Rumen bypass and biodistribution of l-carnitine from dual-layered coated pellets in cows, in vitro and in vivo

In situ and in vitro evaluation of the bioavailability of rumen-protected methionine with coating prototypes

Rumen protected amino acids are supplements that can enhance ruminal performance, yet the coating designed to protect the amino acids might also lead to different effects. Methionine is an essential methyl donor to synthesize protein, and little data exists on the effects of coating materials on its bioavailability. The purpose of this study was to estimate the effect of rumen-protected methionine (RPM) coatings with different ratios of acrylic resin IV (AR), ethyl cellulose (EC), and a mixture of AR and EC (AREC). Fifteen RPMs were prepared according to a single factor design, with 5 proportions each of AR, EC, and AREC to DL-methionine (DL-Met). Twelve hybrid small-tailed Han sheep with rumen fistula were utilized to evaluate in situ escape of RPMs, followed by in vitro abomasum-intestinal release of the RPMs. The results showed a regular variation in both ruminal disappearance and gastrointestinal release of RPMs with different coating prototypes and retention time. The RPMs that were EC and AREC coated presented high bioavailability compared to those with AR. Bioavailability of RPMs was optimal with the 2:20 AREC: DL-Met ratio, when the proportion of AR:EC is 1:1. Additionally, RPMs with a 1:3 ratio of AR:EC confirmed the optimum effect for the RPM of 2:20 AREC: DL-Met. In conclusion, an RPM with a lower AREC ratio coating can achieve better bioavailability and is synergistic to those with EC and AR.

Eficácia da suplementação oral com 1,3-1,6 betaglucano proveniente de Saccharomyces cerevisiae no controle da mastite bovina

RESUMO A mastite bovina, uma das principais doenças do rebanho leiteiro, caracteriza-se por um processo inflamatório no úbere. A inviabilidade econômica, o impacto ambiental negativo e os resíduos antimicrobianos têm estimulado a pesquisa de outros tratamentos alternativos para a prevenção e o tratamento de doenças na bovinocultura leiteira. O betaglucano é um agente imunomodulador com potencial ação preventiva para doenças infecciosas, inclusive a mastite. Este estudo teve como objetivo avaliar a eficácia do uso do betaglucano, por meio de administração oral, em animais em lactação. Foram utilizadas 20 vacas lactantes, distribuídas em dois grupos, um controle e um tratamento, com 10 animais em cada grupo. O grupo tratamento recebeu 5g/dia, durante 60 dias, de 1,3-1,6 betaglucano isolado da parede celular de Saccharomyces cerevisiae diluído em ração após a ordenha, enquanto o grupo controle recebia somente a ração. Foram realizados os testes de California Mastitis Test (CMT), contagem de células somáticas (CCS), produção de leite e percentual de gordura e proteína no leite. Não houve diferença estatisticamente significativa entre os grupos quanto à CCS, ao CMT, à composição do leite ou produção. Não se observou, portanto, eficácia do uso do betaglucano purificado, administrado por via oral, no controle e na prevenção da mastite em vacas leiteiras, quando comparadas com o grupo controle. Atribuem-se esses resultados, principalmente, à degradação ruminal do produto testado. Sugerem-se, portanto, mais pesquisas utilizando o 1,3-1,6 betaglucano purificado de parede de S. cerevisiae por outras vias de administração, tais como intramamária e subcutânea.

A new application of lipid nanoemulsions as coating agent, providing zero-order hydrophilic drug release from tablets

The objective of the present investigation was to evaluate potential of nanoemulsions as a coating material for the tablets. The nanoemulsion of size less than 100 nm was prepared using a simple and low-energy spontaneous emulsification method. Conventional tablets containing theophylline as a model hydrophilic drug were prepared. The theophylline tablets were coated with the nanoemulsion using a fluid bed coater. The effect of different levels of the nanoemulsion coating on the theophylline release was evaluated. The theophylline tablets containing different levels of the nanoemulsion coating could be successfully prepared. Interestingly, the coating of tablet with the nanoemulsion resulted in zero-order release of theophylline from the tablets. The noncoated theophylline tablets release the entire drug in less than 2 minutes, whereas nanoemulsion coating delayed the release of theophylline from tablets. This investigation establishes the proof of concept for the potential of nanoemulsions as a coating material for tablets.

Comparison of release-controlling efficiency of polymeric coating materials using matrix-type casted films and diffusion-controlled coated tablet

Polymeric coating materials have been widely used to modify release rate of drug. We compared physical properties and release-controlling efficiency of polymeric coating materials using matrix-type casted film and diffusion-controlled coated tablet. Hydroxypropylmethyl cellulose (HPMC) with low or high viscosity grade, ethylcellulose (EC) and Eudragit(R) RS100 as pH-independent polymers and Eudragit S100 for enteric coatings were chosen to prepare the casted film and coated tablet. Tensile strength and contact angle of matrix-type casted film were invariably in the decreasing order: EC> Eudragit S100> HPMC 100000> Eudragit RS100>HPMC 4000. There was a strong linear correlation between tensile strength and contact angle of the casted films. In contrast, weight loss (film solubility) of the matrix-type casted films in three release media (gastric, intestinal fluid and water) was invariably in the increasing order: EC < HPMC 100000 < Eudragit RS100 < HPMC 4000 with an exception of Eudragit S100. The order of release rate of matrix-type casted films was EC > HPMC 100000 > Eudragit RS100 > HPMC 4000 > Eudragit S100. Interestingly, diffusion-controlled coated tablet also followed this rank order except Eudragit S100 although release profiles and lag time were highly dependent on the coating levels and type of polymeric coating materials. EC and Eudragit RS100 produced sustained release while HPMC and Eudragit S100 produced pulsed release. No molecular interactions occurred between drug and coating materials using (1)H-NMR analysis. The current information on release-controlling power of five different coating materials as matrix carrier or diffusion-controlled film could be applicable in designing oral sustained drug delivery.