Venlafaxine Hydrochloride Controlled Release Bilayer Tablets: Optimization Of Formulation Variable By Using Dyspnea On Exertion

The current research work was to develop bilayer tablet of venlafaxine hydrochloride to increase drug efficacy for efficient treatment of depression. The satisfactory result of treatment can be achieved upon the maintenance of drug concentration within an effective level in the body, so a uniform and constant drug supply are desirable. An immediate layer of venlafaxine HCl was formulated using super disintegrants, i.e., croscarmellose sodium (CCS) and sodium starch glycolate (SSG); tablet compact by direct compression. HPMC K100M and ethylcellulose (EC) were utilized as release retarding polymers in sustained release layer by wet granulation technique with the help of PVP K30 in IPA solution (10%) as a granulating agent. Full 32 factorial designs were used to find out the optimum quantity of release retardant polymers. Bilayer tablet was evaluated for various parameters, i.e. hardness, friability, weight variation, % drug content, disintegration time (IR layer), and % drug release study. Statically, an analysis was carried out using factor X1 (HPMC K100M) and X2 (EC) for dependent variable % drug release at 8, 12, and 20 hours. A formulation was optimized and a formulation containing 305.36 mg of HPMC K100M and 54.03 mg of ethyl cellulose. Optimized formulation show 47.12 ± 2.1, 59.89 ± 2.2, and 89.06 ± 2.3 drug release at 8, 12, and 20 hours, respectively, which is almost similar to theoretical dose calculation with similarity factor f2 97, 99, and 98%, respectively. Bilayer tablet formulation was observed to be stable and fulfilled all compendia specifications.

Preparation of garcinia glycoside bilayer tablets and its in vitro release / 中国药学杂志

OBJECTIVE: To optimize the prescription and preparation process of garcinia glycoside bilayer tablets and study the drug release mechanism in vitro. METHODS: Solid dispersions were prepared by using water soluble carrier material polyethylene glycol (PEG) and then used to prepare the rapid release layer. Hydroxypropylmethyl cellulose (HPMC) was used as main sustained release material to prepare the sustained release layer. The formulations of rapid release layer and sustained release layer were optimized by using univariate analyses. DDslover software was used to fitting drug release curve. RESULTS: The content of the garcinia glycoside in the bilayer tablets was 98.5% and its release rate was consistent with the rule of release in vitro. The release behavior of the sustained release layer in vitro followed Higuchi equation (r=0.998 3). The main mechanism of drug release was the synergistic action of diffusion and dissolution. CONCLUSION: Garcinia glycoside bilayer tablets prepared by this method can achieve the goal of both rapid-acting and long-acting.

Segregated Delivery of Rifampicin and Isoniazid from Fixed Dose Combination Bilayer Tablets for the Treatment of Tuberculosis.

Aims: Develop an anti-tuberculosis (TB) Fixed Dose Combination (FDC) tablet containing an immediate release layer (IRL) composed of both rifampicin (RIF) and pyrazinamide (PYR) and a retarded release layer (RRL) comprised of isoniazid (INH) which would allow segregated delivery of RIF and INH. Study Design: Trials were conducted on the pre-formulations and formulations to assess the compatibility of excipients and obtain a modified release profile, for an IRL consisting of both RIF and PYR and a RRL containing INH. Place and Duration of Study: This study was performed at the Laboratory of Pharmaceutical Industrial Technology, Drug and Pharmaceutical Department, Faculty of Pharmacy, between March 2008 and April 2010. Methodology: Preformulation studies were performed on RIF and PYR, alone and in combination with excipients. The pharmacopeic attributes of the distinct layers and the FDC tablets were evaluated for hardness, friability and disintegration time. The FDC bilayer tablets were analyzed for their drug content and cumulative dissolution of the drug. Results: Fourier transform infrared, x-ray diffraction and differential scanning calorimetry results revealed the presence of amorphous and crystalline RIF forms and no potentially relevant incompatibilities were identified in the kneaded system containing RIF, PYR and excipients. In vitro drug release from the FDC tablets revealed that the intragranular addition of croscarmellose sodium into the IRL rendered a cumulative dissolution of RIF and PYR within the limits of simulated gastric fluid. And, for RRL, the most effective retardant matrix excipient was found to be hydroxypropyl methylcellulose. Conclusion: Segregated delivery of RIF and INH from bilayer tablets is an option for the development of immediate release FDC tablets and the retarded release of INH, this strategy proved suitable for preventing contact of these two drugs under acidic conditions. This finding suggested that RIF had a high in vivo bioavailability which qualifies this FDC for future bioavailability studies.

BI-Layer technology- an emerging trend: A review.

Combination therapy has various advantages over monotherapy. In the last decade, interest in developing a combination of two or more Active Pharmaceutical Ingredients (API) in a single dosage form (monolithic or bilayer tablet) has increased in the pharmaceutical industry, promoting patient convenience and compliance. Bilayer tablets can be a primary option to avoid chemical incompatibilities between API by physical separation, and to enable the development of different drug release profiles (immediate release with extended release). Several pharmaceutical companies are currently developing bi-layer tablets, for a variety of reasons: patent extension, therapeutic, marketing to name a few. To reduce capital investment, quite often existing but modified tablet presses are used to develop and produce such tablets. This article explains why the development and production of quality bi-layer tablets needs to be carried out on purpose-built tablet presses to overcome common bi-layer problems, such as layer-separation, insufficient hardness, inaccurate individual layer weight control, cross-contamination between the layers, reduced yield etc. Using a modified tablet press may therefore not be best approach in producing a quality bi-layer tablet under GMP conditions, especially when high production output is required. There are various applications of the bi-layer tablet consists of monolithic partially coated or multilayered matrices.

Formulation, optimization and evaluation of bilayered tablets of amlodipine besilate as immediate release and metoprolol succinate as sustained release.

The purpose of the study was to develop a bilayer tablet of Amlodipine besilate (IR) and Metoprolol succinate (SR) having different release pattern, which is indicated for the management of hypertension. The study was planned in three stages. In the first stage six batches (A1, A2, A3, A4, A5 and A6) of immediate release tables of Amlodipine besilate was prepared by direct compression method using sodium starch glycolate and pre-gelatinised starch as super disintegrant. In the second stage, six batches(M1, M2, M3, M4, M5, M6) of Metoprolol succinate sustained release part was prepared using HPMC polymers as rate retardant. Preformulation studies were performed prior to compression. In the third stage compressed bilayer tablets were evaluated for weight variation, dimension, hardness, friability, drug content, and disintegration time and invitro drug release using RP-HPLC. DSC studies revealed no disturbances in the principle peaks of pure drugs Metoprolol succinate and Amlodipine besilate and it confirms the integrity and compatibility of pure drugs with their excipients. The stability studies were performed for optimised batch for three months and it showed acceptable results.