11.6: Formulation and Manufacturing Process: Physical Attributes of Generic Tablets and Capsules

Bioequivalence in generic drugs, such as tablets and capsules, refers to their pharmaceutical equivalence to the brand-name counterparts. However, for therapeutic equivalence, manufacturers must also consider physical attributes like size, shape, and weight (FDA Guidance for Industry, December 2003). Discrepancies in these aspects could impact patient compliance and cause medication errors. For instance, swallowing difficulties, often experienced with larger tablets or capsules, can lead to adverse events and patient noncompliance. Such difficulties also extend esophageal transit time, possibly causing the product to disintegrate in the esophagus, resulting in injury, pain, localized esophagitis, and even serious complications like ulceration.

Research suggests that oval tablets are easier to swallow and have quicker esophageal transit times than round tablets of the same weight. Additionally, heavier tablets or capsules tend to have faster transit times compared to lighter ones of similar size. Other factors influencing esophageal transit time include surface area, disintegration time, and swelling propensity when swallowed. These parameters could affect the drug's performance for its intended use. As a result, they warrant consideration in manufacturing generic drugs intended for intact swallowing.