Santanu Kaity

Microwave assisted synthesis and characterization of acrylamide grafted gellan, application in drug delivery.

The synthesis of acrylamide-grafted-gellan gum was carried out by microwave-assisted free radical polymerization using cerric ammonium nitrate (CAN) as redox initiator. A series of graft copolymers, varying in amount of acrylamide, CAN and microwave irradiation time was prepared. The modified gum was extracted with 20% (v/v) methanol to remove the homopolymer formed during polymerization reaction. These graft copolymers were characterized by FTIR, (13)C NMR, CHN, SEM, rheological studies and DSC studies. Comparison of grafting parameters such as grafting efficiency, percentage grafting and percentage conversion were carried out among various series of graft copolymers and then correlating it with elemental analysis, DSC, viscosity results. The acute oral toxicity study of grated gum was evaluated as per OECD guideline. Tablets were prepared by incorporating antidiabetic drug metformin hydrochloride (MTF) in grafted gum along with excipients. In vitro studies were performed on prepared tablet formulations showing release up to 8 h.

Interpenetrating polymer network (IPN) hydrogel microspheres for oral controlled release application.

Interpenetrating polymer network (IPN) hydrogel microspheres of sodium carboxymethyl cellulose (NaCMC) and poly(vinyl alcohol) (PVA) were prepared by water-in-oil (w/o) emulsion crosslinking method for oral controlled release delivery of a non-steroidal anti-inflammatory drug, diclofenac sodium (DS). The microspheres were prepared with various ratios of NaCMC to PVA, % drug loading and extent of crosslinking density at a fixed polymer weight. The prepared microspheres with loose and rigid surfaces were evidenced by scanning electron microscope (SEM). Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis confirmed the IPN formation. Differential scanning calorimetry (DSC) study was performed to understand the dispersion nature of drug after encapsulation. The in vitro drug release study was extensively evaluated depending on the process variables in both acid and alkaline media. All the formulations exhibited satisfactory physicochemical and in vitro release characteristics. Release data indicated a non-Fickian trend of drug release from the formulations. Based on the results of this study suggest that DS loaded IPN microspheres were suitable for oral controlled release application.

Interpenetrating polymer network of locust bean gum-poly (vinyl alcohol) for controlled release drug delivery.

A novel interpenetrating polymer network (IPN) microspheres of locust bean gum (LBG) and poly (vinyl alcohol) (PVA) was developed for oral controlled release of buflomedil hydrochloride (BH) by emulsion crosslinking method using glutaraldehyde as crosslinker. The effects of gum-polymer ratio, concentration of crosslinker and internal phase viscosity were evaluated thoroughly. Drug entrapment efficiency, particle size distribution, swelling property and in vitro release characteristics with kinetic modelling of microspheres were evaluated. The microspheres were characterised by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), solid state C(13) NMR, X-ray diffraction study (XRD) and differential scanning colorimetry (DSC). The microspheres showed control release property without showing any incompatibility in IPN device. Hence, IPN microspheres of LBG and PVA can be used as a potential carrier for controlled oral delivery of highly water soluble drugs like BH.

Tailoring of locust bean gum and development of hydrogel beads for controlled oral delivery of glipizide

In this study, carboxymethyl derivative of locust bean gum was prepared, characterized, and its gelling ability with different concentrations (1–5% w/v) of aluminum chloride (AlCl3) was utilized for the development of glipizide-loaded beads in a completely aqueous environment. The beads were spherical when observed under a scanning electron microscope. Increase in gelling ion concentration decreased the drug entrapment efficiency from 97.68% to 95.14%. The beads swelled more slowly in pH 1.2 KCl-HCl buffer and exhibited a slower drug release pattern than that observed in pH 7.4 phosphate buffer. Irrespective of the dissolution media, the drug release became slower at higher AlCl3 concentration. The drug release in alkaline medium was found to be controlled by a combination of diffusion as well as polymer relaxation phenomena. Comparing the release profiles, it was observed that the beads treated with 5% AlCl3 provided slower drug release up to 10 h in alkaline medium without any sign of disintegration and, thus, this formulation was selected for further studies. Fourier transform infrared (FTIR) spectroscopy indicated the stable nature of the drug in the beads. Differential scanning calorimetry and X-ray diffraction analysis showed that most of the drug remained in amorphous state in the beads. Stability study indicated no statistical significant difference in drug entrapment efficiency of the beads. In vivo activity of the beads was tested and a prolonged hypoglycemic effect was achieved. Hence, carboxymethyl locust bean beads could be a potential carrier for controlled oral delivery of glipizide.

Microwave assisted synthesis of acrylamide grafted locust bean gum and its application in drug delivery.

Acrylamide grafted copolymer of locust bean gum was prepared by microwave irradiation using ceric ammonium nitrate as redox initiator. The grafting process was optimized in terms of irradiation time, amount of initiator and acrylamide by using constant amount of native locust bean gum. The grafted gum was characterized by Fourier transform infrared spectroscopy (FT-IR), (13)C nuclear magnetic resonance (NMR), scanning electron microscopy (SEM), X-ray diffraction study (XRD), differential scanning calorimetry (DSC), elemental analysis, contact angle, viscosity, molecular weight, swelling and biodegradability studies. The grafted gum was found to be biodegradable and non-toxic. It was further used to prepare controlled-release matrix tablet of buflomedil hydrochloride. The in vitro release profile of the tablet showed the rate controlling property of acrylamide grafted locust bean gum was similar to that of hydroxypropyl methylcellulose (HPMC-K15M).

Development and evaluation of xanthan gum-facilitated ethyl cellulose microsponges for controlled percutaneous delivery of diclofenac sodium

Development and evaluation of xanthan gum-facilitated ethyl cellulose microsponges for controlled percutaneous delivery of diclofenac sodium In this study, xanthan gum-facilitated ethyl cellulose microsponges were prepared by the double emulsification technique and subsequently dispersed in a carbopol gel base for controlled delivery of diclofenac sodium to the skin. Scanning electron microscopy revealed the porous, spherical nature of the microsponges. Increase in the drug/polymer ratio (0.4:1, 0.6:1, 0.8:1, m/m) increased their yield (79.1-88.5 %), drug entrapment efficiency (50.0-64.1 %), and mean particle diameter (181-255 μm). Compared to the microsponges with high drug/polymer ratio (0.8:1, m/m), the flux of entrapped drug through excised rat skin decreased by 19.9 % and 17.0 %, respectively, for the microsponges prepared at low and intermediate drug/polymer ratios. When an equivalent amount of pure drug (not entrapped into microsponges) was dispersed into the gel base and the flux was compared, the microsponges (drug/polymer ratio 0.8:1, m/m) were found to reduce the flux by 33.3 %. Whether the drug was dispersed either in un-entrapped or entrapped form into the gel base, the drug permeation through rat skin followed Higuchis diffusion kinetic model. The microsponges prepared at the lowest drug/polymer ratio exhibited a comparatively slower drug permeation profile and were hence considered most suitable for controlled drug delivery application. FTIR spectroscopy and DSC analyses indicated the chemically stable, amorphous nature of the drug in these microsponges. The gel containing these optimized microsponges was comparable to that of a commercial gel formulation and did not show serious dermal reactions. Hence, the microsponge system obtained at the lowest drug/polymer ratio could be useful for controlled release of diclofenac sodium to the skin. Razvoj i vrednovanje mikrospužvastih sustava etilceluloze i ksantan gume za kontroliranu perkutanu isporuku diklofenak natrija U radu su opisani mikrospužvasti sustavi s etilcelulozom i ksantan gumom pripravljeni metodom dvostruke emulzifikacije i dispergirani u podlogu s karbopol gelom za 0kontrolirano oslobađanje diklofenak natrija na kožu. Elektronska pretražna mikroskopija potvrdila je poroznu, sferičnu strukturu mikrospužvastih sustava. Povećanjem omjera lijeka i polimera (0,4:1, 0,6:1, 0,8:1, m/m) povećalo se iskorištenje (79,1-88,5 %), količina uklopljenog lijeka (50,0-64,1 %) i srednji promjer čestica (181-255 μ/m). Prolaz uklopljenog lijeka kroz izrezane komade kože štakora smanjio se za 19,9 %, odnosno 17,0 %, kada se omjer lijeka i polimera smanjio s visokog (0,8:1, m/m) na niski i srednji. Oslobađanje iz mikrospužvastih struktura s omjerom lijeka i polimera 0,8:1 (m/m) smanjeno je za 33,3 % u odnosu na oslobađanje ekvivalentne količina lijeka koji nije uklopljen već samo dispergiran u geliranu podlogu. Ako je lijek bio dispergiran kao neuklopljen ili kao uklopljen u geliranu podlogu, permeacija lijeka kroz kožu štakora slijedila je Higuchijev difuzijski kinetički model. Mikrospužvaste strukture pripravljene uz najniži omjer lijeka i polimera pokazale su sporiji permeacijski profil pa ih smatramo najpovoljnijima za kontrolirano oslobađanje lijeka. FTIR spektroskopija i DSC analiza pokazale su da je lijek u mikrospružvastim sustavima stabilan i amorfan. Gel s optimiranim mikrospužvastim sustavom sličan je komercijalnom gelu i ne pokazuje ozbiljne kožne reakcije. Sustav pripravljen s najnižim omjerom lijeka i polimera mogao bi biti pogodan za kontrolirano oslobađanje diklofenak natrija na kožu.

Microsponges: A novel strategy for drug delivery system

Microsponges are polymeric delivery systems composed of porous microspheres. They are tiny sponge-like spherical particles with a large porous surface. Moreover, they may enhance stability, reduce side effects and modify drug release favorably. Microsponge technology has many favorable characteristics, which make it a versatile drug delivery vehicle. Microsponge Systems are based on microscopic, polymer-based microspheres that can suspend or entrap a wide variety of substances, and can then be incorporated into a formulated product such as a gel, cream, liquid or powder. The outer surface is typically porous, allowing a sustained flow of substances out of the sphere. Microsponges are porous, polymeric microspheres that are used mostly for topical use and have recently been used for oral administration. Microsponges are designed to deliver a pharmaceutical active ingredient efficiently at the minimum dose and also to enhance stability, reduce side effects, and modify drug release.

Synthesis and Characterization of Poly(acrylic acid)/modified Bentonite Superabsorbent Polymer

A novel poly(acrylic acid)/modified bentonite superabsorbent polymer (SAP) was synthesized through chemical crosslinking by a polymerization technique in a complete aqueous environment. This SAP was fabricated effectively by dispersing modified bentonite in a monomeric solution, using N,N′-methylenebisacrylamide as crosslinker and ammonium persulfate as initiator. Fourier transform infrared (FTIR) spectral analysis showed that the XG chains had intercalated into bentonite sheets. The influence of crosslinking density and XG content were investigated. Results showed modified bentonite not only effectively increases water absorbency, but also improves water retention ability. This can be further used as a carrier matrix for the development of a drug delivery system.

Microwave-induced solid dispersion technology to improve bioavailability of glipizide

The effect of microwave (MW) irradiation and conventional heating (CH) on solid dispersion (SD) of poorly water‐soluble glipizide (GPZ) and polyethylene glycol 4000 (PEG 4000) were studied in detail.

Fabrication and assessment of polyacrylate/(guar gum modified bentonite) superabsorbent polymeric composite

Abstract A superabsorbent composite was synthesized via polymerization in a complete aqueous environment. A polymeric composites was fabricated effectively by varying the concentration of natural gum and crosslinker. Reinforcing of the polymer chains with bentonite sheets was confirmed by Fourier transform infrared (FTIR) spectra. X-ray diffraction (XRD) revealed that bentonite was exfoliated and dispersed in the polymeric matrix. Scanning electron microscopy (SEM) and thermal analysis (TGA/DSC/DTA) were used to study the morphology and thermal stability of the composites, respectively. The effects of natural gum and crosslinker were investigated. Results showed that introducing organic-inorganic composites improved the swelling capability and water retention ability of the superabsorbent.