Atenolol Gastrointestinal Therapeutic System. I. Screening of Formulation Variables

Use of Placket-Burman statistical design to study effect of formulation variables on the release of drug from hot melt sustained release extrudates

The present paper was focused on exploiting Plackett-Burman design to screen the effect of nine factors--poly (ethylene oxide) molecular weight (X(1)), poly (ethylene oxide) amount (X(2)), ethylcellulose amount (X(4)), drug solubility (X(5)), drug amount (X(6)), sodium chloride amount (X(7)), citric acid amount (X(8)), polyethylene glycol amount (X(9)), and glycerin amount (X(11)) on the release of drugs from the extended release extrudates, i.e., release rate and release mechanism. The experiments were carried out according to a nine-factor 12-run statistical model and subjected to an 8-h dissolution study in phosphate buffer pH 6.8. The significance of the model was indicated by the ANOVA and the residual analysis. Poly (ethylene oxide) amount, ethylcellulose amount and drug solubility had significant effect on the T90 values whereas poly (ethylene oxide) amount and ethylcellulose amount had significant effect on the n value.

Osmotically controlled oral drug delivery

It is advantageous to deliver some drugs with short half-life, and which are to be given frequently for chronic ailments, in the form of controlled-release (CR) formulations. The orally administered drugs, in the form of conventional matrix or reservoir type formulations, pose problems of bioavailability fluctuations due to gastric pH variations. Moreover, the release of drug(s) from these systems is affected by the hydrodynamic conditions of the body. Osmotically controlled drug delivery systems utilize the principles of osmotic pressure for the controlled delivery of active agent(s). The release rate of drug(s) from these systems is independent of the physiological factors of the gastrointestinal (GI) tract to a large extent. In the present review, theory underlying the delivery of drugs from osmotic systems is presented. Different types of oral osmotic systems, their advantages over conventional matrix and reservoir types of systems, and their applications are also discussed. Finally, some of the limitations, adverse effects, and patent and market status of these systems are reviewed. These systems form a major segment of drug delivery products. Because of their advantages and strong market potential, it appears that the future of osmotic systems in rate-controlled oral drug delivery is promising.

Recent technological advances in oral drug delivery - a review

Despite disadvantages, oral drug delivery remains the preferred route of drug delivery. Novel technologies with improved performance, patient compliance, and enhanced quality have emerged in the recent past. Oral fast-dispersing dosage forms, three-dimensional Printing (3DP) and electrostatic coating are a few examples of a few existing technologies with the potential to accommodate various physico-chemical, pharmacokinetic and pharmacodynamic characteristics of drugs. This article provides a comprehensive review of these three technologies.

Aqueous-based polymeric dispersion: face-centered cubic design for the development of atenolol gastrointestinal therapeutic system

The main objective of the study was to use the statistical response surface methodology to evaluate the effect of formulation variables and their interaction on drug release in atenolol gastrointestinal therapeutic system (GITS) development coated with cellulose acetate (CA) pseudolatex system. A three-factor, three-level, face-centered design was employed to evaluate the quadratic response surface, and to achieve the desired response in atenolol delivery. Coating was achieved by spraying plasticized CA pseudolatex on atenolol bilayered tablets in a Uni-Glatt fluidized-bed coater. The independent variables were orifice size (X1), percent coating weight gain (X2) and Carbopol 934P (X3). The response variable (Y1) was time for 50% (t50%) drug dissolution with a constraint on cumulative percent released in 24 hr (Y2). The polynomial equation obtained was Y1 = 61.88 - 3779.8X1 + 1.89X2 - 3.95X3 - 266.87 X1X2 - 1675X1X3 + 0.07X2X3 + 215123X1(2) + 0.06X2(2) + 0.10X3(2). Contour and response plots were used to relate the independent and dependent variables. The optimization procedure predicted a t50% of 10.83 hr with 92% atenolol release in 24 hr when orifice size (X1), percent coating weight gain (X2), and Carbopol 934P (X3) were 0.014 in., 13%, and 20 mg, respectively. Preparation and testing of optimized formulation showed a good correlation between the predicted and observed values.

Aqueous based polymeric dispersion: Plackett--Burman design for screening of formulation variables of atenolol gastrointestinal therapeutic system

Bilayered osmotically controlled Gastrointestinal Therapeutic System of atenolol has been obtained by using cellulose acetate pseudolatex prepared by polymer emulsification method. Various factors such as orifice size, coating thickness, amount and nature of polymeric excipients, and amount of osmotic agent influence the drug release from GITS. Therefore, in the present study a 7-factor, 12-run Plackett-Burman screening design was employed to evaluate the formulation variables for atenolol GITS coated with CA pseudolatex. The variables studied were orifice size, %coating weight gain, amounts of sodium chloride. Polyox N80 and 303, and Carbopol 934P and 974P on drug release. The screening design has revealed that orifice size, %coating weight gain and amount of Carbopol 934P have prominent influence on in-vitro atenolol release. The response variable was cumulative percent atenolol released (Y) in 24 h with constraints on percent release at 2, 6, 12 and 18 h. The polynomial equation obtained was Y24 = 149.82 - 0.13 X1 - 0.34X2 + 0.06X3 - 0.13X4 - 0.23X5 - 76.25X6 - 2.46X7. The results indicated that the drug release under constrained conditions was influenced by the factors with decreasing order of importance as %coating weight gain > Carbopol 934P > Polyox N80 > Carbopol 974P > Polyox 303 > amount of sodium chloride > orifice size.

Solid-state stability assessment of controlled release tablets containing Carbopol 971P

A tablet formulation containing dyphylline, Carbomer, magnesium stearate, talc and lactose was prepared by the direct compression method. The objective of the study was to assess the stability of these tablets after subjecting them to exaggerated conditions of temperature (4, 25, 37, 45 and 55 degrees C) and humidity (37 degrees/11%RH, 37 degrees/51%RH and 37 degrees C/91%RH). The samples were analyzed for crystalline, thermal and dissolution changes with time for a period of 12 months using X-ray diffractometry (XRD), differential scanning calorimetry (DSC) and U.S.P. Dissolution Apparatus 2. Moisture sorption studies of all tablets indicated sorption of large amounts of moisture at 37 degrees C/91%RH. The fit factors, f1 andf2, were calculated and used to compare the dissolution profiles. The results showed increased f1 and decreased f2 values at higher humidity, while the samples were fairly stable at lower humidity and at all temperatures studied. Powder XRD patterns of tablets showed a change in crystallinity at higher humidity. The thermal and crystalline data indicated that the change in dissolution behavior at higher humidity may be due to the conversion of dyphylline to its hydrate form.