Variation in Number of Doses, Bottle Volume, and Calculated Yearly Cost of Generic and Branded Latanoprost for Glaucoma

Abstract

Purpose To evaluate discrepancies in doses per bottle, bottle fill volume, and cost among branded and generic formulations of latanoprost Design Comparative economic analysis Methods This study was conducted at the Ruiz Department of Ophthalmology and Visual Science at The University of Texas Health Science Center at Houston (UTHealth). Four regionally available latanoprost formulations were measured. Number of drops per bottle and actual bottle fill volume were measured for a calculated sample size (10 bottles). Annual cost (using average wholesale price), days use per bottle, drops per milliliter, and number of bottles used per year were calculated. Data were summarized using mean and standard deviation; one-way analysis of variance and post hoc Tukey's studentized range test were used for comparing means among manufactures. Results Pfizer's branded lantanoprost, Xalatan (New York, NY), had the largest fill volume (P<0.001). Pfizer had the highest yearly cost at $1,198 (P<0.001) whereas Akorn (Lake Forest, IL) and Bausch & Lomb (Rochester, NY) had the lowest ($184 and $201, respectively). Pfizer and Bausch & Lomb had the most drops per bottle (87.3 and 88.7, respectively), which was statistically more (P<0.001) than either Akorn or Sandoz (Princeton, NJ) (77.6 and 76.6, respectively) but there was no statistical difference among the standard deviation of drops per bottle (Levene 0.14). Conclusions Annual cost and number of doses per bottle, factors important to patients, vary significantly depending on manufacturer of latanoprost. Practitioners can better advise patients being aware of these differences.

An objective assessment of the variability in number of drops per bottle of glaucoma medication

“…Lastly, a recent study found significant variability in the number of eyedrops per bottle of four regionally available formulations of latanoprost when measured by manually counting the number of drops expressed by hand, ranging from 77.6 to 88.7 drops per bottle. The authors estimated a similarly significant difference in estimated annual cost, ranging from $184 to $1198 per formulation [ 20 ].…”

Fill levels, cost comparisons, and expulsion force requirements of commonly used topical ophthalmic steroids

“…The actual bottle fill volume and number of drops per bottle were determined for each bottle tested as described by Queen et al 10 Medications were stored at 25 to 27°C prior to the experiment. Drops were dispensed slowly and evenly at room temperature into a 10 mL graduated cylinder with 0.1 mL graduations.…”

“…In a similar study previously reported in the literature that measured fill levels in antibiotic medications, the authors reported that to detect a difference of 10% between medications, a sample size of 10 bottles per drug was required, using values of 5% significance threshold and 80% power. 10 Masking A member of the institution not involved with the study removed each bottle from its packaging and covered it with an opaque blank label. The bottles were assigned a letter (A to H) for each of the 8 medications tested and a randomly assigned bottle sample identification (1 to 10) for each bottle of each medication.…”

Impact of benzalkonium chloride-preserved and preservative-free latanoprost eye drops on cultured human conjunctival goblet cells upon acute exposure and differences in physicochemical properties of the eye drops

“…In this context, concerns have been raised and, despite few studies in the field, several significant differences in physical and chemical properties of the LT eye drops have been reported. [24][25][26] In the 2020 guidelines from the European Glaucoma Society, closer monitoring of patients is advised when switching between eye drops. 4 In this study, all preserved and PF-LT products available in Denmark as well as Latanelb, were examined.…”

“…Variations in content of excipients as well as minor formulation differences can have an influence on the efficacy and safety of the product. In this context, concerns have been raised and, despite few studies in the field, several significant differences in physical and chemical properties of the LT eye drops have been reported 24–26. In the 2020 guidelines from the European Glaucoma Society, closer monitoring of patients is advised when switching between eye drops 4…”