The purpose of the study was to design bilayer floating tablets of Propranolol hydrochloride and Lovastatin to give immediate release of Lovastatin and controlled release of Propranolol hydrochloride. Bilayer floating tablets comprised of two layers, immediate release layer and controlled release layer. Direct compression method was employed for formulation of the bilayer tablets. Short term accelerated stability studies were carried out on the prepared tablets. All the formulations floated for more than 12h. More than 90% Lovastatin was released within 30 min. from the formulations. HPMC K4M and Xanthan gum retarded the release of Propranolol hydrochloride from the controlled release layer for 12h. After stability studies, apparent degradation of both the drugs were found but the drug content was found to be within the range. Diffusion exponent (n) was determined for all the formulations (0.53-7). Based on coefficient of correlation(R), the release of Propranolol hydrochloride was found to follow mixed release pattern of Hixson-Crowell, Korsmeyer-Peppas and matrix, except formulation F6 and F9, which followed zero order release pattern. Statistical analysis revealed that there was no significant difference in in vitro release pattern of the drugs before and after stability studies.
Table of Contents
1. ABSTRACT
2. INTRODUCTION
3. MATERIALS AND METHODS
3.1 Preparation of Bilayer Floating Tablets
3.2 Floating characteristics
3.3 Drug content
3.3.1 Propranolol HCl
3.3.2 Lovastatin
3.4 Drug release
3.5 Hardness
3.6 Stability
3.7 DSC studies
3.8 Assessment of Similarity factor
3.9 Statistical Analysis
4. RESULTS
4.1 Floating characteristics
4.2 Drug content
4.3 In vitro drug release
4.3.1 Lovastatin
4.3.2 Propranolol hydrochloride
4.4 Hardness
4.5 DSC studies
4.6 Stability studies
4.6.1 Floating characteristics
4.6.2 Drug content
4.6.3 Drug release
4.6.3.1 Lovastatin
4.6.3.2 Propranolol hydrochloride
4.6.4 Hardness
4.6.5 Similarity factor
5. DISCUSSION
6. CONCLUSION
Research Objectives and Themes
The primary objective of this study is the development and evaluation of bilayer floating tablets designed for the biphasic release of two medications: the immediate release of Lovastatin and the controlled release of Propranolol hydrochloride. By employing a gastro-retentive dosage form, the study aims to improve the bioavailability of both drugs and enhance patient compliance through a simplified, once-daily combination therapy for patients suffering from concurrent hypertension and hypercholesterolemia.
- Formulation of bilayer tablets using direct compression.
- Evaluation of gastric-retentive and floating characteristics using polymers like HPMC K4M and Xanthan gum.
- Mathematical modeling of drug release kinetics to determine release mechanisms.
- Assessing drug stability and performance consistency under accelerated storage conditions.
- Comparative analysis of dissolution profiles using similarity factors (f2).
Book Excerpt
DISCUSSION
On contact with dissolution medium, hydrochloric acid in the test medium reacted with the sodium bi carbonate in the controlled release layer of the bilayer tablet, inducing CO2 formation. The generated gas bubble was trapped in the matrix of the polymer and was well protected by gel formed by hydration of polymers. A 5% concentration of sodium bi carbonate was found to optimum to impart floating characteristics to the system. It was observed that concentration of sodium bi carbonate more than 5% led to fast reaction with formation of dispersion of the tablet. Hardness upto 4.5 kg/cm2 was found optimum to impart compactness to the system. Gel formed by polymers alone and in combination was effective for the protection of gas bubble. Further, an increase in bulk volume, presence of internal voids in the dry center of tablet (porosity) made the tablet float on the test medium for 12-24h.
During floating all the formulations showed good matrix integrity, which may be because of the compactness of the system, which is necessary to prevent the sweep of the table in lower part of gastrointestinal tract during interdigestive myloelectric cycle (Phase I-Phase II ). As the concentration of the polymers was increased (F1-F9), it was observed that floating lag time was decreased and floating duration was increased. This can be explained as: As the concentration of polymers was increased there was more gel formation and easy trap of gas bubble in the matrix resulting in decreased lag time. As a function of time, a firm gel was formed increasing the volume of the tablet and decreasing density which resulted in more prolonged floating duration.
Summary of Chapters
ABSTRACT: Provides a high-level summary of the bilayer tablet formulation, including key release profiles for Lovastatin and Propranolol hydrochloride and the results of stability studies.
INTRODUCTION: Establishes the clinical rationale for combined hypertension and hyperlipidemia therapy and reviews existing gastroretentive drug delivery strategies.
MATERIALS AND METHODS: Details the specific ingredients, equipment, and experimental protocols used for tablet preparation, stability testing, and analytical evaluation.
RESULTS: Presents empirical data on tablet floating characteristics, drug content uniformity, in vitro dissolution profiles, and model fitting parameters.
DISCUSSION: Interprets the findings regarding polymer behavior, gas generation, release kinetics, and the overall performance of the optimized formulation.
CONCLUSION: Summarizes the success of the bilayer system and suggests future directions for clinical evaluation to improve patient care.
Keywords
Lovastatin, Propranolol hydrochloride, floating, bilayer tablets, HPMC K4M, Xanthan gum, gastric retention, drug release kinetics, biphasic release, accelerated stability, direct compression, dissolution profile, similarity factor, hypertension, hypercholesterolemia.
Frequently Asked Questions
What is the core purpose of this study?
The study aims to create a single bilayer tablet that combines Lovastatin and Propranolol hydrochloride to provide immediate release for one drug and controlled release for the other, improving therapeutic management for patients with both high blood pressure and high cholesterol.
What are the primary fields of study in this paper?
The research focuses on pharmaceutical technology, specifically gastro-retentive dosage forms, controlled-release matrix systems, and the formulation and stability analysis of bilayer tablets.
What is the ultimate goal of developing these bilayer tablets?
The goal is to enhance patient compliance by combining two necessary treatments into one dosage form, while utilizing gastric retention to optimize the absorption of drugs with narrow absorption windows.
Which scientific methods were employed for this formulation?
The researchers used the direct compression method to create the tablets, incorporated polymers like HPMC K4M and Xanthan gum for controlled release, and utilized gas-generating agents for buoyancy. Performance was evaluated via USP paddle apparatus and validated by kinetic mathematical modeling.
What does the main body of the work cover?
The main body covers the rationale behind the study, the materials and preparation techniques, rigorous testing of floating properties, drug release kinetics analysis, DSC studies for drug compatibility, and stability testing over a three-month period.
Which keywords best describe this research?
Key concepts include bilayer floating tablets, biphasic release profiles, gastric retention, kinetic modeling, and stability testing of combination therapy formulations.
Why were HPMC K4M and Xanthan gum chosen for this study?
These polymers were chosen for their ability to form a viscous gel upon hydration, which acts as a matrix to control the diffusion of Propranolol hydrochloride and protect the gas-generating system required for buoyancy.
How does the system ensure it stays in the stomach?
The system uses sodium bicarbonate to generate CO2 gas upon contact with gastric fluids. This gas is trapped within the polymer matrix, which, combined with the swelling properties of the polymers, provides the buoyancy needed to retain the tablet in the stomach for 12 to 24 hours.
What were the results of the stability studies?
Stability studies showed minor drug degradation, which remained within official standards, and confirmed that the physical properties of the tablets, such as floating duration and release patterns, were successfully maintained after three months of storage.
Which formulation was considered optimal?
Based on the dissolution data, floating characteristics, and the similarity factor (f2 value), Formulation F3 was identified as the most effective or optimized version of the bilayer tablet.
- Quote paper
- Ph.D. Ajit Kulkarni (Author), Manish Bhatia (Author), 2014, Design of Regioselective Bilayer Floating Tablets of Propranolol Hydrochloride and Lovastatin for Biphasic Release Profile, Munich, GRIN Verlag, https://www.grin.com/document/284893
