Influence of talc and hydrogenated castor oil on the dissolution behavior of metformin-loaded pellets with acrylic-based sustained release coating.

Multi-unit pellet system (MUPS) is of great interest as it is amenable to customization. MUPS comprises multi-particulates, usually as pellets or spheroids, which can be coated with diffusion barrier coatings. One commonly used diffusion barrier coating is the methacrylic acid copolymer, which can be used as a taste masking, enteric or sustained release polymer. While the versatility of methacrylic acid copolymers makes them pliable for pellet coating, there are impediments associated with their use. Additives commonly required with this polymer, including plasticizer and anti-adherent, have been shown to weaken the film strength. The objective of this study was to investigate the impact of osmotic pressure within the core on the sustained release coat integrity and functionality. Hydrogenated castor oil (HCO) was chosen as the additive to be studied. Metformin-loaded pellets, prepared via extrusion-spheronization, were coated with ethyl acrylate and methyl methacrylate copolymer (Eudragit RS 30 D) containing talc, talc-HCO, or HCO to different coat thicknesses. Drug release was investigated using the USP dissolution apparatus 2 and an ultraviolet imager. The swelling of the pellets when wetted was monitored by video imaging through a microscope. When coated to 7.5 % coat weight gain, coats with HCO slowed down drug release more than the other pellets. The pellets also swelled the most, which suggests that they were more resistant to the osmotic pressure exerted by metformin. For drugs which exert high osmotic pressure, HCO can serve as an efficient alternative to talc in the preparation of methacrylic acid copolymer coatings.

Lidocaine loaded gelatin/gelatinized tapioca starch films for buccal delivery and the irritancy evaluation using chick chorioallantoic membrane.

The aim of this study was to confirm the feasibility of gelatin/gelatinized tapioca starch (α st) films for buccal delivery and to evaluate their irritancy. Lidocaine (LB) and lidocaine hydrochloride (LH) were used as model drugs and glycerin was used as the plasticizer. The scanning electron microscopy, atomic force electron microscopy, X-ray diffraction and thermogravimetric analysis results confirmed the compatibility of gelatin/α st/glycerin (Gαgly) films. Drug releases of LB- or LH-Gαgly films were evaluated. The drug release profiles of medicated films presented good patterns in both short time and 8 h drug release studies. The permeation study was examined through chick chorioallantoic membrane (CAM) by using modified Franz diffusion cells. Moreover, the irritancy study for buccal films was also examined by a hen's egg test on CAM model (HET-CAM). The results revealed that LB and LH could permeate through CAM, and these Gαgly films created no irritation on HET-CAM. This indicates that the LB- and LH-Gαgly films are possible to use as buccal films.