Introduction: Biopharmaceutics classification system class  II drugs show unpredictable bioavailability based on their solubility. Unfortunately, very few products were manufactured by this technique owing to their poor flowability and stability. The objective of the current investigation was used to improve the flowability by surface solid dispersion (SSD; SD with surface adsorption technology) and improve the absorption of racecadotril (RT) under low pH conditions (i. e., in stomach) to show anti-diarrheal effect by reducing water and electrolyte secretion into the intestine. Materials and Methods: SSDs and physical mixtures (PMs) were prepared using various ratios of hydrophilic carriers (polyethylene glycol 4000, polyethylene glycol 6000, and Gelucire 50/13) and an adsorbent (lactose monohydrate). Fourier-transform infrared spectroscopy, differential scanning calorimetry, X-ray diffractometry, and dissolution studies (in vitro) were conducted to characterize SSDs and PMs. Results: Phase solubility curves represent AL type, indicating that the solubility of drug linearly increased with an increase in the concentration of carrier. Characterization studies indicated that no interactions between carrier and drug. solid-state characterization showed a reduction in crystallinity that further supports increment in solubility and dissolution. The optimized formulation (SDG4) showed 99. 84  ± 1. 5% drug release in 15 min compared to RT plain drug (11. 95  ± 1. 72%). In vivo bioavailability studies of SDG4 revealed a significant (P  <  0. 05) increase in Cmax 65. 38  ± 1. 34  µ g/mL (1. 75-fold) with increased relative bioavailability (180. 22-fold) against the RT plain drug. Conclusion: Formulation of SD with surface adsorption method could enhance solubility, dissolution, and bioavailability of RT.

The present study investigates the possibility of using poloxamers as solubility and dissolution rate enhancing agents of poorly water soluble bioactive constituent patchouli alcohol (PA) that can be used for the preparation of immediate release pellets formulation. Two commercially available grades poloxamer 188 (P 188) and poloxamer 407 (P 407) were selected, and solid dispersions (SDs) containing different weight ratio of PA and poloxamers, and the combination of P 188 and P 407 as dispersing carriers of ternary solid dispersions (tSDs) were prepared by a low temperature melting method and solidified rapidly by dropping into the 10-15 ° C condensing agent atoleine. Both PA/P 188 and PA/P 407 binary solid dispersions (bSDs) could remarkably promote the dissolution rate of PA, increasing approximately 16 times in bSDs with poloxamers in comparison with pure PA within 180 min. P188 contributed to a faster dissolution rate than P 407, however, P 407 had a better solubility. It is interesting to note that the incorporation of P 188 in PA/P 407 bSD pellets could strongly enhance the dissolution rate of PA. DSC and FTIR were used to explore the characteristics of PA-SD pellets. The enhancement of dissolution from the SDs may be attributed partly to the reduction in particle size in PA crystalline due to the formation of eutectic system with poloxamers. Moreover, a simple, accurate in-vitro dissolution test method for volatility drug was established, and the process of PA-SD pellets preparation was simple, rapid, cost effective, uncomplicated and potentially scalable.

Sustained release formulations have many advantages over the conventional dosage forms. There are various techniques to control the release rate of drugs, among which, controlling drug s dissolution rate is most popular due to its success and low cost. Although there are numerous studies to produce sustained release formulations, little studies were carried out to use solid dispersion technique to produce sustained release formulations. Propranolol is a β adrenergic receptor blocker that has some adverse effects. These side effects could be reduced by reduction of usage frequency and producing steady pharmacological effects by preparing sustain release formulation. In this study we tried to use solid dispersion technique to slow down the release rate in water from its tablet formulation. solid dispersion formulations were prepared using molten-solvent technique. The final obtained powder was compressed into tablets and their dissolution were investigated at pH 1.2 and 6.8. FT-IR was used to find any interaction between the drug and excipient. The results showed that solid dispersions produced harder tablets than that of physical mixtures formulations. The amount of eduragit had no significant effect on release rate. It was interesting to note that solid dispersions containing PEG 6000 and eudragit had slow release rate. This indicates that the presence of PEG 6000 to slow down the release of propranolol from eudragit solid dispersion matrices is necessary. It was found that type of Eudragit had not significant effect on the release rate of propranolol from solid dispersions. Ethylcelllose alone was not able to decrease the release rate. Although PEG 6000 is hydrophilic excipient, the reduced release rate in presence of PEG 6000 is due to the enhance effect of PEG 6000 on the hardness of tablets. FT-IR study showed no interaction between the drug and excipients.

In this paper, we examine uid ow and associated dispersion around a circular cylinder under progressive surface wave motion. The ow eld and vortex shedding patterns were studied using ow visualization and Particle Image Velocimetry (PIV). Several patterns of vortex shedding were identi ed around a single cylinder. The vortex shedding patterns under progressive wave motion are similar to those observed in planar oscillatory ow, except in the way the vortices form and in the orientation they take. The observed vortex patterns in progressive wave motion are more unstable than those in planar oscillatory ow. Using particle tracking and the Lagrangian dispersion method, the dispersion coecients were calculated for various ow regimes. The observations con rm the calculations in general. It was also found that wave steepness can aect the shedding pattern. The vortices tend to shed more frequently in a wave direction at low wave steepness.

The main objective of this study is to develop a higher order numerical scheme to simulate the pollutant spreading in surface water resources. The new discretisation schemes in Finite Difference Method are presented in one and two dimensional domain to predict surface water quality. Moreover, the effect of dimensionless computational numbers on numerical processing and errors is investigated for several methods. The grid size sensitivity analysis is made based on numerical results which are obtained in several methods. A real case study is made for thermal pollutant released from cooling water outfall of a power plant into the adjacent river. The numerical results are compared with field measurements and a good agreement is obtained.

Purpose: Our aim was determination of the sheep oocytes ultrastructural changes follow vitrification and in vitro maturation.Materials and Methods: Good quality isolated cumulus-oocyte complexes (COCs) were randomly divided into non-vitrified control, conventional straw, cryotop and solid surface vitrification groups. In the conventional and cryotop methods the vitrified COCs were plunged directly into liquid nitrogen (LN2), whereas in the solid surface group the vitrified COCs were cooled before plunging into LN2. Fresh and vitrified-warmed healthy COCs were matured in vitro and then their ultrastructural changes were evaluated.Results: The results indicated that vitrification by cryotop and solid surface methods preserved the total arrangement of the ooplasm, whereas conventional straw vitrification disturbed the ooplasm organization. Additionally, the number of vacuoles in the ooplasm increased after vitrification, some of these vacuoles were filled partially or completely with lipids and some had filamentous scaffolding. Also, in the mature oocytes, the amount and the density of cortical granules decreased after conventional straw and solid surface vitrification.Conclusion: Cryotop group compared with other vitrification methods could preserve oocyte ultrastructure properly and create a condition the same as like as the control group.

Some drugs have low bioavailability due to their poor aqueous solubility and/or slow dissolution rate in biological fluids. Stiripentol (STP) is a novel anticonvulsant drug that is structurally unrelated to the currently available antiepileptics. It has poor aqueous solubility and its solubility has to be enhanced accordingly. Polyethylene glycol 6000 (PEG-6000) is commonly utilized as a hydrophilic carrier for poorly water soluble drugs in order to improve their bioavailability. STP and PEG-6000 binary system was obtained by physical mixture, solvent evaporation, co-evaporation and melting methods using different weight ratios. The properties of the prepared binary systems were evaluated using dissolution rate, phase solubility, Fourier-transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC) and scanning electron microscope (SEM) studies. The FTIR spectroscopic studies showed the stability of STP and absence of STP-PEG-6000 interaction. The DSC and SEM studies indicated the amorphous state of STP in its binary systems with PEG-6000.Dissolution profile of STP was significantly improved via complexation with PEG-6000 as compared with the pure drug. The binary system which was prepared using melting method showed the highest dissolution rate. The promising results of the prepared binary systems open the avenue for further oral formulation of STP.

Meloxicam is a non steroidal anti-inflammatory drug, used in the treatment of rheumatoid arthritis and oestoarthritis. It is practically insoluble in water leading to poor dissolution, variations in bioavailability and gastric irritation on oral administration. In order to modulate its gastric side effect and to increase aqueous solubility, physical mixture and solid dispersion of the drug were prepared with polyethylene glycol 6000 and polyvinyl pyrrolidine. The analgesic, anti-inflammatory and ulcerogenic effects were assessed for physical mixture and solid dispersion in comparison with meloxicam alone. The results indicate that both physical mixture and solid dispersion possess better analgesic and anti-inflammatory properties with less ulcerogenic potential as compared to pure meloxicam.