Dissolution rate enhancement, in vitro evaluation and investigation of drug release kinetics of chloramphenicol and sulphamethoxazole solid dispersions

Formulation of solid dispersions is one of the effective methods to increase the rate of solubilization and dissolution of poorly soluble drugs. Solid dispersions of chloramphenicol (CP) and sulphamethoxazole (SX) as model drugs were prepared by melt fusion method using polyethylene glycol 8000 (PEG 8000) as an inert carrier. The dissolution rate of CP and SX were rapid from solid dispersions with low drug and high polymer content. Characterization was performed using fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). FTIR analysis for the solid dispersions of CP and SX showed that there was no interaction between PEG 8000 and the drugs. Hyper-DSC studies revealed that CP and SX were converted into an amorphous form when formulated as solid dispersion in PEG 8000. Mathematical analysis of the release kinetics demonstrated that drug release from the various formulations followed different mechanisms. Permeability studies demonstrated that both CP and SX when formulated as solid dispersions showed enhanced permeability across Caco-2 cells and CP can be classified as well-absorbed compound when formulated as solid dispersions. © 2013 Informa Healthcare USA, Inc.

Physicochemical characterisation, drug polymer dissolution and in vitro evaluation of phenacetin and phenylbutazone solid dispersions with polyethylene glycol 8000

Poor water solubility leads to low dissolution rate and consequently, it can limit bioavailability. Solid dispersions, where the drug is dispersed into an inert, hydrophilic polymer matrix can enhance drug dissolution. Solid dispersions were prepared using phenacetin and phenylbutazone as model drugs with polyethylene glycol (PEG) 8000 (carrier), by melt fusion method. Phenacetin and phenylbutazone displayed an increase in the dissolution rate when formulated as solid dispersions as compared with their physical mixture and drug alone counterparts. Characterisation of the solid dispersions was performed using differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). DSC studies revealed that drugs were present in the amorphous form within the solid dispersions. FTIR spectra for the solid dispersions of drugs suggested that there was a lack of interaction between PEG 8000 and the drug. However, the physical mixture of phenacetin with PEG 8000 indicated the formation of hydrogen bond between phenacetin and the carrier. Permeability of phenacetin and phenylbutazone was higher for solid dispersions as compared with that of drug alone across Caco-2 cell monolayers. Permeability studies have shown that both phenacetin and phenylbutazone, and their solid dispersions can be categorised as well-absorbed compounds.

The design and evaluation of an automated drug partitioning system for thermodynamic studies

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The development and evaluation of an evidence-based drug information service

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Paediatric drug development:reformulation, in vitro, genomic and in vivo evaluation

Angiotensin converting enzyme (ACE) inhibitors lisinopril and ramipril were selected from EMA/480197/2010 and the potassium-sparing diuretic spironolactone was selected from the NHS specials list for November 2011 drug tariff with the view to produce oral liquid formulations providing dosage forms targeting paediatrics. Lisinopril, ramipril and spironolactone were chosen for their interaction with transporter proteins in the small intestine. Formulation limitations such as poor solubility or pH sensitivity needed consideration. Lisinopril was formulated without extensive development as drug and excipients were water soluble. Ramipril and spironolactone are both insoluble in water and strategies combating this were employed. Ramipril was successfully solubilised using low concentrations of acetic acid in a co-solvent system and also via complexation with hydroxypropyl-β-cyclodextrin. A ramipril suspension was produced to take formulation development in a third direction. Spironolactone dosages were too high for solubilisation techniques to be effective so suspensions were developed. A buffer controlled pH for the sensitive drug whilst a precisely balanced surfactant and suspending agent mix provided excellent physical stability. Characterisation, stability profiling and permeability assessment were performed following formulation development. The formulation process highlighted current shortcomings in techniques for taste assessment of pharmaceutical preparations resulting in early stage research into a novel in vitro cell based assay. The formulations developed in the initial phase of the research were used as model formulations investigating microarray application in an in vitro-in vivo correlation for carrier mediated drug absorption. Caco-2 cells were assessed following transport studies for changes in genetic expression of the ATP-binding cassette and solute carrier transporter superfamilies. Findings of which were compared to in vitro and in vivo permeability findings. It was not possible to ascertain a correlation between in vivo drug absorption and the expression of individual genes or even gene families, however there was a correlation (R2 = 0.9934) between the total number of genes with significantly changed expression levels and the predicted human absorption.

Paediatric drug development of ramipril:reformulation, in vitro and in vivo evaluation

Ramipril is used mainly for the treatment of hypertension and to reduce incidence of fatality following heart attacks in patients who develop indications of congestive heart failure. In the paediatric population it is used most commonly for the treatment of heart failure, hypertension in type 1 diabetes and diabetic nephropathy. Due to the lack of a suitable liquid formulation, the current study evaluates the development of a range of oral liquid formulations of ramipril along with their in vitro and in vivo absorption studies. Three different formulation development approaches were studied: solubilisation using acetic acid as a co-solvent, complexation with hydroxypropyl-β-cyclodextrin (HP-β-CD) and suspension development using xanthan gum. Systematic optimisation of formulation parameters for the different strategies resulted in the development of products stable for twelve months at long term stability conditions. In vivo evaluation showed CMAX of 10.48 µg/mL for co-solvent, 13.04µg/ml for the suspension and 29.58µg/mL for the cyclodextrin based ramipril solution. Interestingly, both ramipril solution (co-solvent) and the suspension showed a TMAX of 2.5h, however, cyclodextrin based ramipril produced TMAX at 0.75h following administration. The results presented in this study provide translatable products for oral liquid ramipril which offer preferential paediatric use over existing alternatives.

Synthesis and Biological Evaluation of Novel Folic Acid Receptor-Targeted, β-Cyclodextrin-Based Drug Complexes for Cancer Treatment

Drug targeting is an active area of research and nano-scaled drug delivery systems hold tremendous potential for the treatment of neoplasms. In this study, a novel cyclodextrin (CD)-based nanoparticle drug delivery system has been assembled and characterized for the therapy of folate receptor-positive [FR(+)] cancer. Water-soluble folic acid (FA)-conjugated CD carriers (FACDs) were successfully synthesized and their structures were confirmed by 1D/2D nuclear magnetic resonance (NMR), matrix-assisted laser desorption ionization time-of-flight mass spectrometer (MALDI-TOF-MS), high performance liquid chromatography (HPLC), Fourier transform infrared spectroscopy (FTIR), and circular dichroism. Drug complexes of adamatane (Ada) and cytotoxic doxorubicin (Dox) with FACD were readily obtained by mixed solvent precipitation. The average size of FACD-Ada-Dox was 1.5–2.5 nm. The host-guest association constant Ka was 1,639 M−1 as determined by induced circular dichroism and the hydrophilicity of the FACDs was greatly enhanced compared to unmodified CD. Cellular uptake and FR binding competitive experiments demonstrated an efficient and preferentially targeted delivery of Dox into FR-positive tumor cells and a sustained drug release profile was seen in vitro. The delivery of Dox into FR(+) cancer cells via endocytosis was observed by confocal microscopy and drug uptake of the targeted nanoparticles was 8-fold greater than that of non-targeted drug complexes. Our docking results suggest that FA, FACD and FACD-Ada-Dox could bind human hedgehog interacting protein that contains a FR domain. Mouse cardiomyocytes as well as fibroblast treated with FACD-Ada-Dox had significantly lower levels of reactive oxygen species, with increased content of glutathione and glutathione peroxidase activity, indicating a reduced potential for Dox-induced cardiotoxicity. These results indicate that the targeted drug complex possesses high drug association and sustained drug release properties with good biocompatibility and physiological stability. The novel FA-conjugated β-CD based drug complex might be promising as an anti-tumor treatment for FR(+) cancer.

Re-evaluation of central America drug market where to start?

Atral is a Portuguese Pharmaceutical firm devoted to the production of finished drugs. Due to domestic market hurdles, Atral is now, more than ever, focused in the world. The Central America region seams alluring due to its context alignment with firm’s resources bundle. As Atral should approach one regional country at a time, the purpose of this thesis is to find out the most suitable country to approach now. Hence a tailored scoring model was applied, based on contexts analysis and importance of benchmarking indicators to both firm and industry. Upon analysis of the highest scored country, the most appropriate entry modes were assessed.

Evaluation of polycaprolactone scaffold degradation for 6 months in vitro and in vivo

The use of polycaprolactone (PCL) as a biomaterial, especially in the fields of drug delivery and tissue engineering, has enjoyed significant growth. Understanding how such a device or scaffold eventually degrades in vivo is paramount as the defect site regenerates and remodels. Degradation studies of three-dimensional PCL and PCL-based composite scaffolds were conducted in vitro (in phosphate buffered saline) and in vivo (rabbit model). Results up to 6 months are reported. All samples recorded virtually no molecular weight changes after 6 months, with a maximum mass loss of only about 7% from the PCL-composite scaffolds degraded in vivo, and a minimum of 1% from PCL scaffolds. Overall, crystallinity increased slightly because of the effects of polymer recrystallization. This was also a contributory factor for the observed stiffness increment in some of the samples, while only the PCL-composite scaffold registered a decrease. Histological examination of the in vivo samples revealed good biocompatibility, with no adverse host tissue reactions up to 6 months. Preliminary results of medical-grade PCL scaffolds, which were implanted for 2 years in a critical-sized rabbit calvarial defect site, are also reported here and support our scaffold design goal for gradual and late molecular weight decreases combined with excellent long-term biocompatibility and bone regeneration. (C) 2008 Wiley Periodicals, Inc. J Biomed Mater Res 90A: 906-919, 2009

A short-term evaluation of a school-based early adolescent injury prevention program

This paper reports on the development of a school-based intervention to reduce risk-taking and associated injuries. There is limited but important evidence that intervention design should ensure participation does not lead to an increase in target risk behaviors with some studies in alcohol and drug prevention finding unexpected negative effects. The short-term evaluation of Skills for Preventing Injury in Youth (SPIY) examined change in interpersonal violence, alcohol and transport-related risks. Intervention (n = 360) and comparison (n = 180) students were surveyed pre/post-intervention. A qualitative analysis based on focus groups (70 students) explored experiences of change. Findings indicate significant positive changes reinforced by students’ reports. A decrease in reported risk-taking for the intervention group and an increase in the comparison group were observed. These findings endorse SPIY as a useful curriculum approach to reducing injuries and lend support to the future conduct of a long-term outcome evaluation.

Bioengineered 3D platform to explore cell-ECM interactions and drug resistance of epithelial ovarian cancer cells

The behaviour of cells cultured within three-dimensional (3D) structures rather than onto two-dimensional (2D) culture plastic more closely reflects their in vivo responses. Consequently, 3D culture systems are becoming crucial scientific tools in cancer cell research. We used a novel 3D culture concept to assess cell-matrix interactions implicated in carcinogenesis: a synthetic hydrogel matrix equipped with key biomimetic features, namely incorporated cell integrin-binding motifs (e.g. RGD peptides) and the ability of being degraded by cell-secreted proteases (e.g. matrix metalloproteases). As a cell model, we chose epithelial ovarian cancer, an aggressive disease typically diagnosed at an advanced stage when chemoresistance occurs. Both cell lines used (OV-MZ-6, SKOV-3) proliferated similarly in 2D, but not in 3D. Spheroid formation was observed exclusively in 3D when cells were embedded within hydrogels. By exploiting the design flexibility of the hydrogel characteristics, we showed that proliferation in 3D was dependent on cell-integrin engagement and the ability of cells to proteolytically remodel their extracellular microenvironment. Higher survival rates after exposure to the anti-cancer drug paclitaxel were observed in cell spheroids grown in hydrogels (40-60%) compared to cell monolayers in 2D (20%). Thus, 2D evaluation of chemosensitivity may not reflect pathophysiological events seen in patients. Because of the design flexibility of their characteristics and their stability in long-term cultures (28 days), these biomimetic hydrogels represent alternative culture systems for the increasing demand in cancer research for more versatile, physiologically relevant and reproducible 3D matrices.

A three year outcome evaluation of a theory based drink driving education program

This study reports on the impact of a "drink driving education program" taught to grade ten high school students. The program which involves twelve lessons uses strategies based on the Ajzen and Madden theory of planned behavior. Students were trained to use alternatives to drink driving and passenger behaviors. One thousand seven hundred and seventy-four students who had been taught the program in randomly assigned control and intervention schools were followed up three years later. There had been a major reduction in drink driving behaviors in both intervention and control students. In addition to this cohort change there was a trend toward reduced drink driving in the intervention group and a significant reduction in passenger behavior in this group. Readiness to use alternatives suggested that the major impact of the program was on students who were experimenting with the behavior at the time the program was taught. The program seems to have optimized concurrent social attitude and behavior change.

School-based drug prevention programs: a review of what works

This article examines the effectiveness of school-based drug prevention programs in preventing illicit drug use. Our article reports the results of a systematic review of the evaluation literature to answer three fundamental questions: (1) do school-based drug prevention programs reduce rates of illicit drug use? (2) what features are characteristic of effective programs? and (3) do these effective program characteristics differ from those identified as effective in reviews of school-based drug prevention of licit substance use (such as alcohol and tobacco)? Using systematic review and meta-analytic techniques, we identify the characteristics of schoolbased drug prevention programs that have a significant and beneficial impact on ameliorating illicit substance use (i.e., narcotics) among young people. Successful intervention programs typically involve high levels of interactivity, time-intensity, and universal approaches that are delivered in the middle school years. These program characteristics aligned with many of the effective program elements found in previous reviews exploring the impact of school-based drug prevention on licit drug use. Contrary to these past reviews, however, our analysis suggests that the inclusion of booster sessions and multifaceted drug prevention programs have little impact on preventing illicit drug use among school-aged children. Limitations of the current review and policy implications are discussed.

Evaluation of the alkaline comet assay and urinary 3-methyladenine excretion for monitoring DNA damage in melanoma patients treated with dacarbazine and tamoxifen

Purpose: To develop, using dacarbazine as a model, reliable techniques for measuring DNA damage and repair as pharmacodynamic endpoints for patients receiving chemotherapy. Methods: A group of 39 patients with malignant melanoma were treated with dacarbazine 1 g/m2 i.v. every 21 days. Tamoxifen 20 mg daily was commenced 24 h after the first infusion and continued until 3 weeks after the last cycle of chemotherapy. DNA strand breaks formed during dacarbazine-induced DNA damage and repair were measured in individual cells by the alkaline comet assay. DNA methyl adducts were quantified by measuring urinary 3-methyladenine (3-MeA) excretion using immunoaffinity ELISA. Venous blood was taken on cycles 1 and 2 for separation of peripheral blood lymphocytes (PBLs) for measurement of DNA strand breaks. Results: Wide interpatient variation in PBL DNA strand breaks occurred following chemotherapy, with a peak at 4 h (median 26.6 h, interquartile range 14.75- 40.5 h) and incomplete repair by 24 h. Similarly, there was a range of 3-MeA excretion with peak levels 4-10 h after chemotherapy (median 33 nmol/h, interquartile range 20.448.65 nmol/h). Peak 3-MeA excretion was positively correlated with DNA strand breaks at 4 h (Spearman's correlation coefficient, r = 0.39, P = 0.036) and 24 h (r = 0.46, P = 0.01). Drug-induced emesis correlated with PBL DNA strand breaks (Mann Whitney U-test, P = 0.03) but not with peak 3-MeA excretion. Conclusions: DNA damage and repair following cytotoxic chemotherapy can be measured in vivo by the alkaline comet assay and by urinary 3-MeA excretion in patients receiving chemotherapy.