Kelly L. Karlage

A Phase 2a Study of Topical Perillyl Alcohol Cream for Chemoprevention of Skin Cancer

The chemopreventive and antitumor properties of perillyl alcohol (POH) that were studied preclinically indicate that topical POH inhibits both UVB-induced murine skin carcinogenesis (squamous cell tumor models) and 7,12-dimethylbenz(a)anthracene–induced murine melanoma (transgenic models involving tyrosinase-driven Ras). A previous phase 1 clinical trial in participants with normal-appearing skin showed that topical POH cream was well tolerated at a dose of 0.76% (w/w). Here, we performed a 3-month, double-blind, randomized, placebo-controlled phase 2a trial of two different doses of topical POH in individuals with sun-damaged skin. Participants applied POH cream twice daily to each dorsal forearm. Baseline and end-of-study biopsies were taken from each participant to evaluate whether the topical application of POH was effective in reversing actinic damage as evidenced by normalization of quantitative skin histopathologic scores and change in nuclear chromatin pattern as measured by karyometric analysis. There was a borderline reduction in the histopathologic score of the lower-dose POH group compared with the placebo (P = 0.1), but this was not observed in the high-dose group. However, in the high-dose group, a statistically significant reduction in the proportion of nuclei deviating from normal was observed by the use of karyometric analysis (P < 0.01). There was no statistical significance shown in the lower-dose group. No changes were observed in p53 expression, cellular proliferation (by proliferating cell nuclear antigen expression), or apoptosis in either treatment group compared with the placebo group. These results suggest that whereas our karyometric analyses can detect a modest effect of POH in sun-damaged skin, improved delivery into the epidermis may be necessary. Cancer Prev Res; 3(2); 160–9

Stability of sulforaphane for topical formulation.

Abstract Context: Sulforaphane (SFN) is a natural compound that has been investigated as a chemopreventive agent. SFN has been shown to inhibit the activator-protein-1 (AP-1) transcription factor and may be effective for inhibition of ultraviolet (UV) induced skin carcinogenesis. This study was designed to investigate the stability of SFN as a function of pH, temperature and in various solvents and formulations. Materials and methods: Stability was analyzed using high-performance liquid chromatography. A potential lead formulation was identified and evaluated in vivo. Results: SFN was determined to undergo apparent first-order degradation kinetics for the conditions explored. It was observed that SFN undergoes base catalyzed degradation. Buffer species and solvent type impacts stability as well. SFN was found to be very sensitive to temperature with degradation rate changing by a factor of nearly 3.1 for every 10 °C change in temperature (at pH 4.0). SFN completely degraded after 30 days in a conventional pharmaceutical cream formulation. Improved stability was observed in organic formulation components. Stability studies were conducted on two nonaqueous topical formulations: a polyethylene glycol (PEG) ointment base and an organic oleaginous base. Conclusion: Topically applied SFN in the PEG base formulation significantly reduced AP-1 activation after UV stimulation in the skin of a transgenic mouse model, indicating that SFN in this formulation retains efficacy in vivo.

Preformulation and pharmacokinetic studies on antalarmin: A novel stress inhibitor

The preformulation, solubilization and pharmacokinetic evaluation of antalarmin, a stress inhibitor, have been conducted. Antalarmin has a poor water solubility of less than 1 microg/mL and is weakly basic with an experimentally determined pK(a) of 5.0. Multiple solubilization approaches including pH-control either alone or in combination with cosolvents, surfactants and complexing agents have been investigated. The applicability of lipid-based systems has also been explored. Four formulations, each with a targeted drug loading capacity of 100 mg/mL, show potential for oral administration. Three of these formulations are aqueous solutions (10% ethanol + 40% propylene glycol; 20% cremophor EL; 20% sulfobutylether-beta-cyclodextrin) each buffered at pH 1. The fourth formulation is a lipid-based formulation comprising of 20% oleic acid, 40% cremophor EL and 40% Labrasol. No precipitation was observed following dilution of the four formulations with water and enzyme free simulated gastric fluid. However, only the lipid-based formulation successfully resisted drug precipitation following dilution with enzyme free simulated intestinal fluid. Pharmacokinetic analysis conducted in rats revealed that the 20% cremophor EL solution formulation has a fivefold higher oral bioavailability compared to a suspension formulation. The lipid-based formulation resulted in over 12-fold higher bioavailability as compared to the suspension formulation, the highest amongst the formulations examined.

Comparison of Three Pharmaceutical Products Obtained from Mexico and the United States: A Case Study

ABSTRACT In recent years, there has been much debate concerning the relative pros and cons of purchasing medications from foreign markets such as Mexico and Canada. The following study compares the content uniformity and weight variation for three medicinal products, acquired from pharmacies in both Mexico and the United States: amoxicillin capsules (500 mg), amoxicillin/clavulanic acid suspension (400 mg and 57 mg/5 mL, respectively), and furosemide tablets (40 mg). Twenty capsules/tablets were individually weighed and a designated aliquot was taken. Following dissolution in an appropriate solvent and sonication, a sample was taken and analyzed via high performance liquid chromatography (HPLC). The suspensions were prepared according to directions on the label. Five samples of the suspensions were then taken and analyzed via an appropriate HPLC method. The content uniformity for the amoxicillin capsules was found to be 15.4 ± 2.4% and 99.4 ± 9.3%, for Mexican and U.S. capsules, respectively. The percent relative standard deviation (% RSD) for weight variation was found to be 8.7% and 1.5% for capsules obtained from Mexico and the United States, respectively. Content uniformity analysis for the Mexican suspension product resulted in an average of 85.5 ± 1.2% for amoxicillin and 98.6 ± 1.9% for the clavulanic acid content, while the results for the U.S. suspension product were 104.4 ± 3.1% and 117.8 ± 3.6% for amoxicillin and clavulanic acid, respectively. Content uniformity for the furosemide tablets was found to be 90.3 ± 4.8% and 95.6 ± 2.1% for Mexican and U.S. tablets, respectively. The % RSD of weight variation for the Mexican tablets was 2.1%, while the % RSD for the U.S. tablets was found to be 1.0%. From the three products tested, content analysis revealed that the amount of active ingredients for two of the products acquired in Mexico were appreciably less than the concentrations for their U.S. counterparts.

Stability of 5-Fluoro-2′-deoxycytidine and Tetrahydrouridine in Combination

In vivo, the DNA methyltransferase inhibitor, 5-fluoro-2′-deoxycytidine (FdCyd, NSC-48006), is rapidly converted to its unwanted metabolites. Tetrahydrouridine (THU, NSC-112907), a cytidine deaminase inhibitor can block the first metabolic step in FdCyd catabolism. Clinical studies have shown that co-administration with THU can inhibit the metabolism of FdCyd. The National Cancer Institute is particularly interested in a 1:5 FdCyd/THU formulation. The purpose of this study was to investigate the in vitro pH stability of FdCyd and THU individually and in combination. A stability-indicating high-performance liquid chromatography method for the quantification of both compounds and their degradants was developed using a ZIC®-HILIC column. The effect of THU and FdCyd on the in vitro degradation of each other was studied as a function of pH from 1.0 to 7.4 in aqueous solutions at 37°C. The degradation of FdCyd appears to be first-order and acid-catalyzed. THU equilibrates with at least one of its degradants. The combination of FdCyd and THU in solution does not affect the stability of either compound. The stability and compatibility of FdCyd and THU in the solid state at increased relative humidity and at various temperatures are also evaluated.

Preformulation Studies on Piperlongumine.

Piperlongumine is a natural alkaloid extracted from piper plants which has been used traditionally for the treatment of certain diseases. This compound shows interesting in vitro pharmacological activity such as selective anticancer activity and higher cytotoxicity than methotrexate, cyclophosphamide and adriamycin on breast, colon, and osteosarcoma cancers, respectively. However, the physicochemical properties for this compound have not been well characterized. In this research, preformulation studies for piperlongumine have been performed to determine factors which influence solubility and stability which, in turn, can be used to assist future formulation development. The solubility of piperlongumine in water was found to be approximately 26 μg/ml. Using 10% polysorbate 80 as a surfactant resulted in a 27 fold increase in solubility. Cosolvents and cyclodextrins afforded concentrations of 1 mg/ml and higher. The pH degradation rate profile for piperlongumine at various temperatures shows significant instability of the drug at pH values ≥ 7 and 3, and maximum stability around pH 4. It was estimated that it would take approximately 17 weeks for piperlongumine to degrade by 10% at 25°C, pH 4. Additionally, piperlongumine showed marked photo-degradation upon exposure to an ultraviolet light source, especially in aqueous media.

Comparative evaluation of pharmaceutical products obtained in Mexico: Augmenting existing scientific data

Context: The accessibility of pharmacies in neighboring countries has facilitated the trend of acquiring medications outside of local borders. However, scientific data assessing the drug content and quality of these medications has not increased in a corresponding fashion. Objective: This study seeks to augment existing scientific data. Materials and methods: Seventeen products that were obtained from pharmacies in Mexico were evaluated for active ingredient content. The active pharmaceutical ingredients (API) assessed included amoxicillin, ampicillin, ciprofloxacin, levothyroxine, sildenafil citrate, sulfamethoxazole, trimethoprim, and warfarin. API content was analysed with high performance liquid chromatography assays and the resultant data interpreted by applying United States Pharmacopeia (USP) acceptability limits. Results: All of the samples analyzed for the two ciprofloxacin products and the two ampicillin products were found to be within the USP limits. Of the four different sulfamethoxazole/trimethoprim products tested, all were within USP limits for sulfamethoxazole, but contained 2–3 individual units which were outside of USP limits for trimethoprim. Several of the remaining products (amoxicillin, levothyroxine, sildenafil citrate, and warfarin) had individual units that fell outside of the USP limits, although only one of the levothyroxine products (1 out of 20 tablets tested) and both sildenafil citrate products (all of the units tested) contained units outside of ±25% label claim.

A Comparison of Pharmaceutical Product Performance of Albuterol Inhalers Available in the United States and Those Obtained in a Mexican Border Town

Background: American residents travel to Mexico to purchase medications for a fraction of US cost and frequently without prescription requirements. A previous bioequivalence study found differences in lung function measures between 2 brands of Mexican-manufactured albuterol inhalers (both 100 µg/puff). An investigation of the pharmaceutical performance of different inhalers available may illuminate why different clinical results may be observed and offer insight to consumer and provider expectations of such products. Objective: The purpose of this study is to provide some reasonable expectations for a medical tourist who shops in Mexico for albuterol metered dose inhalers (MDIs) or for their health care providers by comparing pharmaceutical product performance of the consumer-available brands. Methods: Five different albuterol MDI products were purchased in Nogales, Mexico. The albuterol content was quantified through high-performance liquid chromatography. The inhalers were analyzed to determine the amount of the albuterol dose that can be considered respirable and compared with the findings from 2 US innovator products. Results: The mean respirable mass for each brand of albuterol MDI was compared with that of the other 4 brands and the 2 US innovator products using Student’s t test. All evaluations showed significant differences (P < .05) except for 3 comparisons (Sacrusyt vs Assal, P = .89; Xeneric-S vs non-US Ventolin, P = .98; Victory vs US Proventil HFA, P = .06). Conclusion: Since pharmaceutical variability was found among the albuterol MDIs evaluated in this study, consumers and clinicians should appreciate possible differences in product performance of albuterol MDIs obtained in Mexico.

Stability of midazolam hydrochloride injection 1-mg/mL solutions in polyvinyl chloride and polyolefin bags

PURPOSE The stability of midazolam hydrochloride injection 1-mg/mL solutions in polyvinyl chloride (PVC) and polyolefin bags under varying conditions was evaluated. METHODS Triplicate solutions of midazolam hydrochloride 1-mg/mL were prepared in polyolefin and PVC i.v. bags by diluting midazolam hydrochloride injection 5 mg/mL with 5% dextrose injection. Bags were then stored under refrigeration (3-4 °C), exposed to light at room temperature (20-25 °C), or protected from light in amber bags at room temperature. Samples were taken immediately after preparation (day 0) and on days 1, 2, 3, 6, 13, 20, and 27 for analysis with a stability-indicating high-performance liquid chromatography assay in order to determine solution concentration. Stability was defined as retention of at least 90% of the initial drug concentration. The pH of each solution was also measured weekly. Sterility of the i.v. bags was determined at the end of the study by microbiological testing with culture in growth media. Differences in concentrations under the various storage conditions and bags used were analyzed using analysis of variance. RESULTS All solutions retained over 98% of the initial midazolam hydrochloride concentration, with no statistically significant (p ≥ 0.05) change in concentration over the four-week period. Stability was not affected by temperature, exposure to light, or bag type. The pH of all solutions remained between 3.2 and 3.4 throughout the study. Sterility after 28 days was retained. CONCLUSION Midazolam hydrochloride 1-mg/mL solutions diluted in 5% dextrose injection remained stable over 27 days in both polyolefin and PVC i.v. bags, regardless of storage condition.

Formulation and in vivo evaluation of chlorpropham (CIPC) oral formulations

The objective of these studies was to examine the in vivo performance of oral formulations of chlorpropham (CIPC). In order to develop a new oral formulation several different solubilization techniques were evaluated, namely: cosolvents, surfactants, and complexing agents. The solubilization data indicated that a conventional solution formulation was not plausible. Two self-emulsifying drug delivery systems (SEDDS) were developed and evaluated for stability. Both SEDDS formulations were found to be chemically stable. In vivo analysis of a SEDDS formulation, a suspension formulation and an intravenous bolus dose was conducted in F344 rats. Pharmacokinetic analysis of the formulation data indicated that the SEDDS formulation provided only marginally better oral bioavailability compared to a suspension formulation. While SEDDS formulations often result in greater bioavailability this was not observed for CIPC. In vivo analysis indicate that CIPC results in a situation where the dissolution rate of CIPC from the suspension is not rate limiting, rather the absorption rate in the GI tract is rate-limiting. This paradigm is the result of CIPCs low melting point and the relatively small particle size of the suspension which facilitate the dissolution in the GI tract.