Formulación y evaluación de liberación sostenida oral de Diltiazem clorhidrato usando resina como material formador de matriz

Rosin, a natural resin, was used as a hydrophobic matrix material for the controlled release, using diltiazem HCl as model drug. Matrix tablets were prepared by direct compression method using rosin as matrix forming material in different proportions and with different diluent combinations. The tablets prepared were flat faced, retained their shape throughout. The method of preparation of matrix system and its concentration were found to have pronounced effect on the release of diltiazem HCl. The release was found to follow both the first order kinetics and fickian diffusion. The drug delivery was analyzed using the paddle method according to USP XXIII. All the studies were done in phosphate buffer pH 7.4. The matrix tablets were evaluated for its thickness, hardness, friability, weight variation, drug content and invitro release studies. The results suggest that the rosin is useful in developing sustained release matrix tablets, prolong release of water soluble drug for up to 24h. Rosin thus promises considerable utility in the development of oral sustained release drug delivery systems.Colofonia, una resina natural, se utilizó como un material de matriz hidrofóbica para la liberación controlada, utilizando HCl diltiazem como fármaco modelo. Los comprimidos de matriz se prepararon por el método de compresión directa usando resina como material formador de matriz en diferentes proporciones y con diferentes combinaciones de diluyente. Las tabletas preparadas eran de cara plana, conservan su forma en todas partes. El método de preparación del sistema de matriz y su concentración se encontró que tenían efecto pronunciado sobre la liberación de diltiazem HCl. La liberación se encontró que sólo deben observarse las cinética de primer orden y de difusión de Fick. La administración de fármacos se analizó mediante el método de paletas de acuerdo con la USP XXIII. Todos los estudios se realizaron en tampón de fosfato de pH 7,4. Se evaluaron los comprimidos de matriz de su espesor, dureza, friabilidad, variación de peso, contenido de drogas y de liberación in vitro estudios. Los resultados sugieren que la colofonia es útil en el desarrollo de tabletas de matriz de liberación sostenida, prolongar la liberación del fármaco soluble en agua durante un máximo de 24 horas. así colofonia promete considerable utilidad en el desarrollo de sistemas de administración de fármacos de liberación sostenida oral

The Murchison Widefield Array Transients Survey (MWATS). A search for low-frequency variability in a bright Southern hemisphere sample

We report on a search for low-frequency radio variability in 944 bright (>4 Jy at 154 MHz) unresolved, extragalactic radio sources monitored monthly for several years with the Murchison Widefield Array. In the majority of sources, we find very low levels of variability with typical modulation indices 2.8 yr) with time-averaged modulation indices M¯¯¯¯¯=3.1−7.1M¯=3.1−7.1 per cent. With 7/15 of these variable sources having peaked spectral energy distributions, and only 5.7 per cent of the overall sample having peaked spectra, we find an increase in the prevalence of variability in this spectral class. We conclude that the variability seen in this survey is most probably a consequence of refractive interstellar scintillation and that these objects must have the majority of their flux density contained within angular diameters less than 50 milliarcsec (which we support with multiwavelength data). At 154 MHz, we demonstrate that interstellar scintillation time-scales become long (∼decades) and have low modulation indices, while synchrotron-driven variability can only produce dynamic changes on time-scales of hundreds of years, with flux density changes less than one milli-jansky (without relativistic boosting). From this work, we infer that the low-frequency extragalactic southern sky, as seen by SKA-Low, will be non-variable on time-scales shorter than 1 yr

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

Simultaneous UV spectrophotometric estimation of ambroxol hydrochloride and levocetirizine dihydrochloride

A novel, simple, sensitive and rapid spectrophotometric method has been developed for simultaneous estimation of ambroxol hydrochloride and levocetirizine dihydrochloride. The method involved solving simultaneous equations based on measurement of absorbance at two wavelengths 242 nm and 231 nm, the γ max of ambroxol hydrochloride and levocetirizine dihydrochloride, respectively. Beer's law was obeyed in the concentration range 10–50 μg/ml and 8–24 μg/ml for ambroxol hydrochloride and levocetirizine dihydrochloride respectively. Results of the method were validated statistically and by recovery studies

Diseño y evaluación de matrices de difusión controlada en parches transdérmicos de clorhidrato de Diltiazem

A matrix dispersion type transdermal drug delivery system of Diltiazem Hydrochloride was developed using differentratios of rosin with Eudragit RL PM and polyvinyl pyrrolidone. The patch prepared by the combination of rosin andpolyvinyl pyrrolidone was not transparent one, and shows an uneven distribution of polyvinyl pyrrolidone, which maybe due to the hydrophilic nature of polyvinyl pyrrolidone. The effect of the polymers on the technological properties,i.e., drug release, water vapor transmission rate, percentage moisture loss and thickness were investigated. The patchcontaining rosin: Eudragit RL PM (6:4) showed a release of 2651 mcg in 24 h. In order to improve the release variousproportions of camphor was included in the formulation. The patch containing rosin: Eudragit RL PM (6:4) with5% w/v of camphor showed a sustained release of the drug extending over a period of 24 h. Formulation F8 emergedas the most satisfactory formulation as far as the technological properties were concerned. Further skin permeationand skin irritation studies were carried out on rat skin and rabbit respectively. Therefore it can be concluded that thepatch containing rosin: Eudragit RL PM in the ratio 6:4 with 5%w/v of camphor achieved the desired objectives oftransdermal drug delivery systems, such as overcoming of fi rst pass effect, extended release and reduced frequency ofadministration.Se desarrolló un sistema matricial de tipo dispersivo para la administración transdérmica de clorhidrato de Diltiazemusando diferentes proporciones de colofonia con Eudragit RL PM y polivinil pirrolidona. El parche preparado concolofonia y polivinil pirrolidona no era transparente y muestra una distribución irregular de polivinil pirrolidona,lo que puede ser debido al carácter hidrófi lo de ésta. Se investigó el efecto de los polímeros sobre las propiedadestecnológicas; es decir, la liberación del fármaco, la velocidad de transmisión del vapor de agua, la pérdida porcentualde humedad y el grosor. El parche con colofonia: Eudragit RL PM (6:4) dio como resultado una liberaciónde 2651 mcg en 24 horas. Con el objeto de mejorar la liberación, se incluyeron distintas proporciones de alcanforen la formulación. El parche con colofonia: Eudragit RL PM (6:4) y un 5% p/v de alcanfor dio como resultadouna liberación constante del fármaco a lo largo de un período de 24 horas. La formulación F8 resultó ser la mássatisfactoria en lo que a las propiedades tecnológicas se refi ere. Se llevaron a cabo estudios posteriores de permeacióne irritación de la piel en ratas y conejos respectivamente. Por lo tanto, se puede concluir que con el parchede colofonia: Eudragit RL PM en proporción 6:4 con un 5% p/v de alcanfor, se alcanzan los objetivos deseablesen sistemas de administración transdérmica de fármacos tales como anular el efecto de primer paso, una amplialiberación y una frecuencia de administración reducida