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Today, developing an optimized nanoparticle (NP) preparation procedure is of paramount importance in all nanoparticulate drug delivery researches, leading to expanding more operative and clinically validated nanomedicines. In this study, a one-at-a-time experimental approach was used for evaluating the effect of various preparation factors on size, loading, and drug release of hydrogel NPs prepared with ionotropic gelation between heparin and chitosan. The size, loading efficiency (LE) and drug release profile of the NPs were evaluated when the chitosan molecular weight, chitosan concentration, heparin addition time to chitosan solution, heparin concentration, pH value of chitosan solution, temperature, and mixing rate were changed separately while other factors were in optimum condition. The results displayed that size and LE are highly influenced by chitosan concentration, getting an optimum of 63 ± 0.57 and 75.19 ± 2.65, respectively, when chitosan concentration was 0.75 mg/ml. Besides, heparin addition time of 3 min leaded to 74.1 ± 0.79 % LE with no sensible effect on size and release profile. In addition, pH 5.5 showed a minimum size of 63 ± 1.87, maximum LE of 73.81 ± 3.13 and the slowest drug release with 63.71 ± 3.84 % during one week. Although LE was not affected by temperature, size and release reduced to 63 ± 0 and 74.21 ± 1.99% when temperature increased from 25°C to 55°C. Also, continuous increase of mixer rate from 500 to 3500 rpm resulted in constant enhancement of LE from 58.3 ± 3.6 to 74.4 ± 2.59 as well as remarkable decrease in size from 148 ± 4.88 to 63 ± 2.64.

Although it is acknowledged that the main impediment of orally administered therapeutic agents is their extensive and changeable pre-systemic metabolism, low absorption and instability in harsh environment of the gastrointestinal (GI) tract are also main influential factors, resulting into inadequate and erratic drug bioavailability. To overcome these shortcomings, nanotechnology has offered new promising strategies to prevent and treat a wide variety of diseases by employing different oral drug-carrier structures capable to enhance therapeutic effects and minimize the toxicity of healthy organs or cells. This review, in general, elucidates some considerable features of in vitro oral drug delivery in three different parts. The first one summarizes the main challenges for oral drug delivery and available absorption mechanisms. The second part embodies an in-depth discussion on the role of the intestinal absorption models used to predict permeability, cellular uptake or even toxicity of nanoparticles, resulting into the design of nanocarriers with optimum efficacy for oral delivery. The third section of the literature is devoted, more particularly, to nanocarriers developed for oral absorption in the past few years, including the behavior of nanovehicles upon oral administration with respect to membrane permeability, retention properties and stability, as well as methods which may lengthen residence time in the GI environment or improve drug absorption.

An available, simple, sensitive, and rapid method has been developed for determination of the 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase inhibitor, lovastatin in human plasma. The analytical procedure involves a one-step liquid-liquid extraction method using atorvastatin as internal standard. Chromatographic separation was carried out on a reversed phase C(18) column using a mixture of 0.05 M phosphate buffer (pH 7) and acetonitrile (44.5 : 55.5, v/v) as mobile phase with UV detection set at 238 nm. The total run time of analysis was 6 min with the retention time of lovastatin being 4.3 min. A complete set of analytical method validation tests were carried out on the method. Accordingly, the method was linear in the wide range of 1-100 ng/ml. The limit of detection (LOD) and limit of quantification (LOQ) for lovastatin were 0.5 and 1 ng/ml, respectively. The method was shown to be precise with average within-run and between-run variations of 10.45+/-6.88 and 8.68+/-5.13%, respectively. The average within-run and between-run accuracy of the method throughout its linear range was 113.33+/-3.98 and 105.72+/-5.07%, respectively. The mean relative recovery of lovastatin from human plasma by the developed method was 88.61+/-7.00%. The applicability of the method in real pharmacokinetic situations was evaluated successfully during a bioequivalence study in 14 fasting healthy male volunteers.

One of the backbones in nanomedicine is to deliver drugs specifically to unhealthy cells. Drug nanocarriers can cross physiological barriers and access different tissues, which after proper surface biofunctionalization can enhance cell specificity for cancer therapy. Recent developments have highlighted the potential of mesoporous silica (PSiO(2)) and silicon (PSi) nanoparticles for targeted drug delivery. In this review, we outline and discuss the most recent advances on the applications and developments of cancer therapies by means of PSiO(2) and PSi nanomaterials. Bio-engineering and fine tuning of anti-cancer drug vehicles, high flexibility and potential for sophisticated release mechanisms make these nanostructures promising candidates for "smart" cancer therapies. As a result of their physicochemical properties they can be controllably loaded with large amounts of drugs and coupled to homing molecules to facilitate active targeting. The main emphasis of this review will be on the in vitro and in vivo studies.