Comparison of the Pharmacokinetics, Bioequivalence and Safety of Aqueous Progesterone Formulation Administered as either Intramuscular or Subcutaneous Injection versus Oil-based Progesterone Formulation Administered as Intramuscular Injection: A Randomised Study

Introduction: Progesterone is the treatment of choice for support of the luteal phase of controlled ovarian stimulation cycles in women undergoing an Assisted Reproductive Technology (ART) treatment. Available progesterone preparations include oral, vaginal and oil-based Intramuscular (i.m.) formulations. Oral formulation has poor bioavailability whereas vaginal formulations cause side-effects such as vaginal discharge and/ or local irritation. Oil-based progesterone formulations for i.m. use are associated with discomfort and pain at the injection site. Hence, a novel aqueous-based progesterone formulation for i.m./Subcutaneous (s.c.) was developed to avoid the local tolerability issues of the existing parenteral formulations. Aim: To assess single-dose Pharmacokinetics (PK) and relative bioavailability of i.m. (test-1; T1) or s.c. (test-2; T2) administration of novel aqueous progesterone formulation with i.m. (reference; R) administration of oil-based progesterone formulation. Materials and Methods: In this open-label, three-sequence, three-period, single-dose, cross-over study, 51 healthy human postmenopausal female subjects between 45 to 65 years of age were included. The study was conducted at Lambda Therapeutic Research Limited, Ahmedabad, Gujarat, India, between 21 May 2018 to 06 July 2018. Subjects were randomised to a single 25 mg dose of T1, T2 or R in three-periods (Period-I: T1, R, T2; Period-II: T2, T1, R; Period-III: R, T2, T1) with ≥18 days washout period. Blood samples were collected at prespecified time points in each period and analysed using validated liquid chromatography with tandem mass spectrometry. PK parameters {maximum plasma concentration (Cmax), time to reach Cmax (Tmax), area under the plasma concentration vs. time curve (AUC0-t), AUC from time 0 to ∞ (AUC0-∞), plasma half-life (t1/2)} were calculated from the plasma concentration vs. time profile by non compartmental model. The total study duration was about 47 days (11 hours prior to the drug administration in Period-I until the last ambulatory sample in Period-III). All patients provided written informed consent form and an approval from the Conscience-Independent Ethics Committee (CIEC) was taken. Descriptive statistics were calculated and reported for PK parameters for baseline corrected and uncorrected data. Results: Of 72 screened patients, 51 patients were included for the PK and statistical analysis. The mean±SD age of the patients was 55.1±4.67 years. The baseline corrected PK data shows that in T1, T2 and R arms, mean (range) Tmax were 1.00 (0.50– 1.75), 1.00 (0.75–1.75) and 8.00 hours (1.00–12.00), mean±SD t ½ (h) were 15.43±5.81, 15.27±6.68 and 19.80±6.35; mean±SD Cmax (ng/mL) were 101.91±73.07, 51.67±14.81 and 18.89±7.89, and mean±SD AUC0-t (ng/mL) were 385.10±89.29, 349.63±64.41 and 371.50±56.25, respectively. Similarly, the AUC0-∞ was also comparable in all three arms. The baseline uncorrected data were also in line with baseline corrected data. For AUC0-t and AUC0-∞, 90% CIs were 98.44-107.06% and 97.96-106.15%, respectively, for T1/R ratio, and 90.01-97.90 and 89.90-97.42, respectively, for T2/R ratio. Six Adverse Events (AEs) in four subjects were reported. All AEs were mild in nature and there were no deaths, significant or serious AEs reported. Overall, all the treatments were well-tolerated without any new safety concerns. Conclusion: Novel aqueous progesterone formulation i.m./s.c was bioequivalent with oil-based progesterone formulation i.m. with respect to AUC. The s.c. administration of aqueous progesterone formulation could offer a convenient alternative to the i.m. oil-based progesterone formulation for luteal phase support to patients undergoing ART treatments