Self-preserving gelatin emulgel containing whole cell probiotic for topical use: preclinical safety, efficacy, and germination studies

ABSTRACT

Background

Dermal disorders, owing to disruption of skin-microflora balance can be served by direct application of probiotics. However, there are few topical whole probiotic products in market because of (i) loss of viability during manufacturing and storage(ii) inadequate germination and retention on skin. Presently we report a novel (IPA 201811010395) emulgel incorporatingBacillus coagulans (Unique IS-2) for possible topical use.

Methods

Developed emulgel was characterized for particle size, texture, rheology, morphology, water activity, self-preservation, safety, and stability.

Results

We successfully incorporated 97 ± 5% (1.7×10⁸CFU/g) Bacillus coagulans in honeycomb network of gelatin nanoparticles (≈600 nm). Maintenance of CFU at 30 ± 2°C, 65 ± 5% RH for 3 months confirmed viability of incorporated probiotic. Low water-activity (0.66–0.732a_w) and challenge test (0.05–0.5% viability) confirmed its self-preserving nature. Early initiation (6 h) and complete (24 h) spore germination was evident onrabbit skin. No cytotoxicity, dermal irritation or translocation established its safety. Faster wound closure and reduced oxidative stress (LPO, catalase, SOD, glutathione reductase) in comparison to Soframycin® (1%w/w Framycetin) was observed in excision wound in mice.

Conclusions

A whole cell probiotic formulation that is self-preserving, maintains probiotic viability, guarantees germination, and has wound healing properties was successfully formulated.

KEYWORDS:

• Bacillus coagulans Unique IS-2
• emulgel
• gelatin
• germination
• probiotics
• wound

Acknowledgments

Bacillus coagulans Unique IS-2 provided by Unique Biotech Limited, Hyderabad, India, is highly acknowledged. UGC-CAS and DST FIST facility of University Institute of Pharmaceutical Sciences and DST-SAIF facility of Panjab University for analysis and characterization is highly appreciated.

Author contributions

Indu Pal Kaur and Garima Sharma are responsible for the conception and design of the manuscript. Analysis and interpretation of the data were undertaken by Prof Indu Pal Kaur, Garima Sharma, Manuhaar Sharma and Rishav Sood. Prof Indu Pal Kaur, Garima Sharma, Jayanthi Neelamraju, Suvarna G. Lakshmi, Ratna Sudha Madempudi and Praveen Rishi are involved in drafting of the paper and revising it critically for intellectual content. Furthermore, all the authors agree to be accountable for all aspects of the work and are responsible for the final approval of the version to be published.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.