Preparation and characterization of microspheres for controlled release of anti HIV drug.

A series of blend microspheres were developed from gelatin and hydroxypropyl cellulose (HPC) by emulsion crosslinking method employing glutaraldehyde (GA) as a crosslinker. Valganociclovir hydrochloride (VHCL), an anti HIV drug, was loaded in to these microspheres via insitu method. These microspheres were characterized by Fourier transform infrared spectroscopy (FTIR), to confirm the formation of crosslinking and absence of chemical interactions between drug, polymer and crosslinking agent. Further the microspheres were characterized by scanning electron microscopy to study the surface morphology of the microspheres and observed that the microspheres have smooth surface with spherical structure and no phase separation. The microspheres with the average particle sizes ranging from 614.5μm to 693.4μm were obtained. X-ray diffraction (X-RD) studies were performed to understand the crystalline nature of drug and its uniform distribution into blend microspheres. An in vitro release study was performed in phosphate buffer solution (pH-7.4) at 370C. The release rates were fitted to an emperical equation to understand the diffusion parameters, which indicate non-Fickian or anomalous trend release of VHCL. Further the results indicated that the release of drug was found for more than 12 h.

Synthesis and Characterization of biodegradable Poly (Vinyl caprolactam) grafted on to sodium alginate and its microgels for controlled release studies of an anticancer drug.

Biodegradable sodium alginate-g-poly (vinyl caprolactam) synthesized by graft copolymerization of N-vinyl caprolactam (VCL) on to sodium alginate (NaAlg) via free radical initiation mechanism using a redox initiation system. Grafting (%), efficiency (%), and conversion (%) were all found to depend on the content of potassium persulfate (KPS), VCL reaction temperature and time. The maximum % of grafting was ascertained to be 251 at the optimum conditions of 65 oC reaction temperature, 180 min of reaction time, 1.1098X10-3 mol of KPS and 7.1844X10-3 mol of VCL. Evidence of graft copolymerization was obtained by fouriertransform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). Further, graft copolymer was used for preparation of microgels (MGs) using Ca+2 as a crosslinking agent. SEM results showed that the MGs are spherical in structure with smooth surface. The effects of pH and temperature on the swelling behaviour of MGs were studied and ascertained that they were sensitive to both pH and temperature. 5-FU drug was successfully loaded in to these MGs and encapsulation efficiency was found 84%. The release of 5-FU was systematically investigated as a function of temperature, pH, amount of crosslinker and % of drug loading concentration. The results indicate that the responsive MGs have the potential to be used as an effective pH and temperature controlled delivery of 5-FU for more than 12 h.

Synthesis and characterization of Interpenetrating polymer network microspheres of acryl amide grafted Carboxymethylcellulose and Sodium alginate for controlled release of Triprolidine hydrochloride monohydrate.

Interpenetrating polymer network [IPN] microspheres of acrylamide (AAm) grafted on Carboxymethyl cellulose (CMC) and Sodium alginate (NaAlg) microspheres were prepared by water-in-oil (W/O) emulsion method. These microspheres were loaded with Triprolidine hydrochloride monohydrate (TPH) and cross-linked with glutaraldehyde. The prepared microspheres were characterized by Differential scanning calorimetry (DSC), Scanning electron microscopy (SEM) and Laser particle size analyzer. DSC thermo grams of TPH loaded AAmg- CMC/NaAlg IPN microspheres confirmed the molecular level distribution in the polymer matrix. SEM of the microspheres suggested the formation of spherical particles. Swelling experiments on the microspheres provided important information on drug diffusion properties. Release data have been analyzed using an empirical equation to understand the nature of transport of drug containing solution through the polymeric matrices. The controlled release characteristic of the matrices for TPH was investigated in pH 7.4 media. Particle size and size distribution of the microspheres was studied by laser light diffraction particle size analyzer. Drug was released in a controlled manner upto 12 h.

Interpenetrating polymer network of cross-linked blend microspheres for controlled release of Acebutolol HCl.

Carbohydrate polymeric blend microspheres consisting of chitosan (CS) and poly (vinyl alcohol) (PVA) were prepared by water-in-oil (W/O) emulsion method. These microspheres were crosslinked with glutaraldehyde and loaded with Acebutolol HCl, an anti hypertensive drug. The microspheres were characterized by Fourier transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), X-Ray diffraction (X-RD) and Scanning electron microscopy (SEM).The FTIR spectroscopy explains the crosslinking between the CS-PVA. DSC& X-RD indicated the molecular level distribution of Acebutolol HCl drug in the polymer matrix. The SEM of the microspheres suggested the formation of spherical particles. Swelling experiments on the microspheres provided important information on drug diffusion properties. Release data have been analyzed using an empirical equation to understand the nature of transport of drug containing solution through the polymeric matrices. The controlled release characteristic of the matrices for Acebutolol HCl was investigated in pH 7.4 media. The results indicate that the drug was released in a controlled manner up to 10 h.

Synthesis, characterization and use of Poly (N-isopropylacrylamide-co-N-vinylcaprolactam) crosslinked thermoresponsive microspheres for control release of Ciproflaxin hydrochloride drug.

Poly (N-isopropylacrylamide-co-N-vinyl caprolactam) copolymer was synthesized as an interesting thermoresponsive material possessing a phase transition temperature around 320C in phosphate buffer, pH 7.4 (PB). Thermoresponsive Poly(N-isopropylacrylamide-co-Nvinylcaprolactam) designated as PNIPA-NVC microspheres crosslinked with N,N’–methylene bisacrylamide (NNMBA) have been prepared by dispersion polymerization using varying amounts of NIPA, NVC and NNMBA., ciproflaxin hydrochloride (CFH) an anti- bacterial drug, was loaded into the microspheres during in situ polymerization and in vitro release of CFH has been studied. The microspheres were characterized by Fourier Transform Infrared Spectroscopy (FTIR) Differential Scanning Calorimetry (DSC), X-Ray Diffractometry (X- RD) and Scanning Electron Microscopy (SEM). The in-vitro release of CFH drug from the microspheres was studied in pH 7.4 medium, at the temperatures 250C & 370C. The microspheres consisting of NIPA and NVC provide thermo responsive nature to the microspheres. The system developed in this study showed a thermoresponsive for the controlled release of CFH. FTIR spectroscopy explained the formation of copolymer. The DSC and XRD techniques indicated the uniform distribution of drug in the microspheres. SEM studies indicated surface morphology of the microspheres. Prolonged and controlled release of CFH was achieved in a controlled manner upto 12 h.

Zinc perchlorate-alumina: A mild, efficient catalyst for ring opening of epoxides with amines: An improved protocol for the synthesis of Β-amino alcohols.

The epoxides undergo smoothly ring-opening reaction with various amines catalyzed by zinc perchlorate on alumina under mild reaction conditions. All the reactions were carried out at room temperature to afford the corresponding b-amino alcohols in excellent yields. The catalyst was recovered and reused further reactions with very good efficiency.