Insight on the Void Ratio-Suction Relationship of Compacted Bentonite during Hydration

Investigation on swelling characteristics of buffer/backfill materials during hydration is an important issue in the design of artificial barriers in high-level radioactive waste (HLW) disposal repositories. In this work, for clarifying the characteristic of void ratio–suction relationship for compacted bentonite on hydration path, suction-controlled swelling deformation tests under constant vertical stresses 0.001~40 MPa were carried out on compacted bentonite specimens. Four different types of void ratio-suction curves indicated that swelling-collapse behavior under hydration depends on suction and over-consolidation ratio (OCR), based on which the swelling index was defined. Then, equations were proposed for describing the swelling-collapse characteristic of void ratio–suction curves. Simulation results of suction-controlled swelling deformation tests show that the different types of the hydration deformation curves could be well described by the proposed equations. Obviously, the proposed equations could be used for description and prediction of swelling characteristics of compacted bentonite during hydration, which is also of great importance for the safety assessment of the HLW repositories.

Metronidazole Based Floating Bioadhesive Drug Delivery System for Potential Eradication of H. pylori: Preparation and In Vitro Characterization

Metronidazole has the potential to produce local stomach specific action in order to treat Helicobacter pylori induced peptic ulcer disease. The current project executes the development of osmotically controlled bioadhesive metronidazole loaded effervescent floating tablets with optimized floating and swelling behavior. Direct compression technique was used to prepare the tablets. The designed formulations exhibited physico-chemical properties within acceptable optimum limits as per pharmacopeial requirements. The results of tablet floating studies revealed that all formulations, except F1 and F5, had good buoyancy characteristics (TFT > 12 h except F2 and F8 with TFT of 6 h). Formulation F2 containing guar gum in higher concentration with carbopol and formulation F8 containing guar gum in 50% decreased concentration in combination with HPMC and carbopol had enhanced FLT appreciably, with least TFT as compared to formulations F3, F4, and F6 (ANOVA; p ≤ 0.05). Formulation batches of F3, F4, and F6 exhibited appreciable FLT as well as TFT and were optimized formulations. Out of the above mentioned optimized batches, F4 and F6 formulations showed low FLT (4 and 5 s respectively). The results of the swelling study indicated a proportionate increase in the swelling index with increase in time. A significantly higher swelling ratio was found with formulation F6 and F4 compared with that of F7 and F8 (ANOVA; p ≤ 0.05). Additionally, the impact of pH change, agitational intensity, as well as increasing concentration of NaCl was investigated on drug release. It was observed that agitational intensity had no effect on drug release rate while increasing concentration of NaCl produced an increased drug release from the dosage form as compared to the drug release exhibited by the formulations in the absence of NaCl. Overall, this project could have valuable contribution in the fabrication of metronidazole loaded effervescent floating tablets. Gastro-retentive systems are expected to enhance local stomach specific action of anti H. pylori agents based on their buoyancy and swelling behavior.

Instant rice-based composite pasta requiring no cooking

The present study was undertaken to develop rice-based composite pasta with improved cooking/rehydrating and nutritional qualities. Pasta samples (T1-T10) having different proportions of rice flour (RF, 60-80%), wheat flour (WF, 40-12%), malted green gram flour (MGGF, 5 and 10%) and guar gum (GG, 1-3%) were prepared using a single screw extruder. Pasta made of 100% WF served as the control (T0). The cooked or rehydrated samples were evaluated for their cooking properties (optimum cooking time, cooking loss and swelling index), whiteness and yellowness indices, textural and organoleptic parameters. Substitution of WF by RF significantly reduced the cooking time, and improved the whiteness and swelling indices of the samples. However, reduction in WF increased the cooking loss, compromised textural and organoleptic attributes in samples with high RF content (80%); nevertheless, addition of GG and MGGF reduced these losses and improved the sensory qualities (p < 0.05). Irrespective of the composition of rice-based pasta, the optimal cooking time ranged within 2-4 min (unlike T0) and these samples could also be rehydrated in hot water within a short span of 5 min to attain textural qualities at par with their cooked counterparts and with sensorial scores well above the limit of acceptable range (≥5) (except T3 (80%RF + 20%WF)); nonetheless the cooked ones led to higher preference from the sensory panel. Adhesiveness of the rehydrated samples was lesser than their cooked counterparts, while vice versa was observed in case of their instrumental firmness/hardness. Among these, T7 (70%RF + 19%WF + 10%MGGF + 1%GG) and T9 (80%RF + 13%WF + 5%MGGF + 2%GG) exhibited high protein content (∼1.17-1.29 times higher than T0) and the most desired low in vitro starch digestibility and calorific values (∼1.16-1.25 fold reduction). Thus low-cost quick-cooking/rehydrating pasta can be successfully developed by adding suitable amount of MGGF and GG into rice-wheat composite flours.

Value of Grayscale and Power Doppler High-Resolution Ultrasound in Assessment of Patients with Clinically Suspected Carpal Tunnel Syndrome

OBJECTIVES

To determine the value of grayscale and power Doppler ultrasound (PDUS) in the evaluation of carpal tunnel syndrome (CTS) in clinically suspected patients.

METHODS

Eighty-seven wrists of 61 patients with clinically suspected CTS and 57 wrists of 30 healthy control participants were included in our study. Median nerve (MN) cross-sectional area (CSA) measurements were performed at the tunnel inlet level (wCSA) and proximal pronator quadratus muscle level (fCSA). Two parameters were calculated: CSA absolute difference (ΔCSA), which was the difference between the two measurements; and CSA ratio (RCSA), calculated by dividing wCSA over fCSA. The MN at the wrist level was evaluated for hypervascularity with PDUS.

RESULTS

The mean wCSA, R-CSA, and ΔCSA values were significantly higher in patients (17 mm² , 2.45, and 9.9 mm² , respectively) than in control participants (8 mm² , 1.29, and 1.65 mm² ; (P < .0001). At their corresponding cutoff values, the wCSA yielded higher sensitivity (95%) and lower specificity (88%) compared to the RCSA and ΔCSA (89% and 93% sensitivity and 93% and 89% specificity). Power Doppler US was the most specific US parameter (100%) but the least sensitive (76%). A multivariate logistic regression model including the wCSA, RCSA, and PDUS yielded 97% diagnostic accuracy at their optimal cutoffs, which increased to 99% after eliminating age and body mass index confounding effects.

CONCLUSIONS

The combination of MN swelling measurements and PDUS increases the diagnostic accuracy of US in patients with clinically suspected CTS.

Isolation, characterization, and evaluation of Cassia fistula Linn. seed and pulp polymer for pharmaceutical application

Introduction:

Present work, is an effort toward exploring the potential of Cassia fistula Linn. seed gum as an extended release polymer and laxative. While, C. fistula pulp polymer has evaluated as suspending agent.

Materials and Methods:

For extended release application, total five batches (F1-F5) were prepared by varying the ratio of drug:polymer as 1:1, 1:2, 1:3, 1:4, and 1:5, respectively. The granules were prepared by wet granulation method and further evaluated for micromeritic properties such as angle of repose (θ), Carr's compressibility index (CCI), and Hausner's ratio. Further compacts were evaluated by hardness, thickness, swelling index, in-vitro dissolution, and so on. Laxative activity was evaluated by administration of seed polymer (100 mg/kg) alone or in combination with bisacodyl (2.5 mg/kg) in 1% Tween 80. Zinc oxide suspension was prepared by varying the concentration of C. fistula pulp polymer and compared with suspension made by use of tragacanth, sodium carboxymethyl cellulose and bentonite.

Results:

Result showed that granules were free flowing, while the compact extended the drug release up to 10 h (72.84 ± 0.98; batch F5) and followed Higuchi matrix release kinetics. This extended release might be due to the formation of polyelectrolyte complex because of gluco-mannose in seed gum. Result of in-vivo laxative activity showed that seed polymer reduced faeces weight after 24 h compared to control (P < 0.01).

Conclusions:

Pulp polymer showed good sedimentation volume, but alone fails to stabilize the suspension for a longer period, so it could be useful in combination with other suspending agents and can be useful as novel excipient.

Formulation and optimization of mucoadhesive bilayer buccal tablets of atenolol using simplex design method

Introduction:

In the present study, mucoadhesive buccal bilayer tablets of atenolol were fabricated with the objective of avoiding first pass metabolism and to improve its bioavailability with reduction in dosing frequency. Hence, the aim of this work was to design oral controlled release mucoadhesive tablets of atenolol and to optimize the drug release profile and bioadhesion.

Materials and Methods:

Bilayer buccal tablets of atenolol were prepared by direct compression method using simplex method of optimization to investigate the combined effect of hydroxypropyl methylcellulose 15 cps (X₁), Carbopol (X₂) and mannitol (X₃); the in vitro drug release (Y₁) and mucoadhesive strength (Y₂) were taken as responses. The designed tablets were evaluated for various physical and biological parameters like drug content uniformity, in vitro drug release, short-term stability, and drug- excipient interactions (FTIR).

Results:

The formulation C containing hydroxypropyl methylcellulose 15 cps (10% w/w of matrix layer), Carbopol 934p (10% w/w of matrix layer) and mannitol (channeling agent, 40% w/w of matrix layer) was found to be promising. This formulation exhibited an in vitro drug release of 89.43% in 9 h along with satisfactory bioadhesion strength (7.20 g). Short-term stability studies on the promising formulation indicated that there are no significant changes in drug content and in vitro dissolution characteristics (P<0.05). IR spectroscopic studies indicated that there are no drug-excipient interactions.