Erythrocytes as carrier for prednisolone: in vitro and in vivo evaluation

Resealed erythrocytes, as drug delivery system has tremendous potential to achieve site specificity and prolonged release of drug thereby enhancing therapeutic index and patient compliance. In the present investigation erythrocytes obtained from healthy volunteers were loaded with prednisolone using preswell dilution and dilution technique with two different cross-linking agents, glutaraldehyde and dimethylsulphoxide. Carrier erythrocytes, having acceptable loading parameters showed increased percentage drug content with the addition of cross-linking agents. In vitro drug release followed zero-order kinetics, haemoglobin content was found to be satisfactory and osmotic fragility study indicated that increased drug entrapment efficiency was found at 0.3%w/v concentration of sodium chloride [hypotonic solution]. In vivo tissue distribution studies were carried out for optimized formulation and order of distribution was found to be Liver>Lung>Kidney> Spleen. The developed drug delivery system is endowed with several exclusive advantages and hence holds potential for further research and clinical application

Theophylline loaded gastroretentive floating tablets based on hydrophilic polymers: preparation and in vitro evaluation

This investigation describes the preparation and in vitro evaluation of gastroretentive floating tablet of theophylline. Two hydrophilic cellulose derivatives, Methocel K100M and Methocel K15MCR were evaluated for their gel forming and release controlling properties. Sodium bicarbonate and citric acid were incorporated as gas generating agents. The effects of soluble components [sodium bicarbonate and citric acid], gel forming agents and amount variation of theophylline on drug release profile and floating properties were investigated. Tablets were prepared by direct compression technique. Formulations were evaluated for in vitro buoyancy and drug release study was evaluated for eight hours using USP XXII paddle-type dissolution apparatus using 0.1N HCl as dissolution medium. The release mechanisms were explored and explained with zero order, first order, Higuchi and Korsmeyer equations. The release rate, extent and mechanisms were found to be governed by polymer and floating agent content. The content of active ingredient was also a vital factor in controlling drug release pattern. It was found that polymer content and amount of floating agent significantly affected the mean dissolution time, percentage drug release after 8 hours, release rate constant and diffusion exponent

Biocompatible glassceramic applied in drug release system / Vitrocerâmico biocompatível aplicado em sistemas de liberação de medicamentos

A anortita é um material inteligente que se degrada apenas em meio ácido. Este comportamento, juntamente com a sua biocompatibilidade, é interessante para aplicações clínicas onde a degradação do biomaterial é desejável, como em sistemas de liberação de medicamentos. O objetivo deste trabalho é avaliar a aplicabilidade das cápsulas de anortita como sistemas de liberação de medicamentos,usando L-Dopa mais benserazida como medicamento de teste. Cápsulas esféricas foram confeccionadas, pesadas, preenchidas com o medicamento, seladas e imersas em solução tampão com pH = 3,5 durante 120 horas, mantida em movimento constante para simular o ambiente corpóreo. No final do ensaio as cápsulas foram esvaziadas, lavadas, secas e pesadas novamente. A perda de massa média foi de 0,004 mais ou menos 0,001 g, demonstrando a degradação do vitrocerâmico em meio ácido. Um espectrofotômetro UV/VIS foi usado para medir a quantidade de medicamento liberada na solução, através de amostras coletadas em períodos de 24, 72 e 120 horas após o início do ensaio. O medicamento foi detectado na solução após 24 horas, com concentração crescente até 72 horas, quando a taxa de liberação do medicamento pareceu diminuir. Através das amostrasanalisadas, foi possível concluir que ocorreu uma liberação contínua do medicamento através das paredes das cápsulas devido à sua porosidade. Os resultados mostraram a possibilidade de utilização da anortita em sistemas de liberação de medicamentos mantendo a liberação contínua da droga no organismo.

The anorthite is an intelligent material which degrades only in acid medium. this behavior along with its biocompatibility is interesting for clinical applications where degradation of a biomaterial is desired, such as in a drug delivery systems. The aim os this work is the assessment of the application of anorthite capsules as drug delivery system...

Evaluation of ball-mill ground mixtures of hydrophilic carriers and phenytoin

Phenytoin [P] powder was ground with several hydrophilic carriers; namely, avicel, lactose, gelatin, partially hydrolyzed gelatin and urea, using a ball-mill to enhance drug dissolution. The effect of mechanical treatment on the physicochemical properties of P was investigated by scanning calorimetry microscopy [SEM], different scanning calorimetry [DSC], infrared spectroscopy [IR] and X-ray diffractometry [X-ray]. Simple and ground mixtures of P with each carrier [in 1:1 and 1:4 ratios] were prepared. Dissolution of P and the different mixtures in 1% sodium lauryl sulfate [SLS] was found to be non-discriminative. When water was used as the dissolution medium, instead of 1% SLS, the ground mixtures exhibited higher dissolution rates. The effect of the carriers in this respect could be arranged as follows: Lactose > urea > avicel > gelatin. Grinding of P with lactose to less extent with other carriers resulted in the loss of DSC-peak symmetry of P. The defined IR absorption b and s in the fingerprint region of P were also obliterated to variable extents by the various carriers, especially with lactose. The results suggested the possibility of P-carrier interactions with higher tendency in case of lactose, through H-bond and van der Waals forces