Comparative palatability of orally disintegrating tablets (ODTs) of praziquantel (L-PZQ and Rac-PZQ) versus current PZQ tablet in African children: a randomized, single-blind, crossover study

BACKGROUND: Praziquantel (PZQ) is currently the only recommended drug for infection and disease caused by the schistosome species that infects humans; however, the current tablet formulation is not suitable for pre-school age children mainly due to its bitterness and the large tablet size. We assessed the palatability of two new orally disintegrating tablet (ODT) formulations of PZQ. METHODOLOGY: This randomized, single-blind, crossover, swill-and-spit palatability study (NCT02315352) was carried out at a single school in Tanzania in children aged 6-11 years old, with or without schistosomiasis infection as this was not part of the assessment. Children were stratified according to age group (6-8 years or 9-11 years) and gender, then randomized to receive each formulation in a pre-specified sequence. Over 2 days, the children assessed the palatability of Levo-Praziquantel (L-PZQ) ODT 150 mg and Racemate Praziquantel (Rac-PZQ) ODT 150 mg disintegrated in the mouth without water on the first day, and L-PZQ and Rac-PZQ dispersed in water and the currently available PZQ 600 mg formulation (PZQ-Cesol) crushed and dispersed in water on the second day. The palatability of each formulation was rated using a 100 mm visual analogue scale (VAS) incorporating a 5-point hedonic scale, immediately after spitting out the test product (VASt = 0 primary outcome) and after 2-5 minutes (VASt = 2-5). PRINCIPAL FINDINGS: In total, 48 children took part in the assessment. Overall, there was no reported difference in the VASt = 0 between the two ODT formulations (p = 0.106) without water. Higher VASt = 0 and VASt = 2-5 scores were reported for L-PZQ ODT compared with Rac-PZQ ODT in older children (p = 0.046 and p = 0.026, respectively). The VASt = 0 and VASt = 2-5 were higher for both ODT formulations compared with the standard formulation (p<0.001 for both time points). No serious adverse events were reported. CONCLUSIONS/SIGNIFICANCE: The new paediatric-friendly formulations dispersed in water were both found to be more palatable than the existing standard formulation of PZQ. There may be gender and age effects on the assessment of palatability. Further research is needed for assessing efficacy and tolerability of the newly ODTs Praziquantel drug in younger children. TRIAL REGISTRATION: The trial was registered on ClinicalTrials.gov (NCT02315352) and in the Pan African Clinical Trials Registry (PACTR201412000959159)

A new mouse model for renal lesions produced by intravenous injection of diphtheria toxin A-chain expression plasmid

BACKGROUND: Various animal models of renal failure have been produced and used to investigate mechanisms underlying renal disease and develop therapeutic drugs. Most methods available to produce such models appear to involve subtotal nephrectomy or intravenous administration of antibodies raised against basement membrane of glomeruli. In this study, we developed a novel method to produce mouse models of renal failure by intravenous injection of a plasmid carrying a toxic gene such as diphtheria toxin A-chain (DT-A) gene. DT-A is known to kill cells by inhibiting protein synthesis. METHODS: An expression plasmid carrying the cytomegalovirus enhancer/chicken β-actin promoter linked to a DT-A gene was mixed with lipid (FuGENE™6) and the resulting complexes were intravenously injected into adult male B6C3F1 mice every day for up to 6 days. After final injection, the kidneys of these mice were sampled on day 4 and weeks 3 and 5. RESULTS: H-E staining of the kidney specimens sampled on day 4 revealed remarkable alterations in glomerular compartments, as exemplified by mesangial cell proliferation and formation of extensive deposits in glomerular basement membrane. At weeks 3 and 5, gradual recovery of these tissues was observed. These mice exhibited proteinuria and disease resembling sub-acute glomerulonephritis. CONCLUSIONS: Repeated intravenous injections of DT-A expression plasmid DNA/lipid complex caused temporary abnormalities mainly in glomeruli of mouse kidney. The disease in these mice resembles sub-acute glomerulonephritis. These DT-A gene-incorporated mice will be useful as animal models in the fields of nephrology and regenerative medicine

The specificity of nephritogenic antibodies: II. Immune-complex glomerulopathy in rats induced by heterologous antithymocyte-serum

Injection of rabbit anti-rat thymocyte serum (ATS) i.v into rats induces a transient glomerulopathy characterized by immune aggregates localized in the mesangium and along the glomerular capillary wall, as detected by immunofluorescence (IF) techniques. Neither light microscopical alterations in the kidney, nor proteinuria could be detected in these animals and no autologous IgG could be observed in the glomeruli during the observation period (45 days). Results from ex vivo perfusion studies showed identical localization of immune aggregates—which, in electron microscopy, appear to be localized subepithelially. The ATS used, was monospecific in that no other specificities could be detected after thorough absorption with rat tissue extracts including tubular brushborder antigens, so it is concluded from these data that ATS is able to participate in the formation of immune complexes in situ by recognizing epitopes both in the mesangium and at the epithelial side of the glomerular basement membrane

The mesangium in anti-Thy-1 nephritis. Influx of macrophages, mesangial cell hypercellularity, and macromolecular accumulation.

Mesangial pathology is a hallmark of focal and segmental glomerulosclerosis (FGS). In an immunologically mediated mesangial cell (MC) injury model, we analyzed the relationship between mesangial hypercellularity, increased macromolecular uptake by the mesangium, and long-term pathologic sequelae. A single injection of monoclonal anti-Thy-1 (AT) antibody induces MC apoptosis, extensive mesangiolysis, proteinuria, MC proliferation, and hypercellularity. Immunohistologic analysis indicated influx of ED 1-positive macrophages after 24 hours, which gradually subsiding thereafter. At day 12, hypercellularity was due to smooth musclelike MCs, and macrophagelike MCs were absent. Injection of iron dextran in nephritic rats indicated that mesangial uptake of iron correlated with mesangial hypercellularity, but was independent of proteinuria. Long-term studies showed no difference after 19 weeks in FGS between nephritic and control rats. In conclusion, although mesangiolysis is accompanied by influx of macrophages, a phase of smooth musclelike MC proliferation and increased macromolecular uptake, these pathologic events do not result in chronic mesangial pathology and FGS

The specificity of nephritogenic antibodies. III. Binding of anti-Fx1A antibodies in glomeruli is dependent on dual specificity.

Rabbit antibodies against rat tubular brushborder antigens (Fx1A) give rise to in situ formation of immune aggregates along the glomerular capillary walls after intravenous injection into rats. These antibodies (anti-Fx1A), able to produce heterologous immune complex glomerulopathy (HIC) in the rat, have previously been shown to bind with brushborders (anti-BB) as well as with rat thymocytes (anti-T). In the present communication, this dual specificity was also demonstrated in antibodies eluted from kidneys of rats with HIC. It further appeared that, when the anti-thymocyte binding activity was selectively removed from these antibodies, using immunoabsorption with rat tissue extracts, these anti-Fx1A antibodies were no longer able to stain glomerular basement membranes (GBM) as demonstrated at the ultrastructural level using the peroxidase technique. Following perfusion of these antibodies in the normal rat kidney ex vivo, binding along the capillary walls was also below the detection level, in contrast to non anti-T depleted anti-Fx1A IgG. Biochemical analysis (including immunoblotting) showed that the anti-T moiety of anti-Fx1A was directed to a 90 kD component of Fx1A, since selective absorption of this specificity prevented staining of this 90 kD component. It is concluded, that this anti-T specificity within rabbit anti-Fx1A plays a crucial role in local immune complex formation in the rat kidney ex vivo. Whether this holds also for its role in the pathogenesis of HIC in vivo awaits further confirmation