Rapid and selective UV spectrophotometric and RP-HPLC methods for dissolution studies of oxybutynin immediate-release and controlled-release formulations

INTRODUCTION/OBJECTIVES: Controlled-release lithium formulations were developed to minimize elevated blood peaks, related to side-effects and intoxications. However, there is little information about the bioavailability of the only controlled-release lithium formulation available in Brazil. The objective of this study was to compare the bioavailability of controlled-release and immediate-release lithium formulations, after single and multiple doses. METHODS: Twelve healthy volunteers received 900 mg of immediate-release or controlled-release lithium carbonate in single or multiple doses during 9 days. After single dose administration, the following parameters were analyzed for each formulation: maximum lithium concentration (Cmax); time to reach Cmax (t max); area under the curve of serum concentration versus time (AUC0-12 and AUC0-<FONT FACE=Symbol>¥</FONT>) and the elimination half-life (t1/2 elim.). After multiple doses, Cmax; t max; AUC0-12; mean (Cmean) and minimum drug concentration (Cmin) and degree of fluctuation (DF) were analyzed. A 90% confidence interval (90%CI) for the ratio between the AUCs for each formulation was constructed. RESULTS/DISCUSSION: Following single dose, the two formulations were bioequivalent; however, they were not after multiple doses. This fact could be a consequence of methodological limitations of lithium level's measurements since, following single dose, these levels could not be detected at time periods 24 and 48h in many volunteers, compromising the calculation of t1/2 elim ,and consequently of the AUC0<FONT FACE=Symbol>-¥</FONT> and the 90%CI to the ratio of these areas. Therefore, the bioequivalence found after single dose may be an unreliable result.

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Preparation and Evaluation of Captopril Oral Floating Controlled Release Formulations

Journal of Pharmaceutical Research International ◽

10.9734/jpri/2021/v33i44b32696 ◽

2021 ◽

pp. 442-452

Author(s):

Ramakrishna Vydana ◽

Chandra Sekhar Kothapalli Bonnoth ◽

Vidyadhara Suryadevara ◽

Sandeep Doppalapudi

Keyword(s):

Controlled Release ◽

Drug Release ◽

Sodium Bicarbonate ◽

Lag Time ◽

Water Soluble ◽

Alternative Formulation ◽

Dissolution Studies ◽

Dosing Frequency ◽

Controlled Release Formulations ◽

Prolonged Drug Release

Aim: Dosing frequency is a major hurdle in geriatrics with frequent drug administration. In such cases, oral controlled release floating formulations are helpful which causes reduction in dosing frequency and fluctuation of drug levels in plasma. The main aim of the current research was to prepare Captopril floating controlled release formulations in order to achieve extended gastric retention in the upper GIT. Methodology: Captopril tablets were prepared using different concentrations of poly ethylene oxide water soluble resin (PEO WSR) 303 (5% to 30%) by direct compression technique. Captopril formulations CSP1 and CSP6 were formulated using PEO WSR 303. Pre and post compression parameters were evaluated. Dissolution studies were performed for the prepared tablets using 0.1N hydrochloric acid as dissolution medium. Results: The dissolution studies showed controlled drug release up to 12h. The formulation CSP5 prepared using 25% w/w of PEO WSR 303 showed maximum drug release of 97.97% at 12h. Almost similar drug release profile was also observed for CSP6 which was prepared using 30%w/w PEO WSR 303. These two formulations were further added with various concentrations of sodium bicarbonate (5% to 15%) and citric acid (2.5% to 10%) which enhanced floating of drug in Gastro intestinal tract (GIT). Formulation CSP8 containing 10% of sodium bicarbonate with 25% PEO WSR 303 showed less buoyancy lag time and prolonged drug release. Formulation CSP15 showed very less buoyancy lag time of 5sec. Characterization studies like Fourier Transform Infra Red spectroscopy (FTIR) and Scanning Electron Microscopy (SEM) were also carried out. Conclusion: The prepared Captopril floating tablets could be an alternative formulation for prolonged drug release.

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Formulation and Evaluation of Metoprolol Controlled Release Formulations

Journal of Pharmaceutical Research International ◽

10.9734/jpri/2021/v33i55b33855 ◽

2021 ◽

pp. 122-132

Author(s):

Ramakrishna Vydana ◽

Chandra Sekhar Kothapalli Bonnoth

Keyword(s):

Controlled Release ◽

Drug Release ◽

Sodium Bicarbonate ◽

Research Work ◽

Lag Time ◽

Drug Formulation ◽

Dissolution Studies ◽

Controlled Release Formulations ◽

Characterization Studies ◽

Prolonged Drug Release

Aim: The main perspective of the present research work was to prepare Metoprolol floating controlled release formulations. Methodology: After performing the characterization studies, Metoprolol tablets were prepared using various concentrations of poly ethylene oxide (PEO) WSR 303 (5% to 30%) by direct compression method. Formulations MP1 and MP6 were formulated using PEO WSR 303. Various pre and post compression parameters were evaluated. Dissolution studies were performed for the prepared tablets using dissolution medium of 0.1N hydrochloric acid. Results: Characterization studies like Fourier Transform Infra Red (FTIR) and Scanning Electron Microscopy (SEM) for Metoprolol, Polyethylene oxide WSR 303 and their combination were carried out, which revealed that there is no interaction between drug and polymer. The dissolution studies showed the controlled release pattern of Metoprolol up to 24h. The formulation MP5 prepared using 25% w/w of PEO WSR 303 showed maximum drug release of 98.22% at 24h. Similar drug release profile was observed for MP6 which was formulated using 30%w/w PEO WSR 303. These two formulations were further added with various concentrations of sodium bicarbonate (5% to 15%) and citric acid (2.5% to 10%) which enhanced floating of drug. Formulation MP8 containing 10% of sodium bicarbonate with 25% PEO WSR 303 showed less buoyancy lag time and prolonged drug release. Formulation MP15 showed very less buoyancy lag time of 4sec. Conclusion: Thus the prepared Metoprolol floating tablets showed prolonged drug release which could be a promising formulation for anti-hypertensive patients.

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