Carboxymethylation Of Karaya Gum: Application In Gastroretentive Drug Delivery For Sustained Release Of Model Drug

Karaya gum (KG) is one of the least soluble of the gums. It does not dissolve in water to give a clear solution but instead absorbs water rapidly to form viscous colloidal sols. Carboxymethylation of Karaya gum is expected to improve its aqueous solubility and gelling behavior. Another objective of the research is to evaluate the potential of carboxymethylated Karaya gum (CMKG) as drug release modulator (in acidic dissolution medium) when combined with HPMC K15M based polymeric matrices bearing Propranolol HCl. In the present study, KG was carboxymethylated using Williamson Ether synthesis. FTIR spectroscopy confirmed the formation of CMKG. The prepared CMKG was used in conjunction with HPMC K15M as a polymer matrix in the formulation capsule dosage form, using Propranolol HCl as model drug. The filled capsules were then coated with Gelucire 43/01 to convert them into hydrodynamically balanced (HBS) capsule dosage form. Dextrose & fructose were also added to the drug-polymer mix as osmogen to facilitate the drug release. The degree of substitution of CMKG was found to be 0.87. HBS capsule dosage forms remained buoyant on 0.1 HCl for up to 6 hr, the buoyancy was attributed to the Gelucire 43/01 coating around the capsule shell. From the experimentation it was observed that CMKG, when mixed with HPMC K15M at 1:3 ratios, extended the release of model drug from HBS capsule dosage forms in 0.1 HCl. At CMKG: HPMC K15M ratio 2:1, release of Propranolol Hydrochloride from hydrodynamically balanced (HBS) capsules revealed fast drug release in 0.1 HCl. From the observations it is evident that KG is amenable to carboxymethylation to form CMKG. It is also evident that it is advantageous to combine CMKG with HPMC K15M as release modulator to retard the release of Propranolol HCl in acidic dissolution medium.

Development of a new single unit dosage form of propranolol HCl extended release non-effervescent floating matrix tablets: In vitro and in vivo evaluation.

The objective of the present investigation was to develop extended release non-effervescent floating matrix tablets of Propranolol Hydrochloride (PPH) to extend the gastric residence time (GRT) and prolong the drug release after oral administration. Different viscosity grades of Hydroxypropyl methylcellulose (HPMC) polymers such as HPMC K4M, HPMC K15M and HPMC K100M were used as drug release retardants. Glyceryl behinate (Compritol 888 ATO) and Glyceryl monosterate (Precirol ATO 5) were used as low density lipids in order to get the desired buoyancy over a prolonged period of time. The drug excipients compatibility study was carried out by using Differential Scanning Calorimetry (DSC). All the formulations were prepared by direct compression technique. The prepared tablets were evaluated for their physical characters, in vitro drug release and in vitro buoyancy. The release and floating property depends on the polymer type, polymer proportion, lipid type and lipid proportions. The drug release profiles of all the formulations were subjected to Zero order, First order, Higuchi and Peppas kinetic models, and the optimized formulation (F7) followed the Peppas model (R2= 0.987) with non-Fickian diffusion mechanism(n>0.5). The optimized formulation was subjected for in vivo radiographic studies in healthy human volunteers (n=3). These studies revealed a mean gastric residence time of 5±1.73 h (n=3).

Development of a Validated HPLC Method for the Estimation of Metformin HCl and Propranolol HCl.

The present investigation targets to develop a simple, specific, sensitive and accurate reverse phase high performance liquid chromatographic (RP-HPLC) method in human plasma for the estimation of metformin HCl and propranolol HCl from bulk drug and also from the marketed products. Human plasma samples were subjected to correct procedure for protein precipitation by methanol and protein free plasma samples were directly injected into HPLC C18 column. Chromatographic determination was performed on a reversed phase C18 column (3.9 mm X 300 mm, particle size 5 μm) using a mixture of acetonitrile and 0.1M pH 4.5 potassium dihydrogenortho phosphate buffer (mL) (40:60) at a flow rate of 0.8 mL/min and maintained at a pressure of 140 to 150 Kg/cm2. The retention time for metformin HCl and propranolol HCl was found to be 9.084 min and 6.132 min respectively at 232 nm without any interference of endogenous compounds in the plasma. The method was linear in the range between 50-2000 ng/mL. The peak areas were reproducible as indicated by low coefficient of variation. It was found that the excipients in the tablet dosage form do not interfere in the quantification of active drug by proposed method.

Formulation of gastroretentive floating drug delivery system using hydrophilic polymers and its in vitro characterization

The aim of the present research is to formulate and evaluate the gastroretentive floating drug delivery system of antihypertensive drug, propranolol HCl. Gastroretentive floating tablets (GRFT) were prepared by using a synthetic hydrophilic polymer polyethylene oxide of different grades such as PEO WSR N-12 K and PEO 18 NF as release retarding polymers and calcium carbonate as gas generating agent. The GRFT were compressed by direct compression strategy and the tablets were evaluated for physico-chemical properties, in vitro buoyancy, swelling studies, in vitro dissolution studies and release mechanism studies. From the dissolution and buoyancy studies, F 9 was selected as an optimized formulation. The optimized formulation followed zero order rate kinetics with non-Fickian diffusion mechanism. The optimized formulation was characterised with FTIR studies and observed no interaction between the drug and the polymers.

O objetivo da presente pesquisa é o de formular e avaliar o sistema de liberação de fármaco gastrorretentivo flutuante, contendo o anti-hipertensivo, cloridrato de propranolol. Comprimidos gastrorretentivo flutuantes (GRFT) foram preparados utilizando um polímero hidrofílico sintético, o óxido de polietileno, de diferentes graus, tais como GE WSR N-12 K e GE 18 NF, como polímeros de retardamento de liberação, e carbonato de cálcio, como agente gerador de gases. Os GRFT foram comprimidos por compressão direta e avaliados para determinação das propriedades físico-químicas, flutuabilidade in vitro, estudos de inchamento, de dissolução in vitro e de mecanismo de liberação. Dos testes de dissolução e de flutuabilidade, selecionou-se F 9 como formulação otimizada. A formulação otimizada seguiu cinética de ordem zero, com mecanismo de difusão não-Fickiano. Essa formulação foi caracterizada por estudos de FTIR, não se observando interação entre o fármaco e os polímeros.

Thermal sintering: a novel technique in the design of gastroretentive floating tablets of propranolol HCl and its evaluation / Sinterización térmica: Una técnica novedosa en el diseño de tabletas flotantes gastroretentivas de HCl propanolol y su evaluación

The aim of the present investigation was to formulate thermally sintered floating tablets of propranolol HCl, and to study the effect of sintering conditions on drug release, as well as their in vitro buoyancy properties. A hydrophilic polymer, polyethylene oxide, was selected as a sintered polymer to retard the drug release. The formulations were prepared by a direct compression method and were evaluated by in vitro dissolution studies. The results showed that sintering temperature and time of exposure greatly influenced the buoyancy, as well as the dissolution properties. As the sintering temperature and time of exposure increased, floating lag time was found to be decreased, total floating time was increased and drug release was retarded. An optimized sintered formulation (sintering temperature 50°C and time of exposure 4 h) was selected, based on their drug retarding properties. The optimized formulation was characterized with FTIR and DSC studies and no interaction was found between the drug and the polymer used.

El propósito de la presente investigación fue la elaboración de tabletas flotantes de HCL propanolol térmicamente sinterizadas y estudiar los efectos de las condiciones de sinterización sobre la liberación de la droga, así como sobre sus propiedades de flotabilidad in vitro. Se seleccionó un polímero hidrofílico, el óxido de polietileno, como polímero sinterizado, para retardar la liberación de la droga. Las fórmulas se prepararon mediante un método de compresión directa y se evaluaron mediante estudios de disolución in vitro. Los resultados demostraron que la temperatura de sinterización y el tiempo de exposición tuvieron una gran influencia sobre las propiedades de flotabilidad y de disolución. Se encontró que el intervalo de retardo en la flotación disminuyó, el tiempo total de flotación aumentó y se retardó la liberación de la droga, a medida que aumentaron la temperatura de sinterización y el tiempo de exposición. Se seleccionó una fórmula óptima de sinterización (temperatura de sinterización de 50°C y tiempo de exposición de 4 h), basados en las propiedades retardativas sobre la droga. La fórmula sinterizada se caracterizó mediante estudios FITR y DSC y no se encontró ninguna interacción entre la droga y el polímero utilizado.

Design and in vitro evaluation of effervescent gastric floating drug delivery systems of propanolol HCl / Diseño y evaluación in vitro de sistemas de administración de tabletas flotantes gástricas everfescentes de HCl propanolol

The purpose of this research was to develop and evaluate effervescent gastric floating tablets of propranolol HCl. The oral delivery of antihypertensive propranolol HCl was facilitated by preparing an effervescent floating dosage form which could increase its absorption in the stomach by increasing the drug’s gastric residence time. In the present work, effervescent floating tablets were prepared with a hydrophilic carrier such as polyethylene oxide (PEO WSR N 60K and PEO WSR 303) as a release retarding agent and sodium bicarbonate as a gas generating agent. The prepared tablets were evaluated for all their physicochemical properties, in vitro buoyancy, drug release and rate order kinetics. From the results, P9 was selected as an optimized formulation based on their 12 h drug release, minimal floating lag time and maximum total floating time. The optimized formulation followed first order rate kinetics with erosion mechanism. The optimized formulation was characterized with FTIR studies and no interaction between the drug and the polymers were observed.

El propósito de la presente investigación fue desarrollar y evaluar tabletas flotantes, efervescentes de HCL propranolol. La administración oral del antihipertensivo HCL propranolol se facilitó mediante la preparación de una forma de dosificación flotante y efervescente que permitiría su absorción en el estómago, mediante el aumento del tiempo de residencia gástrico de la droga. En el presente trabajo, las tabletas flotantes efervescentes fueron preparadas con un portador hidrofílico, tal como el óxido de polietileno (PEO WSR N 60K and PEO WSR 303), como agente retardador y bicarbonato de sodio como un agente generador de gas. Se evaluaron todas las propiedades fisicoquímicas de las tabletas preparadas, su flotación in vitro y su tasa de orden cinético. Se seleccionó el P9 a partir de los resultados obtenidos, como una fórmula óptima, basados en la liberación de la droga a las 12 h, tiempo mínimo de retraso para flotación y máximo tiempo total de flotación. La formulación optimizada siguió una tasa cinética de primer orden con mecanismo de erosión. Esta fórmula óptima se caracterizó mediante estudios FITR y no se observó ninguna interacción entre la droga y los polímeros utilizados.

Development of pH-independent matrix type sustained release drug delivery system of propranolol hydrochloride.

The characteristics of a new Polyvinylacetate/Povidone based excipient, Kollidon® SR were evaluated for application in extended release matrix tablets. The effects of the following formulation and process variables on tablet properties and drug release were tested: Kollidon® SR concentration in the tablet, addition of external binder for wet granulation, presence of an enteric polymer in the matrix, method of manufacturing and compression force. The similarities in release profiles were evaluated by applying the model independent f2 similarity factor. It was found that Kollidon® SR is suitable for pH-independent extended release matrix tablets. A minimum concentration of 30% polymer was necessary to achieve a coherent matrix, able to extend the release of the incorporated drugs. Increasing the Kollidon® SR concentration in the tablet led to a slower drug release. Drug release followed square root of time dependent kinetics, thus indicating a diffusion-controlled release mechanism. The drug release was influenced by the aqueous solubility of the drug. The drug release rate was faster for wet granulation than direct compression, thus making direct compression the method of choice for manufacturing Kollidon® SR extended release systems. It was found that Kollidon® SR was the main release controlling agent in the presence of an external binder or enteric polymer in the matrix. A significant reduction in the dissolution rates associated with an increase in tablet hardness was observed during the stability test under accelerated conditions. The developed propranolol matrix tablets formulation was compared to the reference listed product (Inderal® LA capsules). It was concluded that Kollidon® SR is a potentially useful excipient for the production of pH-independent extended release matrix tablets.