Protheragen-ING is an expert in drug formulation development and dosage form optimization, and can design semi-solid dosage (SSD) form formulations based on the characteristics of the API and the development goals of the customer. We offer a one-stop shop for all your SSD formulation needs. Whether you're planning to develop a topical or transdermal dosage form, we can help you master SSD forms with confidence.

Understanding Semi-solid Dosage Forms

SSDs are drug formulations characterized by a semi-solid consistency. These formulations are typically used for topical applications such as the skin, nasal mucosa, cornea, rectal or vaginal tissues (usually via suppositories), oral tissues, ears, or urethral membranes.

SSD forms typically involve two phases: oil and water. One phase is continuous, or external, while the other phase is dispersed, or internal. The active ingredient can be dissolved in one or both phases.

Fig. 1 Development of a semisolid dosage form of meglumine antimonate for topical treatment of cutaneous leishmaniasis. (Berenguer D, et al. 2019)

Protheragen-ING's Formulation Development Capabilities

• Ointment

Ointments usually consist of an oil base (e.g., petroleum jelly) and may also contain water. They form a protective barrier on the skin that aids in moisturization and drug absorption.

We have extensive experience in developing ointment formulations for a variety of applications, including dermatology, wound healing, and transdermal drug delivery. We work closely with our customers to understand their requirements and develop customized ointment formulations that meet their desired specifications, such as viscosity, stability, and drug release profile.

• Gel

Gels consist of a three-dimensional network of solid particles dispersed in a liquid. They are commonly used for topical and transdermal drug delivery applications.

We have expertise in developing gel formulations with controlled release properties, enhanced bioavailability, and improved skin permeability. We utilize advanced technologies and formulation strategies to optimize the rheological properties, drug release kinetics, and stability of gel formulations.

• Cream

Creams are emulsion-based semi-solid dosage forms that combine an oil phase with an aqueous phase and are widely used in dermatology and cosmetic applications. We specialize in developing stable and elegant cream formulations that provide optimal drug release, desirable sensory properties, and improved patient compliance.

• Suppository

Suppositories are solid dosage forms that are inserted into body cavities for localized or systemic drug delivery.

We have in-depth knowledge of suppository formulation development, including both lipophilic and hydrophilic suppositories. We can help you design and optimize suppository formulations with precise drug release profiles, compatibility with body fluids, and ease of administration.

General Steps in SSD Formulation Development

(1) Define the objective - Define the use and objective of the semi-solid dosage form, e.g., to treat a specific skin disorder or to provide localized relief.

(2) Select the matrix - Select a matrix that is suitable for the desired drug release and application characteristics. Common matrices include water, oils (e.g., petroleum jelly and vegetable oils), and polymers (e.g., hydroxypropylmethylcellulose, polyacrylic acid).

(3) Active ingredient selection - Select the active ingredient(s) suitable for the target drug and determine its appropriate concentration range.

(4) Excipient selection - Addition of auxiliary ingredients, such as thickeners, emulsifiers, humectants, preservatives, etc., as needed.

(5) Formulation optimization - Optimize the formulation through testing and evaluation to obtain the desired drug release characteristics, texture, and stability.

(6) Quality control - Ensuring the quality, consistency, and stability of the formulation. This includes conducting tests for physical properties (e.g., viscosity, pH), drug release, and microbiological detection.

(7) Clinical evaluation - Evaluating semi-solid dosage forms during preclinical and clinical evaluations, including studies of skin irritation, permeability, drug absorption, etc.

(8) Production scale-up - Once the formulation has been finalized as a suitable semi-solid dosage form, it can be scaled up for production.

Advantages of Semi-solid Dosage Forms

• The fact that the SSD form is applied topically makes it easier for many patients to take it, thus improving compliance.
• Topical formulations can effectively treat dermatologic conditions without the need for systemic exposure, thereby reducing the number of side effects experienced by patients.
• Transdermal medications are absorbed into the bloodstream, avoiding first-pass metabolism, thereby improving consistency and predictability.
• Some transdermal delivery systems offer controlled release, which means that the level of the drug in the bloodstream fluctuates less. This can result in fewer side effects and a more consistent therapeutic effect.

Contact us today to discuss your program requirements and explore how we can help you achieve your formulation goals.