Anegundha Srinatha

Ionic cross-linked chitosan beads for extended release of ciprofloxacin: In vitro characterization

Chitosan beads loaded with ciprofloxacin hydrochloride were fabricated by ionic cross-linking with sodium tripolyphosphate. The beads showed an excellent water retention property. The degradation of fabricated beads was influenced by the pH of test medium. High drug load was achieved within the bead with a short curing time. Drug release was high in acidic medium (pH 1.2) vis-à-vis intestinal medium (pH 7.4). Ciprofloxacin hydrochloride release increased with an increasing concentration of ciprofloxacin and decreasing proportion of chitosan. Drug release followed both first-order and Higuchis root time kinetics showing non-Fickian release mechanism.

Long acting ophthalmic formulation of indomethacin: Evaluation of alginate gel systems

Different types of in situ gelling systems of indomethacin, in sodium alginate vehicle, were prepared and evaluated for their pharmaceutical properties including viscosity, sterility and drug content uniformity. The gelling efficacy of the prepared systems was evaluated by using an in house fabricated gelation cell. The in vitro release kinetics of the prepared systems was determined in simulated tear. The gelling time and the nature of the gel formed were dependent on the concentration of sodium alginate present in the systems. The drug release from these systems was extended up to 8 h and predominately followed zero-order kinetics.

Floating drug delivery of a locally acting H2-antagonist: An approach using an in situ gelling liquid formulation

Floating drug delivery of a locally acting H2-antagonist: An approach using an in situ gelling liquid formulation In the present work, a gastroretentive in situ gelling liquid formulation for controlled delivery of ranitidine was formulated using sodium alginate (low, medium and high viscosity grades), calcium carbonate (source of cations) and ranitidine. Prepared formulations were evaluated for viscosity, buoyancy lag time and buoyancy duration, drug content and in vitro drug release. Formulation variables such as concentration of sodium alginate, calcium carbonate and drug significantly affected the formulation viscosity, floating behavior and in vitro drug release. Analysis of the release pattern showed that the drug release from in situ gel followed a diffusion mechanism. Isporuka tekućeg pripravka H2-antagonista s lokalnim djelovanjem: Primjena tekućeg ljekovitog oblika koji gelira in situ U radu je opisana priprava tekućeg pripravka za kontroliranu isporuku ranitidina s produljenim zadržavanjem u želucu. Pripravak gelira in situ, a načinjen je iz natrijeva alginata niske, srednje i visoke viskoznosti, kalcijeva karbonata (izvor kationa) i ranitidina. Pripravcima je ispitana viskoznost, vrijeme plutanja, sadržaj ranitidina i oslobađanje ljekovite tvari in vitro. Koncentracije natrijeva alginata, kalcijeva karbonata i ljekovite tvari značajno utječu na viskoznost, vrijeme plutanja i oslobađanje ranitidina. Utvrđeno je da se ljekovita tvar iz gela oslobađa difuzijom.

Multi-Unit Floating Alginate System: Effect of Additives on Ciprofloxacin Release

In an attempt to fabricate floating beads of ciprofloxacin, drugloaded alginate beads were prepared by simultaneous external and internal gelation. The effect of blending of alginate with gellan, hydroxypropyl methylcellulose, starch, and chitosan on the bead properties were evaluated. Beads were spherical with incorporation efficiency in the range of 52.81 ± 2.64 to 78.95 ± 1.92%. Beads exhibited buoyancy over a period of 7–24 hr based on the formulation variables. In vitro release of ciprofloxacin from the alginate beads in simulated gastric fluid (SGF) (0.1 N HCl, pH 1.2), was influenced significantly (p < 0.001) by the properties and concentration of additives. Among the polymers incorporated into alginate beads. Hydroxy propyl methylcellulose (HPMC) provided an extended release over 7 hr. The drug release predominately followed Higuchis square root model.

Chitosan inserts for periodontitis : Influence of drug loading, plasticizer and crosslinking on in vitro metronidazole release

Chitosan inserts for periodontitis: Influence of drug loading, plasticizer and crosslinking on in vitro metronidazole release Chitosan based metronidazole (MZ) inserts were fabricated by the casting method and characterized with respect to mass and thickness uniformity, metronidazole loading and in vitro metronidazole release kinetics. The fabricated inserts exhibited satisfactory physical characteristics. The mass of inserts was in the range of 5.63 ± 0.42 to 6.04 ± 0.89 mg. The thickness ranged from 0.46 ± 0.06 to 0.49 ± 0.08 mm. Metronidazole loading was in the range of 0.98 ± 0.09 to 1.07 ± 0.07 mg except for batch CM3 with MZ loading of 2.01 ± 0.08 mg. The inserts exhibited an initial burst release at the end of 24 h, irrespective of the drug to polymer ratio, plasticizer content or cross-linking. However, further drug release was sustained over the next 6 days. Cross-linking with 10% (m/m) of glutaraldehyde inhibited the burst release by ~30% and increased the mean dissolution time (MDT) from 0.67 to 8.59 days. The decrease in drug release was a result of reduced permeability of chitosan due to cross-linking. Kitozanski umetci za periodontitis: Utjecaj količine lijeka, plastifikatora i umrežavanja na oslobađanje metronidazola in vitro Umetci metronidazola na bazi kitozana načinjeni su kasting metodom. Proučavana je ujednačenost mase i debljine, količina ljekovite tvari i kinetika oslobađanja metronidazola in vitro. Fizičke karakteristike umetaka bile su zadovoljavajuće: masa je bila u rasponu od 5,63 ± 0,42 - 6,04 ± 0,89 mg, debljina od 0.46 ± 0.06 - 0.49 ± 0.08 mm, količina metronidazola od 0,98 ± 0,09 - 1,07 ± 0,07 mg osim u pripravku CM3 s MZ 1,07 ± 0,07 mg. Nakon 24 h, neovisno o omjeru ljekovite tvari i polimera, količini plastifikatora ili umrežavanju, dio metronidazola se naglo oslobodio iz svih umetaka. Međutim, daljnje je oslobađanje bilo polagano, tijekom 6 dana. Umrežavanje s 10% (m/m) otopinom glutaraldehida spriječilo je naglo oslobađanje za ~30% i povećalo srednje vrijeme oslobađanja (MDT) s 0,67 na 8,59 dana. Smanjenje u oslobađanju ljekovite tvari posljedica je smanjenja permeabilnosti umreženog kitozana.

Niridazole Biodegradable Inserts for Local Long-Term Treatment of Periodontitis: Possible New Life for an Orphan Drug

Periodontal pocket inserts of niridazole (NZ) made with Resomer® (grades RG 503H and RG858, designated as RH and RG, respectively) were studied. Various formulation variables were evaluated to obtain a biodegradable delivery systems showing device degradation and drug depletion parallel to each other in vitro. Drug release from the prepared inserts was evaluated using a static dissolution setup (for 1 month). Incorporation of 3 parts of RG in 1 part of RH inserts caused a 50% decrease in the initial release rate. The RH-NZ inserts showed a spurt in release around the 10th day of the study, which coincided with the decrease in device weight, suggesting onset of device degradation. Pilot-scale clinical trials in 12 patients indicated improvements in clinical indices from the baseline values. The average pocket depth was reduced significantly (α = 0.05) from 6.34 ± 1.86 mm at baseline to 5.94 ± 0.28 mm after 28 days of treatment.

Alternate Polyelectrolyte Coating of Chitosan Beads for Extending Drug Release

In the present study, we addressed the factors modifying ciprofloxacin release from multiple coated beads. Beads were prepared by simple ionic cross-linking with sodium tripolyphoshate and coated with alginate and/or chitosan to prepare single, double, or multilayered beads. The water uptake capacity depended on the nature of beads (coated or uncoated) and pH of test medium. The number of coatings given to the beads influenced ciprofloxacin release rate. The coating significantly decreased the drug release from the beads in comparison to uncoated beads (p < 0.001). When the beads were given three coatings, viz., alginate, chitosan, and again alginate, the drug release appeared to follow the pattern exhibited by colon-targeted drug delivery systems with time dependent release behavior. The increase in coating formed a barrier for easy ingress of dissolution medium into the bead matrix, reducing the diffusion of drug.

Ethylcellulose Inserts of an Orphan Drug for Periodontitis: Preparation, In Vitro, and Clinical Studies

Ethylcellulose inserts of niridazole fabricated by casting were studied for in vitro release and in vivo clinical effectiveness. The in vitro drug release was steady and sustained for over 7 days and followed diffusion kinetics. Selected batch, EN3, was evaluated clinically in patients with periodontitis for 6 months. A significant improvement (α ≤ 0.05) in clinical indices from baseline was observed. Intergroup study revealed a significant (α ≤ 0.01) change in the bleeding index, gingival index, plaque index, calculus criteria, and pocket depth. Significant reduction in total bacterial count in gingival crevicular fluid was observed before and postdevice insertion, as well as between control and treatment groups.

Studies on indomethacin intraocular implants using different in vitro release methods

Intra ocular implants of sodium alginate alone and in combination with hydroxypropylmethylcellulose with or without calcium chloride were formulated with indomethacin as a model drug. The drug release from the implants was evaluated using static method, continuous flow through apparatus (developed in house), USP dissolution and agar diffusion. Except in the static method, indomethacin particle size did not impart any effect on the drug release. In agar diffusion method, an increase in agar concentration from 1 to 2% resulted in a significant decrease (P< 0.005) in the amount of drug released. Inclusion of hydroxypropylmethylcellulose (33.3, 41.6 and 50% w/w), resulted in decrease of indomethacin release irrespective of the method of dissolution study. The agar diffusion method and the continuous flow through methods seem to simulate to a certain extent the in vivo conditions as far as the placement of the device and the hydrodynamic diffusion layer around the intra ocular implant is concerned. The static method and USP method affected the hydrodynamic diffusion layer either too slowly or too fast.