Volume 62 (2012): Issue 4 (December 2012)

In the era of nanoparticulate controlled and site specific drug delivery systems, use of solid lipids to produce first generation lipid nanoparticles, solid lipid nanoparticles (SLN), became a revolutionary approach in the early nineties. The present review is designed to provide an insight into how SLN are finding a niche as promising nanovectors and forms a sound basis to troubleshoot the existing problems associated with traditional systems. Herein, authors had tried to highlight the frontline aspects prominent to SLN. An updated list of lipids, advanced forms of SLN, methods of preparation, characterization parameters, and various routes of administration of SLN are explored in-depth. Stability, toxicity, stealthing, targeting efficiency and other prospectives of SLN are also discussed in detail. The present discussion embodies the potential of SLN, now being looked up by various research groups around the world for their utility in the core areas of pharmaceutical sciences, thereby urging pharmaceutical industries to foster their scale-up.

Drug-eluting stents (DESs) prevail in the treatment of carotid artery diseases in the interventional cardiology world owing to their efficacy for significant reduction of restenosis. A current successful DES requires a polymer coating for drug delivery. Clinical trials examining several pharmaceutical agents have demonstrated marked reduction in restenosis following stenting. The development of DES is one of the major revolutions in the field of interventional cardiology. The ideal drug to prevent restenosis must have an anti-proliferative and anti-migratory effect on smooth muscle cells but, on the other hand, it must also enhance re-endothelialization in order to prevent late thrombosis. Additionally, it should effectively inhibit the anti-inflammatory response after balloon induced arterial injury. Although DES have significantly reduced the angiographic restenosis rate and have improved clinical outcomes, late thrombosis and restenosis remain an important subject of ongoing research.

The objective of this work was to investigate the influence of selected individual variables (binder content, inlet air temperature, and product endpoint temperature) of in situ fluid bed melt granulation on the granule particle size distribution and percentage of dissolved carvedilol using a three-factor, five-level circumscribed central composite design. Increased binder content had the effect of increasing the granule particle size and drug dissolution rate. The effect of inlet air temperature and product endpoint temperature was found to be more pronounced in case of granule particle size parameters. Within the studied intervals, the optimal quantity of binder as well as optimal process parameters were identified and validated using response surface methodology. Utilizing these optimal process and formulation parameters, successful scaling up of the fluid bed melt granulation process was carried out. Granule characteristics obtained at pilot scale are comparable to those obtained at laboratory scale.

Influence of some commercially available types of microcrystalline cellulose (MCC) on the stability of certain active pharmaceutical ingredients (APIs), when in contact, has been investigated. Two structurally similar APIs, perindopril erbumine (PER) and enalapril maleate (EM), both well-known angiotensin-converting enzyme inhibitors were used. The main properties of an MCC that could determine the stability for each API were measured and correlated to the stability of these two APIs in binary mixtures. The stability of these APIs differed when in contact with different types of MCC. The dominant properties of MCC from one manufacturer were surface features that influenced the stability of PER and acidity that influenced the stability of EM. In the case of MCC from other manufacturers, unbound water was stability determining for both substances.

The aim of the study was to prepare site specific drug delivery of naproxen sodium using sodium alginate and Eudragit S-100 as a mucoadhesive and pH-sensitive polymer, respectively. Core microspheres of alginate were prepared by a modified emulsification method followed by cross-linking with CaCl₂, which was further coated with the pH dependent polymer Eudragit S-100 (2.5 or 5 %) to prevent drug release in the upper gastrointestinal environment. Microspheres were characterized by FT-IR spectroscopy, X-ray diffraction, differential scanning calorimetry and evaluated by scanning electron microscopy, particle size analysis, drug loading efficiency, in vitro mucoadhesive time study and in vitro drug release study in different simulated gastric fluids. Stability studies of the optimized formulation were carried out for 6 months. SEM images revealed that the surface morphology was rough and smooth for core and coated microspheres, respectively. Core microspheres showed better mucoadhesion compared to coated microspheres when applied to the mucosal surface of freshly excised goat colon. The optimized batch of core microspheres and coated microspheres exhibited 98.42 ± 0.96 and 95.58 ± 0.74 % drug release, respectively. Drug release from all sodium alginate microsphere formulations followed Higuchi kinetics. Moreover, drug release from Eudragit S-100 coated microspheres followed the Korsmeyer-Peppas equation with a Fickian kinetics mechanism. Stability study suggested that the degradation rate constant of microspheres was minimal, indicating 2 years shelf life of the formulation.

The aim of this study was to develop new solid lipid nanoparticles of isotretinoin (IT-SLNs) and evaluate the ability of IT-SLNs to improve photostability, reduce skin permeation and irritating effects. IT-SLNs were prepared by the hot high pressure homogenization method. Size, zeta potential and morphological characteristics of the preparations were assessed by transmission electron microscopy (TEM) and thermotropic properties with differential scanning calorimetry (DSC). IT-SLNs had a small average diameter of 74.05 ± 8.91 nm and high encapsulation efficiency (EE) of 80.6 ± 1.2 %. The results showed that the entrapment of IT into SLNs reduced significantly its photodegradation. The in vitro permeation data showed that IT-SLNs can accumulate in the different layers of the skin and prevent systemic uptake of IT in mouse skin. IT-SLNs also significantly increased IT accumulation in the different layers of the stratum corneum of human skin. IT-SLN formulation was significantly less irritating compared to commercial IT-GEL, which shows its potential for improving skin tolerability and being a carrier for topical delivery of IT.

The aim of the study was to develop and evaluate a self- -emulsifying drug delivery system (SEDDS) formulation to improve solubility and dissolution and to enhance systemic exposure of a BCS class II anthelmetic drug, albendazole (ABZ). In the present study, solubility of ABZ was determined in various oils, surfactants and co-surfactants to identify the microemulsion components. Pseudoternary phase diagrams were plotted to identify the microemulsification existence area. SEDDS formulation of ABZ was prepared using oil (Labrafac Lipopfile WL1349) and a surfactant/ co-surfactant (Tween 80/PEG 400) mixture and was characterized by appropriate studies, viz., microemulsifying properties, droplet size measurement, in vitro dissolution, etc. Finally, PK of the ABZ SEDDS formulation was performed on rats in parallel with suspension formulation. It was concluded that the SEDDS formulation approach can be used to improve the dissolution and systemic exposure of poorly water-soluble drugs such as ABZ.

We evaluated the influence of some morphological changes of the NCI-H125 cell line in surface expression of the epidermal growth factor receptor (EGFR) and their impact on some biological activity assays using this molecule as target. Hematoxylin and eosin (H/E) staining, light microscopy immunocytochemistry, flow cytometric antibody-receptor binding test, cell viability determination and cell cycle analysis were performed. Phenotypic changes and inconsistency in EGFR expression were detected in NCI-H125 cell cultures. A significant reduction in the growth rate, mainly characterized by cell cycle arrest in the G0-G1 phase, was also evidenced. Differential distribution of cell viability in NCI-H125 subpopulations and its relationship with the EGFR surface expression were determined. Nuclear alterations observed in NCI- -H125 were not apoptosis related. A lack of control of cell cultures affects the reliability and reproducibility of biomedical and biotechnological research using EGFR as target. Therefore, rigorous control of the above mentioned parameters in these experiments is recommended.

3-[2-(4-Bromphenyl)hydrazono]-5-phenyl-furan-2(3H)-one () was used for preparation of some novel pyrazole, pyridazinone, oxadiazole, triazole, thiazolidine and thioxopyrimidine derivatives. Some of the prepared products were tested for anti-avian influenza virus activity and revealed promising antiviral activity against H5N1 virus [A/Chicken/Egypt/1/20 % (H5N1)] by determination of both EC₅₀ and LD₅₀ and confirmed by plaque reduction assay on Madin-Darby canine kidney cells. Compounds 3-[2-(4-bromophenyl)hydrazono]-5-phenylfuran-2(3H)-one (1), 1-(4-bromophenyl)-N-hydroxy-5-phenyl-1H-pyrazole-3-carboxamide (5) and 1-(4-bromophenyl)-N-{2,3-dihydro-4-hydroxy-3-phenyl-6-oxo-2-thioxopyrimidin-1(6H)-yl}-5-phenyl-1H-pyrazole-3-carboxamide (12a) showed the highest effects. Detailed synthesis, spectroscopic data, and antiviral activity of the synthesized compounds are reported.

The objective of the study is to explore the anticancer activity of di-(2-ethylhexyl) phthalate (DEHP) isolated from Calotropis gigantea flower against Ehrlich ascites carcinoma cells (EAC) in Swiss albino mice. The activity of DEHP was evaluated at doses of 10, 20 and 40 mg kg^-1 body mass applied intraperitoneally. DEHP showed a significant decrease in viable cell count (p < 0.05), mass gain (due to tumour burden) and elevated the life span of EAC cell bearing mice. Altered hematological profiles such as RBC, hemoglobin, WBC and differential count were reverted to normal levels in DEHP-treated mice. DEHP also brought back altered biochemical parameters (glucose, cholesterol, triglycerides, blood urea, SALP and SGOT) to normal level. Results of this study indicate that DEHP show potent dose dependent antitumour activity against EAC in vivo.