Development and Optimization of Controlled Porosity Osmotic Tablets of Lamotrigine Solid Dispersion.

BACKGROUND: The purpose of this study was to investigate the application of a controlled porosity osmotic tablet (CPOT) utilizing solid dispersion (SD) of poorly soluble drug. The patents on Cyclobenzaprine HCl (US4968507 A) and Venlafaxine salts (EP 2085078 A1) helped in the selection of drug and polymers. METHOD: The SDs having different ratio of drug to carrier (PVP K 30) were prepared by kneading method and optimized. Effect of three independent variables, total amount of osmogen (mannitol& potassium chloride), total amount of polymer (polyethylene oxide WSR 301, hydroxy propyl methyl cellulose K100 M) and polymer1: polymer 2 ratio were investigated using Box Behnken design. Core and coated tablets were evaluated for various parameters. In-vitro drug release profiles of CPOT tablets were compared with reference product Diffcore tablet, Lamictal XR (GlaxoSmith Kline Inc., USA). RESULTS: All formulations showed acceptable parameters. Drug release from CPOT was determined as complete, zero order and pH-independent within the physiological pH range of the GI tract. Drug release was directly proportional to initial level of polymers and osmogens. CONCLUSION: The present results confirmed that prepared LTG SD serves as solubility modulator. Further, CPOT of LTG based on SD proved to be successful in delivering the drug in a controlled manner ensuring the once daily dosing for the treatment of convulsive disorders.

Development of controlled release osmotic pump tablet of glipizide solid dispersion.

PURPOSE: To develop controlled release osmotic pump tablets (COPT) of glipizide (GZ) solid dispersion (SD). METHODS: In elementary osmotic pump (EOP) tablets, an osmotic core with the drug is surrounded by a semi-permeable membrane which is drilled with a delivery orifice. COPT tablets eliminate the need of drilling process as controlled release can be achieved by the presence of osmogen in the coating. Poorly water soluble drug molecule cannot give satisfactory drug release hence GZ solid dispersion was prepared in the present study. The SDs having different ratio of drug to Poloxamer (PXM) 188 were prepared by hot melt method and optimized by solubility study, drug content estimation and in vitro dissolution study. Effect of two independent variables, amount of osmogen (potassium chloride) and hydrophilic polymer (polyethylene oxide WSR 303), were investigated using 3(2) factorial design. Core and coated tablets were evaluated for pharmacotechnical parameters. In-vitro drug release profiles of COPT tablets were compared with marketed with push-pull osmotic pump tablet, Glucotrol XL. RESULTS: Prepared core and coated tablets showed acceptable pharmacotechnical parameters. Drug release was directly proportional to initial level of hydrophilic polymer, but inversely related to the osmogen, confirming osmotic mechanism. Zero order drug release pattern was achieved which was comparable to marketed product. CONCLUSION: Novel oral controlled release of glipizide was successfully achieved by incorporating glipizide solid dispersion into osmotic system.

Recent patents on stimuli responsive hydrogel drug delivery system.

Hydrogels are cross-linked hydrophilic polymer structures that imbibe large quantities of water or biological fluids. Hydrogels are an upcoming class of polymer-based controlled release drug delivery systems, embracing numerous biomedical and pharmaceutical applications. Hydrogels are swellable polymeric materials, and are being widely investigated as a carrier for drug delivery systems. Besides exhibiting swelling-controlled drug release, hydrogels also show stimuli responsive changes in their structural network and hence leading to the drug release. The present manuscript is concerned with the classification, method of preparation; application in drug deliveryand FDA approved market products of hydrogels with the patent review on hydrogel composition and its manufacturing process. It also highlights recent advances in hydrogel drug delivery especially stimuli-responsive hydrogel and its patents. This patent review is useful in the synthesis methods of hydrogel drug delivery and its application.

Formulation and in vivo hypoglycemic effect of glipizide solid dispersion.

The present study was carried out with a view to enhance dissolution rate of poorly water-soluble drug glipizide (GZ) (BCS class II) using polyethylene glycol (PEG) 6000, PEG 8000 and poloxamer (PXM) 188 as carriers. Solid dispersions (SDs) were prepared by melting method using different ratios of glipizide to carriers. Phase solubility study was conducted to evaluate the effect of carrier on aqueous solubility of glipizide. SD was optimized by drug content estimation and in vitro dissolution study and optimised SD was subjected to bulk characterization, Scanning electron microscopy (SEM), Fourier transformation infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC) and X-ray diffraction study (XRD). Preclinical study was performed in mice to study the decrease in blood glucose level from prepared SD compared with pure drug. Due to high solubility and drug release, PXM 188 in weight ratio of 1:2 was optimized. Decrease in blood glucose level in mice from SD was significantly higher (p < 0.05) compared to pure glipizide. Thus, solid dispersion technique can be successfully used for the improvement of the dissolution profile of GZ.

Nanorobot: a versatile tool in nanomedicine.

Miniaturizing in chip technology, optics, micro mechanics, medicine, gene and biotechnology requires highly precise positioning techniques. The motivation for the new manipulation technology is the desire to enter the micro- and nanoworld not only by viewing but also acting, altering micro- and nanosized objects. A new era on medicine are expected to happen in the coming years. Due to the advances in the field of nanotechnology, nanodevice manufacturing has been growing gradually. From such achievements in nanotechnology and recent results in biotechnology and genetics, the first operating biological nanorobots are expected to appear in the coming 5 years and more complex diamondoid based nanorobots will become available in about 10 years. In terms of time, it means a very near better future with significant improvements in medicine.