Development and characterization of lecithin stabilized glibenclamide nanocrystals for enhanced solubility and drug delivery

Novel LNCs (lipid nanocrystals) were developed with an aim to improve the solubility, stability and targeting efficiency of the model drug glibenclamide (GLB). PEG 20000, Tween 80 and soybean lecithin were used as polymer, surfactant and complexing agent, respectively. GLB nanocrystals (NCs) were prepared by precipitation process and complexed using hot and cold melt technique. The LNCs were evaluated by drug loading, saturation solubility (SL), optical clarity, in vitro dissolution, solid state characterization, in vivo and stability analysis. LNCs exhibited a threefold increase in SL and a higher dissolution rate than GLB. The percentage dissolution efficiency was found to decrease with increase in PEG 20000. The average particle size was in the range of 155-842 nm and zeta potential values tend to increase after complexation. X-ray powder diffractometry and differential scanning calorimetry results proved the crystallinity prevailed in the samples. Spherical shaped particles (<1000 nm) with a lipid coat on the surface were observed in scanning electron microscopy analysis. Fourier transform infrared results proved the absence of interaction between drug and polymer and stability study findings proved that LNCs were stable. In vivo study findings showed a decrease in drug concentration to pancreas in male Wistar rats. It can be concluded that LNCs are could offer enhanced solubility, dissolution rate and stability for poorly water soluble drugs. The targeting efficiency of LNCs was decreased and further membrane permeability studies ought to be carried out.

Hepatoprotective properties of Caesalpinia sappan Linn. heartwood on carbon tetrachloride induced toxicity

Aim of the study was to investigate the methanol and aqueous extracts of heartwood of C. sappan for its hepatoprotective activity against CCl4 induced toxicity in freshly isolated rat hepatocytes and animals. Freshly isolated rat hepatocytes were exposed to CCl4 (1%) along with/without various concentrations of methanolic and aqueous extract of C. sappan (1000-800 microg/ml) and the levels of selected liver enzymes were estimated. Antihepatotoxic effect of methanolic extract was observed in freshly isolated rat hepatocytes at concentrations 1000-800 microg/ml and was found to be similar to that of standard drug silymarin. Wistar strain albino rat model was used for the investigation of in vivo hepatoprotective properties of aqueous and methanolic extract of C. sappan (100 and 200 mg/kg body weight). Liver damage was induced by ip administration of CCl4 (30%) suspended in olive oil (1 ml/kg body weight). Both the tested extracts showed potent hepatoprotective activity at 200 mg/kg body weight test dose which was comparable with that of the standard silymarin used in similar test dose. The methanolic and aqueous extract was able to restore the biochemical levels to normal which were altered due to CCl4 intoxication in freshly isolated rat hepatocytes and also in animals.

In vivo Evaluation of Single Dose Tetanus Toxoid Vaccine Formulation with Chitosan Microspheres

Chitosan adsorbed microspheres containing tetanus toxoid were prepared in the size range of 10 mum to 75 mum, by emulsion-cross linking technique at different speeds of agitation. The amount of tetanus toxoid incorporated into chitosan microspheres were estimated by limes flocculation test and in vivo evaluation of tetanus toxoid adsorbed chitosan microspheres were determined by toxin neutralization method using albino mice. The results of in vivo release for the batches of 10 mum and 25 mum correlates with the results of in vitro in which both the batches passes the limit of IP standard (4 Lf) where as, for the batches of 50 mum and 75 mum, the in vitro release of tetanus toxoid was 2 Lf. But our in vivo studies for the batches of 50 mum and 75 mum fail to pass the limit stated in IP. The release of tetanus toxoid from the chitosan microspheres was found to be sustained for the period of 6 months.

Antiviral activity of medicinal plants of Nilgiris

BACKGROUND & OBJECTIVES

Medicinal plants have been traditionally used for different kinds of ailments including infectious diseases. There is an increasing need for substances with antiviral activity since the treatment of viral infections with the available antiviral drugs often leads to the problem of viral resistance. Herpes simplex virus (HSV) causes a variety of life threatening diseases. Since the chemotherapeutic agents available for HSV infections are either low in quality or limited in efficiency, there is a need to search for new and more effective antiviral agents for HSV infections. Therefore in the present study 18 plants with ethnomedical background from different families were screened for antiviral activity against HSV-1.

METHODS

Different parts of the plants collected from in and around Ootacamund, Tamil Nadu were extracted with different solvents to obtain crude extracts. These extracts were screened for their cytotoxicity against Vero cell line by assay microculture tetrazolium (MTT) trypan blue dye exclusion, proteins estimation and 3H labeling. Antiviral properties of the plant extracts were determined by cytopathic effect inhibition assay and virus yield reduction assay.

RESULTS

Three plant extracts Hypericum mysorense, Hypericum hookerianum and Usnea complanta exhibited significant antiviral activity at a concentration non toxic to the cell line used. The extracts of Melia dubia, Cryptostegia grandiflora and essential oil of Rosmarinus officinalis showed partial activity at higher concentrations.

INTERPRETATION & CONCLUSION

Some of the medicinal plants have shown antiviral activity. Further research is needed to elucidate the active constituents of these plants which may be useful in the development of new and effective antiviral agents.

In vitro cytotoxicity and antitumour properties ofHypericum mysorense andHypericum patulum

The methanol extracts of the aerial parts of Hypericum mysorense and Hypericum patulum were tested for in vitro cytotoxicity on HEp-2, RD and Vero cell lines and antitumour activity using DLA and HEp-2 cell lines. The cell viability and morphological changes were assessed. Of these extracts, Hypericum patulum (stem) extract showed strong cytotoxicity against all the cell lines used. The CTC50 of the Hypericum patulum (stem) extract was 1.71 microg/mL for HEp-2, 1.53 microg/mL for RD and 2.23 microg/mL for Vero cell lines. The Hypericum patulum (leaves) and Hypericum mysorense (aerial parts) extracts showed moderate cytotoxicity and Hypericum patulum (aerial parts) extract did not show any cytotoxicity up to 1,000 microg/mL concentration. In the clonogenic assay, no colony formation was observed at a concentration of 300 micro g/mL and above for Hypericum mysorense (aerial parts), 400 microg/mL and above for Hypericum patulum (leaves) and 500 microg/mL and above for Hypericum patulum (stem) extracts. In the short term antitumour studies using DLA cells, 50% viability was observed in the concentration range 100-200 microg/mL for Hypericum patulum (leaves and stem) and 200-400 microg/mL for Hypericum mysorense (aerial) extract. In the long term antitumour activity using the HEp-2 cell line, no colony formation was observed over a concentration of 1.6 microg/mL for the Hypericum patulum (stem) extract.

A study on the preparation and anti-tumor efficacy of bovine serum albumin nanospheres containing 5-fluorouracil

The therapeutic profile of many anti-cancer drugs has been improved by their modified distribution through a colloidal carrier system. Hence, bovine serum albumin nanospheres containing 5-fluorouracil were prepared by pH-coacervation methods. To select the most suitable cryoprotector for the formulated nanosphere system, a study on the effect of cryoprotectors in the prevention of particle agglomeration was done. Using glucose and mannitol at various concentrations during freeze drying, glucose at a concentration of 5% was observed to be relatively more effective in the prevention of particle agglomeration than the other cryoprotectors. The carrier capacity was determined through the drug-to-albumin ratio. The particle size of all the drug-loaded batches was analyzed before and after freeze drying. The batch of nanospheres with uniform size distribution, and highest drug loading, was used for other subsequent studies. The effect of surfactant in drug loading was estimated through various concentrations of sodium lauryl sulfate, and it was observed that the surfactant has no influence on drug loading at the selected concentrations. The batch of nanospheres with highest drug loading was evaluated for its in-vitro release, and the drug release was found to be in a bi-phasic pattern. To evaluate the efficacy of 5-fluorouracil-loaded nanospheres against cancer cells, an in vitro cytotoxicity study was carried out using HEp-2 cell lines. The nanosphere-bound drug was observed to produce a better cytotoxic effect than the free drug. The anti-tumor efficacy of drug-loaded nanosphere was investigated in DLA tumor-induced mice models, and the percentage tumor inhibition was relatively higher in animals treated with nanosphere-bound drug than with free drug.

Study of biodistribution of methotrexate-loaded bovine serum albumin nanospheres in mice

Nanospheres made from natural hydrophilic polymers have been proved efficient in terms of better drug-loading capacity, biocompatibility, and possibility less opsonization by reticuloendothelial system (RES) through an aqueous stearic barrier. Hence, nanospheres containing methotrexate were prepared from bovine serum albumin (BSA) by a novel pH coacervation method. A drug-to-polymer ratio study was carried out to determine the carrier capacity. The batch with the highest drug loading was subjected to in vitro analysis. It was found to provide a slow release after an initial burst release. Biodistribution of nanosphere-bound drug was compared with that of free drug in mice. It was observed that the percentage increase in drug distribution to the lungs, liver, and spleen was markedly high from the nanosphere when compared to free drug.

Nonliposomal approach--a study of preparation of egg albumin nanospheres containing amphotericin-B

The stability of liposomes after introduction into the body is presently being discussed and needs thorough understanding. Hence, as a nonliposomal approach, egg albumin nanospheres were prepared by the pH-coacervation method, and a preliminary study was carried out of the influence of process variables on the size and shape of nanospheres by changing the pH of the albumin solution, concentration of albumin solution, and volume of cross-linking agent. The batch prepared with an albumin medium of pH 9, 2% concentration, and 100 microliters of 4% glutaraldehyde-ethanol solution was found to have a spherical uniform shape with an average size of 497.6 nm. The ideal batch was loaded with the systemic antifungal drug amphotericin-B. Drug-loaded nanospheres were evaluated to study their in vitro release. They were found to exhibit a biphasic pattern with a cumulative percentage release of 97.7%.

Anticandidal activity of Santolina chamaecyparissus volatile oil

A search for naturally occurring drugs with antifungal activity lead to Santolina oil, a volatile oil distillate of Santolina chamaecyparissus. The studies revealed that Santolina oil was effective in controlling experimental candidiasis in vitro and in vivo. It had a synergistic effect on clotrimazole in controlling Candida albicans in vitro. It significantly controlled experimental vaginal candidiasis and experimental systemic candidosis. Santolina oil was able to control the superficial cutaneous mycoses. It is recommended as a potential candidate for further studies, including clinical studies.