Metformin HCl microspheres were prepared with the aim of increasing its bioavailability and decreasing gastrointestinal side effects by means of sustained action. Eudragit RSPO and Eudragit RLPO, polymers of different permeability characteristics were used to prepare different microspheres. Emulsification solvent evaporation technique using acetone as the internal phase and liquid paraffin as the external phase was the method of choice. Six formulations were prepared using two polymers. The effect of drug loading and polymeric property on the surface morphology, entrapment efficiency, particle size and release characteristics of the microspheres were examined. FTIR and DSC studies established compatibility of the drug with the polymers. SEM studies clearly revealed the effect of drug loading and polymeric nature on the surface morphology of the microspheres.Entrapment efficiencies were within 77.09-97.11% and particle size of all the batches were in the acceptable range.Release data were treated with different mathematical kinetic models. The drug release profile showed that Eudragit RSPO and Eudragit RLPO have opposite effect on drug release. On the other hand, increase in drug loading results in increased drug release. Kinetic modeling of in vitro dissolution profiles revealed that the drug release mechanism varies from diffusion controlled to anomalous type.

Gastro retentive floating tablet of Simvastatin was prepared by direct compression technique using Methocel K4M as the rate controlling polymer. The hydrophilic cellulose derivative, Methocel K4M was evaluated for its gel forming and release controlling properties. Sodium bicarbonate and citric acid were incorporated as gas generating agents. The effects of soluble components (sodium bicarbonate and citric acid) and gel forming agents on drug release profile and floating properties were investigated. The tablets from all formulations were evaluated for thickness, diameter, weight variation, hardness, and friability. The tablets were also tested for the buoyancy studies and in vitro drug release studies. The drug release study was evaluated for eight hours using USP XXII paddle-type dissolution apparatus using 0.1N HCl with 1% Sodium Lauryl Sulphate as dissolution medium. The release mechanisms were explored and explained with zero order, first order, Higuchi, Hixon Crowell and Korsmeyer equations. The release rate, extent and mechanisms were found to be governed by the polymer content. It was found that the mean dissolution time, percentage drug release, release rate constant and diffusion exponent were influenced significantly by the amount of polymer incorporation.

Naproxen, a well-known non-steroidal anti-inflammatory drug was encapsulated with cellulosic and polymethacrylic polymers to provide sustained action and to minimize gastro esophageal side effects by avoiding the release of drug in the upper gastrointestinal tract. Emulsification-solvent evaporation technique using Ethyl Cellulose, Eudragit RSPO and their combination as release retardant was the method of choice. The formulations were prepared by keeping the amount of drug fixed to 1g and the total amount of polymer fixed to 1g in which Ethyl Cellulose and Eudragit RSPO were used in varying combination. In-vitro drug release was studied in a paddle type dissolution apparatus (USP type II) for eight hours in phosphate buffer having pH 7.4. After 8 hours, the release of drug was 86.20% for F6 which contains equal amount of Ethyl Cellulose and Eudragit RS PO and 71.57% for F7 which contains only Eudragit RSPO. The release mechanisms were explored and explained with zero order, first order, Higuchi, Korsmeyer-Peppas and Hixson Crowell models. The correlation-coefficient values of the trend lines of the graphs showed that the formulations were best fitted with Korsmeyer-Peppas release pattern. Microspheres surface morphological study was done by Scanning Electron Microscopy (SEM). Drug polymer incompatibility studies were performed by Differential Scanning Calorimetry (DSC) and Fourier Transform Infrared Spectroscopy (FTIR). The absence of endothermic melting peak of Naproxen in DSC thermogram revealed that the drug might be dispersed in the polymer as solid solution or in a metastable molecular dispersion. But the chemical integrity of Naproxen was not changed or destroyed within the microsphere which was confirmed by FTIR report.

Glimepiride (GMP) is poorly water soluble drug, so solubility is the main constraint for its oral bioavailability. Because, poor aqueous solubility and slow dissolution rate of the glimepiride lead to irreproducible clinical response or therapeutic failure in some cases due to sub therapeutic plasma drug levels. In this study, binary and ternary solid dispersion of glimepiride were prepared with polyethylene glycol 6000 (PEG 6000) and polyethylene glycol 4000 (PEG 4000) at different weight ratios using the solvent evaporation and melting method. It was found the drug was released 0.46% after 5 minutes and only 15.83% within 60 minutes from active glimepiride on the other hand the release pattern of glimepiride from the binary formulation containing PEG 4000 in 1:5 (Formulation coding: G5) showed the best result. It was found that the ternary different SD formulation containing(PEG4000:Glimepiride:Povidone) In ratio 1:1:0.25 (Formulation coding were : G13) showed the best result. The drug was changed to amorphous form after solid dispersion. Itwas also evident that solid dispersions improve solubility of drug particles thus enhancing dissolution characteristics of drugs they increase the oral bioavailability. Peer Review History: UJPR follows the most transparent and toughest ‘Advanced OPEN peer review’ system. The identity of the authors and, reviewers will be known to each other. This transparent process will help to eradicate any possible malicious/purposeful interference by any person (publishing staff, reviewer, editor, author, etc) during peer review. As a result of this unique system, all reviewers will get their due recognition and respect, once their names are published in the papers. We expect that, by publishing peer review reports with published papers, will be helpful to many authors for drafting their article according to the specifications. Auhors will remove any error of their article and they will improve their article(s) according to the previous reports displayed with published article(s). The main purpose of it is ‘to improve the quality of a candidate manuscript’. Our reviewers check the ‘strength and weakness of a manuscript honestly’. There will increase in the perfection, and transparency. Received file Average Peer review marks at initial stage: 4.5/10 Average Peer review marks at publication stage: 7.5/10 Reviewer(s) detail: Name: Dr. Mohammed Abdel-Wahab Sayed Abourehab  Affiliation: Umm Al-Qura University;  Makkah Al-Mukarramah, Saudi Arabia E-mail: maabourehab@uqu.edu.sa   Name: Dr. Evren Alğin Yapar Affiliation: Turkish Medicines and Medical Devices Agency, Turkiye E-mail: evren.yapar@yahoo.com Comments of reviewer(s):

The purpose of this research work was to improve the aqueous solubility and dissolution rate of carbamzepine by solid dispersion (SD) technique. Polyethylene Glycol 6000, Polyethylene Glycol 4000, poloxamer 407 and povidone k 30 were used as water soluble polymer for preparing solid dispersion. Solid dispersions were prepared by the solvent evaporation method. Methanol was used as solvent. Drug-carrier physical mixtures were also prepared to compare the rate of dissolution. Effects of different polymer were studied for solid dispersion formulation as well as physical mixtures. A significant increase, almost 100% in the release of carbamzepine within one hour was observed in case of the solid dispersion formulations containing PEG 6000 in combination with poloxamer 407 at the ratio of 1: 1: 5. By far, Fourier Transform Infrared (FTIR) spectroscopic studies showed the stability of carbamazepine and absence of well-defined drug-polymer interactions. The Scanning Electron Microscopy (SEM) studies indicated that the incorporation of polymers transforms crystalline carbamazepine into amorphous state, thus increasing its solubility and dissolution rate. Asian Australas. J. Biosci. Biotechnol. 2016, 1 (2), 213-220