In vitro penetration testing (IVPT) provides an effective method to evaluate transdermal drug release and can assess manufacturing quality over time with a properly validated method. It is an important tool for optimizing topical and transdermal formulations and developing product specifications. As experts in protein and peptide transdermal formulations, CD Formulation is committed to helping you design and deploy appropriate IVRTs to obtain reliable information that can both help guide formulation development and optimization and establish useful drug product specifications.

Why is IVPT Important for Protein and Peptide Transdermal Formulations?

Proteins and peptides are bioactive big molecules that are difficult to penetrate the skin barrier to reach the target site. They must be loaded in a suitable carrier, such as nanoemulsions, nanocapsules, microemulsions, liposomes, etc., for delivery to exert their efficacy effectively. IVPT as an analytical tool is used to evaluate the ability of these transdermal formulations with loaded protein and peptide to penetrate the skin barrier and understand the factors that affect the permeation of proteins and peptides, such as preparation ingredients, skin characteristics and methods of use. In addition, IVPT can help optimize the transdermal formulations of proteins and peptides by identifying potential permeation barriers and guiding the selection of appropriate excipients and delivery systems.

Explore Our Proteins & Peptides Formulation Analysis Services

CD Formulation offers customers the option to perform IVPT and permeation testing using the classic static vertical diffusion cells (i.e., Franz cells). Our team of scientists has spent years perfecting procedures to minimize the variability of this complex technology and to make critical preclinical decisions for your protein or peptide product, justify formulation choices, and demonstrate the bioequivalence of generic transdermal products.

Our IVPT experts will work with your internal team to design and conduct IVPT studies together while adhering to OECD Test Guideline 428 and the accompanying Guidance Document No if required. We are able to perform the following, including but not limited to:

• IVPT analysis methods development and optimization for protein and peptide transdermal formulations.
• IVPT analysis methods validation for protein and peptide transdermal formulations.
• IVPT analysis methods transfer for protein and peptide transdermal formulations.
• Optimization and characterization of Protein and peptide transdermal formulations performance.
• Bioequivalence study of generic and original drugs.
• Permeation profile and permeation kinetics analysis of protein and peptide transdermal formulations.
• GLP regulatory studies according to OECD TG 428, EMA, and FDA guidelines.

Our Workflow for IVPT Services for Protein and Peptide Transdermal Formulations

Fig. 1 Workflow of IVPT for protein and peptide transdermal formulations. (CD Formulation)

Permeability Membrane Selection

Animal skin, including that from rats, rodents, porcine/pig, monkeys, and snakes, are used as permeable membranes, and that is where rat and rodent skin are most commonly used.

Experimental Apparatus Preparation

The skin prepared in the above step was cut into appropriate sizes and immediately mounted in a vertical Franz-type diffusion cell. Phosphate buffered saline (PBS) (pH 7.4) was loaded into the receptor chamber as the receptor phase and maintained at 37°C.

Fig. 2 static vertical diffusion Franz cells. (Supe S, et al., 2021)

Sample Preparation

Take a certain amount of protein or peptide drug to be tested and add it to the donor side. Cut a certain area of the transdermal patch and apply it to the skin on the donor side if it is a patch.

Skin Permeation Testing

At specific time points up to 24 hours, an appropriate amount of receptor solution is drawn out, and an equal amount of fresh PBS is added to the receptor chamber to maintain the total volume. Then, the receptor solution is processed and analyzed by various quantitative methods such as fluorescence spectrophotometer, ultra-high performance liquid chromatography, ELISA, etc., for the proteins or peptides that through the permeable membrane at different time points.

Skin Retention Testing

In order to evaluate the amount of protein or peptide in the skin, the protein or peptide is extracted from the skin according to a certain method, and fluorescence spectrophotometry, ultra-high performance liquid chromatography or ELISA analyzes the amount of protein or peptide drug extracted from the skin.

Drug Distribution Testing (Skin)

In order to identify the skin permeability of target protein or peptide drugs, we will also fluorescently label the target preparations based on your formulation, such as FITC and coumarin 6, and use confocal microscopy to observe the distribution of fluorescently labeled protein or peptide preparations in the skin at different permeation time points.

Data Analysis

The following models are used to determine the correlation coefficients of the permeation kinetics of the test substances: Higuchi model, Korsmeyer-Peppas model, Weibull model, zero-order model, and first-order model.

Skin-PAMPA Services for Protein and Peptide Transdermal Formulations

Apart from the widely used static Franz diffusion cells system, the skin-parallel artificial membrane permeability assay (PAMPA) system is another important tool we use for evaluating transdermal formulations of proteins and peptides. This system is a method that measures the passive permeation of transdermal drugs through an artificial membrane that simulates human skin.

Skin-PAMPA Testing Procedure

The test is performed in a 96-well plate with the membrane placed between a donor compartment and a receptor compartment filled with a buffer solution at pH 7.4 (simulating blood pH). The permeation through the membrane is measured by determining the fraction of substance that appears in the receptor compartment after incubation (passive diffusion). Quantification is performed using a suitable analytical method, such as ELISA, UV-visible spectrophotometry or liquid chromatography.

Fig. 3 Experimental design of the skin-PAMPA method. (Zsikó S, et al., 2019)

Why Choose Us for Protein and Peptide Transdermal Formulations IVPT Services?

• Has extensive expertise and experience in evaluating protein and peptide transdermal formulations using the IVPT tool.
• Provides flexible, tailor-made solutions to meet our customers’ specific needs and requirements.
• Equipped with advanced equipment and technology can test any protein or peptide transdermal formulation.
• Strict quality assurance protocols ensure that all analyses are performed to the highest standards and in compliance with industry standards.
• Fast, efficient service ensures that our customers’ projects are delivered on time.

Publication

CD Formulation is committed to providing you with a powerful analytical tool for the development of your protein or peptide transdermal formulations to characterize its release and permeation performance in a carrier. Our team has extensive experience and expertise and can design and execute specialized experimental protocols based on customer needs, including transdermal performance analysis, release kinetics studies, transdermal delivery efficiency evaluation, etc. Please feel free to contact us if you are interested in our services. We will provide you with the best solutions and support.