Search

Objective(s): 4-aminosalicylic acid (4-ASA) is an isomer of mesalazine that has recently been shown to be effective against inflammatory bowel disease (IBD), and more specifically, ulcerative colitis. However, the majority of orally administered 4-ASA is readily and extensively absorbed from the stomach and small intestine, so only a small amount is transported to the colon. A mutual ester and azo prodrug of 4-ASA was synthesized with polyethylene glycol (PEG) and dimethylaniline, respectively , to overcome this issue. Materials and Methods: The 4-ASA prodrug was synthesized via a two-step process and then characterized by 1H-NMR. The stability of the prodrug was evaluated in simulated gastric fluid (pH 1.2). Furthermore, the in vitro release profiles of the drug conjugate was evaluated at pH 1.2, as well as pH 6.8 in the absence or presence of rat cecal content. Results: The prepared prodrug was stable at pH 1.2, indicating that it could be protected from the acidic environment of the stomach. Also, the results of drug release at pH 6.8 showed that the amount of 4-ASA released was 63% within 12 hr in the absence of rat cecal content, while in the presence of rat cecal content, 97% of 4-ASA was released from the prodrug in 6 hr. Conclusion: Overall, the synthesized PEGylated azo-based 4-ASA prodrug could be a potential candidate for targeted drug delivery to the inflamed gut tissue in IBD. [ABSTRACT FROM AUTHOR]

Objective(s): Gastric cancer is the third leading cause of cancer-related death worldwide. The overall survival rate of patients is poor because gastric cancers are usually diagnosed at the late stages. Therefore, further research is needed and appropriate research tools are required to develop novel therapeutic approaches. Materials and Methods: Eight female athymic nude mice with a C57BL/6 background were used in this study. AGS cells were inoculated into the flank. The tumor volumes were calculated and growth curves were drawn. When the volume of the tumors reached 1000 mm3, the animals were humanely euthanized with CO2 gas. After harvesting, tumors were analyzed with Hematoxylin and Eosin (H&E) and immunohistochemistry (IHC). A pathologist confirmed tumor entity through H&E staining. Tumors were evaluated for expression of HER-2, P53, Ki-67, CD34, cytokeratin 8 (CK8), vimentin, estrogen receptor (ER), and progesterone receptor (PR) utilizing immunohistochemistry. Results: The tumor take rate was 62.5%, mean doubling time was 40.984 d, and the latency period was 30.62 days. The H&E staining results showed highly malignant hyperchromatin epithelial cells. IHC assessment showed the mutation status of P53 gene. The expression score of the CK8 protein in the tumor cells was +3. Vimentin protein was not expressed and changes in mesenchymal phenotype were not observed. Ki-67 IHC indicated that the proliferation rate was >43% and angiogenesis was defined as high MVD. Conclusion: The respective AGS xenograft model provides an opportunity to understand the pattern of tumor growth as well as to evaluate new gastric cancer therapies in in vivo studies. [ABSTRACT FROM AUTHOR]

Objective(s): This study evaluates the effect of substitution of microcrystalline cellulose (MCC) with ethylcellulose (EC) on mechanical and release characteristics of theophylline pellets. Materials and Methods: The effect of addition of EC was investigated on characteristics of pellets with varying drug content prepared by extrusion-spheronization. Also the effect of type of granulating liquid (water or Surelease) was investigated on characteristics of selected pellets. The pellets were characterized for particle size (sieve analysis), mechanical strength, morphology (microscopy), thermal (DSC) and dissolution behaviors. Results: The exrtudability of the wet mass was reduced upon inclusion of EC so that complete replacement of MCC was not possible. Increase in EC percentage led to lower production yield and formation of pellets with larger diameter and slightly rough surfaces. Inclusion of EC also affected the mechanical properties of pellets but had negligible effect on drug release profile. The surface of selected pellets became smoother and their production yield increased upon the use of Surelease as granulating liquid. In addition the rate of drug release decreased to some extent when Surelease was used. Conclusion: Preparation of theophylline pellets with EC alone was not possible in process of extrusionspheronization. Partial replacement of MCC with EC changed physicomechanical properties of pellets but hardly affected drug release. Although the use of Surelease as granulation liquid slightly decreased the rate of drug release, desirable matrix pellets with sustained drug release could not be produced. Despite this outcome however, these pellets could benefit from reduced coating thickness for drug release control. [ABSTRACT FROM AUTHOR]

Objective(s): Solid dispersion formulation is the most promising strategy to improve oral bioavailability of poorly water soluble drugs. The aim of this study was to compare the effect of polyvinylpyrrolidone K30 (PVP) and poloxamer-188 (PLX) as carrier in solid dispersion formulations of celecoxib (CLX). Materials and Methods: Solid dispersions of CLX:PVP or CLX:PLX were prepared at different ratios (2:1, 1:1, 1:2, 1:4, 1:6) by solvent evaporation and melting methods, respectively. The characterization of samples was performed using differential scanning calorimetery (DSC), X-Ray powder diffraction (XRPD) and Fourier transform infrared spectroscopy (FT-IR). The Gordon-Taylor equation was used to estimate the Tg of solid dispersion systems and the possibility of the interaction between CLX and PVP. Also, the dissolution rate of all samples was determined. Results: DSC and XRPD analyses confirmed the presence of amorphous state of drug in solid dispersion systems. FT-IR studies showed CLX could participate in hydrogen bonding with PVP whilst no specific interaction between CLX and PLX was observed. Both PVP and PLX enhanced the dissolution rate of drug in solid dispersion samples. The dissolution rate was dependent on the ratio of drug: carrier. Interestingly, the solid dispersion samples of PLX at 2:1 and 1:1 drug: carrier showed slower dissolution rate than pure CLX, whilst these results were not observed for PVP. Conclusion: The effect of PVP on dissolution rate enhancement was more pronounced compared to the other carrier. Having a higher Tg and more effect on dissolution rate, PVP could be considered as a more suitable carrier compared to PLX in solid dispersion formulation of CLX. [ABSTRACT FROM AUTHOR]

Objective(s): This study was performed aiming to investigate the effect of particle engineering via spray drying of hydroalcoholic solution on solid states and physico-mechanical properties of acetaminophen. Materials and Methods: Spray drying of hydroalcoholic solution (25% v/v ethanol/water) of acetaminophen (5% w/v) in the presence of small amounts of polyninylpyrrolidone K30 (PVP) (0, 1.25, 2.5 and 5% w/w based on acetaminophen weight) was carried out. The properties of spray dried particles namely morphology, surface characteristics, particle size, crystallinity, dissolution rate and compactibility were evaluated. Results: Spray drying process significantly changed the morphology of acetaminophen crystals from acicular (rod shape) to spherical microparticle. Differential scanning calorimetery (DSC) and x-ray powder diffraction (XRPD) studies ruled out any polymorphism in spray dried samples, however, a major reduction in crystallinity up to 65%, especially for those containing 5% w/w PVP was observed. Spray dried acetaminophen particles especially those obtained in the presence of PVP exhibited an obvious improvement of the dissolution and compaction properties. Tablets produced from spray dried samples exhibited excellent crushing strengths and no tendency to cap. Conclusions: The findings of this study revealed that spray drying of acetaminophen from hydroalcoholic solution in the presence of small amount of PVP produced partially amorphous particles with improved dissolution and excellent compaction properties. [ABSTRACT FROM AUTHOR]

Objective(s) The aim of this study was to investigate the possibility of production of ibuprofen pellets with high amount of rate retarding polymer by aid of PEG400 as plasticizer. Materials and Methods Polyethylene glycol (PEG400) in concentrations of 1, 3 or 5% w/w with respect to Eudragit RL was used in production of pellets containing 60% ibuprofen and 40% excipient (2% polyvinylpyrrolidone (PVP), 7.6 or 0% microcrystalline cellulose (MCC) and 30.4 or 38% Eudragit RL). Physicomechanical and release properties of pellets were evaluated. Results In presence of PEG400, formulations containing 30.4% Eudragit RL and 7.6% MCC could easily form pellets. In formulations without any MCC pellets were obtained only in presence of 3 or 5% PEG400. Pellets containing MCC with 0 or 1% PEG400 showed brittle properties but those with 3% or 5% PEG400 showed plastic nature under pressure. Elastic modulus dramatically decreased with increasing PEG400 indicating softening of pellets. This was due to shift of Eudragit structure from glassy to rubbery state which was supported by DSC studies. Mean dissolution time (MDT) increased with addition of 1 or 3% PEG400 but this was not the case for pellets with 5% PEG400. Conclusion Overall PEG400 is a potential plasticizer in production of pellets based on Eudragit RL and ibuprofen. The ease in process of extrusion-spheronization, increasing the mean dissolution time and change in mechanical properties of pellets from brittle to plastic behavior were advantages of using PEG400. Changes in mechanical properties of pellets are important when pellets are intended to be compressed as tablets. [ABSTRACT FROM AUTHOR]