Hydroxy Propyl Methyl Cellulose (HPMC), Span 80, Span 20, and other materials required for preparing reagents were purchased from S.D Fine Chem Ltd., Mumbai, India. Food grade Olive oil and Coconut oil were obtained from the Local Market in standard packs. Terbinafine was gifted by KLM Laboratories Pvt Ltd, Vadodara, Gujarat, India. Candida albicans was obtained as an isolated culture from Food and Drug Laboratory, Vadodara, Gujarat, India.
The polar phase (hydrogels) and nonpolar phase (organogel) were prepared individually.
Preparation of hydrogel
For the hydrogel preparation, 2 percent w/w gel was made by dissolving 2 g of HPMC K-100 in water and diluting it to 100ml at 60-700C,500 RPM. Similarly, 4 percent HPMC K-100 hydrogel was prepared as shown in table no.1 
Preparation of organogel
For the preparation of surfactant-based organogel, the surfactant (Span 80 and Span) 20 were dispersed in different oil (Olive oil and Coconut oil) at 60 °C, 500 RPM and subsequently cooled to 250C as shown in table no.2  Based on the RHLB value of coconut oil and olive oil (i.e. 8 and 7 respectively), the surfactant mixture of span 20(9%) and span 80(1%) was added in the organogel phase.
Preparation of bigel
For the preparation of bigel, the nonpolar phase (organogel) was gently added into the polar phase (hydrogel), with an overhead stirrer (60-700C, 500 RPM.). The stirring was repeated till the uniform & homogeneous mixture was formed.  The drug was incorporated in both phases, 0.2% in hydrogel and 0.8% in organogel during the time of mixing.
At various time intervals, the pH, Spreadability, color, odour, and appearance of the gels were evaluated.
Viscosity: The rheological characteristics of the bigel as a function of time have been investigated using the Brookfield viscometer (Version DVELV).
Spreadability: Spreadability of the formulated gels was determined by putting 0.5 g formulated gel inside a circle of 1 cm diameter premarked on a glass plate. On the top of this glass plate, a similar glass plate was placed. The 500 g weight was kept on the upper glass plate for 5 min. The increased diameter (cm) caused by the spreading of the gel was measured. 
M=Weight put on the upper slide
D= diameter of spreading
T=Time for spreading
The microscopy was performed on a Scanning Electron microscope.
For three months, the stability study was carried out in accordance with ICH recommendations. The goal of the stability studies is to offer information on how the API changes over time as a result of environmental factors like humidity, temperature, and light. The study was conducted at 25ºC±2ºC (60%RH) & 45ºC±2ºC (75%RH). All the prepared mixtures were crimped into an aluminum collapsible tube. The packaged bigels were then stored under the different temperature and environmental conditions listed above. Following the completion of the trial, the bigels were analyzed for percent drug content, viscosity, spreadability, and pH.
The thermal properties (Tm) of the produced bigels were obtained using the drop-ball method with the EI melting point apparatus-931. A differential scanning calorimeter (DSC 200F3 Maia) was used to examine the thermal profiles of the bigels. Bigels were precisely weighed and wrapped in aluminum pans with punctured covers. The analysis was carried out in a nitrogen atmosphere with a flow rate of 40 ml/min. Scanning at a frequency of 5.0 °C/min inside the temperature range of 0 to 300°C yielded the heating and cooling DSC profiles. 
In-vitro drug release
The in vitro release patterns of drugs from bigels were investigated using a two-compartment modified Franz's diffusion cell. Simulated Vaginal Fluid (SVF) was used for the release trials. One gram of each sample was precisely weighed and deposited on the donor compartment (goat vaginal membrane). The donor compartment was immersed in an SVF-containing receptor compartment while being stirred at 100 rpm (37 °C). Specimens were taken at regular intervals and examined spectroscopically with a UV-vis spectrophotometer. The CPDR (cumulative percentage of drug release) was computed. 
The agar well diffusion technique is frequently used to assess the antibacterial activity of drugs. The agar plate surface is colonized in the same way that the disk-diffusion technique is, by spreading a volume of microbial inoculum across the whole agar surface. Using a sterile cork borer or tip, a hole with a width of 6 mm is aseptically punched, and a volume (20–100 L) of the terbinafine is put into the well. Then, test micro-organisms i.e., Candida albicans were incubated under appropriate conditions. The antimicrobial agent spreads in the agar medium, inhibiting the development of the tested microbial strain. 
The most common diagnostic test of gelation is to turn a beaker containing the sample upside down and then note whether the sample flows under its own weight. It was performed for bigels.