Generic for omeprazole
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Generic Omeprazole: Efficacy, Bioavailability, and Quality
Introduction to Generic Omeprazole
Omeprazole, a widely used proton pump inhibitor (PPI), is essential for treating various acid-related gastrointestinal disorders. With the expiration of the patent on the original omeprazole, several generic versions have entered the market. This article synthesizes research findings on the efficacy, bioavailability, and quality of generic omeprazole compared to the original formulation.
Acid-Suppressive Effects of Generic Omeprazole
Comparative Studies on Acid Suppression
A study comparing the acid-suppressive effects of three brands of generic omeprazole with the original omeprazole found significant differences. While all formulations increased intragastric pH compared to placebo, some generics like Omeprazole-Towa and Omerap did not maintain higher pH levels during the night-time period, indicating variability in their acid-suppressive effects1. This suggests that not all generic formulations may provide the same clinical outcomes as the original omeprazole.
Bioavailability of Generic Omeprazole
Bioequivalence Studies
Several studies have evaluated the bioavailability of generic omeprazole formulations. A study in healthy Mexican volunteers demonstrated that the test formulation (Inhibitron) was bioequivalent to the reference formulation (LosecA 20 mg), with similar pharmacokinetic properties such as Cmax and AUC3. Another study confirmed the bioequivalence of two generic omeprazole capsules with the brand-name product, Losec, based on pharmacokinetic parameters4. These findings indicate that many generic formulations meet the bioequivalence criteria set by regulatory authorities.
Variability in Bioavailability
Despite the general bioequivalence, some studies noted high intra-subject variability in Cmax and between-subject variability in pharmacokinetic profiles, likely due to the multi-unit type of formulations studied5. This variability underscores the importance of considering individual patient responses when prescribing generic omeprazole.
Quality and Performance of Generic Omeprazole
In Vitro Performance
An investigation into the in vitro performance of five different marketed generic omeprazole delayed-release capsules found that all met the United States Pharmacopeia (USP) standards for dissolution characteristics. The study concluded that there is no scientific evidence to support claims of inferior performance of generic omeprazole compared to the brand product in vitro2.
Elemental Impurities
Elemental impurities in drug formulations can pose pharmacological and toxicological risks. An analysis of elemental impurities in various omeprazole brands, including generics, found that the levels of contaminants such as As, Ba, Cd, and Pb were below the limits proposed by the USP. This suggests that the quality of generic omeprazole in terms of elemental impurities is comparable to that of the reference products6.
Conclusion
The research indicates that while generic omeprazole formulations generally meet bioequivalence and quality standards, there can be variability in their acid-suppressive effects and pharmacokinetic profiles. Clinicians should be aware of these differences and consider individual patient responses when prescribing generic omeprazole. Overall, generic omeprazole remains a viable and effective alternative to the original formulation for treating acid-related gastrointestinal disorders.
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Most relevant research papers on this topic
Acid-suppressive effects of generic omeprazole: comparison of three brands of generic omeprazole with original omeprazole.
Some brands of generic omeprazole have different acid-suppressive effects compared to original omeprazole, which may impact clinical outcomes.
RCTGeneric omeprazole delayed-release capsules: in vitro performance evaluations
Generic omeprazole delayed-release capsules meet USP standards and perform similarly to brand omeprazole products in vitro, despite some complaints about their therapeutic effect.
In Vitro StudyBioavailability of two single-dose oral formulations of omeprazole 20 mg: an open-label, randomized sequence, two-period crossover comparison in healthy Mexican adult volunteers.
Inhibitron and LosecA 20 mg oral formulations of omeprazole 20 mg show bioequivalence in healthy Mexican adult volunteers, with no significant differences in bioavailability.
RCTRELATIVE BIOAVAILABILITY OF OMEPRAZOLE CAPSULES AFTER ORAL DOSING
Two generic omeprazole capsules were found to be bioequivalent to brand-name omeprazole, with pharmacokinetic parameters similar to Losec.
RCTBioequivalence evaluation of two omeprazole enteric-coated formulations in humans.
Omeprazole enteric-coated formulations show high intra-subject variability and variability between subject profiles, potentially due to the multi-unit type of formulations studied.
Elemental impurities analysis in name-brand and generic omeprazole drug samples
Elemental impurities in omeprazole drugs from different brands showed no significant difference in concentrations, meeting USP regulations and similar to those in generic drugs.
Stability of omeprazole in SyrSpend SF Alka (reconstituted).
Omeprazole in SyrSpend SF Alka (reconstituted) has a shelf life of at least 92 days when refrigerated and protected from light.
Omeprazole 10 milligrams once daily, omeprazole 20 milligrams once daily, or ranitidine 150 milligrams twice daily, evaluated as initial therapy for the relief of symptoms of gastro-oesophageal reflux disease in general practice.
Omeprazole, 20 mg, is the most effective initial therapy for relief of gastro-oesophageal reflux disease symptoms.
RCT
Large Human Trial
Highly CitedPharmacokinetic drug interaction profile of omeprazole with adverse consequences and clinical risk management
Omeprazole can cause adverse drug interactions with various medications, requiring enhanced clinical risk management to avoid adverse consequences.
Systematic Review
Rigorous JournalHighly CitedOmeprazole. A review of its use in Helicobacter pylori infection, gastro-oesophageal reflux disease and peptic ulcers induced by nonsteroidal anti-inflammatory drugs.
Omeprazole is effective in treating Helicobacter pylori infection, gastro-oesophageal reflux disease, and gastrointestinal damage caused by nonsteroidal anti-inflammatory drugs, with potential for triple therapy regimens.
Literature ReviewHighly Cited