Intarakumhaeng R, Shi Z, Wanasathop A, Stella QC, Wei KS, Styczynski PB, Li C, Smith ED, Li SK.  In vitro skin penetration of petrolatum and soybean oil and effects of glyceryl monooleate.   Int J Cosmet Sci. 2018 Aug;40(4):367-376. doi: 10.1111/ics.12469.  

Glyceryl monooleate proved to be an enhancer of skin penetration of petrolatum in this in vitro analysis.

van Heugten AJP, Landman J, Petukhov AV, Vromans H. Study of petrolatum structure: Explaining its variable rheological behavior. Int J Pharm. 2018 Apr 5;540(1-2):178-184. doi: 10.1016/j.ijpharm.2018.02.016. 

The rheological properties of petrolatum, which depend on both temperature and thermal history, were studied, and it was shown that the rheological differences in petrolatum can be explained by the number of lamellar stacks present, so the more lamellar stacks there are, the stiffer the petrolatum is (3).

Penven K, Leroy D, Verneuil L, Faguer K, Dompmartin A. Evaluation of vaseline oil applied prior to UVB TL01 phototherapy in the treatment of psoriasis. Photodermatol Photoimmunol Photomed. 2005 Jun;21(3):138-41. doi: 10.1111/j.1600-0781.2005.00157.x.

Abstract. Background: Use of emollient prior to phototherapy could enhance UV transmission through psoriasis plaques on the condition that the emollient is not photoprotective. Emollient pretreatment with narrow-band phototherapy (313 nm) has not been studied extensively. We conducted a study to assess if vaseline oil prior to UVB TL01, in chronic psoriasis plaques could accelerate psoriasis clearance. Methods: Fifteen patients with chronic psoriasis plaques were enrolled in a prospective, single-blind, controlled study. For each patient, one to three symmetrical pairs of plaque were selected and scored initially and after every six exposures. Results: On the vaseline oil pretreated side, significantly more plaques were cleared, especially in severe psoriasis. Scaling and infiltration were significantly improved. Application of vaseline oil was more interesting in thick and scaly psoriasis probably because the oil penetrates the intercellular space allowing an optical matching effect which increases the UV transmission. Conclusion: We strongly recommend vaseline oil pretreatment with UVB TL01 phototherapy in psoriasis, especially in severe psoriasis.

Mirrashed, F., & Sharp, J. C. (2004). In vivo quantitative analysis of the effect of hydration (immersion and Vaseline treatment) in skin layers using high‐resolution MRI and magnetisation transfer contrast. Skin Research and Technology, 10(1), 14-22.

Abstract. Background/aims: Many claims are made as to the efficacy of topical preparations in moisturising the skin, yet most of these claims cannot be substantiated by scientific study for the skin layers beneath the stratum corneum, and yield no information on the remainder of the epidermis and dermis. This argues for an in vivo quantitative method for measuring the effect of water loading extended to various layers of the skin. Methods: Detailed high-resolution in vivo MRI studies of hydration and dehydration of finger pad skin layers were conducted on one normal subject using two moisturisation methods (topical white soft paraffin (Vaseline) and water immersion). The dehydration study was carried out immediately following removal from prolonged skin moisturisation. Inter-individual variability for skin hydration (group study) was studied in seven healthy volunteers at 0 and 7 h hydration with Vaseline. Location dependence in skin hydration was investigated on the same subject by looking into the hydration of forearm and finger pad skin. System stability and measurement reproducibility was verified through a detailed phantom study. Results: Images of normal and hydrated human skin were obtained in vivo at voxel dimensions of 50 μm×150 μm×1000 μm. The effect of hydration and dehydration as a function of exposure to moisturiser (i.e. water and Vaseline) on the image signal intensity, observed T1, and interaction of free and bound water in specific tissues were identified and correlated with existing physiological knowledge. Swelling of stratum corneum due to hydration was expressed as an in vivo model of tissue hydration. Conclusion: Results of the dehydration study showed that the changes due to the previous hydration of the skin are reversible for all skin layers. For both moisturisation methods (i.e. Vaseline and skin bathing), the effects of hydration and dehydration on the skin were similar. The trends of the MRI parameters for finger pad and arm skin were similar. The group study showed low inter-subject variability of hydration on stratum corneum and epidermis.

Berman, B., & Tomondy, P. (2022). Human Skin Absorption and Penetration Study of Four Different Topical Formulations of 5-Fluorouracil. SKIN The Journal of Cutaneous Medicine, 6(6), s107-s107.

Abstract. Cunningham et al1 compared the efficacy and tolerability of 5% 5-fluorouracil (FU) cream + 0.005% calcipotriol ointment combination (FU+C) with FU + vaseline combination (FU+V) treatment of actinic keratosis (AKs). The FU+V control resulted in 0% of participants having complete clearance of face AKs and an unexpectedly low 4% of participants developing severe erythema, possibly due to vaseline interfering with FU absorption.. Mohney et al2 concluded that petrolatum + 5-FU is an inappropriate control and no superiority claims from that study can be made vs topical FU.. We report a 20-fold reduced penetration of FU in the presence of vaseline (FU+V), and a 73% reduction in FU penetration in the presence of calcipotriol ointment (FU+C)....

Meng H, Yin Y, Wu W, Liu Y, Li L, Dong Y, Fan Y, Li Y, He Y. Raman spectroscopic analysis of skin penetration and moisturizing effects of Bionics vernix caseosa cream compared with Vaseline. Technol Health Care. 2021;29(S1):327-334. doi: 10.3233/THC-218030. 

Abstract. Background: The stratum corneum (SC) is the outermost layer of human skin and deemed as barrier against chemical exposure and water loss. Moisturizers have beneficial effects in treating dry skin, especially the SC. Confocal Raman spectroscopy (CRS) was used to evaluate the efficacy of moisturizers on skin hydration and penetration, with such agents posing inherent characteristics of being noninvasive, nondestructive, timesaving, and cost effective. Bionics vernix caseosa (BVC) cream mimics the composition of vernix caseosa (VC), which could protect the newborn skin....Results: The penetration depth of Vaseline was deeper than that of Bionics vernix caseosa cream. Specifically, BVC cream penetrated 18 μm into human skin, while Vaseline penetrated at least 20 μm. Compared with Vaseline, only BVC cream increased skin hydration, with a moisturizing effect lasting for 4 h. At 6 h, the Vaseline moisturizing effect decreased significantly.

Geranmayeh M, Rezaei Habibabadi Z, Fallahkish B, Farahani MA, Khakbazan Z, Mehran A. Reducing perineal trauma through perineal massage with vaseline in second stage of labor. Arch Gynecol Obstet. 2012 Jan;285(1):77-81. doi: 10.1007/s00404-011-1919-5. 

Abstract. Purpose: Maintaining an intact perineum is a highly regarded aim in delivery procedures today. Since perineal massage is a common practice during delivery, the present study aims to investigate the effect of perineal massage with Vaseline on perineal trauma (rate of episiotomy procedures and perineal tears)....Results: The two groups were homogeneous in terms of demographic data, weight gain during pregnancy, gestational age, abortion history and fetal weight. The second stage of delivery was significantly shorter in the massage group than the control group and the massage group had significantly more intact perineum (P = 0.004). In addition, lower episiotomy and higher first- and second-degree perineal tears were seen in the massage group in comparison with the control one (P < 0.001). Neither of the groups suffered from third- and fourth-degree tears. Conclusion: The findings showed that the perineal massage with Vaseline in the second stage of labor increases perineal integrity and decreases perineal traumas (episiotomy and tears). So, it seems that the perineal massage could be an effective way to preserve an intact perineum in labor.

Bao Q, Burgess DJ. Perspectives on Physicochemical and In Vitro Profiling of Ophthalmic Ointments. Pharm Res. 2018 Oct 15;35(12):234. doi: 10.1007/s11095-018-2513-3.

Abstract. Ophthalmic ointments are unique in that they combine features of topical drug delivery, the ophthalmic route and ointment (semisolid) formulations. Accordingly, these complex formulations are challenging to develop and evaluate and therefore it is critically important to understand their physicochemical properties as well as their in vitro drug release characteristics. Previous reports on the characterization of ophthalmic ointments are very limited. Although there are FDA guidance documents and USP monographs covering some aspects of semisolid formulations, there are no FDA guidance documents nor any USP monographs for ophthalmic ointments. This review summarizes the physicochemical and in vitro profiling methods that have been previously reported for ophthalmic ointments. Specifically, insight is provided into physicochemical characterization (rheological parameters, drug content and content uniformity, and particle size of the API in the finished ointments) as well as important considerations (membranes, release media, method comparison, release kinetics and discriminatory ability) in in vitro release testing (IVRT) method development for ophthalmic ointments. Graphical Abstract Summary of the physicochemcial profiling and in vitro drug release testing (IVRT) for ophthalmic ointments.

Safety

Kilaru H, Prasad S, Radha S, Nallagonda R, Kilaru SC, Nandury EC. Nasal application of petrolatum ointment - A silent cause of exogenous lipoid pneumonia: Successfully treated with prednisolone. Respir Med Case Rep. 2017 Jul 8;22:98-100. doi: 10.1016/j.rmcr.2017.07.003. 

This study reports the case of a young woman who contracted exogenous lipoid pneumonia due to chronic use of petrolatum-based Vicks VapoRub nasal ointment. A rather rare case.