A Study on Pharmacokinetics of Acetylsalicylic Acid Mini-Tablets in Healthy Adult Males-Comparison with the Powder Formulation.

Children with Kawasaki disease are prescribed acetylsalicylic acid powder as an antipyretic analgesic and antiplatelet agent; however, some of it remains in the mouth, leading to a bitter or sour taste. To address this issue, an in-hospital mini-tablet formulation of acetylsalicylic acid was developed. In order to use the mini-tablets safely and effectively, dissolution tests alone are not sufficient. Therefore, an open-label crossover study on six healthy participants was conducted to evaluate comparative pharmacokinetic parameters. The pharmacokinetic parameters of salicylic acid were Cmax: 4.80 ± 0.79 mg/L (powder; P), 5.03 ± 0.97 mg/L (mini-tablet; MT), AUC0-12: 18.0 ± 3.03 mg-h/L (P), 18.9 ± 4.59 mg-h/L (MT), those of acetylsalicylic acid Cmax: 0.50 ± 0.20 mg/L (P), 0.41 ± 0.24 mg/L (MT), AUC0-12: 0.71 ± 0.27 mg-h/L (P), 0.61 ± 0.36 mg-h/L (MT), with no significant differences between the mini-tablet and powder formulations. Although pharmacokinetic results obtained from adults cannot be directly applied to children, the results of this study are important for predicting pharmacokinetics. Furthermore, a formulation that can improve medication adherence in children who have difficulty taking acetylsalicylic acid powder, thus contributing to pediatric drug therapy.

Comparison of Bitterness Intensity between Prednisolone and Quinine in a Human Sensory Test Indicated Individual Differences in Bitter-Taste Perception.

Prednisolone is a frequently prescribed steroid with a bitter, unpalatable taste that can result in treatment refusal. Oral suspensions or powder dosage forms are often prescribed, particularly to pediatric patients, as they improve swallowability and ease of dose adjustment. Consequently, the bitterness of prednisolone is more apparent in these dosage forms. Few studies have investigated prednisolone's bitterness. Thus, in this study, 50 adults evaluated the bitterness of prednisolone using the generalized Labeled Magnitude Scale (gLMS), in comparison with quinine, a standard bitter substance. Overall, prednisolone-saturated solution demonstrated the same extent (mean gLMS score: 46.8) of bitterness as 1 mM quinine solution (mean gLMS score: 40.1). Additionally, large individual differences were observed in the perception of the bitterness of prednisolone and quinine. Perceived flavors of some drugs are reportedly associated with bitter-taste receptor (TAS2Rs) polymorphisms. Therefore, we investigated the relationship between subjects' genetic polymorphisms of TAS2R19, 38, and 46, and their sensitivity to bitterness. Although a relationship between TAS2R19 polymorphisms and the perception of quinine bitterness was observed, no significant relationship was found between the perceived bitterness of prednisolone and the investigated genes. Ultimately, the results show that despite individual differences among subjects, the cause of prednisolone's strong bitterness is yet to be elucidated.

Visualizing fluid transport inside orally disintegrating tablets and changes in tablets using real-time X-ray radiography and X-ray computed tomography.

OBJECTIVE: To investigate the disintegration of wet- and dry-compressed orally disintegrating (OD) tablets, with synchrotron radiation as the X-ray source. SIGNIFICANCE: Pharmaceutical tablets are vital for the treatment of various diseases. Therefore, they are constantly developed to ensure desirable characteristics. In particular, OD tablets need to disintegrate immediately after absorbing saliva. How these tablets absorb saliva is key to enhancing rapid product development. Recently, absorption processes have been investigated using various noninvasive techniques, including X-ray radiography and X-ray computed tomography. However, X-ray radiography studies on how water without a contrast agent is absorbed, moves, and causes a tablet to swell are scarce. The use of a contrast agent is associated with some shortcomings, including complex data analysis in some instances, alterations in the viscosity of water, and potential influence on fluid transport inside the tablet, thus possibly affecting the disintegration process. METHODS: Real-time X-ray radiography was used to monitor the disintegration of various tablets, while X-ray computed tomography and software were used to create 3 D images. RESULTS: We demonstrated how pure water penetrated the wet-compressed tablet faster than inside the dry-compressed tablet, and how the latter swelled more. X-ray computed tomography showed the presence of voids in the tablets following water absorption. CONCLUSION: Our methods are promising for nondestructive fluid absorption and transport investigations inside OD tablets.

Effect of xanthan gum-based food thickeners on the dissolution profile of fluoroquinolones oral formulations.

BACKGROUND: Xanthan gum-based food thickeners (XG-FTs) are often ingested by patients with dysphagia to prevent aspiration during drug treatment. Reportedly, XG-FTs affect tablet disintegration, drug dissolution rates, and reduce the efficacy of postprandial antihyperglycemic agents. The absorption rate and quantity of fluoroquinolone antimicrobial agents correlate with drug efficacy, raising concern about the impact of XG-FTs. Previously, we reported that film-coated tablets were less susceptible to the effects of XG-FT than conventional and orally disintegrating tablets. Here, we compare the effect of XG-FTs on dissolution profiles of three oral fluoroquinolone-based film-coated tablets by evaluating the dissolution of crushed products, fine granules, and film-coated fine granules. METHODS: We examined formulations of tosufloxacin tosylate monohydrate (TFLX), levofloxacin hemihydrate (LVFX), and ciprofloxacin hydrochloride hydrate (CPFX). The formulations were immersed in 20 mL of 1.5% (w/v) XG-FT aqueous solution for 2.5 min followed by a dissolution test using the paddle method according to the Japanese Pharmacopoeia (dissolution test solution pH 1.2; volume 900 mL; temperature 37 ± 0.5 °C). The dissolution profile was evaluated according to the dissolution quantity indicated in product specifications and guidelines for bioequivalence testing of generic drugs. The 15-min mean dissolution rate was determined for a formulation immersed in 1.5% (w/v) XG-FT aqueous solution and compared with that for a non-immersed formulation (control). Fluoroquinolone film-coated tablets were mixed with starch-based FTs, guar gum-based FTs, or XG-FTs to observe their appearances. RESULTS: The dissolution profile of LVFX film-coated tablets was not affected by XG-FTs, but the dissolution of TFLX and CPFX was delayed. For crushed film-coated tablets, the 15-min mean dissolution rate was significantly delayed for all three fluoroquinolones when compared with that of uncrushed products. The dissolution profile of TFLX film-coated fine granules was unchanged by XG-FTs. CPFX film-coated tablets and crushed products produced a gel-like precipitate when mixed with XG-FTs and failed to meet product-dissolution specifications. A gel-like precipitate was also observed with guar gum-based FTs. CONCLUSION: The effect of XG-FTs on the dissolution profile of film-coated fluoroquinolone formulations varied depending on the formulation. The CPFX formulation formed a gel-like precipitate when immersed in XG-FTs resulting in a significantly delayed dissolution.

Effect of Disintegrants on Prolongation of Tablet Disintegration Induced by Immersion in Xanthan Gum-Containing Thickening Solution: Contribution of Disintegrant Interactions with Disintegration Fluids.

In clinical practice, a thickening solution is frequently used to allow easy swallowing of tablets by patients suffering from dysphagia. This study investigated the effect of the thickening solution on tablet disintegration. Model tablets containing different disintegrants were prepared and their disintegration times (DTs) measured using standard methods. We also performed an additional disintegration test on the model tablets after immersing them for 1 min in thickening solution containing xanthan gum (XTG-SOL) ("modified disintegration test"). The DTs of the test tablets were substantially prolonged by immersion in XTG-SOL. Furthermore, the effect of the XTG-SOL on the DTs differed depending on the type of disintegrant contained in the tablets. To investigate in more detail this prolongation of tablet disintegration, we examined the contribution of tablet properties to their DTs. The properties analyzed included contact angle, T2 relaxation time, wetting time, and water absorption ratio. The contributions of these properties to the DTs were analyzed using multiple regression analysis. This analysis clarified that the tablet properties affecting DTs changed after immersion in XTG-SOL: wetting time significantly affected the DTs measured in the normal disintegration test, while T2 was crucial for the DTs of tablets immersed in XTG-SOL. These findings provide valuable information for design of tablet formulations, and for clinical medication management for older patients with dysphagia.

Characterization of cytoplasmic female sterility in an alloplasmic and monosomic addition line of Brassica rapa carrying the cytoplasm and one chromosome of Diplotaxis tenuifolia.

Alloplasmic plants exhibit various phenotypic changes such as cytoplasmic male sterility (CMS). We have been attempting to produce an alloplasmic Brassica rapa CMS line (2n = 20) carrying Diplotaxis tenuifolia cytoplasm (cyt-Dt) for several years, but a single extra chromosome always remained in all lines produced. We confirmed a D. tenuifolia-specific band in the alloplasmic line carrying D. tenuifolia cytoplasm by RAPD analysis, indicating that the additional chromosome was derived from D. tenuifolia. Here, we observed the phenotypic characteristics of the alloplasmic B. rapa monosomic addition line, named (cyt-Dt) B. rapa MAL, and investigated why a single extra chromosome is required in its genetic background for viability. When the (cyt-Dt) B. rapa MALs were crossed with pollen of several B. rapa lines, approximately 50% of the ovules attracted pollen tubes, and all the progeny had the additional chromosome. These results suggested that only the female gametes with n = 11 rather than n = 10 were fertilized and developed into mature seeds, and that cytoplasmic female sterility was overcome by nuclear restorer gene(s) derived from the cytoplasmic donor species.

Development of sensory neuropathy in streptozotocin-induced diabetic mice.

Diabetic polyneuropathy is a major complication of diabetes and the most common cause of peripheral neuropathy. Sensory-dominant neuropathy is the most common type. We previously used streptozotocin (STZ)-induced diabetic ddY mice with sensory neuropathy to evaluate the therapeutic effects of vascular endothelial growth factor and placental growth factor isoforms. In this study, to characterize the development of diabetic sensory neuropathy, electrophysiological, behavioral, and histopathological studies were performed in these diabetic mice. A significant difference in sensory conduction velocity in the tail nerve was observed between healthy and diabetic mice at 1 week after STZ injection. Diabetic mice developed hypoalgesia at 5 weeks after STZ injection. Axon area and myelin thickness of the myelinated fibers were increased in 17-week-old healthy mice compared with those in 8-week-old healthy mice. However, these increases were retarded in 17-week-old diabetic mice. In unmyelinated fibers, axon area was significantly reduced in 17-week-old diabetic mice compared with 8- and 17-week-old healthy mice. These findings suggest that both impaired maturation of myelinated fibers and atrophy of unmyelinated fibers simultaneously occur in the early stage of diabetes in these mice. Our mouse model may be useful for studying the pathogenesis of and therapies for diabetic sensory neuropathy.

Placental growth factor-2 gene transfer by electroporation restores diabetic sensory neuropathy in mice.

Placental growth factor-2 (PlGF-2) exhibits neurotrophic activity in dorsal root ganglion (DRG) neurons through the neuropilin-1 (NP-1) receptor in vitro. To examine the potential utility of PlGF-2 therapy for treating diabetic neuropathy, we performed intramuscular PlGF-2 gene transfer by electroporation, and examined its effects on sensory neuropathy in diabetic mice. PlGF-2 was overexpressed in the tibial anterior (TA) muscles of streptozotocin-induced diabetic mice with hypoalgesia using a PlGF-2 plasmid injection with electroporation. The nociceptive threshold was measured using a paw-pressure test. In addition, we overexpressed PlGF-1, an isoform of PlGF that does not bind NP-1. The sciatic nerve and skin were examined 3weeks after PlGF-2 electro-gene transfer. The overexpression and secretion of PlGF-2 in TA muscles were confirmed by an increase in PlGF levels in TA muscles and plasma, and strongly PlGF positive myofibers in TA muscles. Two weeks after electro-gene transfer into the bilateral TA muscles, the previously elevated nociceptive threshold was found to be significantly decreased in all treated mice. PlGF-1 gene transfer by electroporation did not significantly decrease the nociceptive threshold in diabetic mice. No increase in the number of endoneurial vessels in the sciatic nerve was found in the PlGF-2 plasmid-electroporated mice. A reduction of area of immunoreactivity in epidermal nerves in diabetic mice was restored by PlGF-2 gene transfer. These findings suggest that PlGF-2 electro-gene therapy can significantly ameliorate sensory deficits (i.e. hypoalgesia) in diabetic mice through NP-1 in DRG and peripheral nerves.

Characterization and cDNA cloning of aminopeptidase A from the venom of Gloydius blomhoffi brevicaudus.

The aminopeptidase activities of snake venoms from Gloydius blomhoffi brevicaudus, Gloydius halys blomhoffii, Trimeresurus flavoviridis, Bothrops jararaca and Crotalus atrox were investigated. Aminopeptidase A (APA), aminopeptidase B and aminopeptidase N activities were present in all snake venoms. The strongest APA activity was found in venom from G. blomhoffi brevicaudus. The susceptibility to metallopeptidase inhibitors and the pH optimum of the partially purified enzyme from G. blomhoffi brevicaudus venom were similar to those of known APAs from mammals. A G. blomhoffi brevicaudus venom gland cDNA library was screened to isolate cDNA clones using probes based on highly conserved amino acid sequences in known APAs. Molecular cloning of APA from G. blomhoffi brevicaudus venom predicted that it was a type II integral membrane protein containing 958 amino acid residues with 17 potential N-linked glycosylation sites. It possessed a His-Glu-Xaa-Xaa-His-(Xaa)(18)-Glu zinc binding motif that allowed the classification of this protein as a member of the M1 family of zinc-metallopeptidases, or gluzincins. The deduced amino acid sequence shows approximately 60% sequence identity to mammalian APA sequences. This is the first study to report the primary structure of APA from a reptile.

A novel peptide from the ACEI/BPP-CNP precursor in the venom of Crotalus durissus collilineatus.

In crotaline venoms, angiotensin-converting enzyme inhibitors [ACEIs, also known as bradykinin potentiating peptides (BPPs)], are products of a gene coding for an ACEI/BPP-C-type natriuretic peptide (CNP) precursor. In the genes from Bothrops jararaca and Gloydius blomhoffii, ACEI/BPP sequences are repeated. Sequencing of a cDNA clone from venom glands of Crotalus durissus collilineatus showed that two ACEIs/BPPs are located together at the N-terminus, but without repeats. An additional sequence for CNP was unexpectedly found at the C-terminus. Homologous genes for the ACEI/BPP-CNP precursor suggest that most crotaline venoms contain both ACEIs/BPPs and CNP. The sequence of ACEIs/BPPs is separated from the CNP sequence by a long spacer sequence. Previously, there was no evidence that this spacer actually coded any expressed peptides. Aird and Kaiser (1986, unpublished) previously isolated and sequenced a peptide of 11 residues (TPPAGPDVGPR) from Crotalus viridis viridis venom. In the present study, analysis of the cDNA clone from C. d. collilineatus revealed a nearly identical sequence in the ACEI/BPP-CNP spacer. Fractionation of the crude venom by reverse phase HPLC (C(18)), and analysis of the fractions by mass spectrometry (MS) indicated a component of 1020.5 Da. Amino acid sequencing by MS/MS confirmed that C. d. collilineatus venom contains the peptide TPPAGPDGGPR. Its high proline content and paired proline residues are typical of venom hypotensive peptides, although it lacks the usual N-terminal pyroglutamate. It has no demonstrable hypotensive activity when injected intravenously in rats; however, its occurrence in the venoms of dissimilar species suggests that its presence is not accidental. Evidence suggests that these novel toxins probably activate anaphylatoxin C3a receptors.

Molecular cloning of serine proteinases from Bothrops jararaca venom gland.

Snake venom is known to contain an abundance of enzyme isoforms, and various disorders associated with envenomation have been ascribed partially to their diversified functions. Crude venom of Bothrops jararaca was subjected to conventional two-dimensional SDS-PAGE, followed by immunoblot analysis using an antiserum raised against KN-BJ 2, a serine proteinase previously isolated from this venom. A number of immunoreactive proteins with comparable molecular masses and different pIs emerged, implying the venom contains yet-unknown serine proteinases. A B. jararaca venom gland cDNA library was subsequently screened with a labeled KN-BJ 2 cDNA as a probe. Among a number of positive cDNA clones, three--HS112, HS114, and HS120--were selected and sequenced. These clones each had an open reading frame of 759-774 bp, and their deduced amino acid sequences illustrated considerable similarities to that of KN-BJ 2 as well as to those of serine proteinases of different origins. However, no apparent match to any of the deposited sequences was found in the current GenBank/EMBL databases, indicating that each of these cDNA clones encodes a serine proteinase distinct from the known enzymes. Analyses of the nucleotide and amino acid sequences of these cDNA clones support the accelerated evolution hypothesis proposed for snake venom enzymes.

Identification of multiple cytochrome P450 genes belonging to the CYP4 family in Xenopus laevis: cDNA cloning of CYP4F42 and CYP4V4.

In order to obtain cDNA clones coding for CYP4 proteins in frog Xenopus laevis, degenerate primers were designed utilizing the conserved sequences of known CYP4s and were used to amplify partial cDNA fragments from liver mRNA. Five new CYP genes were identified. Three of these genes, XL-1, -2 and -3, were assigned to the CYP4T subfamily found previously in fish and amphibians. The other two genes, XL-4 and XL-5, were quite similar to CYP4F and CYP4V subfamilies, respectively. Subsequently, two full-length cDNA clones corresponding to XL-4 and XL-5 were isolated and characterized. The resultant cDNAs, designated as CYP4F42 and CYP4V4, had open reading frames encoding proteins of 528 and 520 residues, respectively. RT-PCR analysis indicated that the expression of CYP4F42 was limited to the liver, kidney, intestine and brain. In contrast, CYP4V4 mRNA was expressed ubiquitously.

The unusual high molecular mass of Bothrops protease A, a trypsin-like serine peptidase from the venom of Bothrops jararaca, is due to its high carbohydrate content.

Bothrops protease A (BPA) is a serine peptidase isolated from the venom of Bothrops jararaca. Unlike many venom enzymes, it is stable at pHs between 3 and 9 and resists heating at 86 degrees C for 10 min. Mature snake venom serine peptidases of the chymotrypsin family are in general glycoproteins composed of around 232 amino acids and their molecular masses vary between 25 and 40 kDa. BPA is a glycosylated protein that migrates on SDS-polyacrylamide gel electrophoresis (PAGE) as a single band of 67 kDa. In order to find out whether BPA has the typical serine peptidase primary structure or if it is composed of a longer amino acid sequence, we cloned a cDNA encoding BPA. Its deduced amino acid sequence showed that BPA is composed of 234 residues with a calculated molecular mass of 25,409 Da implying that approximately 62% of its molecular mass assessed by SDS-PAGE is due to carbohydrate moieties. Eight putative N-glycosylation and two putative O-glycosylation sites were found in BPA amino acid sequence. Deglycosylation experiments indicated that all 10 potential glycosylation sites in BPA are utilized. Complete N- and O-deglycosylation was only achieved under denaturing conditions and generated main products of 25 and 55 kDa, respectively, which were enzymatically inactive. N-deglycosylation under non-denaturing conditions was only partial and gave a main product of 50 kDa and fragments ranging from 25 to approximately 10 kDa. Kinetic parameters K(m) and V(max) of partially N-deglycosylated BPA upon substrate Bz-Arg-pNA were similar to the native form. However, when partially N-deglycosylated BPA was submitted to pH 3 and pH 10, it appeared to be unstable as it underwent hydrolysis, as shown by the presence of two main products of 30 and 12 kDa while the 50 kDa protein band disappeared. These changes also had effects on V(max) upon Bz-Arg-pNA which dropped to approximately 45%, while K(m) values remained unchanged. Fluorescence emission spectroscopy indicated that in partially N-deglycosylated BPA, tryptophan residues are more exposed to a polar environment than in the fully glycosylated protein. Taken together, these studies indicate that glycosylation has a stabilizing effect on BPA.

Molecular cloning and expression analysis of the aryl hydrocarbon receptor of Xenopus laevis.

The aryl hydrocarbon receptor (AHR) is a member of the basic helix-loop-helix/Per-Arnt-Sim (bHLH/PAS) family of transcription factors. Although this receptor has been known to mediate the toxic effects of environmental pollutants, its physiological functions remain elusive. Here, we describe the isolation and expression pattern of the Xenopus AHR gene. The predicted amino acid sequence contained regions characteristic of other vertebrate AHRs. However, in line with previously described fish AHR genes, no distinct Q-rich domain was found. Phylogenetic analysis demonstrated that Xenopus AHR was clustered within the AHR1 clade. As in the case of mammalian AHR genes, the Xenopus AHR gene was expressed in all the adult tissues tested. Xenopus AHR was also expressed during early development, in parallel with expression of the CYP1A7 gene, which is thought to be regulated by AHR. These results suggest that while frogs are relatively tolerant to TCDD toxicity, the AHR of frogs has characteristics similar to those of other vertebrate AHRs.

A Protein That Binds an Exogastrula-Inducing Peptide, EGIP-D, in the Hyaline Layer of Sea Urchin Embryos: (exogastrula-inducing peptide (EGIP)/binding protein/hyaline layer/sea urchin/exogastrulation).

Exogastrula-inducing peptides are present in eggs and embryos of the sea urchin Anthocidaris crassispina. They induce exogastrulation when added exogenously to the embryos. In the present study, we investigated an EGIP-D-binding protein in the embryos. EGIP-D was incubated with homogenates of embryos. EGIP-D was then cross-linked to the binding protein by use of disuccinimidyl suberate (DSS) and the complex was analyzed by western blotting with an EGIP-D-specific antibody. A 30-kDa protein was detected in both eggs and embryos. To examine the localization of this protein, EGIP-D was added to intact embryos, cross-linked to proteins by use of DSS, and the complexes were again analyzed by western blotting. The EGIP-D-binding protein was detected in intact embryos but not in embryos treated with Ca2+ - and Mg2+ -free seawater (CMF-SW) that removes the hyaline layer (HL). It appeared, therefore, that this protein was present on the outer surface of the embryo, being a constituent of the HL. The CMF-SW extract that contained EGIP-D-binding protein, inhibited the induction of exogastrulation by EGIP-D. Furthermore, the treatment of embryos with CMF-SW prevented EGIP-D from inducing exogastrulation. Our observations indicate that the interaction between EGIP-D and the binding protein is a prerequisite for induction of exogastrulation by EGIP-D.

Maternal Exogastrula-Inducing Peptides (EGIPs) and Their Changes during Development in the Sea Urchin Anthocidaris crassispina.

Exogastrula-inducing activity was examined in eggs and embryos of the sea urchin Anthocidaris crassispina at various stages. During fractionation on a column of DEAE-cellulose, the exogastrula-inducing activity was found in the flow-through fraction at all developmental stages. In particular, the activity present in the flow-through fraction of unfertilized eggs represents the presence of maternal exogastrula-inducing peptides (EGIPs). The flow-through fractions from the column of DEAE-cellulose were applied to a column of Sephadex G-100 and the activities in the eluate were assayed. The active low-molecular-weight fraction was obtained in all cases with the exception of pluteus larvae, extracts of which contained another active fraction. Immunoblots of protein samples from eggs and embryos probed with antiserum against EGIP-D indicated that there is a major immunoreactive protein that migrates with an apparent molecular weight of about 6 kDa in all cases with the exception of pluteus larvae, and that there are two major immunoreactive proteins that migrate with apparent molecular weights of 6 kDa and 35 kDa, respectively, in pluteus larvae.