Drug Delivery Challenges: Issues and Opportunities for Solid Dosage Products

The field of pharmaceutical oral solid dosage drug delivery faces several challenges, including the harsh gastrointestinal tract (GIT) environment, low bioavailability, and patient-centric issues. The oral route is the most preferred for drug delivery due to its ease of administration, painlessness, and high patient compliance. However, the GIT’s physiological and physicochemical environment limits the bioavailability and targeted design of oral drug delivery systems.¹

Patient-centric issues have a significant impact on oral solid dosage drug delivery. These issues include swallowing difficulties, convenience, and adherence. For instance, the geriatric population often faces challenges such as dysphagia, making it difficult to take medications, which demands formulation adjustments to create smaller and easier-to-swallow pills.² Furthermore, the design of drug delivery forms must consider biopharmaceutical issues, as well as the pharmacokinetics of each active substance, sometimes requiring a controlled release.² Additionally, patient-centric drug products can lead to improved therapeutic outcomes, maintain independent living, and improve the quality of life, reducing overall healthcare costs.³

To address these challenges, pharmaceutical companies are increasingly focusing on patient-centric drug product design. This approach involves customizing existing drug products to be more patient-friendly, considering factors such as swallowability, dosing frequency, and packaging. For instance, the development of orally disintegrating tablets and multi-particulate, fast-dissolving dosage forms aims to improve patient adherence and reduce pill burden.² Moreover, advancements in technology and formulation techniques, such as supersaturation and novel excipients, are addressing the challenge of poor water solubility, which impacts a significant percentage of drugs on the market.⁵

Patient-centric design considerations for oral solid dosage forms encompass various factors aimed at improving medication adherence and acceptance. Some examples of these considerations include:

Packaging: Designing packaging to meet patient needs, such as aiding in medication intake reminders, enhancing readability through braille inscriptions, and incorporating dose dispensing devices to facilitate administration.⁶

Dose Dispensing Devices: Including devices like inhalers in the packaging to ease administration, especially for patients with specific needs.⁶

Applicators for Topical Treatments: Develop applicators that facilitate the application of topical treatments, thereby avoiding the use of hands and reducing the risk of medication errors.⁶

Font and Graphical Aspects: Using readable fonts, high dark/ light contrast, and larger point sizes on packaging and leaflets to enhance readability, especially for the elderly. Including specific information for the elderly, such as drug interaction information.⁶

Fixed Dose Combinations (FDCs): Developing FDCs, especially for multimorbid patients, to reduce pill burden and improve medication adherence.⁶

Orodispersible Dosage Forms: Formulating oro-dispersible dosage forms to address swallowing difficulties, a common issue in the geriatric and pediatric populations.⁶

Size and Shape Optimization: Optimizing the size and shape of tablets and capsules to improve swallowability, especially for children and older adults.⁶

Customization for Specific Patient Populations: Customizing dosage forms to meet the needs of specific patient populations such as pediatrics, geriatrics, and patients with swallowing difficulties.⁷

Palatability and Swallowability: Developing multiparticulate dosage forms, orodispersible tablets, and films to improve palatability and swallowability, especially for patients with difficulty swallowing conventional solid dosage forms.⁸

Safety and Efficacy: Ensuring drug product quality and safety aspects about patient safety and efficacy, including mechanical strength, container closure systems, and acceptability of packaging components.⁸

Medication Identification and Memorability: Develop dosage forms with characteristics that aid in medication identification and memorability, such as using bright colors, interesting shapes, and two-colored preparations to improve identification and aid memorability of indications.⁸

These considerations aim to enhance the patient experience with oral solid dosage forms, ultimately improving medication adherence and therapeutic outcomes.

Technologies to Improve Drug Delivery

Nanoparticulate Formulations: Innovative pharmaceutical approaches, including nanoparticulate formulations, have been explored to optimize drug targeting and bioavailability.¹

Gastroretentive Drug Delivery Systems: These systems prolong the gastric residence time of the formulations, suitable for drugs absorbed or working in the stomach or upper GIT, or for drugs not stable in intestinal alkaline conditions.¹

Excipients: The selection of optimal excipients is crucial to making oral delivery a viable alternative to injection for biopharmaceuticals. Recent advancements in excipient development offer various benefits to manufacturers, including enabling fixed-dose combinations and providing healthier options.⁹

Future Outlook

Nanomedicines: The future of drug delivery systems aims to achieve results of targeting drugs to cells and organelles after oral administration, which will improve the efficiency of targeting.¹

Biologics: Despite the challenges, advancements in oral solid dosage biologics are increasingly viable, offering possibilities for self-administration and reduced in-clinic visits.⁹

Solubility Enhancement: Advancements in technology and formulation techniques, such as supersaturation and novel excipients, are addressing the challenge of poor water solubility, which impacts a significant percentage of drugs on the market.¹⁰

Pharmaceutical oral solid dosage drug delivery faces challenges related to patient-centric issues, dosing frequency, disease types, and technologies. However, ongoing advancements in drug delivery systems offer opportunities to overcome these challenges and improve the efficiency and effectiveness of oral drug delivery.

References

Author Details 

Mike Auerbach, Editor in Chief - Tablets & Capsules

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