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High-Throughput Absorption Depth Profiling in Stratum Corneum

High-Throughput Corneal/Scleral Absorption and Pentration Screening

High-Throughput In Vitro Release Testing (HT-IVRT)

High-Throughput Nail Penetration Screening

High-Throughput Screening of Compound Library for Topical and Transdermal Delivery

High-Throughput Skin Absorption and Penetration Screening

In Vitro Skin Barrier Integrity and Skin Irritation/Corrosion Test

Ophthalmic Formulation Development and Optimization

Preformulation, design, Development, and Screening

Skin Absorption and Penetration Enhancement and Retardation Development

Topical Formulation Development And Optimization

Frequently Asked Questions
  1. What type of services do you offer?

High-throughput formulation screening services for topical and transdermal as well as personal care product development.  Specifically, we provide high-throughput in vitro tissue absorption and penetration screening services.  We also offer topical formulation design, development, and optimization services.

  1. What is the difference between your technology and Franz Cell technology?

Both Zyleris' high-throughput and standard Franz Cell technology operate on the same principle, that is, each cell contains a donor and receptor chamber separated by a skin membrane.


However, our proprietary technology has a number of innovative features.  These features allow a large number of parallel screening experiments to be conducted rapidly and cost-effectively, thereby increasing productivity and lowering cost per formulation screened.  For more information, please refer to “Technology” page. 

  1. What factors influence cost?

Price for screening service is quoted on per formulation basis.  The factors include: type of the study, number of formulations, number of replicates and data points per formulation, number of API per formulation, and analytical requirement.  Please refer to “Services” page for details. 

  1. What is the typical turnaround time? 

We strive to deliver highest quality of data within fastest turnaround time.


Currently, for up to 70 formulations in Screening Protocol, the following is a typical guideline with assumption that we’ll adopt your analytical method or active ingredient is well-characterized.


If you do your own analysis, we can offer even faster turnaround time.  Generally, we can send the collected samples back to you within two to three weeks.


Screening prep and set-up: Week one

Screening: Week two

Analysis, QC of data and report: Week three and four

  1. What is your current capacity?

Our current screening capacity is 70 formulations per week.  We have 2,200 HTS Franz Cell in hand, which could be used to equip 20 HTS stations.  The 20 HTS stations can be easily placed on four 6-foot standard laboratory benches.  If needed, our capacity can be easily and immediately expanded. 

  1. What type of tests do you do to ensure integrity of skin membranes used in screening experiments?

We use measurement of transepidermal electrical resistance (TEER, Z value) across skin membranes to check the skin barrier integrity using a LCR meter.  We have collected extensive data in terms of values of electrical resistance (ER) as a function of measurement frequency and tape-stripping cycles.  Tape-stripping technique is used to mimic damage to skin barrier (each stripping cycle = 1 tape strip iteration).  The threshold ER value is established for intact pig ear skin.  The threshold ER value is dependent upon a number of factors including frequency, temperature, skin type, testing medium, etc.  Lower frequency (100 or 1,000 Hz) is generally preferred for greater sensitivity and better differentiation.  For human cadaver skin, the threshold value will be evaluated for each individual lot.  The threshold value for intact pig ear skin is found to be about 5 Kohms at 100 Hz under our experimental conditions.  Only skin samples with ER values greater than the threshold value are used in the screening experiments.  

  1. Why pig ear skin? 

Histological and biochemical properties of pig skin have been repeatedly shown to be similar to human skin.  Pig ear skin is particularly well-suited for absorption and penetration studies and gives comparable results to human skin.  Thickness of stratum corneum (SC) layer in pigs is about 21-26 um, which is comparable to human skin.  The viable epidermis in porcine ear skin is about 66-72 um, which is very similar to the human (shoulder) epidermal thickness of 70 um.  The follicular structure of pig skin also resembles that of humans, with hairs and infundibula extending deeply into the dermis. An average of 20 hairs is present per 1 cm2 of pig ear skin as compared to 14–32 hairs (except the forehead area) in humans.  Moreover, the vascular anatomy and collagen fiber arrangement in the dermis, as well as the contents of SC glycosphingolipids and ceramides are similar in man and in pig.


Pig ear skin is a valuable and yet inexpensive alternative to human skin.  It is particularly suitable for high-throughput screening studies for comparing topical and transdermal pharmaceutical as well as personal care product formulations and identifying formulation leads.

Zyleris has a collection of scientific literature on pig ear skin model.  Please contact us for more information.

  1. What kind of data will I receive from a study?

For skin penetration studies, cumulative amount collected in the receptor medium at each data point will be provided.


For epidermis/dermis absorption studies, cumulative amount absorbed in the epidermis/dermis layer at each data point will be provided.


For mass balance studies, in addition to cumulative amount collected in the receptor medium, residual dose left on skin surface, amounts absorbed into stratum corneum and epidermis/dermis layer will also be determined.  The data will be reported as total amounts.

    9.  Regulatory and industry standards?

In addition to our internal standard operating procedure (SOP),  we follow industry standards and published guidelines of various regulatory agencies (FDA, OECD, COLIPA) for skin absorption and penetration studies.