbances related to decreased GFR.

INTRODUCTION

The aim of the study was to evaluate the skeletal status in children in different stages of chronic kidney disease (CKD) or treated with glucocorticoids, using either densitometry (DXA) or quantitative ultrasound (QUS) methods.

METHODS

Seventy-six subjects (27 girls/49 boys) at the mean age of 11.8 ± 4.0 years were enrolled to the reported study. They were divided into three subgroups: with normal glomerular filtration rate (GFR) but treated with glucocorticoids (GCs, n = 38), with decreased GFR (CKD 2-5, n = 26) and with normal GFR and without any bone-toxic treatment (CKD 1, n = 12). DXA scans were carried out at lumbar spine (LS) and at total body (TB), and quantitative ultrasound (QUS) imaging was done at hand phalanges. QUS results were compared to those obtained from 310 healthy matched controls.

RESULTS

The average Z-score for LS-BMD and TB-BMD was below zero in all the study subgroups. Neither were there any significant differences in the mean Z-score for LS among the subgroups. The mean Z-score for TB was significantly the lowest in the CKD 2-5 subgroup. The percentage of subjects with TB Z-score ≤ - 2.0 was the highest in the CKD 2-5 subgroup (69.2%), whereas the percentage of subjects with LS Z-score ≤ - 2.0 was the highest in the GC subgroup (23.7%). QUS results in CKD 2-5 were significantly lower than those in the controls, whereas the results, obtained in GC and CKD 1 subgroups, were similar to those in healthy subjects.

CONCLUSIONS

Skeletal status assessment in children and adolescents with different renal conditions should not be based on single diagnostic approach. DXA scanning, performed at lumbar spine, is potentially more appropriate to reveal disturbances secondary to long-term GC therapy, whereas TB-DXA is highly effective in the identification of skeletal disturbances related to decreased kidney function. QUS at hand phalanges seems to be a useful diagnostic means in CKD with diminished GFR but insufficient to detect GC-related disturbances.

Skeletal status in children, adolescents and young adults with end-stage renal failure treated with hemo- or peritoneal dialysis

The skeletal status in 30 children, adolescents and young adults (18 females, 12 males) with end-stage renal failure (ESRF) aged 9-23 years (mean 15.8 +/- 3.6 years) was evaluated using measurements of bone mineral density (BMD, g/cm2) at the spine and total body (TB) (Lunar DPX-L, USA), quantitative ultrasound (QUS) of the hand phalanges (DBM Sonic 1200, IGEA, Italy) and laboratory investigations (parathyroid hormone, serum total and ionized calcium, serum phosphate). Eleven subjects were treated with hemodialysis and 19 with peritoneal dialysis. The mean value of the amplitude-dependent speed of sound (Ad-SoS, m/s) measured by QUS was significantly decreased in comparison with the value obtained in a group of 686 age-matched controls (1942 +/- 74 m/s vs 2050 +/- 77 m/s, p<0.0001). BMD measurements were also decreased in comparison with mean values for the healthy population (Z-scores for spine -1.47, and for TB -1.53). Duration of dialysis correlated significantly with spine-BMD, TB-BMD and Ad-SoS (r = -0.37, r = -0.45, r = -0.55, respectively, p<0.05), while duration of ESRF did not have such an influence. Laboratory investigations did not correlate with skeletal parameters. Ad-SoS correlated significantly with spine-BMD (r = 0.45, p<0.05) and TB-BMD (r = 0.56, p<0.01). Both QUS and BMD values correlated significantly with Tanner stages (r ranged from 0.59 to 0.69, p<0.001) and did not increase with age except for correlation between age and TB-BMD. In conclusion, skeletal status in the population studied is strongly affected by ESRF. Both QUS and BMD measurements show an ability to express skeletal changes in a similar manner, though the QUS parameter seems to be more sensitive at revealing changes due to renal failure.

[The usefulness of echocardiography in prospective heart function evaluation in children on maintenance haemodialysis]

Echocardiography evaluation of heart systolic and diastolic function is applied in monitoring of cardiovascular changes in end-stage renal disease children on maintenance haemodialysis. The aim of the study was the comparison of cardiac cavities diameters and heart walls thickness changes, as well as, indices of left ventricle (LV) function in 12 end-stage renal disease children before and after haemodialysis session, before (initial examination) and after half-year duration of maintenance haemodialysis treatment (control examination). In 5 dialysed children the comparison of above-mentioned parameters was done after 3 years of maintenance haemodialysis duration. In both examinations significant increase of relative wall thickness (RWT) of LV without the features of asymmetric hypertrophy and decrease of left atrium transverse diameter after haemodialysis session was noted. There was no progression of LV hypertrophy during the six months and three years of treatment. After 3 years of maintenance haemodialysis duration significant decrease of LV mass index was revealed in examined children. There was no significant change of cardiac cavity diameters and indices of LV function during the time of observation.

Restoration of the phosphaturic effect of parathyroid hormone in lithium-treated rats

The purpose of this study was to clarify the means by which lithium induced a greatly diminished phosphaturic response to parathyroid hormone (PTH). Acutely thyroparathyroidectomized lithium-treated rats did not respond to PTH whereas similarly prepared animals in the presence of metabolic or respiratory acidosis exhibited a large phosphaturic response. Respiratory alkalosis significantly decreased fractional phosphate excretion and blocked the phosphaturic effect of PTH whereas PTH induced increases in cyclic AMP excretion in these animals. Lithium increased urinary excretion of oxoglutarate and citrate. In metabolic acidosis the restoration of PTH-dependent phosphaturia is accompanied by decreased organic acid excretion. No significant decrease of urinary citrate and oxoglutarate excretion occurred in respiratory acidosis in lithium-treated rats. It is suggested that PTH-dependent phosphate transport is mediated by intracellular pH but the increased excretion of citrate and oxoglutarate may reflect high intracellular levels of bicarbonate.