Effect of hydrophilic natural gums in formulation of oral-controlled release matrix tablets of propranolol hydrochloride

In order to develop a controlled delivery of highly water-soluble propranolol hydrochloride [PPHCl] using hydrophilic natural gums [xanthan gum [X] and locust bean gum [LBG]] as cost-effective, nontoxic, easily available. The granules of PPHCl were prepared by wet granulation method using a different ratios drug: gum ratios of X, LBG and XLBG[X and LBG in 1:1 ratios]. To increase the flowability and compressibility of the granules, and to prevent its adhesion to punch and die, magnesium stearate and talc were added to the granules in 1:2 ratios before punching. The tablets was analysed to determine hardness, friability,% assay and invitro release study was carried out. The release of PPHCl from a gelatinous swollen mass, which controls the diffusion of drug molecules through the polymeric material into aqueous medium. The XLBG matrices shows precise controlled release than the X and LBG matrices because of burst effect and fast release in case of X and LBG matrices respectively and there was no chemical interaction between drug and polymers in XLBG formulation as confirmed by FTIR studies. First pass effect of PPHCl can be avoided by these formulations. Matrices with XLBG show zero-order release via swelling, diffusion and relaxation mechanism. The XLBG matrices leads to more precise result than X and LBG alone by the utilization of synergistic interaction between two biopolymers and uniformity in the hydration layer in dissolution media. However, according to the similarity factor [f2] XLBG3 were the most similar formulation to Lol-SR as the reference standard

effect of the ratio of two acrylic polymers on the in vitro release kinetics of ketoprofen from pellets prepared by extrusion and spheronisation Technique

The aim of this study was to investigate the effect of physico-chemical properties of the polymers on the release profile of ketoprofen from the pellets dosage form. Ammonio Methacrylate Copolymer Type A [Eudragit RL 30 D] and Ammonio Methacrylate Copolymer Type B [Eudragit RS 30 D] were used as release rate retarding polymers. The drug containing core pellets were prepared by extrusion spheronisation technique and subsequently coated with 15% [w/w] polymer load of the combination of Eudragit RL 30 D and Eudragit RS 30 D having ratio 1:0, 4:1, 3:2, 1:1, 2:3, 1:4, 0:1 respectively. Significant differences were found among the drug release profile from different formulations. It was revealed that Eudragit RL 30 D has the effect to increase the initial drug release more significantly where as Eudragit RS 30 D has the effect to minimize the initial drug release but increase the terminal drug release more significantly. In acid media about 50% drug was released from pellets coated only with Eudragit RL 30 D where was only 5% drug was released in case of Eudragit RS 30 D but maximum 10% drug was released from pellets when coated with the combination of Eudragit RL 30 D and Eudragit RS 30 D. In buffer media, evidence of burst release was observed for the pellets coated with Eudragit RL 30 D and Eudragit RS 30 D having ratio of 1:0, 4:1, 3:2 respectively. It was also observed that drug release increases sharply as well as the release best fit to the zero order release kinetics when pellets coated with 1:1 ratio of Eudragit RL 30 D and Eudragit RS and follows Higuchi's release kinetics when ratio was 1:0 and 3:2. The results generated in this study showed that proper selection of polymeric materials based on their physico-chemical properties is important in designing sustained release pellets dosage form with suitable dissolution profile

Preparation and evaluation of oxytetracycline hydrochloride microbeads for delayed release

Oxytetracycline HCl microbeads were prepared with sodium alginate and pectin using ionic gelation method and evaluated for morphology, flow properties, drug content and in vitro drug release study. SEM confirmed spherical structure of microbeads with rough and porous surfaces and microbeads possessed average particle size range of 639.86 to 685.74 mm. In vitro drug release study was carried out in simulated gastric fluid [SGF] for first 2 h and simulated intestinal fluid [SIF] for next 6 h. Selected formulation was coated using enteric polymer cellulose acetate phthalate to minimize burst drug release along with delayed drug release in intestinal medium

comparative study of dissolution characteristics of polymeric and wax granulations of theophylline and their tablets

Matrix [non disintegrating] granules of theophylline have been formed and their dissolution characteristics investigated for sustained release application. The polymeric granulations were formed by massing the drug powder with a concentrated [40%w/w] ethanolic solution of an acrylatemethacrylate copolymer [ERS100R]. Wax granulations were also formed by massing the drug powder with previously melted carnuba wax followed by screening and drying. The content of polymer or wax in the resulting granules was 16.7%w/w. Conventional granules of theophylline were formed by massing the drug powder with starch mucilage [20%w/v]. Resulting granules were subjected to particle size analysis and in vitro dissolution tests. The granules were further compressed to tablets [weight 500 +/- 4.2mg each] at a constant load [30 arbitrary units on the load scale]. The tablets were subjected to hardness, disintegration and dissolution tests. The dissolution kinetics were also considered. The mean granule size was 646.5 +/- 4.3 micro m [convention al], 821.4 +/- 4.8 micro m [polymeric granulations] and 892.7 +/- 5.4 micro m [wax granulations], the matrix granules were therefore larger than the conventional granules. Dissolution of the granules generally followed a first order rate kinetic. The rate constant [k1] for the conventional, polymeric and wax granulations were [h-1]: 0.53, 0.31 and 0.27 respectively. Thus, the wax granulations appeared to be more effective than the polymeric granulations in retarding drug release from the granules but the difference was not statistically significant [p > 0.05]. The tensile strength of tablets derived from the conventional, polymeric and wax granulations were [MNm-2] 0.85, 1.68 and 1.96 respectively, indicating that the matrix granules [compared with the conventional granules] produced harder tablets at the same compression load. The corresponding first order dissolution rate constants were [h-1]: 0.46, 0.28 and 0.21. Thus, tableting of the matrix granules produced a slight but significant decrease in dissolution rates, attributabl e to the disintegration of the tablets to more compact particles