Design of in-situ implant for the brain-targeted drug delivery using cross-linked gellan gum polymer through response surface methodology.

The analysis aimed to prepare an in-situ implant (ISFI) formulation holding dimethyl fumarate as (a model drug) using cross-linked gellan gum by homogenization method. Cross-linking of gellan gum was done with L-cysteine to improve its gelation properties. Fourier transform infrared spectroscopy (FTIR) and (DSC) Differential scanning calorimetry were used to test the compatibility of the drug-polymer. The diverse formulations were prepared and tested using Design Expert® ver 8.0.1 software to optimize the experiment technique and employ the response surface. The tissue compatibility of the test verified the existence of non-irritants in the established formulation. All preparations contained the drug content from approximately 97.98 to 99.88%. Viscosities are ideal for injection in the optimized formulation (1,55 percent w/w in water). The optimized formula was monitored, and up to 156hours, it was found to be 95.7%. The result was that ISFI can effectively monitor and control the delivery of several powerful drug products.

Polymeric Micelles as Novel Carriers for Poorly Soluble Drugs--A Review.

Polymeric micelles are used as 'smart drug carriers' for targeting certain areas of the body by making them stimuli-sensitive or by attachment of a specific ligand molecule onto their surface. The main aim of using polymeric micelles is to deliver the poorly water soluble drugs. Now-a-days they are used especially in the areas of cancer therapy also. In this article we have reviewed several aspects of polymeric micelles concerning their mechanism of formation, chemical nature, preparation and characterization techniques, and their applications in the areas of drug delivery.

Development of pH sensitive microparticles of Karaya gum: By response surface methodology.

The objective of the proposed work was to prepare pH sensitive microparticles (MP) of Karaya gum using distilled water as a solvent by spray drying technique. Different formulations were designed, prepared and evaluated by employing response surface methodology and optimal design of experiment technique using Design Expert(®) ver 8.0.1 software. SEM photographs showed that MP were roughly spherical in shape and free from cracks. The particle size and encapsulation efficiency for optimized MP was found to be between 3.89 and 6.5 µm and 81-94% respectively with good flow properties. At the end of the 12th hour the in vitro drug release was found to be 96.9% for the optimized formulation in pH 5.6 phosphate buffer. Low prediction errors were observed for Cmax and AUC0-∞ which demonstrated that the Frusemide IVIVC model was valid. Hence it can be concluded that pH sensitive MP of Karaya gum were effectively prepared by spray drying technique using aqueous solvents and can be used for treating various diseases like chronic hypertension, Ulcerative Colitis and Diverticulitis.

Freeze dried chitosan/ poly-(glutamic acid) microparticles for intestinal delivery of lansoprazole.

Lansoprazole sodium is a proton pump inhibitor used in treating gastroesophageal reflux disease (GERD). It is highly acid-labile and presents many formulation challenges. Therefore, this drug needs to be protected from the harsh environment in the stomach. In order to achieve this, a pH-sensitive microparticle system composed of chitosan and γ- poly-(glutamic acid) was prepared and loaded with Lansoprazole. The prepared microparticles were not stable in gastric pH. To overcome this problem microparticles were freez-dried and filled in an enteric-coated capsule. Upon oral administration, the enteric-coated capsule remained intact in the acidic environment of the stomach, but dissolved rapidly in the distal segment of the GIT. Consequently, all the microparticles loaded in the capsule were brought into the intestine, thus enhancing the intestinal absorption of drug. Drug encapsulation efficiency of formulation F3 was found to be 82.82 % and in vitro release of prepared formulation F3 was found to be 94% after 8 h of dissolution in 7.4 pH phosphate buffer. FTIR and DSC studies showed no interaction between the drug and polymer. The formulation showed good swelling property. SEM photographs showed that microparticles are spherical and lies in size range of 300-400 µm. From the above, it can be concluded that the prepared chitosan/ γ-poly-(glutamic acid) microparticles can be used as carriers for the intestinal delivery of acid liable drugs such as lansoprazole.