D-optimal mixture design inspired modified release tablet formulation of lamotrigine for the treatment of seizures: An in-depth characterization.

OBJECTIVE: Lamotrigine (LTG) an anticonvulsant drug with a dissociation constant (pKa: 5.7), suffers from enhanced blood plasma spike after each dose, when administered as fast release tablet. Being BCS class-II candidate and pH dependent solubility, development of release-controlled tablets of LTG is a major challenge. This investigation aims at designing the release-controlled tablet (RCT) formulation of LTG using a solid dispersion (SD) technique via addressing its solubility and release problems. MATERIAL AND METHODS: RCT of LTG was fabricated using SD blend of Eudragit RL and Eudragit RS and PVP K-30 with different polymer blend ratio (1:5 and 1:7). The optimization of RCT of LTG was performed using D-optimal mixture design with three independent variables, three response variables, and one constraint. The dissolution rate was determined and data were then fitted to different mathematical models. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) studies and tableting parameters were analyzed. RESULT: In vitro studies of predicted optimized batches (POBs) have shown that drug release over a period of 12hours was 88.05±3.4% in media I, 86.10±3.7% in media II and 85.84±4.2% in media III. An in vitro kinetic model equating R2-value for all the tested models indicated that the first order and Higuchi release kinetics model were the most appropriate. CONCLUSION: Based on the optimized formulation consisting of SD of LTG with Eudragit RL, Eudragit RS and PVP K-30, the release rate was consistently similar throughout the GI tract, regardless of the pH of the environment.

Features and Facts of a Gastroretentive Drug Delivery System-A Review.

English oral delivery of drug was the commonly used modality because of patient compliance and ease of administration. After oral administration of any drug, its bioavailability is affected by its residence time in stomach. Recently, gastroretentive drug delivery systems (GRDDS) have gained wide acceptance for drugs with a narrow absorption window, decreased stability at high alkaline pH, and increased solubility at low pH. This approach develops a drug delivery system, which gets retained within gastric fluid, thereby releasing its active principles in the stomach. Some methods used to achieve gastric retention of drugs include the use of effervescence agents, mucoadhesive polymers, magnetic material, bouncy enhancing excipient, and techniques that form plug-like devices that resist gastric emptying. This review provides a concise account of various attributes of recently developed approaches for GRDDS.

Development of an Aloe vera-based Emulgel for the Topical Delivery of Desoximetasone

Objectives: Desoximetasone (DMS) is a widely recommended drug for the topical treatment of plaque psoriasis. However, low water solubility and short half life of DMS present major obstacles in the development of an effective topical formulation. Thus, there is a demand for the development of a safe and effective topical system to deliver hydrophobic DMS. The present study aimed to develop an Aloe vera-based emulgel formulation to ensure enhanced skin deposition of DMS for effective treatment of plaque psoriasis. Materials and Methods: Different formulations (DE1-DE4) of Aloe vera emulgel were prepared using dispersion technique, wherein varying concentrations of propylene glycol (6-14% w/w) and carbopol 934 (0.5-1.0% w/w) were used. Results: Zetasizer measurements revealed that the globule size of the formulations ranged from 10.34 µm±0.9 to 14.60 µm±1.4 (n=50). Extrudability analysis for the DE3 and DE2 formulations revealed an extrudability of 5.6±0.11 g/cm2 and 5.8±0.13 g/cm2, respectively. The pH of the formulations was recorded in the range of 5.8-6.8. Among these formulations, DE3 showed a maximum drug content of 94.64%±0.29 (n=3), and thus was used for further in vitro evalutions. A texture analyzer showed that an optimized DE3 formulation was firmer and exhibited optimal spreadability in comparison with the DE2 formulation. For DE3, the mean max force that represented "firmness" was recorded to be 833.37 g, where as the mean area, denoting "work of shear", was 324.230 g.sec. The DE3 formulation exhibited DMS permeation of 95.40±1.6% over a period of 7 h, as detrmined using an in house fabricated Franze diffusion cell. Evaluation of in vitro release kinetics revealed that the release of DMS fitted into the Korsmeyer-Peppas model. Conclusion: Physicochemical characteristics and enhanced in vitro permeation of DMS from Aloe vera emulgel highlight its suitability to be efficiently employed for the topical treatment of skin ailments.

2-Amino-5-sulfanyl-1,3,4-thiadiazoles: a new series of selective cyclooxygenase-2 inhibitors.

A new series of cyclooxygenase-2 inhibitors with 2-amino-5-sulfanyl-1,3,4-thiadiazole as the central scaffold unit has been synthesized. The newly synthesized compounds were characterized by analytical and spectral methods. Compounds were screened for cyclooxygenase inhibitory activity by the colorimetric COX (ovine) inhibitor screening assay, anti-inflammatory activity by the carrageenean induced rat paw oedema test and analgesic activity by the tail flick method. Some compounds exhibited significant biological activity.