Polymers derived from Xanthomonas campesteris and Cyamopsis tetragonolobus used as retardant materials for the formulation of sustained release floating matrix tablet of atenolol.

The objective of the present study was to develop, optimize, in vitro, and in vivo evaluation of floating matrix tablet of atenolol using polymer blend derived from Xanthomonas campesteris and Cyamopsis tetragonolobus that are characterized by release requirements of sustained-release product and to improve the oral bioavailability of the drug. A 3(2) full factorial design was employed to optimize the tablets, where content of polymer blend (X1) and ratio of xanthan gum-to-guar gum (X2) were considered as independent variables. The effects of independent variables on dependent variables, i.e. floating time, diffusion exponent, and time to release 50% of atenolol were evaluated. The in vivo pharmacokinetic parameters of the optimized formulation were compared with the marketed sustained release formulation of atenolol (Aten(®)). The optimized formulation containing 20% (w/w) of polymer blend and 50:50 ratio of xanthan gum-to-guar gum was able to float more than 12h and showed the desired sustained drug release from the tablets. In vivo retention studies in rabbit stomach showed the gastric residence of tablet up to 6h. The in vivo study of optimized tablets illustrated significant improvement in the oral bioavailability of atenolol in rabbits. It can be concluded that floating matrix tablet of atenolol prepared by using xanthan gum and guar gum has potential for sustained release of the drug as well as improved oral bioavailability through enhanced gastric residence time of formulation in stomach.

Preparation and evaluation of SnO2-based 68Ge/68Ga generator made from 68Ge produced through (nat)Zn(α,xn) reaction.

(68)Ge was produced by (nat)Zn(α,xn)(68)Ge reaction and its production yield was 31.82 kBq/µAh (0.86 µCi/µAh) at the end of irradiation (EOI). A simple chromatographic method using a SnO2 column was employed to separate (68)Ge from the target material and the co-produced non-isotopic radioisotope impurities. (68)Ge retained in the column served as the (68)Ge/(68)Ga generator. Elution efficiency of the column was about 60%. First 2 ml of the eluate contained more than 95% of the elutable activity. Post-elution purification cum concentration was done with a small cation exchange resin column. The presence of the inactive tin ions in the (68)Ga eluate was determined by the ICP-OES technique and was found to be about 0.03 ppm. Radiochemical purity of the final (68)Ga preparation was more than 99.99% and it was found to be suitable for making complex with ethylenediamine-N,N,N',N'-tetrakis(methylene phosphonic acid) (EDTMP).

A computerized compact module for separation of (99m)Tc-radionuclide from molybdenum.

An automated closed cycle module for the separation and recovery of various isotopes, radioactive or non-radioactive, using solvent extraction and column chromatography techniques, and in particular, for separation and recovery of (99m)Tc from low-medium specific activity (99)Mo, is described. The module may also be applicable for separation of (99m)Tc produced in a cyclotron. The module is safe and reliable to avoid human interference and hazards posed by handling of radioactive and hazardous chemicals. The entire system of automation includes a user-friendly PC based graphical user interface (GUI) that actually supervises the process via an embedded system based electronic controller.

Preparation and evaluation of 99mTc-cefuroxime, a potential infection specific imaging agent: a reliable thin layer chromatographic system to delineate impurities from the 99mTc-antibiotic.

Technetium-99m labelled cefuroxime, a second-generation cephalosporin antibiotic and potential bacteria specific infection imaging agent was evaluated. A good radiochemical purity (95%) of the labelled product was obtained after filtering the reaction mixture through a 0.22 µm filter. Scintigraphy study of the purified product showed uptake in infectious lesions 45 min after injection and abscess-to-muscle ratios were found to be 1.80, 1.85 and 1.88 at 45 min, 1.5 hr and 3 hr, respectively. A versatile and reliable chromatographic technique to assess the radiochemical purity of (99m)Tc-cefuroxime has also been described.

Production of 61Cu using natural cobalt target and its separation using ascorbic acid and common anion exchange resin.

(61)Cu was produced by (nat)Co(α, xn)(61)Cu reaction. (61)Cu production yield was 89.5 MBq/µAh (2.42 mCi/µAh) at the end of irradiation (EOI). A simple radiochemical separation method using anion exchange resin and ascorbic acid has been employed to separate the product radionuclide from inactive target material and co-produced non-isotopic impurities. The radiochemical separation yield was about 90%. Radiochemical purity of (61)Cu was >99% 1 h after EOI. Final product was suitable for making complex with N(2)S(2) type of ligands.

A novel technique for the effective concentration of 99mTc from a large alumina column loaded with low specific-activity (n,gamma)-produced 99Mo.

Molybdenum-99 of low-to-medium specific activity, 7.4-14.8 GBq/g, obtained by the (98)Mo(n,gamma)(99)Mo reaction in research reactors requires a large alumina column to adsorb the molybdenum since the capacity of alumina to adsorb Mo is limited (20 mg Mo/g of alumina). The large size of alumina column, in turn, requires large eluant volumes to elute the (99m)Tc, and the radioactive concentration (RAC) of the pertechnetate becomes unacceptably low for radiopharmaceutical applications. This study describes a method for obtaining high RAC pertechnetate solutions from a column generator loaded with (99)Mo of low specific activity. Molybdenum-99 of specific activity, 7.4 GBq/g, was absorbed on an alumina column [60 g, 70 mm, (H) x 35 mm (diam.)]. The (99m)TcO(4)(-), eluted with 60 ml normal saline (0.15N NaCl), was applied to a 12 mm (H) x 1 mm (diam.) column containing 15 mg of the strong anion exchanger Dowex 1 x 8. The retained pertechnetate was eluted with 5 ml of 0.5 mM tetrabutylammonium bromide (TBAB) solution in methylene chloride. The organic solvent was subsequently removed under vacuum and the dry residue was reconstituted with the desired volume of normal saline. All the operations were carried out in a closed cycle with sterile connecting tubes and multi-way stop-cocks. The concentrated pertechnetate obtained contained about 90% of the total saline eluate and had a pH of 6-7, a radiochemical purity (RCP) consistently >99%, the (99)Mo breakthrough was around 10(-4)%. Colorimetric spot tests (limit tests) for Al and Mo showed <10 ppm in the final (99m)TcO(4)(-) solution. The RCP of the labelled compounds prepared using the pertechnetate obtained and five different radiopharmaceutical kits were >95%. The procedure may be equally applicable for the effective concentration of (188)ReO(4)(-) from (188)W-(188)Re generators.