Formulation and optimization of floating matrix tablets of clarithromycin using simplex lattice design

The purpose of the present study was to prepare floating matrix tablets of clarithromycin employing simplex lattice design. Hydroxypropyl methylcellulose [HPMC] and Ethyl Cellulose [EC] were used as matrix forming agents; sodium bicarbonate and citric acid as effervescence producing agents. Simplex lattice design was used as optimization technique employing three independent formulation variables viz. concentration of HPMC [X[1]], Citric Acid [X[2]], EC [X[3]] whereas floating lag time, t[50%], t[90%], and MDT [Mean Dissolution Time] were the response [dependent] variables. Seven formulations [F1-F7] were prepared and evaluated for dissolution studies, floating characteristics, weight variation, hardness, thickness, friability.t[50%] of the formulations was found to be ranging from 317 +/- 2.54 to 522 +/- 2.39 minutes. The t[90%] and MDT of the tablets were found to be ranging between 659.65 +/- 1.89 to 967.35 +/- 1.67 minutes and 527.20 +/- 1.22 to 846.78 +/- 2.61 minutes respectively. Total floating time of the formulations was more than 12 hours and the drug content was in the range of 98.54 +/- 0.46 to 99.92 +/- 0.32. The amount of both HPMC and EC were found to play a dominating role in controlling the release of the drug from the formulation whereas ratios of sodium bicarbonate and citric acid were showing significant effect on the floating lag time. The release exponent [n] from Korsmeyer-Peppas model was found to be between 0.62 and 0.75 indicating non-Fickian or anomalous drug release behavior from the formulated floating matrix tablets. Simplex lattice design was reported to be an effective optimization technique for optimizing pharmaceutical formulations against desired responses

Exploiting the interaction of polymethacrylates with iron oxide for the enhancement of mucoadhesive strength

The present investigation was aimed at preparation of polymethacrylate[s]- iron oxide conjugates and to evaluate mucoadhesive performance using texture analyzer. Eudragit RL-iron oxide or Eudragit RS-iron oxide conjugate granules were prepared by solvent evaporation technique. The mucoadhesive strength of pure Eudragit RL and RS was found to be 11.25 +/- 2.02 and 7.78 +/- 0.92 g respectively, whereas the same was found to be 36.42 +/- 4.01 and 24.32 +/- 4.44 for the iron oxide conjugates of Eudragit RL and RS respectively. Hence, mucoadhesive strength of polymethacrylates was found to be enhanced by this technique while, retaining their pH resistant property. A correlation [p>0.05] of 0.97 between mucoadhesive strength and zeta potential indicated conjugation of iron oxide contributed positive surface charge that causes enhancement of mucoadhesion. Further, the ATR-FTIR spectral analysis as well as DSC analysis supported existence of ionic interactions between conjugates [Eudragit RS or RL with iron oxide] and the tissue surface. Hence, the findings point out toward the expected potential use and application of Eudragit RL-iron oxide conjugate in mucoadhesive drug delivery systems, gastro retentive drug delivery systems, etc

Formulation and optimization of tramadol loaded alginate beads using response surface methodology

Tramadol loaded alginate beads were formulated by ionic cross-linking technique employing calcium chloride as cross-linking agent. Several parameters like bead size, swelling index, incorporation efficiency, in vitro release and in vivo drug activity studies were investigated. Tramadol loading and concentration of calcium chloride were found to have a significant effect on the selected parameters. Tramadol release decreased with decreasing drug loading and increasing concentration of cross-linking agent. Kinetic modeling indicates the involvement of both swelling and erosion on the release characteristics of the drug from the beads. A 2 factors-3 levels central composite design [CCD] was employed to evaluate the effect of critical formulation variables, namely drug loading [X1] and concentration of calcium chloride [X2] on various responses. Multiple linear regression analysis generated polynomial mathematical models for various response variables and the corresponding response surface and contour plots were drawn. X1 was found to have more significant effect than X2 on the dependent variables. In vivo drug activity studies of the alginate beads demonstrated significant antinociceptive effect of tramadol

Tuberous sclerosis--a multi system disease.

Tuberous sclerosis is a genetic disease with autosomal dominant inheritance, associated with hamartomas in several organs and various skin findings. A case of a ten year old boy is presented here to highlight the multisystem involvement in tuberous sclerosis. The child had seizures, facial papular naevi and peri-ungual fibromas. MRI revealed cortical tubers, white matter lesions and subependymal nodules. Orbital ultrasound showed retinal hamartoma on the left side. Ultrasound of the abdomen revealed a soft tissue mass at the upper pole of left kidney with a small cyst in right kidney.