Design and evaluation of floating drug delivery systems of Metformin with natural gums as release retarding polymers

Metformin hydrochloride floating tablets were prepared by wet granulation method by using optimized concentrations of gas generating agents, binding agents and natural gums as polymers like gum kondagogu and gum karaya. The formulations F1-F4 with concentrations 2-3.5% were prepared to optimize binding agent and formulations F5-F7 with concentrations 15-20% to optimize gas generating agent where optimum percentage of binding agent was found around 2.3% and gas generating agent was found around 17.25% to get quick floating lag time. The prepared granules evaluated for various parameters showed good results in which the Carrs index, hausner ratio and angle of repose, the values were found in between 9.05-16.78, 1.02-1.46 and 23.17-32.64 respectively. All compressed formulations were evaluated for various parameters and results of hardness, friability, drug content, were found around 7.1-8.8kg/cm2, 0.56-1.48% and 499.3-499.8mg respectively. The tablets prepared by these granules of two natural gums as polymers showed desired floating properties. F6 formulation containing gum kondagogu and F11 formulation containing gum karaya showed good release retardation with release 99.42% and 99.75% respectively after 12 hours in in vitro drug release studies. Formulations F6 and F11 after stability studies showed good results proving stable. In vivo studies also showed good correlation with the results of in vitro and X-ray pictograms proved the formulations is stable in vivo. Formulations F6 and F11 contains natural gums Kondagogu and karaya with 17.25% concentration were considered as best formulation as they showed good release retardation and, in release kinetic studies the n-value found appropriate for controlled release formulations

Formulation and evaluation of CFC free inhalers for beclomethasone dipropionate

Beclomethasone dipropionate CFC free inhalation formulations were developed with a view to treat asthma prophylactically. Dry powder inhalers (DPI) for beclomethasone dipropionate were prepared with different grades of lactose monohydrate. The influence of carrier and overages on performance of DPI was studied. Metered dose inhalers (MDI) with HFA based propellants were formulated with various doses, overages and different concentrations of alcohol. Formulated DPI and MDI were evaluated for various official and unofficial quality control tests. The influence of over doses on valve delivery, effect of overages on emitted dose and influence of alcohol on spray pattern from MDI were studied. The better fine particle fraction and emitted dose were obtained from the DPI formulated with 10:90 ratio of fine lactose: coarse lactose and with 20% w/w overages. The studies on MDI revealed that the 15% of overdoses are required for effective valve delivery and 20% overages are required for 100% drug delivery. 5-10%v/v alcohol was found to be preferable to get optimum emitted dose and fine particle fraction.Desenvolveram-se formulações por inalação de dipropionato de beclometasona, livres de CFC, com o objetivo de tratar a asma profilaticamente. Prepararam-se inaladores de pó seco (DPI) para o dipropionato de beclometasona com diferentes gradações de lactose monoidratada. Estudou-se a influência do transportador e dos excessos de fármaco em relação ao rotulado no desempenho do DPI. Inaladores de dose calibrada (MDI) com propelentes à base de hidrofluoralcanos (HFA) foram formulados com várias doses, excessos de fármaco em relação ao rotulado e diferentes concentrações de álcool. Avaliaram-se as DPI e MDI formuladas por vários métodos oficiais e não oficiais de controle de qualidade. Estudaram-se a influência da superdosagem na liberação da válvula, o efeito dos excessos na dose emitida e a influência do álcool no padrão do spray do MDI. Obtiveram-se a melhor partícula fina e a dose emitida do DPI formulado com proporção de 10:90 de lactose fina:lactose grossa e 20% p/p de excesso. Os estudos em MDI revelaram que 15% de sobredose são requeridos para a liberação efetiva da válvula e 20% de excessos, para a liberação de 100% dos fármacos. Álcool a 5-10% v/v permitiu alcançar ótima dose emitida e fração de partícula fina