Manju Nagpal

Dissolution Improvement of Atorvastatin Calcium using Modified Locust Bean Gum by the Solid Dispersion Technique.

The present research was aimed at the enhancement of the dissolution rate of atorvastatin calcium by the solid dispersion technique using modified locust bean gum. Solid dispersions (SD) using modified locust bean gum were prepared by the modified solvent evaporation method. Other mixtures were also prepared by physical mixing, co-grinding, and the kneading method. The locust bean gum was subjected to heat for modification. The prepared solid dispersions and other mixtures were evaluated for equilibrium solubility studies, content uniformity, FTIR, DSC, XRD, in vitro drug release, and in vivo pharmacodynamic studies. The equilibrium solubility was enhanced in the solid dispersions (in a drug:polymer ratio of 1:6) and other mixtures such as the co-grinding mixture (CGM) and kneading mixture (KM). Maximum dissolution rate was observed in the solid dispersion batch SD3 (i.e. 50% within 15 min) with maximum drug release after 2 h (80%) out of all solid dispersions. The co-grinding mixture also exhibited a significant enhancement in the dissolution rate among the other mixtures. FTIR studies revealed the absence of drug-polymer interaction in the solid dispersions. Minor shifts in the endothermic peaks of the DSC thermograms of SD3 and CGM indicated slight changes in drug crystallinity. XRD studies further confirmed the results of DSC and FTIR. Topological changes were observed in SEM images of SD3 and CGM. In vivo pharmacodynamic studies indicated an improved efficacy of the optimized batch SD3 as compared to the pure drug at a dose of 3 mg/kg/day. Modified locust bean gum can be a promising carrier for solubility enhancement of poorly water-soluble drugs. The lower viscosity and wetting ability of MLBG, reduction in particle size, and decreased crystallinity of the drug are responsible for the dissolution enhancement of atorvastatin. The co-grinding mixture can be a good alternative to solid dispersions prepared by modified solvent evaporation due to its ease of preparation and significant improvement in dissolution characteristics.

Formulation Development and Evaluation of Alginate Microspheres of Ibuprofen

The present study was designed to investigate the effects of different variables on the release profile of ibuprofen microspheres formulated using modified emulsification method. Eight batches of microspheres (F1-F8) were prepared by applying 2 3 factorial design. The amount of sodium alginate, amount of calcium chloride, and amount of magnesium stearate were selected as formulation variables. All the batches were evaluated in terms of percentage yield, percentage encapsulation efficiency and in vitro release characteristics. The batch F7 was found to be optimum batch and was further characterized via scanning electron microscopy (SEM) and particle size analysis. Multiple linear regression was applied to confirm significant effect of each variable on release characteristics. The model developed in the present study can be effectively utilized to achieve the formulation with desired release characteristics.

Synthesis characterization and in vitro drug release from acrylamide and sodium alginate based superporous hydrogel devices

Objective: Present investigation was aimed at developing gastroretentive superporous hydrogels (SPHs) having desired mechanical characteristics with sustained release. Materials and Methods: The acrylamide based SPHs of various generations (1st, 2nd and 3rd) were synthesized by gas blowing technique. The prepared SPHs were evaluated for swelling, mechanical strength studies and scanning electron microscopy studies. Verapamil hydrochloride was loaded into selected SPHs by aqueous drug loading method and characterized via Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (X-RD), differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR) and in vitro drug release studies. Results: SPHs of third generation were observed to have desired mechanical strength with sufficient swelling properties. Integrity of the drug was maintained in hydrogel polymeric network as indicated by FTIR, X-RD, and DSC and NMR studies. Initially, fast drug release (up to 60%) was observed in 30 min in formulation batches containing pure drug only (A, C and E), which was further sustained untill 24 h. Discussion: The increase in mechanical strength was due to the chemical cross-linking of secondary polymer in hydrogel network. The initial burst release was due to the presence of free drug at the surface and later sustained drug release was due to diffusion of entrapped drug in polymeric network. Significant decrease in drug release was observed by the addition of hydroxypropyl methyl cellulose. Conclusion: SPH interpenetrating networks with fast swelling and sufficient mechanical strength were prepared, which can be potentially exploited for designing gastroretentive drug delivery devices.

Dissolution enhancement of glimepiride using modified gum karaya as a carrier.

Objective: The aim of present investigation is to enhance in vitro dissolution of poorly soluble drug glimepiride by preparing solid dispersions using modified gum karaya. Materials and Methods: Solid dispersions of drug were prepared by solvent evaporation method using modified gum karaya as carrier. Four batches of solid dispersion (SD1, SD4, SD9, and SD14) and physical mixture (PM1, PM4, PM9, and PM14) were prepared and characterized by differential scanning colorimetry (DSC), Fourier transform infrared (FTIR) spectroscopy, powder X-Ray diffraction (X-RD), and scanning electron microscopy (SEM) studies. Equilibrium solubility studies were carried out in shaker incubator for 24 h and in vitro drug release was determined using USP Dissolution Apparatus-II. Results: Maximum solubility and in vitro dissolution were observed with Batch SD4. No significant enhancement of dissolution characteristics were observed in the corresponding physical mixture PM4. Low viscosity with comparable swelling characteristics as compared to GK of modified form of gum karaya may lead to improvement in dissolution behavior of solid dispersion batches. Also, the conversion of crystalline form of drug to amorphous form may be a responsible factor, which was further confirmed by DSC, FTIR studies, and X-RD studies. SEM photographs of batch SD4 revealed porous nature of particle surface. Conclusion: Modified forms of natural carriers prove beneficial in dissolution enhancement of poorly soluble drugs and exhibited a great potential in novel drug delivery systems.

Superporous hybrid hydrogels based on polyacrylamide and chitosan: Characterization and in vitro drug release

Objective: Current research was aimed at the development of the drug delivery systems based on the superporous hydrogels (SPH) with the desired swelling and the mechanical properties. Materials and Methods: Superporous hydrogel composites (SPHCs) and superporous hybrid hydrogels (SPHHs) based on the chitosan and the polyacrylamide were synthesized using the gas blowing technique. The prepared hydrogels were evaluated for swelling studies, mechanical strength and scanning electron microscopy. The selected hydrogels were loaded with the drug (verapamil hydrochloride) by aqueous loading method. Drug integrity with in polymeric network was evaluated via fourier transform infrared spectroscopy (FTIR), X-ray diffraction (X-RD), differential scanning calorimetry (DSC), proton nuclear magnetic resonance (1HNMR) studies. In vitro drug release studies were carried out using the united state pharmacopoeial (USP) dissolution apparatus (type II). Results and Discussion: The mechanical strength was observed to be higher in SPH hybrids in comparison to that in SPHCs while no significant difference was observed in swelling behavior. In situ crosslinking of chitosan with glutaraldehyde (GA) may be responsible for high mechanical strength. The equilibrium swelling time was slight higher in SPHH than in SPHCs. The integrity of pores was maintained in ethanol treated hydrogels as observed in scanning electron micrographs. Whereas, freeze dried SPH samples showed non-uniform pores. No drug polymer interaction was observed as indicated by DSC, FTIR, X-RD and NMR studies. However, the crosslinking of chitosan with GA was clearly indicated by these studies. The in vitro drug release studies from SPH hybrids indicated initial fast release (65%) with in first 2 h and then sustained release at the end of 24 h (95%). The addition of hydroxypropyl methyl cellulose with drug; however, leads to a significant decrease in drug release (56% at the end of 24 h). Conclusion: Superporous hybrid hydrogels can be promising devices for the sustained delivery of drug candidates to the gastrointestinal region.

Prospectives of Solid Self-Microemulsifying Systems In Novel Drug Delivery

BACKGROUND More than 60% of the new drug molecules are lipophilic in nature. Low aqueous solubility and thus poor bioavailability is the main issue for these drugs for successful formulations into oral dosage form. Self-microemulsifying drug delivery systems (SMEDDS) have gained much attention. These are isotropic mixtures of different components (oil, surfactant and cosurfactant) that quickly disperse in gastrointestinal fluid yielding micro/nano-emulsions. These systems contain solubilized drug that is absorbed by lymphatic pathway along with other pathways like diffusion, collisional transfer, intracellular junctions, biliary acid pathway (BA), biliary acid mixed micelles pathway (BAMM) etc. and thus hepatic first pass metabolism is reduced. Stability of conventional SEDDS is considered very high with reference to other drug delivery systems as liposome, nanoparticles, nanoemulsion and micro emulsion. In fact SEDDS does not contain water in their composition which enhances their chemical and physical stability. Very few works have studied the stability of conventional SEDDS as it was confirmed. The major drawback for conventional SEDDS could be- i) high manufacturing cost (as they have to be filled in soft gelatin capsules); ii) interaction of capsule shell components with SEDDS. Therefore, attention has been given to transform liquid into solid SMEDDS by several techniques such as spray drying, spray cooling, super critical fluid technology and using adsorption carriers. Adsorption using solid carriers (Neusilin, Fujicalin, and dextran) is the successful inexpensive technique at initial research level whereas other requires expensive instrumentation. CONCLUSION Current review focuses on biopharmaceutical aspects, characterization of SMEDDS and excipients used in the formulation, techniques used for conversion of liquid SMEDDS to solid SMEDDS (including examples of various research reports where these techniques are used). Various adsorbent carriers (alongwith their different features) which have been reported in research papers have been detailed. It thoroughly covers patent literature on SMEDDS and research carried on solid SMEDDS as well which is the most imperative part of the review.

Formulation Development and Optimization of Fast Dissolving Tablets of Aceclofenac Using Natural Superdisintegrant

The current research work involves preparation of fast dissolving tablets of Aceclofenac by direct compression method using different concentrations of Lepidium sativum mucilage as natural superdisintegrant. A two-factor three-level (32) factorial design is being used to optimize the formulation. Nine formulation batches (D1–D9) were prepared accordingly. Two factors as independent variables (X 1-amount of β-cyclodextrin and X 2-amount of Lepidium sativum mucilage) were taken with three levels (+1, 0, −1). The levels of two factors were selected on the basis of preliminary experiments conducted and their effect on three dependent variables (disintegration time, wetting time, and in vitro drug release) was studied along with their % prediction error. All the active blends were evaluated for postcompression parameters (angle of repose, Carrs index, Hausner ratio, etc.) and the tablets were evaluated for postcompression parameters (weight variation, hardness, and friability, wetting time, disintegration time, water absorption ratio, and in vitro drug release studies). The optimum batch was further used for SEM and stability studies. Formulation D5 was selected by the Design-Expert software which exhibited DT (15.5 sec), WT (18.94 sec), and in vitro drug release (100%) within 15 minutes.

Development and Comparison of Nanosponge and Niosome based Gel for the Topical Delivery of Tazarotene

BACKGROUND Tazarotene is used as topical retinoid for the treatment of acne, psoriasis and sun damaged skin. But its topical formulation has many side-effects including itching, burning, dryness, redness, stinging, rash blistering, skin discolouration, peeling at the site of application and low bioavailability. OBJECTIVE The present study focuses on the reduction of side effects and enhancement of solubility and topical bioavailability of tazarotene by formulating nanosponge and niosomes based gel for topical application. METHODOLOGY Nanosponge and niosomes of tazarotene were prepared by emulsion solvent evaporation technique and thin film hydration method respectively. The prepared formulations were characterized for drug content, morphology, size distribution, PDI, viscosity, % swelling and in vitro permeation. The nanosponge and niosome formulations were incorporated into carbomer 940 (gel matrix) to convert them into nanosponge and niosome based gel. The gel formulations were subjected to drug content determination, pH determination, spreadability, viscosity, rheological behaviour and in vitro permeation studies using wistar rat skin by Franz diffusion cell for optimization. The optimized nanosponge (NSG1) containing ethyl cellulose, PVA and dichloromethane and optimized niosomes (NMG5) containing tween 20, cholesterol, chlororform were formulated into gels and compared with nanosponge (NS1), niosomes (NM5), plain drug gel and marketed formulation (Tazaorac) for skin permeation and retention characteristics. RESULTS The nanosponge (NSG1) and niosome (NMG5) gel formulations had lower cumulative amount of drug permeated, flux, enhancement ratio and higher skin retention within the skin layers and local accumulation efficiency (LAE) than plain drug gel and marketed formulation. CONCLUSION Thus, the study showed that nanosponge and niosome based gel formulation can be a possible alternative to conventional formulations of tazarotene with enhanced bioavailability and skin retention characteristics for topical application.

Nano Era of Dentistry-An Update

BACKGROUND Management of the health of oral tissues is a prime requirement in dentistry. The prevention of tooth decay and the treatment of lesions and cavities are ongoing challenges. The limitations in dental materials, medications, instruments, procedures put off the accomplishment of this goal. Rationalization of science and technology has made possible to work out these limitations. Nanotechnology which is the outcome of this rationalization has become one of the most favored technologies in medical and dental application. The substantial contribution of nano dental materials is the identification of oral health related problems by better diagnosis and management of dental disorders by bionanomaterials. CONCLUSION Application of nanodentistry holds promise for comprehensive dental care by utilizing nanomaterials and ultimately by nanorobots. This review discusses the rationale of nanodentistry, nanocarriers researched in treatment of different dental diseases, the latest innovations in nanomaterials in various disciplines of dentistry; patent literature and related marketed products. Advances in nanotechnology have placed plenty of hopes in terms of improving the oral health care of dental patients.

An Update on Some Recent Solubility Enhancers as Pharmaceutical Excipients

At present the pharmaceutical academia and industries are focusing on the use of natural materials and resources for development of pharmaceutical product. Due to advances in drug delivery technology, currently, excipients are included in novel dosage forms to fulfill specific functions. Various natural polymers are widely being studied as a potential carrier material for site specific drug delivery because of its non-toxic and biocompatible in nature. Natural polymers (polysaccharides) have been investigated for drug delivery applications as well as in biomedical fields. Modified polymer or synthetic polymers have found its application as a support material for cell culture, tissue engineering and gene delivery. Recent trends towards use of natural products or plant based products demand the replacement of synthetic additives with natural ones. These natural materials have many advantages over synthetic ones as they are biodegradable, chemically inert, less expensive, nontoxic and widely available. This review provides an overview of the different modified polymer derivatives and their applications with special consideration being put on biomedical engineering and controlled drug delivery.