Geeta Aggarwal

Formulation, in vitro and in vivo evaluation of transdermal patches containing risperidone

The efficacy of oral risperidone treatment in prevention of schizophrenia is well known. However, oral side effects and patient compliance is always a problem for schizophrenics. In this study, risperidone was formulated into matrix transdermal patches to overcome these problems. The formulation factors for such patches, including eudragit RL 100 and eudragit RS 100 as matrix forming polymers, olive oil, groundnut oil and jojoba oil in different concentrations as enhancers and amount of drug loaded were investigated. The transdermal patches containing risperidone were prepared by solvent casting method and characterized for physicochemical and in vitro permeation studies through excised rat skin. Among the tested preparations, formulations with 20% risperidone, 3:2 ERL 100 and ERS 100 as polymers, mixture of olive oil and jojoba oil as enhancer, exhibited greatest cumulative amount of drug permeated (1.87 ± 0.09 mg/cm2) in 72 h, so batch ROJ was concluded as optimized formulation and assessed for pharmacokinetic, pharmacodynamic and skin irritation potential. The pharmacokinetic characteristics of the optimized risperidone patch were determined using rabbits, while orally administered risperidone in solution was used for comparison. The calculated relative bioavailability of risperidone transdermal patch was 115.20% with prolonged release of drug. Neuroleptic efficacy of transdermal formulation was assessed by rota-rod and grip test in comparison with control and marketed oral formulations with no skin irritation. This suggests the transdermal application of risperidone holds promise for improved bioavailability and better management of schizophrenia in long-term basis.

Formulation, in vitro, and in vivo evaluation of matrix-type transdermal patches containing olanzapine

Transdermal patches of olanzapine were aimed to be prepared to overcome the side effects by oral application. The strategy was formulation of eudragit-based polymeric films to prepare transdermal patches by using nonionic (span-20), anionic (sodium lauryl sulfate), cationic surfactant (benzalkonium chloride), and vegetable oil (olive oil) as permeation enhancers. The patches were subjected to physicochemical, in vitro release and ex vivo permeation studies. On the basis of in vitro release performance, ERL 100:ERS 100 in the ratio of 3:2 was selected for incorporation of permeation enhancers. The permeation studies showed that formulation containing 10% span 20 (OD3) exhibited greatest cumulative amount of drug permeated (19.02 ± 0.21 mg) in 72 h, so OD3 was concluded as optimized formulation and assessed for pharmacokinetic, pharmacodynamic, and skin irritation potential. In vivo studies of optimized olanzapine patch in rabbit model revealed prolongation of action with Frel 116.09% during 72-h study period. Neuroleptic efficacy of transdermal patch was comparable to oral formulation during rotarod and grip test in Wistar albino rats with no skin irritation. Thus, developed formulation of olanzapine is expected to improve the patient compliance, form better dosage regimen, and provide maintenance therapy to psychotic patients.

Natural Oils as Skin Permeation Enhancers for Transdermal Delivery of Olanzapine: In Vitro and In Vivo Evaluation

The feasibility of development of transdermal delivery system of olanzapine utilizing natural oils as permeation enhancers was investigated. Penetration enhancing potential of corn (maize) oil, groundnut oil and jojoba oil on in vitro permeation of olanzapine across rat skin was studied. The magnitude of flux enhancement factor with corn oil, groundnut oil and jojoba oil was 7.06, 5.31 and 1.9 respectively at 5mg/ml concentration in solvent system. On the basis of in vitro permeation studies, eudragit based matrix type transdermal patches of olanzapine were fabricated using optimized concentrations of natural oils as permeation enhancers. All transdermal patches were found to be uniform with respect to physical characteristics. The interaction studies carried out by comparing the results of ultraviolet, HPLC and FTIR analyses for the pure drug, polymers and mixture of drug and polymers indicated no chemical interaction between the drug and excipients. Corn oil containing unsaturated fatty acids was found to be promising natural permeation enhancer for transdermal delivery of olanzapine with greatest cumulative amount of drug permeated (1010.68 μg/cm²/h) up to 24 h and caused no skin irritation. The fabricated transdermal patches were found to be stable. The pharmacokinetic characteristics of the final optimized matrix patch (T2) were determined after transdermal application to rabbits. The calculated relative bioavailability of TDDS was 113.6 % as compared to oral administration of olanzapine. The therapeutic effectiveness of optimized transdermal system was confirmed by tranquillizing activity in rotarod and grip mice model.

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.

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.